Develop Reference

Canvas doesn't draw correctly my scale text

I see scale with only 0 written! As in the picture and two strange zeros out of the schema: (GALAXY NEXUS 4.2.1)
As in the example at http://mindtherobot.com/blog/272/android-custom-ui-making-a-vintage-thermometer/comment-page-1/#comment-106122%29 this is my custom view:
package com.wikibuyers.barometro;
import java.util.List;
import android.annotation.SuppressLint;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.BitmapShader;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.LightingColorFilter;
import android.graphics.LinearGradient;
import android.graphics.Matrix;
import android.graphics.Paint;
import android.graphics.Path;
import android.graphics.RadialGradient;
import android.graphics.RectF;
import android.graphics.Shader;
import android.graphics.Typeface;
import android.hardware.Sensor;
import android.hardware.SensorEvent;
import android.hardware.SensorEventListener;
import android.hardware.SensorManager;
import android.os.Bundle;
import android.os.Handler;
import android.os.Parcelable;
import android.util.AttributeSet;
import android.util.Log;
import android.view.View;
public class Barometro extends View implements SensorEventListener{
private static final String TAG = Barometro.class.getSimpleName();
private Handler handler;
// drawing tools
private RectF rimRect;
private Paint rimPaint;
private Paint rimCirclePaint;
private RectF faceRect;
private Bitmap faceTexture;
private Paint facePaint;
private Paint rimShadowPaint;
private Paint scalePaint;
private RectF scaleRect;
private Paint titlePaint;
private Path titlePath;
private Paint logoPaint;
private Bitmap logo;
private Matrix logoMatrix;
private float logoScale;
private Paint handPaint;
private Path handPath;
private Paint handScrewPaint;
private Paint backgroundPaint;
// end drawing tools
private Bitmap background; // holds the cached static part
// scale configuration
private static final int totalNicks = 100;
private static final float degreesPerNick = 360.0f / totalNicks;
private static final int centerDegree = 40; // the one in the top center (12 o'clock)
private static final int minDegrees = -30;
private static final int maxDegrees = 110;
// hand dynamics -- all are angular expressed in F degrees
private boolean handInitialized = false;
private float handPosition = centerDegree;
private float handTarget = centerDegree;
private float handVelocity = 0.0f;
private float handAcceleration = 0.0f;
private long lastHandMoveTime = -1L;
public Barometro(Context context) {
super(context);
init();
}
public Barometro(Context context, AttributeSet attrs) {
super(context, attrs);
init();
}
public Barometro(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
init();
}
#Override
protected void onAttachedToWindow() {
super.onAttachedToWindow();
attachToSensor();
}
#Override
protected void onDetachedFromWindow() {
detachFromSensor();
super.onDetachedFromWindow();
}
#Override
protected void onRestoreInstanceState(Parcelable state) {
Bundle bundle = (Bundle) state;
Parcelable superState = bundle.getParcelable("superState");
super.onRestoreInstanceState(superState);
handInitialized = bundle.getBoolean("handInitialized");
handPosition = bundle.getFloat("handPosition");
handTarget = bundle.getFloat("handTarget");
handVelocity = bundle.getFloat("handVelocity");
handAcceleration = bundle.getFloat("handAcceleration");
lastHandMoveTime = bundle.getLong("lastHandMoveTime");
}
#Override
protected Parcelable onSaveInstanceState() {
Parcelable superState = super.onSaveInstanceState();
Bundle state = new Bundle();
state.putParcelable("superState", superState);
state.putBoolean("handInitialized", handInitialized);
state.putFloat("handPosition", handPosition);
state.putFloat("handTarget", handTarget);
state.putFloat("handVelocity", handVelocity);
state.putFloat("handAcceleration", handAcceleration);
state.putLong("lastHandMoveTime", lastHandMoveTime);
return state;
}
#SuppressLint({ "NewApi", "InlinedApi" })
private void init() {
handler = new Handler();
setLayerType(View.LAYER_TYPE_SOFTWARE, null);
initDrawingTools();
}
private String getTitle() {
return "wikibuyers.com";
}
private SensorManager getSensorManager() {
return (SensorManager) getContext().getSystemService(Context.SENSOR_SERVICE);
}
private void attachToSensor() {
SensorManager sensorManager = getSensorManager();
List<Sensor> sensors = sensorManager.getSensorList(Sensor.TYPE_PRESSURE);
if (sensors.size() > 0) {
Sensor sensor = sensors.get(0);
sensorManager.registerListener(this, sensor, SensorManager.SENSOR_DELAY_NORMAL, handler);
} else {
Log.e(TAG, "No pressure sensor found");
}
}
private void detachFromSensor() {
SensorManager sensorManager = getSensorManager();
sensorManager.unregisterListener(this);
}
private void initDrawingTools() {
rimRect = new RectF(0.1f, 0.1f, 0.9f, 0.9f);
// the linear gradient is a bit skewed for realism
rimPaint = new Paint();
rimPaint.setFlags(Paint.ANTI_ALIAS_FLAG);
rimPaint.setShader(new LinearGradient(0.40f, 0.0f, 0.60f, 1.0f,
Color.rgb(0xf0, 0xf5, 0xf0),
Color.rgb(0x30, 0x31, 0x30),
Shader.TileMode.CLAMP));
rimCirclePaint = new Paint();
rimCirclePaint.setAntiAlias(true);
rimCirclePaint.setStyle(Paint.Style.STROKE);
rimCirclePaint.setColor(Color.argb(0x4f, 0x33, 0x36, 0x33));
rimCirclePaint.setStrokeWidth(0.005f);
float rimSize = 0.02f;
faceRect = new RectF();
faceRect.set(rimRect.left + rimSize, rimRect.top + rimSize,
rimRect.right - rimSize, rimRect.bottom - rimSize);
faceTexture = BitmapFactory.decodeResource(getContext().getResources(),
R.drawable.plastic);
BitmapShader paperShader = new BitmapShader(faceTexture,
Shader.TileMode.MIRROR,
Shader.TileMode.MIRROR);
Matrix paperMatrix = new Matrix();
facePaint = new Paint();
facePaint.setFilterBitmap(true);
paperMatrix.setScale(1.0f / faceTexture.getWidth(),
1.0f / faceTexture.getHeight());
paperShader.setLocalMatrix(paperMatrix);
facePaint.setStyle(Paint.Style.FILL);
facePaint.setShader(paperShader);
rimShadowPaint = new Paint();
rimShadowPaint.setShader(new RadialGradient(0.5f, 0.5f, faceRect.width() / 2.0f,
new int[] { 0x00000000, 0x00000500, 0x50000500 },
new float[] { 0.96f, 0.96f, 0.99f },
Shader.TileMode.MIRROR));
rimShadowPaint.setStyle(Paint.Style.FILL);
scalePaint = new Paint();
scalePaint.setStyle(Paint.Style.STROKE);
scalePaint.setColor(0x9f004d0f);
scalePaint.setStrokeWidth(0.005f);
scalePaint.setAntiAlias(true);
scalePaint.setTextSize(0.045f);
scalePaint.setTypeface(Typeface.SANS_SERIF);
scalePaint.setTextScaleX(0.8f);
scalePaint.setTextAlign(Paint.Align.CENTER);
float scalePosition = 0.10f;
scaleRect = new RectF();
scaleRect.set(faceRect.left + scalePosition, faceRect.top + scalePosition,
faceRect.right - scalePosition, faceRect.bottom - scalePosition);
titlePaint = new Paint();
titlePaint.setColor(0xaf946109);
titlePaint.setAntiAlias(true);
titlePaint.setTypeface(Typeface.DEFAULT_BOLD);
titlePaint.setTextAlign(Paint.Align.CENTER);
titlePaint.setTextSize(0.05f);
titlePaint.setTextScaleX(0.8f);
titlePath = new Path();
titlePath.addArc(new RectF(0.24f, 0.24f, 0.76f, 0.76f), -180.0f, -180.0f);
logoPaint = new Paint();
logoPaint.setFilterBitmap(true);
logo = BitmapFactory.decodeResource(getContext().getResources(), R.drawable.logo);
logoMatrix = new Matrix();
logoScale = (1.0f / logo.getWidth()) * 0.3f;;
logoMatrix.setScale(logoScale, logoScale);
handPaint = new Paint();
handPaint.setAntiAlias(true);
handPaint.setColor(0xff392f2c);
handPaint.setShadowLayer(0.01f, -0.005f, -0.005f, 0x7f000000);
handPaint.setStyle(Paint.Style.FILL);
handPath = new Path();
handPath.moveTo(0.5f, 0.5f + 0.2f);
handPath.lineTo(0.5f - 0.010f, 0.5f + 0.2f - 0.007f);
handPath.lineTo(0.5f - 0.002f, 0.5f - 0.32f);
handPath.lineTo(0.5f + 0.002f, 0.5f - 0.32f);
handPath.lineTo(0.5f + 0.010f, 0.5f + 0.2f - 0.007f);
handPath.lineTo(0.5f, 0.5f + 0.2f);
handPath.addCircle(0.5f, 0.5f, 0.025f, Path.Direction.CW);
handScrewPaint = new Paint();
handScrewPaint.setAntiAlias(true);
handScrewPaint.setColor(0xff493f3c);
handScrewPaint.setStyle(Paint.Style.FILL);
backgroundPaint = new Paint();
backgroundPaint.setFilterBitmap(true);
}
#Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
Log.d(TAG, "Width spec: " + MeasureSpec.toString(widthMeasureSpec));
Log.d(TAG, "Height spec: " + MeasureSpec.toString(heightMeasureSpec));
int widthMode = MeasureSpec.getMode(widthMeasureSpec);
int widthSize = MeasureSpec.getSize(widthMeasureSpec);
int heightMode = MeasureSpec.getMode(heightMeasureSpec);
int heightSize = MeasureSpec.getSize(heightMeasureSpec);
int chosenWidth = chooseDimension(widthMode, widthSize);
int chosenHeight = chooseDimension(heightMode, heightSize);
int chosenDimension = Math.min(chosenWidth, chosenHeight);
setMeasuredDimension(chosenDimension, chosenDimension);
}
private int chooseDimension(int mode, int size) {
if (mode == MeasureSpec.AT_MOST || mode == MeasureSpec.EXACTLY) {
return size;
} else { // (mode == MeasureSpec.UNSPECIFIED)
return getPreferredSize();
}
}
// in case there is no size specified
private int getPreferredSize() {
return 300;
}
private void drawRim(Canvas canvas) {
// first, draw the metallic body
canvas.drawOval(rimRect, rimPaint);
// now the outer rim circle
canvas.drawOval(rimRect, rimCirclePaint);
}
private void drawFace(Canvas canvas) {
canvas.drawOval(faceRect, facePaint);
// draw the inner rim circle
canvas.drawOval(faceRect, rimCirclePaint);
// draw the rim shadow inside the face
canvas.drawOval(faceRect, rimShadowPaint);
}
private void drawScale(Canvas canvas) {
canvas.drawOval(scaleRect, scalePaint);
canvas.save(Canvas.MATRIX_SAVE_FLAG);
for (int i = 0; i < totalNicks; ++i) {
float y1 = scaleRect.top;
float y2 = y1 - 0.020f;
canvas.drawLine(0.5f, y1, 0.5f, y2, scalePaint);
if ((i % 5) == 0) {
int value = nickToDegree(i);
if ((value >= minDegrees) && (value <= maxDegrees)) {
String valueString = Integer.toString(value);
canvas.drawText(valueString, 0.5f, y2 - 0.015f, scalePaint);
}
}
canvas.rotate(degreesPerNick, 0.5f, 0.5f);
}
canvas.restore();
}
private int nickToDegree(int nick) {
int rawDegree = ((nick < totalNicks / 2) ? nick : (nick - totalNicks)) * 2;
int shiftedDegree = rawDegree + centerDegree;
return shiftedDegree;
}
private float degreeToAngle(float degree) {
return (degree - centerDegree) / 2.0f * degreesPerNick;
}
private void drawTitle(Canvas canvas) {
String title = getTitle();
canvas.drawTextOnPath(title, titlePath, 0.0f,0.0f, titlePaint);
}
private void drawLogo(Canvas canvas) {
canvas.save(Canvas.MATRIX_SAVE_FLAG);
canvas.translate(0.5f - logo.getWidth() * logoScale / 2.0f,
0.5f - logo.getHeight() * logoScale / 2.0f);
int color = 0x00000000;
float position = getRelativePressurePosition();
if (position < 0) {
color |= (int) ((0xf0) * -position); // blue
} else {
color |= ((int) ((0xf0) * position)) << 16; // red
}
//Log.d(TAG, "*** " + Integer.toHexString(color));
LightingColorFilter logoFilter = new LightingColorFilter(0xff338822, color);
logoPaint.setColorFilter(logoFilter);
canvas.drawBitmap(logo, logoMatrix, logoPaint);
canvas.restore();
}
private void drawHand(Canvas canvas) {
if (handInitialized) {
float handAngle = degreeToAngle(handPosition);
canvas.save(Canvas.MATRIX_SAVE_FLAG);
canvas.rotate(handAngle, 0.5f, 0.5f);
canvas.drawPath(handPath, handPaint);
canvas.restore();
canvas.drawCircle(0.5f, 0.5f, 0.01f, handScrewPaint);
}
}
private void drawBackground(Canvas canvas) {
if (background == null) {
Log.w(TAG, "Background not created");
} else {
canvas.drawBitmap(background, 0, 0, backgroundPaint);
}
}
#Override
protected void onDraw(Canvas canvas) {
drawBackground(canvas);
float scale = (float) getWidth();
canvas.save(Canvas.MATRIX_SAVE_FLAG);
canvas.scale(scale, scale);
drawLogo(canvas);
drawHand(canvas);
canvas.restore();
if (handNeedsToMove()) {
moveHand();
}
}
#Override
protected void onSizeChanged(int w, int h, int oldw, int oldh) {
Log.d(TAG, "Size changed to " + w + "x" + h);
regenerateBackground();
}
private void regenerateBackground() {
// free the old bitmap
if (background != null) {
background.recycle();
}
background = Bitmap.createBitmap(getWidth(), getHeight(), Bitmap.Config.ARGB_8888);
Canvas backgroundCanvas = new Canvas(background);
float scale = (float) getWidth();
backgroundCanvas.scale(scale, scale);
drawRim(backgroundCanvas);
drawFace(backgroundCanvas);
drawScale(backgroundCanvas);
drawTitle(backgroundCanvas);
}
private boolean handNeedsToMove() {
return Math.abs(handPosition - handTarget) > 0.001f;
}
private void moveHand() {
if (! handNeedsToMove()) {
return;
}
if (lastHandMoveTime != -1L) {
long currentTime = System.currentTimeMillis();
float delta = (currentTime - lastHandMoveTime) / 1000.0f;
float direction = Math.signum(handVelocity);
if (Math.abs(handVelocity) < 90.0f) {
handAcceleration = 5.0f * (handTarget - handPosition);
} else {
handAcceleration = 0.0f;
}
handPosition += handVelocity * delta;
handVelocity += handAcceleration * delta;
if ((handTarget - handPosition) * direction < 0.01f * direction) {
handPosition = handTarget;
handVelocity = 0.0f;
handAcceleration = 0.0f;
lastHandMoveTime = -1L;
} else {
lastHandMoveTime = System.currentTimeMillis();
}
invalidate();
} else {
lastHandMoveTime = System.currentTimeMillis();
moveHand();
}
}
#Override
public void onAccuracyChanged(Sensor sensor, int accuracy) {
}
#Override
public void onSensorChanged(SensorEvent sensorEvent) {
if (sensorEvent.values.length > 0) {
float pressureAtm = sensorEvent.values[0]/20;
//Log.i(TAG, "*** Temperature: " + temperatureC);
float pressureMmg = (9.0f / 5.0f) * pressureAtm + 32.0f;
setHandTarget(pressureAtm);
} else {
Log.w(TAG, "Empty sensor event received");
}
}
private float getRelativePressurePosition() {
if (handPosition < centerDegree) {
return - (centerDegree - handPosition) / (float) (centerDegree - minDegrees);
} else {
return (handPosition - centerDegree) / (float) (maxDegrees - centerDegree);
}
}
private void setHandTarget(float pressure) {
if (pressure < minDegrees) {
pressure = minDegrees;
} else if (pressure > maxDegrees) {
pressure = maxDegrees;
}
handTarget = pressure;
handInitialized = true;
invalidate();
}
}
This is focus on drawScale() method:
private void drawScale(Canvas canvas) {
canvas.drawOval(scaleRect, scalePaint);
canvas.save(Canvas.MATRIX_SAVE_FLAG);
for (int i = 0; i < totalNicks; ++i) {
float y1 = scaleRect.top;
float y2 = y1 - 0.020f;
canvas.drawLine(0.5f, y1, 0.5f, y2, scalePaint);
if ((i % 5) == 0) {
int value = nickToDegree(i);
if ((value >= minDegrees) && (value <= maxDegrees)) {
String valueString = Integer.toString(value);
canvas.drawText(valueString, 0.5f, y2 - 0.015f, scalePaint);
}
}
canvas.rotate(degreesPerNick, 0.5f, 0.5f);
}
canvas.restore();
}

Android Donut Chart

I have created a donut chart, which is shown below:
MY resultant Donut chart should be in the following way:
My Question is, How can i achieve the lines with image (They are rounded off in second screen shot)
For reference, Here is the code which I have written:
public class PieChartView extends View {
private int[] values = {30, 60, 90, 100, 150};
private int c[] = {Color.MAGENTA,Color.BLUE,Color.RED,Color.CYAN,Color.YELLOW};
private int valuesLength = values.length;
private RectF rectF;
private Paint slicePaint, textPaint;
private Path path;
public PieChartView(Context context, AttributeSet attrs) {
super(context, attrs);
valuesLength = values.length;
slicePaint = new Paint();
slicePaint.setAntiAlias(true);
slicePaint.setDither(true);
slicePaint.setStyle(Paint.Style.FILL);
path = new Path();
}
#SuppressLint("DrawAllocation")
#Override
protected void onDraw(Canvas canvas) {
if(values != null) {
int startTop = 0;
int startLeft = 0;
int endBottom = getHeight();
int endRight = endBottom;// This makes an equal square.
rectF = new RectF(startLeft, startTop, endRight, endBottom);
float[] scaledValues = scale();
float sliceStartPoint = 0;
path.addCircle(rectF.centerX(), rectF.centerY(), 125, Direction.CW);
canvas.clipPath(path, Op.DIFFERENCE);
for(int i = 0; i < valuesLength; i++) {
slicePaint.setColor(c[i]);
path.reset();
path.addArc(rectF, sliceStartPoint, scaledValues[i]);
path.lineTo(rectF.centerX(), rectF.centerY());
canvas.drawPath(path, slicePaint);
sliceStartPoint += scaledValues[i];//This updates the starting point of next slice.
}
}
}
private float[] scale() {
float[] scaledValues = new float[this.values.length];
float total = getTotal(); //Total all values supplied to the chart
for (int i = 0; i < this.values.length; i++) {
scaledValues[i] = (this.values[i] / total) * 360; //Scale each value
}
return scaledValues;
}
private float getTotal() {
float total = 0;
for (float val : this.values)
total += val;
return total;
}
}
Also, How can I find out a co-ordinate from an angle(Start or sweep angle). If i want to draw a line from centre of a circle to the coordinate?

Here's how i finally did it after two days of search with help of this library https://github.com/Ken-Yang/AndroidPieChart
And equations to center text done with help of my friends and alot of search
on MainActivity onCreate or oncreateView if you are using fragments:
PieChart pie = (PieChart) rootView.findViewById(R.id.pieChart);
ArrayList<Float> alPercentage = new ArrayList<Float>();
alPercentage.add(2.0f);
alPercentage.add(8.0f);
alPercentage.add(20.0f);
alPercentage.add(10.0f);
alPercentage.add(10.0f);
alPercentage.add(10.0f);
alPercentage.add(10.0f);
alPercentage.add(10.0f);
alPercentage.add(10.85f);
alPercentage.add(9.15f);
try {
// setting data
pie.setAdapter(alPercentage);
// setting a listener
pie.setOnSelectedListener(new OnSelectedLisenter() {
#Override
public void onSelected(int iSelectedIndex) {
Toast.makeText(getActivity(),
"Select index:" + iSelectedIndex,
Toast.LENGTH_SHORT).show();
}
});
} catch (Exception e) {
if (e.getMessage().equals(PieChart.ERROR_NOT_EQUAL_TO_100)) {
Log.e("kenyang", "percentage is not equal to 100");
}
}
public class PieChart extends View {
public interface OnSelectedLisenter {
public abstract void onSelected(int iSelectedIndex);
}
private OnSelectedLisenter onSelectedListener = null;
private static final String TAG = PieChart.class.getName();
public static final String ERROR_NOT_EQUAL_TO_100 = "NOT_EQUAL_TO_100";
private static final int DEGREE_360 = 360;
private static String[] PIE_COLORS = null;
private static int iColorListSize = 0;
ArrayList<Float> array;
private Paint paintPieFill;
private Paint paintPieBorder;
private Paint paintCenterCircle;
private ArrayList<Float> alPercentage = new ArrayList<Float>();
private int mCenterX = 320;
private int mCenterY = 320;
private int iDisplayWidth, iDisplayHeight;
private int iSelectedIndex = -1;
private int iCenterWidth = 0;
private int iShift = 0;
private int iMargin = 0; // margin to left and right, used for get Radius
private int iDataSize = 0;
private Canvas canvas1;
private RectF r = null;
private RectF centerCircle = null;
private float fDensity = 0.0f;
private float fStartAngle = 0.0f;
private float fEndAngle = 0.0f;
float fX;
float fY;
public PieChart(Context context, AttributeSet attrs) {
super(context, attrs);
PIE_COLORS = getResources().getStringArray(R.array.colors);
iColorListSize = PIE_COLORS.length;
array = new ArrayList<Float>();
fnGetDisplayMetrics(context);
iShift = (int) fnGetRealPxFromDp(30);
iMargin = (int) fnGetRealPxFromDp(40);
centerCircle = new RectF(200, 200, 440, 440);
// used for paint circle
paintPieFill = new Paint(Paint.ANTI_ALIAS_FLAG);
paintPieFill.setStyle(Paint.Style.FILL);
// used for paint centerCircle
paintCenterCircle = new Paint(Paint.ANTI_ALIAS_FLAG);
paintCenterCircle.setStyle(Paint.Style.FILL);
paintCenterCircle.setColor(Color.WHITE);
// used for paint border
paintPieBorder = new Paint(Paint.ANTI_ALIAS_FLAG);
paintPieBorder.setStyle(Paint.Style.STROKE);
paintPieBorder.setStrokeWidth(fnGetRealPxFromDp(3));
paintPieBorder.setColor(Color.WHITE);
Log.i(TAG, "PieChart init");
}
// set listener
public void setOnSelectedListener(OnSelectedLisenter listener) {
this.onSelectedListener = listener;
}
float temp = 0;
#Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
Log.i(TAG, "onDraw");
float centerX = (r.left + r.right) / 2;
float centerY = (r.top + r.bottom) / 2;
float radius1 = (r.right - r.left) / 2;
radius1 *= 0.5;
float startX = mCenterX;
float startY = mCenterY;
float radius = mCenterX;
float medianAngle = 0;
Path path = new Path();
for (int i = 0; i < iDataSize; i++) {
// check whether the data size larger than color list size
if (i >= iColorListSize) {
paintPieFill.setColor(Color.parseColor(PIE_COLORS[i
% iColorListSize]));
} else {
paintPieFill.setColor(Color.parseColor(PIE_COLORS[i]));
}
fEndAngle = alPercentage.get(i);
// convert percentage to angle
fEndAngle = fEndAngle / 100 * DEGREE_360;
// if the part of pie was selected then change the coordinate
if (iSelectedIndex == i) {
canvas.save(Canvas.MATRIX_SAVE_FLAG);
float fAngle = fStartAngle + fEndAngle / 2;
double dxRadius = Math.toRadians((fAngle + DEGREE_360)
% DEGREE_360);
fY = (float) Math.sin(dxRadius);
fX = (float) Math.cos(dxRadius);
canvas.translate(fX * iShift, fY * iShift);
}
canvas.drawArc(r, fStartAngle, fEndAngle, true, paintPieFill);
float angle = (float) ((fStartAngle + fEndAngle / 2) * Math.PI / 180);
float stopX = (float) (startX + (radius/2) * Math.cos(angle));
float stopY = (float) (startY + (radius/2) * Math.sin(angle));
// if the part of pie was selected then draw a border
if (iSelectedIndex == i) {
canvas.drawArc(r, fStartAngle, fEndAngle, true, paintPieBorder);
canvas.drawLine(startX, startY, stopX, stopY, paintPieFill);
canvas.restore();
}
fStartAngle = fStartAngle + fEndAngle;
}
}
#Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
// get screen size
iDisplayWidth = MeasureSpec.getSize(widthMeasureSpec);
iDisplayHeight = MeasureSpec.getSize(heightMeasureSpec);
if (iDisplayWidth > iDisplayHeight) {
iDisplayWidth = iDisplayHeight;
}
/*
* determine the rectangle size
*/
iCenterWidth = iDisplayWidth / 2;
int iR = iCenterWidth - iMargin;
if (r == null) {
r = new RectF(iCenterWidth - iR, // top
iCenterWidth - iR, // left
iCenterWidth + iR, // right
iCenterWidth + iR); // bottom
}
if (centerCircle == null) {
// centerCircle=new RectF(left, top, right, bottom);
}
setMeasuredDimension(iDisplayWidth, iDisplayWidth);
}
#Override
public boolean onTouchEvent(MotionEvent event) {
// get degree of the touch point
double dx = Math.atan2(event.getY() - iCenterWidth, event.getX()
- iCenterWidth);
float fDegree = (float) (dx / (2 * Math.PI) * DEGREE_360);
fDegree = (fDegree + DEGREE_360) % DEGREE_360;
// get the percent of the selected degree
float fSelectedPercent = fDegree * 100 / DEGREE_360;
// check which pie was selected
float fTotalPercent = 0;
for (int i = 0; i < iDataSize; i++) {
fTotalPercent += alPercentage.get(i);
if (fTotalPercent > fSelectedPercent) {
iSelectedIndex = i;
break;
}
}
if (onSelectedListener != null) {
onSelectedListener.onSelected(iSelectedIndex);
}
invalidate();
return super.onTouchEvent(event);
}
private void fnGetDisplayMetrics(Context cxt) {
final DisplayMetrics dm = cxt.getResources().getDisplayMetrics();
fDensity = dm.density;
}
private float fnGetRealPxFromDp(float fDp) {
return (fDensity != 1.0f) ? fDensity * fDp : fDp;
}
public void setAdapter(ArrayList<Float> alPercentage) throws Exception {
this.alPercentage = alPercentage;
iDataSize = alPercentage.size();
float fSum = 0;
for (int i = 0; i < iDataSize; i++) {
fSum += alPercentage.get(i);
}
if (fSum != 100) {
Log.e(TAG, ERROR_NOT_EQUAL_TO_100);
iDataSize = 0;
throw new Exception(ERROR_NOT_EQUAL_TO_100);
}
}
<com.example.piecharts.PieChart
android:id="#+id/pieChart"
android:layout_width="match_parent"
android:layout_height="match_parent" >
</com.example.piecharts.PieChart>

how to draw doughnut chart? like this given image

i have tired to find library or any other stuff to make doughnut chart in android so please help me!
need like

Try the below library this may give some idea about that design..
Holograph
http://www.androidviews.net/2013/07/holographlibrary/
Source
https://bitbucket.org/danielnadeau/holographlibrary/wiki/Home

Try this link you may get what you want from this library:
https://github.com/PhilJay/MPAndroidChart
Or you can go for this PAID but Highly customisable 3rd party Library
https://nchart3d.com/nchart/

Kotlin example but you can adjust easily in java.
import android.content.Context
import android.graphics.Canvas
import android.graphics.Paint
import android.graphics.RectF
import android.util.AttributeSet
import android.view.View
import androidx.core.content.ContextCompat
import ro.lifeishard.broker.agent.pro.R
class DoughnutChartView(
context: Context,
attrs: AttributeSet?
): View(context, attrs) {
private val oval = RectF()
private val strokeWidthPx = 32f
private val backgroundPaint = buildPaint(R.color.gray)
private var percentageValueList = mapOf<Int, Double>()
private fun buildPaint(colorResId: Int): Paint {
return Paint().apply {
isAntiAlias = true
color = ContextCompat.getColor(context, colorResId)
style = Paint.Style.STROKE
strokeWidth = strokeWidthPx
}
}
override fun onDraw(canvas: Canvas?) {
super.onDraw(canvas)
//background
canvas?.drawArc(oval, 0f, 360f, false, backgroundPaint)
//values
var lastEndAngle = 0f
percentageValueList.forEach {
val angle = (it.value.toFloat() / 100) * 360
val color = it.key
canvas?.drawArc(oval, lastEndAngle, angle, false, buildPaint(color))
lastEndAngle += angle
}
}
override fun onSizeChanged(w: Int, h: Int, oldw: Int, oldh: Int) {
oval.set(
strokeWidthPx / 2,
strokeWidthPx / 2,
w.toFloat() - strokeWidthPx,
h.toFloat() - strokeWidthPx
)
}
fun setPercentages(valueColorMap: Map<Int, Double>) {
percentageValueList = valueColorMap
invalidate()
}
}
Usage:
In your xml layout:
<com.example.view.custom.DoughnutChartView
android:id="#+id/doughnut_chart"
android:layout_width="#dimen/doughnut_size"
android:layout_height="#dimen/doughnut_size"
/>
In your view controller:
doughnutChart.setPercentages(
mapOf(
R.color.red to 33.3,
R.color.blue to 33.3,
R.color.yellow to 33.3
)
)

Here's how i finally did it after two days of search with help of this library https://github.com/Ken-Yang/AndroidPieChart
And equations to center text done with help of my friends and alot of search
on MainActivity onCreate or oncreateView if you are using fragments:
PieChart pie = (PieChart) rootView.findViewById(R.id.pieChart);
ArrayList<Float> alPercentage = new ArrayList<Float>();
alPercentage.add(2.0f);
alPercentage.add(8.0f);
alPercentage.add(20.0f);
alPercentage.add(10.0f);
alPercentage.add(10.0f);
alPercentage.add(10.0f);
alPercentage.add(10.0f);
alPercentage.add(10.0f);
alPercentage.add(10.85f);
alPercentage.add(9.15f);
try {
// setting data
pie.setAdapter(alPercentage);
// setting a listener
pie.setOnSelectedListener(new OnSelectedLisenter() {
#Override
public void onSelected(int iSelectedIndex) {
Toast.makeText(getActivity(),
"Select index:" + iSelectedIndex,
Toast.LENGTH_SHORT).show();
}
});
} catch (Exception e) {
if (e.getMessage().equals(PieChart.ERROR_NOT_EQUAL_TO_100)) {
Log.e("kenyang", "percentage is not equal to 100");
}
}
public class PieChart extends View {
public interface OnSelectedLisenter {
public abstract void onSelected(int iSelectedIndex);
}
private OnSelectedLisenter onSelectedListener = null;
private static final String TAG = PieChart.class.getName();
public static final String ERROR_NOT_EQUAL_TO_100 = "NOT_EQUAL_TO_100";
private static final int DEGREE_360 = 360;
private static String[] PIE_COLORS = null;
private static int iColorListSize = 0;
ArrayList<Float> array;
private Paint paintPieFill;
private Paint paintPieBorder;
private Paint paintCenterCircle;
private ArrayList<Float> alPercentage = new ArrayList<Float>();
private int mCenterX = 320;
private int mCenterY = 320;
private int iDisplayWidth, iDisplayHeight;
private int iSelectedIndex = -1;
private int iCenterWidth = 0;
private int iShift = 0;
private int iMargin = 0; // margin to left and right, used for get Radius
private int iDataSize = 0;
private Canvas canvas1;
private RectF r = null;
private RectF centerCircle = null;
private float fDensity = 0.0f;
private float fStartAngle = 0.0f;
private float fEndAngle = 0.0f;
float fX;
float fY;
public PieChart(Context context, AttributeSet attrs) {
super(context, attrs);
PIE_COLORS = getResources().getStringArray(R.array.colors);
iColorListSize = PIE_COLORS.length;
array = new ArrayList<Float>();
fnGetDisplayMetrics(context);
iShift = (int) fnGetRealPxFromDp(30);
iMargin = (int) fnGetRealPxFromDp(40);
centerCircle = new RectF(200, 200, 440, 440);
// used for paint circle
paintPieFill = new Paint(Paint.ANTI_ALIAS_FLAG);
paintPieFill.setStyle(Paint.Style.FILL);
// used for paint centerCircle
paintCenterCircle = new Paint(Paint.ANTI_ALIAS_FLAG);
paintCenterCircle.setStyle(Paint.Style.FILL);
paintCenterCircle.setColor(Color.WHITE);
// used for paint border
paintPieBorder = new Paint(Paint.ANTI_ALIAS_FLAG);
paintPieBorder.setStyle(Paint.Style.STROKE);
paintPieBorder.setStrokeWidth(fnGetRealPxFromDp(3));
paintPieBorder.setColor(Color.WHITE);
Log.i(TAG, "PieChart init");
}
// set listener
public void setOnSelectedListener(OnSelectedLisenter listener) {
this.onSelectedListener = listener;
}
float temp = 0;
#Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
Log.i(TAG, "onDraw");
float centerX = (r.left + r.right) / 2;
float centerY = (r.top + r.bottom) / 2;
float radius1 = (r.right - r.left) / 2;
radius1 *= 0.5;
float startX = mCenterX;
float startY = mCenterY;
float radius = mCenterX;
float medianAngle = 0;
Path path = new Path();
for (int i = 0; i < iDataSize; i++) {
// check whether the data size larger than color list size
if (i >= iColorListSize) {
paintPieFill.setColor(Color.parseColor(PIE_COLORS[i
% iColorListSize]));
} else {
paintPieFill.setColor(Color.parseColor(PIE_COLORS[i]));
}
fEndAngle = alPercentage.get(i);
// convert percentage to angle
fEndAngle = fEndAngle / 100 * DEGREE_360;
// if the part of pie was selected then change the coordinate
if (iSelectedIndex == i) {
canvas.save(Canvas.MATRIX_SAVE_FLAG);
float fAngle = fStartAngle + fEndAngle / 2;
double dxRadius = Math.toRadians((fAngle + DEGREE_360)
% DEGREE_360);
fY = (float) Math.sin(dxRadius);
fX = (float) Math.cos(dxRadius);
canvas.translate(fX * iShift, fY * iShift);
}
canvas.drawArc(r, fStartAngle, fEndAngle, true, paintPieFill);
float angle = (float) ((fStartAngle + fEndAngle / 2) * Math.PI / 180);
float stopX = (float) (startX + (radius/2) * Math.cos(angle));
float stopY = (float) (startY + (radius/2) * Math.sin(angle));
// if the part of pie was selected then draw a border
if (iSelectedIndex == i) {
canvas.drawArc(r, fStartAngle, fEndAngle, true, paintPieBorder);
canvas.drawLine(startX, startY, stopX, stopY, paintPieFill);
canvas.restore();
}
fStartAngle = fStartAngle + fEndAngle;
}
}
#Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
// get screen size
iDisplayWidth = MeasureSpec.getSize(widthMeasureSpec);
iDisplayHeight = MeasureSpec.getSize(heightMeasureSpec);
if (iDisplayWidth > iDisplayHeight) {
iDisplayWidth = iDisplayHeight;
}
/*
* determine the rectangle size
*/
iCenterWidth = iDisplayWidth / 2;
int iR = iCenterWidth - iMargin;
if (r == null) {
r = new RectF(iCenterWidth - iR, // top
iCenterWidth - iR, // left
iCenterWidth + iR, // right
iCenterWidth + iR); // bottom
}
if (centerCircle == null) {
// centerCircle=new RectF(left, top, right, bottom);
}
setMeasuredDimension(iDisplayWidth, iDisplayWidth);
}
#Override
public boolean onTouchEvent(MotionEvent event) {
// get degree of the touch point
double dx = Math.atan2(event.getY() - iCenterWidth, event.getX()
- iCenterWidth);
float fDegree = (float) (dx / (2 * Math.PI) * DEGREE_360);
fDegree = (fDegree + DEGREE_360) % DEGREE_360;
// get the percent of the selected degree
float fSelectedPercent = fDegree * 100 / DEGREE_360;
// check which pie was selected
float fTotalPercent = 0;
for (int i = 0; i < iDataSize; i++) {
fTotalPercent += alPercentage.get(i);
if (fTotalPercent > fSelectedPercent) {
iSelectedIndex = i;
break;
}
}
if (onSelectedListener != null) {
onSelectedListener.onSelected(iSelectedIndex);
}
invalidate();
return super.onTouchEvent(event);
}
private void fnGetDisplayMetrics(Context cxt) {
final DisplayMetrics dm = cxt.getResources().getDisplayMetrics();
fDensity = dm.density;
}
private float fnGetRealPxFromDp(float fDp) {
return (fDensity != 1.0f) ? fDensity * fDp : fDp;
}
public void setAdapter(ArrayList<Float> alPercentage) throws Exception {
this.alPercentage = alPercentage;
iDataSize = alPercentage.size();
float fSum = 0;
for (int i = 0; i < iDataSize; i++) {
fSum += alPercentage.get(i);
}
if (fSum != 100) {
Log.e(TAG, ERROR_NOT_EQUAL_TO_100);
iDataSize = 0;
throw new Exception(ERROR_NOT_EQUAL_TO_100);
}
}
In Layout:
<com.example.piecharts.PieChart
android:id="#+id/pieChart"
android:layout_width="match_parent"
android:layout_height="match_parent" >
</com.example.piecharts.PieChart>

getting android. view.inflateException when I use zoomView for pageCurlView

please tell me how can i remove the exception. or give me idea to implement zoom view with curlview.....
my xml file is like this,
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:id="#+id/relat">
<com.example.image.ZoomView
>
<com.example.image.PageCurlView
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:id="#+id/dcgpagecurlPageCurlView1"
>
</com.example.image.PageCurlView>
my java file is
package com.example.image;
public class StandaloneExample extends Activity {
Button bt;LinearLayout lr;
/** Decoded bitmap image */
private Bitmap mBitmap;
private ZoomView zoomview;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
this.setContentView(R.layout.standalone_example);
View v1 = ((LayoutInflater)getSystemService(Context.LAYOUT_INFLATER_SERVICE)).inflate(R.layout.standalone_example, null, false);
v1.setLayoutParams(new LinearLayout.LayoutParams(LayoutParams.FILL_PARENT, LayoutParams.FILL_PARENT));
zoomview.addView(v1);
lr = (LinearLayout) findViewById(R.id.relat);
lr.addView(zoomview);
}
#Override
public void onDestroy(){
super.onDestroy();
System.gc();
finish();
}
public void lockOrientationLandscape() {
lockOrientation(ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE);
}
public void lockOrientationPortrait() {
lockOrientation(ActivityInfo.SCREEN_ORIENTATION_PORTRAIT);
}
public void lockOrientation( int orientation ) {
setRequestedOrientation(orientation);
}
}
i have implemented zoomView.java as described in a link
pagecurlview.java class is
public class PageCurlView extends View {
private final static String TAG = "PageCurlView";
private Paint mTextPaint;
private TextPaint mTextPaintShadow;
private int mCurlSpeed;
private int mUpdateRate;
private int mInitialEdgeOffset;
private int mCurlMode;
public static final int CURLMODE_SIMPLE = 0;
public static final int CURLMODE_DYNAMIC = 1;
private boolean bEnableDebugMode = false;
private WeakReference<Context> mContext;
private FlipAnimationHandler mAnimationHandler;
private float mFlipRadius;
private Vector2D mMovement;
private Vector2D mFinger;
private Vector2D mOldMovement;
private Paint mCurlEdgePaint;
private Vector2D mA, mB, mC, mD, mE, mF, mOldF, mOrigin;
private int mCurrentLeft, mCurrentTop;
private boolean bViewDrawn;
private boolean bFlipRight;
private boolean bFlipping;
private boolean bUserMoves;
private boolean bBlockTouchInput = false;
private boolean bEnableInputAfterDraw = false;
private Bitmap mForeground;
private Bitmap mBackground;
private ArrayList<Bitmap> mPages;
private int mIndex = 0;
private class Vector2D
{
public float x,y;
public Vector2D(float x, float y)
{
this.x = x;
this.y = y;
}
#Override
public String toString() {
// TODO Auto-generated method stub
return "("+this.x+","+this.y+")";
}
public float length() {
return (float) Math.sqrt(x * x + y * y);
}
public float lengthSquared() {
return (x * x) + (y * y);
}
public boolean equals(Object o) {
if (o instanceof Vector2D) {
Vector2D p = (Vector2D) o;
return p.x == x && p.y == y;
}
return false;
}
public Vector2D reverse() {
return new Vector2D(-x,-y);
}
public Vector2D sum(Vector2D b) {
return new Vector2D(x+b.x,y+b.y);
}
public Vector2D sub(Vector2D b) {
return new Vector2D(x-b.x,y-b.y);
}
public float dot(Vector2D vec) {
return (x * vec.x) + (y * vec.y);
}
public float cross(Vector2D a, Vector2D b) {
return a.cross(b);
}
public float cross(Vector2D vec) {
return x * vec.y - y * vec.x;
}
public float distanceSquared(Vector2D other) {
float dx = other.x - x;
float dy = other.y - y;
return (dx * dx) + (dy * dy);
}
public float distance(Vector2D other) {
return (float) Math.sqrt(distanceSquared(other));
}
public float dotProduct(Vector2D other) {
return other.x * x + other.y * y;
}
public Vector2D normalize() {
float magnitude = (float) Math.sqrt(dotProduct(this));
return new Vector2D(x / magnitude, y / magnitude);
}
public Vector2D mult(float scalar) {
return new Vector2D(x*scalar,y*scalar);
}
}
class FlipAnimationHandler extends Handler {
#Override
public void handleMessage(Message msg) {
PageCurlView.this.FlipAnimationStep();
}
public void sleep(long millis) {
this.removeMessages(0);
sendMessageDelayed(obtainMessage(0), millis);
}
}
public PageCurlView(Context context) {
super(context);
init(context);
ResetClipEdge();
}
public PageCurlView(Context context, AttributeSet attrs) {
super(context, attrs);
init(context);
// Get the data from the XML AttributeSet
{
TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.PageCurlView);
// Get data
bEnableDebugMode = a.getBoolean(R.styleable.PageCurlView_enableDebugMode, bEnableDebugMode);
mCurlSpeed = a.getInt(R.styleable.PageCurlView_curlSpeed, mCurlSpeed);
mUpdateRate = a.getInt(R.styleable.PageCurlView_updateRate, mUpdateRate);
mInitialEdgeOffset = a.getInt(R.styleable.PageCurlView_initialEdgeOffset, mInitialEdgeOffset);
mCurlMode = a.getInt(R.styleable.PageCurlView_curlMode, mCurlMode);
Log.i(TAG, "mCurlSpeed: " + mCurlSpeed);
Log.i(TAG, "mUpdateRate: " + mUpdateRate);
Log.i(TAG, "mInitialEdgeOffset: " + mInitialEdgeOffset);
Log.i(TAG, "mCurlMode: " + mCurlMode);
// recycle object (so it can be used by others)
a.recycle();
}
ResetClipEdge();
}
private final void init(Context context) {
// Foreground text paint
mTextPaint = new Paint();
mTextPaint.setAntiAlias(true);
mTextPaint.setTextSize(16);
mTextPaint.setColor(0xFF000000);
// The shadow
mTextPaintShadow = new TextPaint();
mTextPaintShadow.setAntiAlias(true);
mTextPaintShadow.setTextSize(16);
mTextPaintShadow.setColor(0x00000000);
// Cache the context
mContext = new WeakReference<Context>(context);
// Base padding
setPadding(3, 3, 3, 3);
// The focus flags are needed
setFocusable(true);
setFocusableInTouchMode(true);
mMovement = new Vector2D(0,0);
mFinger = new Vector2D(0,0);
mOldMovement = new Vector2D(0,0);
// Create our curl animation handler
mAnimationHandler = new FlipAnimationHandler();
// Create our edge paint
mCurlEdgePaint = new Paint();
mCurlEdgePaint.setColor(Color.WHITE);
mCurlEdgePaint.setAntiAlias(true);
mCurlEdgePaint.setStyle(Paint.Style.FILL);
mCurlEdgePaint.setShadowLayer(10, -5, 5, 0x99000000);
// Set the default props, those come from an XML :D
mCurlSpeed = 30;
mUpdateRate = 33;
mInitialEdgeOffset = 20;
mCurlMode = 1;
// LEGACY PAGE HANDLING!
// Create pages
mPages = new ArrayList<Bitmap>();
mPages.add(BitmapFactory.decodeResource(getResources(), R.drawable.princess));
mPages.add(BitmapFactory.decodeResource(getResources(), R.drawable.temp));
// Create some sample images
mForeground = mPages.get(0);
mBackground = mPages.get(1);
}
public void ResetClipEdge()
{
// Set our base movement
mMovement.x = mInitialEdgeOffset;
mMovement.y = mInitialEdgeOffset;
mOldMovement.x = 0;
mOldMovement.y = 0;
// Now set the points
// TODO: OK, those points MUST come from our measures and
// the actual bounds of the view!
mA = new Vector2D(mInitialEdgeOffset, 0);
mB = new Vector2D(this.getWidth(), this.getHeight());
mC = new Vector2D(this.getWidth(), 0);
mD = new Vector2D(0, 0);
mE = new Vector2D(0, 0);
mF = new Vector2D(0, 0);
mOldF = new Vector2D(0, 0);
// The movement origin point
mOrigin = new Vector2D(this.getWidth(), 0);
}
private Context GetContext() {
return mContext.get();
}
public boolean IsCurlModeDynamic()
{
return mCurlMode == CURLMODE_DYNAMIC;
}
public void SetCurlSpeed(int curlSpeed)
{
if ( curlSpeed < 1 )
throw new IllegalArgumentException("curlSpeed must be greated than 0");
mCurlSpeed = curlSpeed;
}
public int GetCurlSpeed()
{
return mCurlSpeed;
}
public void SetUpdateRate(int updateRate)
{
if ( updateRate < 1 )
throw new IllegalArgumentException("updateRate must be greated than 0");
mUpdateRate = updateRate;
}
public int GetUpdateRate()
{
return mUpdateRate;
}
public void SetInitialEdgeOffset(int initialEdgeOffset)
{
if ( initialEdgeOffset < 0 )
throw new IllegalArgumentException("initialEdgeOffset can not negative");
mInitialEdgeOffset = initialEdgeOffset;
}
public int GetInitialEdgeOffset()
{
return mInitialEdgeOffset;
}
public void SetCurlMode(int curlMode)
{
if ( curlMode != CURLMODE_SIMPLE &&
curlMode != CURLMODE_DYNAMIC )
throw new IllegalArgumentException("Invalid curlMode");
mCurlMode = curlMode;
}
public int GetCurlMode()
{
return mCurlMode;
}
public void SetEnableDebugMode(boolean bFlag)
{
bEnableDebugMode = bFlag;
}
public boolean IsDebugModeEnabled()
{
return bEnableDebugMode;
}
#Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
int finalWidth, finalHeight;
finalWidth = measureWidth(widthMeasureSpec);
finalHeight = measureHeight(heightMeasureSpec);
setMeasuredDimension(finalWidth, finalHeight);
}
private int measureWidth(int measureSpec) {
int result = 0;
int specMode = MeasureSpec.getMode(measureSpec);
int specSize = MeasureSpec.getSize(measureSpec);
if (specMode == MeasureSpec.EXACTLY) {
// We were told how big to be
result = specSize;
} else {
// Measure the text
result = specSize;
}
return result;
}
private int measureHeight(int measureSpec) {
int result = 0;
int specMode = MeasureSpec.getMode(measureSpec);
int specSize = MeasureSpec.getSize(measureSpec);
if (specMode == MeasureSpec.EXACTLY) {
// We were told how big to be
result = specSize;
} else {
// Measure the text (beware: ascent is a negative number)
result = specSize;
}
return result;
}
#Override
public boolean onTouchEvent(MotionEvent event) {
if (!bBlockTouchInput) {
// Get our finger position
mFinger.x = event.getX();
mFinger.y = event.getY();
int width = getWidth();
// Depending on the action do what we need to
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN:
mOldMovement.x = mFinger.x;
mOldMovement.y = mFinger.y;
// If we moved over the half of the display flip to next
if (mOldMovement.x > (width >> 1)) {
mMovement.x = mInitialEdgeOffset;
mMovement.y = mInitialEdgeOffset;
// Set the right movement flag
bFlipRight = true;
} else {
// Set the left movement flag
bFlipRight = false;
// go to next previous page
previousView();
// Set new movement
mMovement.x = IsCurlModeDynamic()?width<<1:width;
mMovement.y = mInitialEdgeOffset;
}
break;
case MotionEvent.ACTION_UP:
bUserMoves=false;
bFlipping=true;
FlipAnimationStep();
break;
case MotionEvent.ACTION_MOVE:
bUserMoves=true;
// Get movement
mMovement.x -= mFinger.x - mOldMovement.x;
mMovement.y -= mFinger.y - mOldMovement.y;
mMovement = CapMovement(mMovement, true);
// Make sure the y value get's locked at a nice level
if ( mMovement.y <= 1 )
mMovement.y = 1;
// Get movement direction
if (mFinger.x < mOldMovement.x ) {
bFlipRight = true;
} else {
bFlipRight = false;
}
// Save old movement values
mOldMovement.x = mFinger.x;
mOldMovement.y = mFinger.y;
// Force a new draw call
DoPageCurl();
this.invalidate();
break;
}
}
// TODO: Only consume event if we need to.
return true;
}
private Vector2D CapMovement(Vector2D point, boolean bMaintainMoveDir)
{
// Make sure we never ever move too much
if (point.distance(mOrigin) > mFlipRadius)
{
if ( bMaintainMoveDir )
{
// Maintain the direction
point = mOrigin.sum(point.sub(mOrigin).normalize().mult(mFlipRadius));
}
else
{
// Change direction
if ( point.x > (mOrigin.x+mFlipRadius))
point.x = (mOrigin.x+mFlipRadius);
else if ( point.x < (mOrigin.x-mFlipRadius) )
point.x = (mOrigin.x-mFlipRadius);
point.y = (float) (Math.sin(Math.acos(Math.abs(point.x-mOrigin.x)/mFlipRadius))*mFlipRadius);
}
}
return point;
}
public void FlipAnimationStep() {
if ( !bFlipping )
return;
int width = getWidth();
// No input when flipping
bBlockTouchInput = true;
// Handle speed
float curlSpeed = mCurlSpeed;
if ( !bFlipRight )
curlSpeed *= -1;
// Move us
mMovement.x += curlSpeed;
mMovement = CapMovement(mMovement, false);
// Create values
DoPageCurl();
// Check for endings :D
if (mA.x < 1 || mA.x > width - 1) {
bFlipping = false;
if (bFlipRight) {
//SwapViews();
nextView();
}
ResetClipEdge();
// Create values
DoPageCurl();
// Enable touch input after the next draw event
bEnableInputAfterDraw = true;
}
else
{
mAnimationHandler.sleep(mUpdateRate);
}
// Force a new draw call
this.invalidate();
}
private void DoPageCurl()
{
if(bFlipping){
if ( IsCurlModeDynamic() )
doDynamicCurl();
else
doSimpleCurl();
} else {
if ( IsCurlModeDynamic() )
doDynamicCurl();
else
doSimpleCurl();
}
}
private void doSimpleCurl() {
int width = getWidth();
int height = getHeight();
// Calculate point A
mA.x = width - mMovement.x;
mA.y = height;
// Calculate point D
mD.x = 0;
mD.y = 0;
if (mA.x > width / 2) {
mD.x = width;
mD.y = height - (width - mA.x) * height / mA.x;
} else {
mD.x = 2 * mA.x;
mD.y = 0;
}
double angle = Math.atan((height - mD.y) / (mD.x + mMovement.x - width));
double _cos = Math.cos(2 * angle);
double _sin = Math.sin(2 * angle);
mF.x = (float) (width - mMovement.x + _cos * mMovement.x);
mF.y = (float) (height - _sin * mMovement.x);
// If the x position of A is above half of the page we are still not
// folding the upper-right edge and so E and D are equal.
if (mA.x > width / 2) {
mE.x = mD.x;
mE.y = mD.y;
}
else
{
// So get E
mE.x = (float) (mD.x + _cos * (width - mD.x));
mE.y = (float) -(_sin * (width - mD.x));
}
}
private void doDynamicCurl() {
int width = getWidth();
int height = getHeight();
mF.x = width - mMovement.x+0.1f;
mF.y = height - mMovement.y+0.1f;
if(mA.x==0) {
mF.x= Math.min(mF.x, mOldF.x);
mF.y= Math.max(mF.y, mOldF.y);
}
// Get diffs
float deltaX = width-mF.x;
float deltaY = height-mF.y;
float BH = (float) (Math.sqrt(deltaX * deltaX + deltaY * deltaY) / 2);
double tangAlpha = deltaY / deltaX;
double alpha = Math.atan(deltaY / deltaX);
double _cos = Math.cos(alpha);
double _sin = Math.sin(alpha);
mA.x = (float) (width - (BH / _cos));
mA.y = height;
mD.y = (float) (height - (BH / _sin));
mD.x = width;
mA.x = Math.max(0,mA.x);
if(mA.x==0) {
mOldF.x = mF.x;
mOldF.y = mF.y;
}
// Get W
mE.x = mD.x;
mE.y = mD.y;
// Correct
if (mD.y < 0) {
mD.x = width + (float) (tangAlpha * mD.y);
mE.y = 0;
mE.x = width + (float) (Math.tan(2 * alpha) * mD.y);
}
}
#Deprecated
private void SwapViews() {
Bitmap temp = mForeground;
mForeground = mBackground;
mBackground = temp;
}
private void nextView() {
int foreIndex = mIndex + 1;
if(foreIndex >= mPages.size()) {
foreIndex = 0;
}
int backIndex = foreIndex + 1;
if(backIndex >= mPages.size()) {
backIndex = 0;
}
mIndex = foreIndex;
setViews(foreIndex, backIndex);
}
private void previousView() {
int backIndex = mIndex;
int foreIndex = backIndex - 1;
if(foreIndex < 0) {
foreIndex = mPages.size()-1;
}
mIndex = foreIndex;
setViews(foreIndex, backIndex);
}
private void setViews(int foreground, int background) {
mForeground = mPages.get(foreground);
mBackground = mPages.get(background);
}
#Override
protected void onDraw(Canvas canvas) {
mCurrentLeft = getLeft();
mCurrentTop = getTop();
if ( !bViewDrawn ) {
bViewDrawn = true;
onFirstDrawEvent(canvas);
}
canvas.drawColor(Color.WHITE);
Rect rect = new Rect();
rect.left = 0;
rect.top = 0;
rect.bottom = getHeight();
rect.right = getWidth();
// First Page render
Paint paint = new Paint();
// Draw our elements
drawForeground(canvas, rect, paint);
drawBackground(canvas, rect, paint);
drawCurlEdge(canvas);
// Draw any debug info once we are done
if ( bEnableDebugMode )
drawDebug(canvas);
// Check if we can re-enable input
if ( bEnableInputAfterDraw )
{
bBlockTouchInput = false;
bEnableInputAfterDraw = false;
}
// Restore canvas
//canvas.restore();
}
protected void onFirstDrawEvent(Canvas canvas) {
mFlipRadius = getWidth();
ResetClipEdge();
DoPageCurl();
}
private void drawForeground( Canvas canvas, Rect rect, Paint paint ) {
canvas.drawBitmap(mForeground, null, rect, paint);
// Draw the page number (first page is 1 in real life :D
// there is no page number 0 hehe)
drawPageNum(canvas, mIndex);
}
private Path createBackgroundPath() {
Path path = new Path();
path.moveTo(mA.x, mA.y);
path.lineTo(mB.x, mB.y);
path.lineTo(mC.x, mC.y);
path.lineTo(mD.x, mD.y);
path.lineTo(mA.x, mA.y);
return path;
}
private void drawBackground( Canvas canvas, Rect rect, Paint paint ) {
Path mask = createBackgroundPath();
// Save current canvas so we do not mess it up
canvas.save();
canvas.clipPath(mask);
canvas.drawBitmap(mBackground, null, rect, paint);
// Draw the page number (first page is 1 in real life :D
// there is no page number 0 hehe)
drawPageNum(canvas, mIndex);
canvas.restore();
}
private Path createCurlEdgePath() {
Path path = new Path();
path.moveTo(mA.x, mA.y);
path.lineTo(mD.x, mD.y);
path.lineTo(mE.x, mE.y);
path.lineTo(mF.x, mF.y);
path.lineTo(mA.x, mA.y);
return path;
}
private void drawCurlEdge( Canvas canvas )
{
Path path = createCurlEdgePath();
canvas.drawPath(path, mCurlEdgePaint);
}
private void drawPageNum(Canvas canvas, int pageNum)
{
mTextPaint.setColor(Color.WHITE);
String pageNumText = "- "+pageNum+" -";
drawCentered(canvas, pageNumText,canvas.getHeight()-mTextPaint.getTextSize()-5,mTextPaint,mTextPaintShadow);
}
public static void drawTextShadowed(Canvas canvas, String text, float x, float y, Paint textPain, Paint shadowPaint) {
canvas.drawText(text, x-1, y, shadowPaint);
canvas.drawText(text, x, y+1, shadowPaint);
canvas.drawText(text, x+1, y, shadowPaint);
canvas.drawText(text, x, y-1, shadowPaint);
canvas.drawText(text, x, y, textPain);
}
public static void drawCentered(Canvas canvas, String text, float y, Paint textPain, Paint shadowPaint)
{
float posx = (canvas.getWidth() - textPain.measureText(text))/2;
drawTextShadowed(canvas, text, posx, y, textPain, shadowPaint);
}
private void drawDebug(Canvas canvas)
{
float posX = 10;
float posY = 20;
Paint paint = new Paint();
paint.setStrokeWidth(5);
paint.setStyle(Style.STROKE);
paint.setColor(Color.BLACK);
canvas.drawCircle(mOrigin.x, mOrigin.y, getWidth(), paint);
paint.setStrokeWidth(3);
paint.setColor(Color.RED);
canvas.drawCircle(mOrigin.x, mOrigin.y, getWidth(), paint);
paint.setStrokeWidth(5);
paint.setColor(Color.BLACK);
canvas.drawLine(mOrigin.x, mOrigin.y, mMovement.x, mMovement.y, paint);
paint.setStrokeWidth(3);
paint.setColor(Color.RED);
canvas.drawLine(mOrigin.x, mOrigin.y, mMovement.x, mMovement.y, paint);
posY = debugDrawPoint(canvas,"A",mA,Color.RED,posX,posY);
posY = debugDrawPoint(canvas,"B",mB,Color.GREEN,posX,posY);
posY = debugDrawPoint(canvas,"C",mC,Color.BLUE,posX,posY);
posY = debugDrawPoint(canvas,"D",mD,Color.CYAN,posX,posY);
posY = debugDrawPoint(canvas,"E",mE,Color.YELLOW,posX,posY);
posY = debugDrawPoint(canvas,"F",mF,Color.LTGRAY,posX,posY);
posY = debugDrawPoint(canvas,"Mov",mMovement,Color.DKGRAY,posX,posY);
posY = debugDrawPoint(canvas,"Origin",mOrigin,Color.MAGENTA,posX,posY);
posY = debugDrawPoint(canvas,"Finger",mFinger,Color.GREEN,posX,posY);
}
private float debugDrawPoint(Canvas canvas, String name, Vector2D point, int color, float posX, float posY) {
return debugDrawPoint(canvas,name+" "+point.toString(),point.x, point.y, color, posX, posY);
}
private float debugDrawPoint(Canvas canvas, String name, float X, float Y, int color, float posX, float posY) {
mTextPaint.setColor(color);
drawTextShadowed(canvas,name,posX , posY, mTextPaint,mTextPaintShadow);
Paint paint = new Paint();
paint.setStrokeWidth(5);
paint.setColor(color);
canvas.drawPoint(X, Y, paint);
return posY+15;
}
}

How to update text with canvas.drawText in OnDraw? Android

I have a custom view for my app and I'm trying to update a text everytime OnDraw is called.
(some of) my code lookes like this:
#Override
protected void onDraw(Canvas canvas) {
Log.e(TAG,"onDraw");
drawBackground(canvas);
float scale = (float) getWidth();
canvas.save(Canvas.MATRIX_SAVE_FLAG);
canvas.scale(scale, scale);
drawTitle(canvas);
drawHand(canvas);
canvas.restore();
if (handNeedsToMove()) {
moveHand();
}
}
private void drawTitle(Canvas canvas) {
String title = getTitle();
Log.i("drawtitle",title);
titlePaint = new Paint();
titlePaint.setColor(0xffffffff);
titlePaint.setAntiAlias(true);
titlePaint.setTypeface(Typeface.MONOSPACE);
titlePaint.setTextAlign(Paint.Align.CENTER);
titlePaint.setTextSize(0.05f);
titlePaint.setTextScaleX(0.8f);
canvas.drawText(title, 0.45f, 0.95f, titlePaint);
}
#Override
protected void onSizeChanged(int w, int h, int oldw, int oldh) {
Log.d(TAG, "Size changed to " + w + "x" + h);
regenerateBackground();
}
private void regenerateBackground() {
if (background != null) {
background.recycle();
}
//Some stuff here
drawInstruments(backgroundCanvas);
drawTitle(backgroundCanvas);
}
The text get updated when it's called by regenerateBackground but stays the same on OnDraw. Why? How to fix? Maby there is a better way than using canvas.drawText? I am making a speedometer and I just want to print the value of which the "needle" is pointing at...
edit: full code
public final class Dashboard extends View {
private static final String TAG = Dashboard.class.getSimpleName();
// drawing tools
private Paint dashPaint;
private static Bitmap dash;
private Matrix dashMatrix;
private float dashScalex;
private float dashScaley;
private Paint handPaint;
private Path handPath;
private Paint handScrewPaint;
private Paint backgroundPaint;
// end drawing tools
private Bitmap background; // holds the cached static part
private Paint titlePaint;
private Path titlePath;
// scale configuration
private static final int totalNicks = 100;
private static final float degreesPerNick = 360.0f / totalNicks;
private static final int centerDegree = 40; // the one in the top center (12 o'clock)
private static final int minDegrees = -30;
private static final int maxDegrees = 110;
// hand dynamics -- all are angular expressed in F degrees
private boolean handInitialized = true;
private float handPosition = centerDegree;
private float handTarget = centerDegree;
private float handVelocity = 0.0f;
private float handAcceleration = 0.0f;
private long lastHandMoveTime = -1L;
private static float circlePosx = 0.5f;
private static float circlePosy = 0.36f;
private static float circleRadius = 0.1f;
public Dashboard(Context context) {
super(context);
init();
}
public Dashboard(Context context, AttributeSet attrs) {
super(context, attrs);
init();
}
public Dashboard(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
init();
}
#Override
protected void onRestoreInstanceState(Parcelable state) {
Bundle bundle = (Bundle) state;
Parcelable superState = bundle.getParcelable("superState");
super.onRestoreInstanceState(superState);
handInitialized = bundle.getBoolean("handInitialized");
handPosition = bundle.getFloat("handPosition");
handTarget = bundle.getFloat("handTarget");
handVelocity = bundle.getFloat("handVelocity");
handAcceleration = bundle.getFloat("handAcceleration");
lastHandMoveTime = bundle.getLong("lastHandMoveTime");
}
#Override
protected Parcelable onSaveInstanceState() {
Parcelable superState = super.onSaveInstanceState();
Bundle state = new Bundle();
state.putParcelable("superState", superState);
state.putBoolean("handInitialized", handInitialized);
state.putFloat("handPosition", handPosition);
state.putFloat("handTarget", handTarget);
state.putFloat("handVelocity", handVelocity);
state.putFloat("handAcceleration", handAcceleration);
state.putLong("lastHandMoveTime", lastHandMoveTime);
return state;
}
public static float[] getCircle(){
float[] circle = {circlePosx,circlePosy,circleRadius};
return circle;
}
public static int[] getCanvasSize(){
int[] size = {dash.getWidth(),dash.getHeight()};
return size;
}
private void init() {
initDrawingTools();
}
private void initDrawingTools() {
/******/
dashPaint = new Paint();
dashPaint.setFilterBitmap(true);
dash = BitmapFactory.decodeResource(getContext().getResources(), R.drawable.dashboard);
dashMatrix = new Matrix();
dashScaley = 1f/dash.getHeight();// * 0.3f;;
dashScalex = 1f/dash.getWidth();
dashMatrix.setScale(dashScalex, dashScaley);
Log.i("dash width", "= "+dash.getWidth()+" - "+getWidth());
Log.i("dash height", "= "+dash.getHeight());
Log.i("dash scale x ", "= "+1f/dash.getHeight());
Log.i("dash scale y ", "= "+dashScaley);
/******/
handPaint = new Paint();
handPaint.setAntiAlias(true);
handPaint.setColor(0xffff0000);
handPaint.setShadowLayer(0.01f, -0.005f, -0.005f, 0x7f000000);
handPaint.setStyle(Paint.Style.FILL);
handPath = new Path();
handPath.moveTo(circlePosx-0.01f, circlePosy+0.06f);
handPath.lineTo(circlePosx, circlePosy - 0.16f);
handPath.lineTo(circlePosx+0.01f, circlePosy + 0.06f);
handPath.addCircle(circlePosx, circlePosy, 0.025f, Path.Direction.CW);
handScrewPaint = new Paint();
handScrewPaint.setAntiAlias(true);
handScrewPaint.setColor(0xf0000021);
handScrewPaint.setStyle(Paint.Style.FILL);
backgroundPaint = new Paint();
backgroundPaint.setFilterBitmap(true);
titlePaint = new Paint();
titlePaint.setColor(0xffffffff);
titlePaint.setAntiAlias(true);
titlePaint.setTypeface(Typeface.DEFAULT_BOLD);
titlePaint.setTextAlign(Paint.Align.CENTER);
titlePaint.setTextSize(0.05f);
titlePaint.setTextScaleX(0.8f);
titlePath = new Path();
titlePath.moveTo(0.5f, 0.8f);
titlePath.lineTo(0.6f, 0.8f);
//titlePath = new Path();
//titlePath.addArc(new RectF(0.24f, 0.24f, 0.76f, 0.76f), -180.0f, -180.0f);
}
#Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
Log.d(TAG, "Width spec: " + MeasureSpec.toString(widthMeasureSpec));
Log.d(TAG, "Height spec: " + MeasureSpec.toString(heightMeasureSpec));
int widthMode = MeasureSpec.getMode(widthMeasureSpec);
int widthSize = MeasureSpec.getSize(widthMeasureSpec);
int heightMode = MeasureSpec.getMode(heightMeasureSpec);
int heightSize = MeasureSpec.getSize(heightMeasureSpec);
int chosenWidth = chooseDimension(widthMode, widthSize);
int chosenHeight = chooseDimension(heightMode, heightSize);
setMeasuredDimension(chosenWidth, chosenHeight);
//int chosenDimension = Math.min(chosenWidth, chosenHeight);
//setMeasuredDimension(chosenDimension, chosenDimension);
}
private int chooseDimension(int mode, int size) {
if (mode == MeasureSpec.AT_MOST || mode == MeasureSpec.EXACTLY) {
return size;
} else { // (mode == MeasureSpec.UNSPECIFIED)
return getPreferredSize();
}
}
// in case there is no size specified
private int getPreferredSize() {
return 600;
}
private int nickToDegree(int nick) {
int rawDegree = ((nick < totalNicks / 2) ? nick : (nick - totalNicks)) * 2;
int shiftedDegree = rawDegree + centerDegree;
return shiftedDegree;
}
private float degreeToAngle(float degree) {
return (degree - centerDegree) / 2.0f * degreesPerNick;
}
private void drawInstruments(Canvas canvas){
canvas.save(Canvas.MATRIX_SAVE_FLAG);
canvas.translate(0.5f - dash.getWidth() * dashScalex / 2.0f,
0.5f - dash.getHeight() * dashScaley / 2.0f);
//canvas.drawBitmap(dash, 0, 0, dashPaint);
canvas.drawBitmap(dash, dashMatrix, dashPaint);
canvas.restore();
}
private void drawHand(Canvas canvas) {
Log.e(TAG, "drawHand");
if (handInitialized) {
float handAngle = degreeToAngle(handPosition);
canvas.save(Canvas.MATRIX_SAVE_FLAG);
canvas.rotate(handAngle, circlePosx, circlePosy);
canvas.drawPath(handPath, handPaint);
canvas.restore();
canvas.drawCircle(0.5f, 0.36f, 0.01f, handScrewPaint);
}
}
private String getTitle(){
return String.valueOf(handPosition);
}
private void drawTitle(Canvas canvas) {
String title = getTitle();
//canvas.drawTextOnPath(title, titlePath, 0.0f,0.0f, titlePaint);
//canvas.drawPaint(titlePaint);
Log.i("drawtitle",title);
canvas.drawText(title, 0.45f, 0.95f, titlePaint);
//invalidate();
}
private void drawBackground(Canvas canvas) {
if (background == null) {
Log.w(TAG, "Background not created");
} else {
canvas.drawBitmap(background, 0, 0, backgroundPaint);
}
}
#Override
protected void onDraw(Canvas canvas) {
Log.e(TAG,"onDraw");
drawBackground(canvas);
float scale = (float) getWidth();
canvas.save(Canvas.MATRIX_SAVE_FLAG);
canvas.scale(scale, scale);
drawTitle(canvas);
drawHand(canvas);
canvas.restore();
if (handNeedsToMove()) {
moveHand();
}
}
#Override
protected void onSizeChanged(int w, int h, int oldw, int oldh) {
Log.d(TAG, "Size changed to " + w + "x" + h);
regenerateBackground();
}
private void regenerateBackground() {
// free the old bitmap
if (background != null) {
background.recycle();
}
Log.e("Width="+getWidth(), "Height="+getHeight());
background = Bitmap.createBitmap(getWidth(), getHeight(), Bitmap.Config.ARGB_8888);
Canvas backgroundCanvas = new Canvas(background);
float scalex = (float) getWidth();
float scaley = (float) getHeight();
backgroundCanvas.scale(scalex, scaley);
drawInstruments(backgroundCanvas);
}
private boolean handNeedsToMove() {
return Math.abs(handPosition - handTarget) > 0.01f;
}
private void moveHand() {
Log.e(TAG, "moveHand!!");
if (! handNeedsToMove()) {
return;
}
if (lastHandMoveTime != -1L) {
long currentTime = System.currentTimeMillis();
float delta = (currentTime - lastHandMoveTime) / 1000.0f;
float direction = Math.signum(handVelocity);
if (Math.abs(handVelocity) < 90.0f) {
handAcceleration = 5.0f * (handTarget - handPosition);
} else {
handAcceleration = 0.0f;
}
handPosition += handVelocity * delta;
handVelocity += handAcceleration * delta;
if ((handTarget - handPosition) * direction < 0.01f * direction) {
handPosition = handTarget;
handVelocity = 0.0f;
handAcceleration = 0.0f;
lastHandMoveTime = -1L;
} else {
lastHandMoveTime = System.currentTimeMillis();
}
invalidate();
} else {
lastHandMoveTime = System.currentTimeMillis();
moveHand();
}
}
private float getRelativeTemperaturePosition() {
if (handPosition < centerDegree) {
return - (centerDegree - handPosition) / (float) (centerDegree - minDegrees);
} else {
return (handPosition - centerDegree) / (float) (maxDegrees - centerDegree);
}
}
public void setHandTarget(float temperature) {
Log.e(TAG, "setHandTarget!");
if (temperature < minDegrees) {
temperature = minDegrees;
} else if (temperature > maxDegrees) {
temperature = maxDegrees;
}
handTarget = temperature;
Log.e(TAG, "handTarget="+handTarget);
handInitialized = true;
invalidate();
}
public float getHandTarget(){
return handTarget;
}
}

Remove the call to drawTitle() from regenerateBackground() and call invalidate inside your setTitle() method.