Related
In android I have create custom view.I have first drawn circle and now I want to draw a line angle wise within a circle. I want like this with animation.
https://drive.google.com/file/d/1Qx0MBu-77JIlQTByqGTyD-KtGKOB8naG/view?usp=sharing
I have used canvas to draw circle and lines.I have taken viewpager.If I swipe viewpager then pie graphics will rotate.
What I have done uptill now. When animating it's always start from zero:
https://drive.google.com/file/d/12mmAUOeY77jAlj_GmM3Ymcx5m34vli3X/view?usp=sharing
I have done below code:
public class PieView : View
{
int w, h, pl, pr, pt, pb, usableWidth, usableHeight, radius, cx, cy, lineLenght;
Paint paint;
public Canvas canvas;
public float firstLineangle = 0;
public float secondLineangle = 40;
public float thirdLineangle = 120;
float currentAngle,maxAngle;
public override void Draw(Canvas canvas)
{
base.Draw(canvas);
w = Width;
h = Height;
pl = PaddingLeft;
pr = PaddingRight;
pt = PaddingTop;
pb = PaddingBottom;
this.canvas = canvas;
usableWidth = w - (pl + pr);
usableHeight = h - (pt + pb);
radius = Math.Min(usableWidth, usableHeight) / 2;
cx = pl + (usableWidth / 2);
cy = pt + (usableHeight / 2);
lineLenght = radius - (pl * 2) - (pr * 2);
paint = new Paint();
paint.Color = Android.Graphics.Color.White;
paint.SetStyle(Paint.Style.Stroke);
paint.StrokeWidth = 5;
canvas.DrawCircle(cx, cy, radius - 5, paint);
Drawline(canvas, firstLineangle);
Drawline(canvas, secondLineangle);
Drawline(canvas, thirdLineangle);
PostInvalidateDelayed(500);
Invalidate();
}
public void Drawline(Canvas canvas, float angle)
{
float displacedAngle = angle - 90;
float x = cx + ((float)Math.Cos(degreesToRadians(displacedAngle)) * (radius - 5)); //convert angle to radians for x and y coordinates
float y = cy + ((float)Math.Sin(degreesToRadians(displacedAngle)) * (radius - 5));
canvas.DrawLine(cx, cy, x, y, paint); //draw a line from center point back to the point
}
public double degreesToRadians(double degrees)
{
return (degrees * Math.PI) / 180;
}
}
public class PieAnimation : Android.Views.Animations.Animation
{
private PieView pieView;
private float firstLineangle;
private float secondLineangle;
private float thirdLineangle;
public PieAnimation(PieView pieView, float firstLineangle,float secondLineangle,float thirdLineangle)
{
this.pieView = pieView;
this.firstLineangle = firstLineangle;
this.secondLineangle = secondLineangle;
this.thirdLineangle = thirdLineangle;
}
protected override void ApplyTransformation(float interpolatedTime, Transformation t)
{
pieView.firstLineangle = 0 + ((firstLineangle) * interpolatedTime);
pieView.secondLineangle = 0 + ((secondLineangle) * interpolatedTime);
pieView.thirdLineangle = 0 + ((thirdLineangle) * interpolatedTime);
pieView.RequestLayout();
}
}
public class TourPager : Java.Lang.Object, ViewPager.IOnPageChangeListener, ViewPager.IPageTransformer
{
private ViewPager mViewPager;
private float mLastOffset;
public TourView _context;
public TourPager(ViewPager viewpager, TourView context)
{
mViewPager = viewpager;
viewpager.AddOnPageChangeListener(this);
_context = context;
}
public void OnPageSelected(int position)
{
if (position == 0)
{
PieAnimation animation = new PieAnimation(_context._pieView, 0, 40, 120);
animation.Duration = (1000);
_context._pieView.StartAnimation(animation);
}
if (position==1)
{
PieAnimation animation = new PieAnimation(_context._pieView, 100, 140, 200);
animation.Duration=(1000);
_context._pieView.StartAnimation(animation);
}
if(position==2)
{
PieAnimation animation = new PieAnimation(_context._pieView, 180, 270, 10);
animation.Duration = (1000);
_context._pieView.StartAnimation(animation);
}
}
There is running GIF.
There is PieView.cs.
public class PieView:View
{
int w, h, pl, pr, pt, pb, usableWidth, usableHeight, radius, cx, cy, lineLenght;
int handTruncation, hourHandTruncation = 0;
Paint paint;
int[] numbers = { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12 };
Rect rect = new Rect();
public PieView(Context context) : base(context)
{
}
public PieView(Context context, IAttributeSet attrs) : base(context, attrs)
{
}
public PieView(Context context, IAttributeSet attrs, int defStyleAttr) : base(context, attrs, defStyleAttr)
{
}
public PieView(Context context, IAttributeSet attrs, int defStyleAttr, int defStyleRes) : base(context, attrs, defStyleAttr, defStyleRes)
{
}
public override void Draw(Canvas canvas)
{
base.Draw(canvas);
w = Width;
h = Height;
pl = PaddingLeft+10;
pr = PaddingRight+10;
pt = PaddingTop+10;
pb = PaddingBottom+10;
usableWidth = w - (pl + pr);
usableHeight = h - (pt + pb);
radius = Math.Min(usableWidth, usableHeight) / 2;
cx = pl + (usableWidth / 2);
cy = pt + (usableHeight / 2);
int min = Math.Min(usableWidth, usableHeight);
handTruncation = min / 20;
hourHandTruncation = min / 7;
lineLenght = radius - (pl * 2) - (pr * 2);
paint = new Paint();
paint.Color = Android.Graphics.Color.White;
paint.SetStyle(Paint.Style.Stroke);
paint.StrokeWidth = 5;
canvas.DrawCircle(cx, cy, radius , paint);
drawNumeral(canvas);
drawHands(canvas);
PostInvalidateDelayed(200);
Invalidate();
}
private void drawHands(Canvas canvas)
{
Calendar c = Calendar.Instance;
float hour = c.Get(CalendarField.HourOfDay);
hour = hour > 12 ? hour - 12 : hour;
drawHand1(canvas, (hour + c.Get(CalendarField.Minute) / 60) * 5f,true);
drawHand1(canvas, c.Get(CalendarField.Minute),false);
drawHand1(canvas, c.Get(CalendarField.Second),false);
}
private void drawNumeral(Canvas canvas)
{
paint.TextSize=50;
foreach (var number in numbers)
{
string tmp = number.ToString();
paint.GetTextBounds( tmp, 0, tmp.Length, rect); //getTextBounds(tmp, 0, tmp.length(), rect);
double angle = Math.PI / 6 * (number - 3);
int x = (int)(w / 2 + Math.Cos(angle) * radius - rect.Width() / 2);
int y = (int)(h / 2 + Math.Sin(angle) * radius + rect.Height() / 2);
canvas.DrawText(tmp, x, y, paint);
}
}
private void drawHand1(Canvas canvas, double loc, bool isHour)
{
double angle = Math.PI * loc / 30 - Math.PI / 2;
int handRadius = isHour ? radius - handTruncation - hourHandTruncation : radius - handTruncation;
canvas.DrawLine(Width / 2, Height / 2,
(float)(Width / 2 + Math.Cos(angle) * handRadius),
(float)(Height / 2 + Math.Sin(angle) * handRadius),
paint);
}
}
You can use it in MainActivity.cs
RelativeLayout relativeLayout1 = FindViewById<RelativeLayout>
(Resource.Id.relativeLayout1);
relativeLayout1.SetBackgroundColor(Color.Black);
AddContentView(new PieView(this),new ViewGroup.LayoutParams(-1,-1));
I am graphically representing audio on x and y axis. From those y-axis points I want to generate audio again.
Followed https://github.com/billthefarmer/scope this to get points on y-axis. I have all of the values of y-axis points. These points can be used to represent a wave graphically.
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Path;
import android.util.AttributeSet;
import android.util.Log;
import android.view.MotionEvent;
import android.view.View;
import java.io.IOException;
import java.io.OutputStreamWriter;
import java.util.Locale;
// Scope
public class Scope extends View {
private int width;
private int height;
private Path path;
private Canvas cb;
private Paint paint;
private Bitmap bitmap;
private Bitmap graticule;
protected boolean storage;
protected boolean clear;
protected float step;
protected float scale;
protected float start;
protected float index;
protected float yscale;
protected boolean points;
protected MainActivity.Audio audio;
// Scope
public Scope(Context context, AttributeSet attrs) {
super(context, attrs);
// Create path and paint
path = new Path();
paint = new Paint();
}
// On size changed
#Override
protected void onSizeChanged(int w, int h, int oldw, int oldh) {
super.onSizeChanged(w, h, oldw, oldh);
// Get dimensions
width = w;
height = h;
// Create a bitmap for trace storage
bitmap = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888);
cb = new Canvas(bitmap);
// Create a bitmap for the graticule
graticule = Bitmap.createBitmap(width, height,
Bitmap.Config.ARGB_8888);
Canvas canvas = new Canvas(graticule);
// Black background
canvas.drawColor(Color.BLACK);
// Set up paint
paint.setStrokeWidth(2);
paint.setStyle(Paint.Style.STROKE);
paint.setColor(Color.argb(255, 0, 63, 0));
// Draw graticule
for (int i = 0; i < width; i += MainActivity.SIZE)
canvas.drawLine(i, 0, i, height, paint);
canvas.translate(0, height / 2);
for (int i = 0; i < height / 2; i += MainActivity.SIZE) {
canvas.drawLine(0, i, width, i, paint);
canvas.drawLine(0, -i, width, -i, paint);
}
// Draw the graticule on the bitmap
cb.drawBitmap(graticule, 0, 0, null);
cb.translate(0, height / 2);
}
private int max;
// On draw
#Override
protected void onDraw(Canvas canvas) {
// Check for data
if ((audio == null) || (audio.data == null)) {
canvas.drawBitmap(graticule, 0, 0, null);
return;
}
// Draw the graticule on the bitmap
if (!storage || clear) {
cb.drawBitmap(graticule, 0, -height / 2, null);
clear = false;
}
// Calculate x scale etc
float xscale = (float) (2.0 / ((audio.sample / 100000.0) * scale));
int xstart = Math.round(start);
int xstep = Math.round((float) 1.0 / xscale);
int xstop = Math.round(xstart + ((float) width / xscale));
if (xstop > audio.length)
xstop = (int) audio.length;
// Calculate y scale
if (max < 4096)
max = 4096;
yscale = (float) (max / (height / 2.0));
max = 0;
// Draw the trace
path.rewind();
path.moveTo(0, 0);
if (xscale < 1.0) {
for (int i = 0; i < xstop - xstart; i += xstep) {
if (max < Math.abs(audio.data[i + xstart]))
max = Math.abs(audio.data[i + xstart]);
float x = (float) i * xscale;
float y = -(float) audio.data[i + xstart] / yscale;
path.lineTo(x, y);
Log.d("y values", "y = " + String.valueOf(y)); // KING
writeToFile("y = " + String.valueOf(y), getContext());
}
} else {
for (int i = 0; i < xstop - xstart; i++) {
if (max < Math.abs(audio.data[i + xstart]))
max = Math.abs(audio.data[i + xstart]);
float x = (float) i * xscale;
float y = -(float) audio.data[i + xstart] / yscale;
path.lineTo(x, y);
Log.d("y values", "y = " + String.valueOf(y)); // KING
writeToFile("y = " + String.valueOf(y), getContext());
// Draw points at max resolution
if (points) {
path.addRect(x - 2, y - 2, x + 2, y + 2, Path.Direction.CW);
path.moveTo(x, y);
Log.d("y values", "y = " + String.valueOf(y)); // KING
writeToFile("y = " + String.valueOf(y), getContext());
}
}
}
// Green trace
paint.setColor(Color.GREEN);
paint.setAntiAlias(true);
cb.drawPath(path, paint);
// Draw index
if (index > 0 && index < width) {
// Yellow index
paint.setColor(Color.YELLOW);
paint.setAntiAlias(false);
cb.drawLine(index, -height / 2, index, height / 2, paint);
paint.setAntiAlias(true);
paint.setTextSize(height / 48);
paint.setTextAlign(Paint.Align.LEFT);
// Get value
int i = Math.round(index / xscale);
if (i + xstart < audio.length) {
float y = -audio.data[i + xstart] / yscale;
// Draw value
String s = String.format(Locale.getDefault(), "%3.2f",
audio.data[i + xstart] / 32768.0);
cb.drawText(s, index, y, paint);
}
paint.setTextAlign(Paint.Align.CENTER);
// Draw time value
if (scale < 100.0) {
String s = String.format(Locale.getDefault(),
(scale < 1.0) ? "%3.3f" :
(scale < 10.0) ? "%3.2f" : "%3.1f",
(start + (index * scale)) /
MainActivity.SMALL_SCALE);
cb.drawText(s, index, height / 2, paint);
// Log.d("y values", "y = " + String.valueOf(y));
} else {
String s = String.format(Locale.getDefault(), "%3.3f",
(start + (index * scale)) /
MainActivity.LARGE_SCALE);
cb.drawText(s, index, height / 2, paint);
}
}
canvas.drawBitmap(bitmap, 0, 0, null);
}
private void writeToFile(String data, Context context) {
try {
OutputStreamWriter outputStreamWriter = new OutputStreamWriter(context.openFileOutput("Sinusoids.txt", Context.MODE_PRIVATE));
outputStreamWriter.write(data);
outputStreamWriter.close();
} catch (IOException e) {
Log.e("Exception", "File write failed: " + e.toString());
}
}
// On touch event
#Override
public boolean onTouchEvent(MotionEvent event) {
float x = event.getX();
float y = event.getY();
// Set the index from the touch dimension
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN:
index = x;
break;
case MotionEvent.ACTION_MOVE:
index = x;
break;
case MotionEvent.ACTION_UP:
index = x;
break;
}
return true;
}
}
Generate byte array from y-axis points. The array can then be converted to sound.
I've managed to draw a staircase and also a smiley face (called Avatar in the code) using paths in my custom view. Id like to move the happy face up the stairs using my nextStep function. nextStep iterates the current step and then calls a function called moveToStep(int step) which offsets the Avatar to the location of the specified step. Lastly, nextStep calls this.invalidate so that onDraw gets called again in hopes that the Avatar is redrawn at the new offset. The problem is that after nextStep is called, the Avatar disappears even though the staircase still remains. I know its not offscreen because I checked the coordinates the smiley is offset to.
Custom View Code
public class StaircaseView extends View {
// setup initial color
private final int paint_color = Color.BLACK;
private int curr_step = 1;
int STEPS = 5;
private float avatar_radius;
// defines paint and canvas
private Paint DrawPaint;
private int view_width, view_height, view_size;
private Path StaircasePath, Avatar;
private float scale, side_length;
private char constrainer;
public StaircaseView(Context context, AttributeSet attrs) {
super(context, attrs);
setupPaint();
}
#Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
Log.d("StaircaseView", "onDraw called");
canvas.drawPath(StaircasePath, DrawPaint);
canvas.drawPath(Avatar, DrawPaint);
}
#Override
protected void onSizeChanged(int xNew, int yNew, int xOld, int yOld){
super.onSizeChanged(xNew, yNew, xOld, yOld);
view_height = yNew;
view_width = xNew;
view_size = Math.min(view_height, view_width);
if (view_width == view_size) {
constrainer = 'w';
} else {
constrainer = 'h';
}
scale = (float)view_size/100;
Log.i("StaircaseView", "onSizeChanged --> view width: " + String.valueOf(xNew) + ", view height: " + String.valueOf(yNew) + ", scale: " + String.valueOf(scale) + ", view size: " + String.valueOf(view_size));
float padding = 5 * scale;
StaircasePath = createStaircase(padding);
avatar_radius = 7*scale;
Avatar = createAvatar(0, 0, avatar_radius);
StaircasePath.offset(0, view_height);
moveToStep(curr_step);
}
public void nextStep() {
if (curr_step < STEPS) {
curr_step++;
} else {
curr_step = 1;
}
moveToStep(curr_step);
this.invalidate();
}
private void moveToStep(int step) {
float x = step * side_length - avatar_radius;
float y = view_height - (step - 1) * side_length - avatar_radius;
Log.i("StaircaseView", String.valueOf(x) + ", " + String.valueOf(y));
Avatar.offset(x, y);
}
// Setup paint with color and stroke styles
private void setupPaint() {
DrawPaint = new Paint();
DrawPaint.setColor(paint_color);
DrawPaint.setAntiAlias(true);
DrawPaint.setStrokeWidth(5);
DrawPaint.setStyle(Paint.Style.STROKE);
DrawPaint.setStrokeJoin(Paint.Join.ROUND);
DrawPaint.setStrokeCap(Paint.Cap.ROUND);
}
private Path createStaircase(float padding) {
if (constrainer == 'w') {
side_length = (view_size-padding)/(STEPS+1);
} else {
side_length = (view_size-padding)/STEPS;
}
Path path = new Path();
float curr_x = 0;
float curr_y = 0;
path.moveTo(curr_x, curr_y);
curr_x += side_length;
path.lineTo(curr_x, curr_y);
for(int i=0; i<STEPS; i++) {
curr_y -= side_length;
path.lineTo(curr_x, curr_y);
curr_x += side_length;
path.lineTo(curr_x, curr_y);
}
path.lineTo(curr_x, 0);
path.lineTo(0, 0);
return path;
}
private Path createShape(ArrayList<PointF> points) {
Path path = new Path();
path.moveTo(points.get(0).x, points.get(0).y);
for(int i=1; i< points.size(); i++) {
path.lineTo(points.get(i).x, points.get(i).y);
}
return path;
}
private Path createAvatar(int x, int y, float radius){
Path avatar = new Path();
float width = radius*2;
avatar.addCircle(x, y, radius, Path.Direction.CW);
avatar.addCircle(x - (radius /2), y - (radius / 5), radius/5, Path.Direction.CW);
avatar.addCircle(x + (radius / 2), y - (radius / 5), radius / 5, Path.Direction.CW);
avatar.addRect((float) x - (radius / 5), (float) y - (radius / 5), (float) x + (radius / 5), (float) y - (radius/5), Path.Direction.CCW);
return avatar;
}
}
After looking at this question decided to figure out another way to do this. So what I did was I changed my moveToStep method to return the coordinates to move the Avatar to instead of offsetting him. I then passed these coordinates to the createAvatar method as start coordinates. It worked after that.
New Code
/**
* Created by yako on 11/5/15.
*/
public class StaircaseView extends View {
// setup initial color
private final int paint_color = Color.BLACK;
private int curr_step = 1;
int STEPS = 5;
private float avatar_radius;
// defines paint and canvas
private Paint DrawPaint;
private int view_width, view_height, view_size;
private Path StaircasePath, Avatar;
private float scale, side_length;
private char constrainer;
public StaircaseView(Context context, AttributeSet attrs) {
super(context, attrs);
setupPaint();
}
#Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
Log.d("StaircaseView", "onDraw called");
canvas.drawPath(StaircasePath, DrawPaint);
canvas.drawPath(Avatar, DrawPaint);
}
#Override
protected void onSizeChanged(int xNew, int yNew, int xOld, int yOld){
super.onSizeChanged(xNew, yNew, xOld, yOld);
view_height = yNew;
view_width = xNew;
view_size = Math.min(view_height, view_width);
if (view_width == view_size) {
constrainer = 'w';
} else {
constrainer = 'h';
}
scale = (float)view_size/100;
Log.i("StaircaseView", "onSizeChanged --> view width: " + String.valueOf(xNew) + ", view height: " + String.valueOf(yNew) + ", scale: " + String.valueOf(scale) + ", view size: " + String.valueOf(view_size));
float padding = 5 * scale;
// Log.i("StaircaseView", String.valueOf(view_height/2 + padding/2));
StaircasePath = createStaircase(padding);
// Center the staircase in the view
// if (constrainer == 'w') {
// StaircasePath.offset(padding/2, view_height - (view_height - view_width - padding*2));
// } else {
// StaircasePath.offset(view_height/2 - padding/2, view_height-padding/2);
// }
avatar_radius = 7*scale;
Avatar = createAvatar(moveToStep(curr_step), avatar_radius);
StaircasePath.offset(0, view_height);
}
public void nextStep() {
if (curr_step <= STEPS) {
curr_step++;
} else {
curr_step = 1;
}
Avatar = createAvatar(moveToStep(curr_step), avatar_radius);
this.invalidate();
}
private float[] moveToStep(int step) {
float[] offset = new float[2];
offset[0] = step * side_length - avatar_radius;
offset[1] = view_height - (step - 1) * side_length - avatar_radius;
Log.i("StaircaseView", "Moving avatar to "+ String.valueOf(offset[0]) + ", " + String.valueOf(offset[1]));
return offset;
}
// Setup paint with color and stroke styles
private void setupPaint() {
DrawPaint = new Paint();
DrawPaint.setColor(paint_color);
DrawPaint.setAntiAlias(true);
DrawPaint.setStrokeWidth(5);
DrawPaint.setStyle(Paint.Style.STROKE);
DrawPaint.setStrokeJoin(Paint.Join.ROUND);
DrawPaint.setStrokeCap(Paint.Cap.ROUND);
}
private Path createStaircase(float padding) {
if (constrainer == 'w') {
side_length = (view_size-padding)/(STEPS+1);
} else {
side_length = (view_size-padding)/(STEPS+1);
}
Path path = new Path();
float curr_x = 0;
float curr_y = 0;
path.moveTo(curr_x, curr_y);
curr_x += side_length;
path.lineTo(curr_x, curr_y);
for(int i=0; i<STEPS; i++) {
curr_y -= side_length;
path.lineTo(curr_x, curr_y);
curr_x += side_length;
path.lineTo(curr_x, curr_y);
}
path.lineTo(curr_x, 0);
path.lineTo(0, 0);
return path;
}
private Path createShape(ArrayList<PointF> points) {
Path path = new Path();
path.moveTo(points.get(0).x, points.get(0).y);
for(int i=1; i< points.size(); i++) {
path.lineTo(points.get(i).x, points.get(i).y);
}
return path;
}
private Path createAvatar(float[] offset, float radius){
float x = offset[0];
float y = offset[1];
Path avatar = new Path();
float width = radius*2;
avatar.addCircle(x, y, radius, Path.Direction.CW);
avatar.addCircle(x - (radius /2), y - (radius / 5), radius/5, Path.Direction.CW);
avatar.addCircle(x + (radius / 2), y - (radius / 5), radius / 5, Path.Direction.CW);
avatar.addRect((float) x - (radius / 5), (float) y - (radius / 5), (float) x + (radius / 5), (float) y - (radius/5), Path.Direction.CCW);
return avatar;
}
}
I am currently trying to create a meter that can be adjusted in the percentage of fill. The problem I have is I'm not good at math at all. I want to start drawing an arc in the 'north' (first image), as opposed to a normal arc having its 0 deg point in the 'east' (as shown in second image).
I want to be able to increase the blue area in image 1 in size (angle) by dragging/touching it along the screen. Now these are things I am able to do in some kind of fashion now. The real problem I am facing is this:
I use the following code to draw the blue area:
mStart = -90;
int degree = (int)((theta + Math.PI) * 180 / Math.PI);
mSweep = degree;
RectF mOvals = new RectF(c.x - outerRadius + circleThickness, c.y - outerRadius + circleThickness, c.x + outerRadius - circleThickness, c.y + outerRadius - circleThickness );
mArcSetLevel = new Path();
if(mArcSetLevel != null ) {
canvas.drawArc(mOvals, mStart, mSweep, true, arcPaint);
}
Setting the start at -90 makes it start 90 deg earlier. To track the angle of the touch I use this formula, but this is where it goes wrong:
int py = (int)event.getY() - c.y;
int px = (int)event.getX() - c.x;
theta = (float) ((float) Math.atan2(py, px) - (Math.PI / 2)); // - Math.PI / 2 to correct -90 start
When I go further than exactly 270 degrees the blue area gets reset and draws itself from north to west in a much smaller angle (because of the 'false' start of -90, shown in third image). My math skills are simply not good enough for me to be able to solve this, although I can think of why it is happening I cannot seem to find the solution.
The (very messy) code to the entire view I made is as follows:
private Canvas canvas;
//Canvas width and height
private int h = -1;
private int w = -1;
//circle properties
private Paint paint;
private Paint arcPaint;
private Path circle;
private Point c;
private int outerRadius;
private int circleThickness = 20;
//point click in wheel
private float theta = 0;
private float mStart;
private float mSweep;
private Paint mBgPaints = new Paint();
private Path mArcSetLevel;
int padding = 10;
OnMeterWheelChangeListener onMeterWheelChangeListener = null;
public MeterWheel(Context context){
super(context);
initCircleSeekBar();
}
public MeterWheel(Context context, AttributeSet attrs) {
super(context, attrs);
initCircleSeekBar();
}
private void initCircleSeekBar() {
canvas = new Canvas();
circle = new Path();
paint = new Paint();
arcPaint = new Paint();
c = new Point();
mBgPaints.setAntiAlias(true);
mBgPaints.setStyle(Paint.Style.FILL);
mBgPaints.setColor(0x88FF0000);
mBgPaints.setStrokeWidth(0.5f);
mArcSetLevel = new Path();
this.draw(canvas);
}
#Override
protected void onSizeChanged(int width, int height, int oldw, int oldh) {
// TODO Auto-generated method stub
super.onSizeChanged(width, height, oldw, oldh);
w = width;
h = height;
Log.i("POWERWHEEL", String.valueOf(w) + " " + String.valueOf(h));
c.set(w/2, h/2);
drawCircle();
}
private void drawCircle() {
outerRadius = Math.min(h,w)/2;
circleThickness = (int) (outerRadius*0.15);
circle.addArc(new RectF(c.x - outerRadius + circleThickness/2, c.y - outerRadius + circleThickness/2, c.x + outerRadius - circleThickness/2, c.y + outerRadius - circleThickness/2 ), 0, 360);
circle.moveTo(c.x, c.y);
//paint.setShader(new SweepGradient(w/2,h/2, colourarry, null));
paint.setColor(Color.GRAY);
paint.setStyle(Style.STROKE);
paint.setStrokeWidth(circleThickness);
paint.setAntiAlias(true);
arcPaint.setColor(Color.BLUE);
arcPaint.setStyle(Style.FILL);
arcPaint.setStrokeWidth(circleThickness);
arcPaint.setAntiAlias(true);
}
#SuppressLint("DrawAllocation")
#Override
protected void onDraw(Canvas canvas) {
// TODO Auto-generated method stub
super.onDraw(canvas);
if(circle != null){
//draw circle
canvas.drawPath(circle, paint);
mStart = -90;
int degree = (int)((theta + Math.PI) * 180 / Math.PI);
Log.d("POWERWHEEL", "" + degree);
mSweep = degree;
RectF mOvals = new RectF(c.x - outerRadius + circleThickness, c.y - outerRadius + circleThickness, c.x + outerRadius - circleThickness, c.y + outerRadius - circleThickness );
mArcSetLevel = new Path();
if(mArcSetLevel != null ) {
canvas.drawArc(mOvals, mStart, mSweep, true, arcPaint);
}
}
}
#Override
public boolean onTouchEvent(MotionEvent event) {
if (!isEnabled()) {
return false;
}
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN:
setPressed(true);
onStartTrackingTouch(event);
trackTouchEvent(event);
break;
case MotionEvent.ACTION_MOVE:
trackTouchEvent(event);
break;
case MotionEvent.ACTION_UP:
trackTouchEvent(event);
onStopTrackingTouch();
setPressed(false);
invalidate();
break;
case MotionEvent.ACTION_CANCEL:
onStopTrackingTouch();
setPressed(false);
invalidate();
break;
}
return true;
}
#Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
int width = MeasureSpec.getSize(widthMeasureSpec);
int height = MeasureSpec.getSize(heightMeasureSpec);
setMeasuredDimension(width,height);
}
private void onStartTrackingTouch(MotionEvent event) {
}
private void onStopTrackingTouch() {
}
private void trackTouchEvent(MotionEvent event) {
int py = (int)event.getY() - c.y;
int px = (int)event.getX() - c.x;
theta = (float) ((float) Math.atan2(py, px) - (Math.PI / 2));
Log.d("POWERWHEEL", "theta: " + theta);
this.invalidate();
}
public void setSize(int x, int y){
h = y;
w = x;
}
public void setCirleThickness(int t){
circleThickness = t;
}
public void setOnMeterWheelChangeListener (OnMeterWheelChangeListener listener) {
onMeterWheelChangeListener = listener;
}
public interface OnMeterWheelChangeListener{
public void onStartTrackingTouch (MeterWheel colourWheel);
public void onStopTrackingTouch (MeterWheel colourWheel);
}
Thanks a million in advance!
When calculating theta, you use atan2 which returns the angle in +/- pi. So when being in the upper left quadrant it will return a value in the range -pi/2 to -pi (asuming y is positive downwards and x is positve rightwards). You substract pi/2 directly with gives a range of -pi to -3pi/2. In onDraw you then add pi again (confusing) giving a range of 0 to -pi/2 of the sweep for this quadrant. This means it will paint the arc 0 to pi/2 (or 0 to 90 degrees) counterclockwise from your starting position at the top. You must make sure your sweep always keeps in the range 0 to pi. Nicest solution is to shift the coordinates by -pi/2, so that instead of Math.atan2(py, px), you do Math.atan2(px, -py) and then if theta is negative you add 2*pi. Something like (I don't write android)
theta = (float) Math.atan2(px, -py);
if (theta < 0) theta += 2 * Math.PI;
and then in onDraw
int degree = (int)(theta * 180 / Math.PI);
Log.d("POWERWHEEL", "" + degree);
mSweep = degree;
If you are still experiencing problems check that mSweep is always in the range 0 to 360 degrees.
i was draw a pie chart using canvas in android and using the below code i draw a text on each slice of that pie chart (draw arc on path), now i want to draw the text length wise i.e. from center to end of the each slice,so how to rotate the arc using start and sweep angle.
p.addArc(mEventsRect, fStartAngle, fSweepAngle);
mBgPaints.setColor(iTextColor);
canvas.drawTextOnPath(sTextValue, p, fHOffSet, fVOffSet, mBgPaints);
You can try this snippet: (from: http://www.helloandroid.com/tutorials/how-use-canvas-your-android-apps-part-2)
int x = 75;
int y = 185;
paint.setColor(Color.GRAY);
paint.setTextSize(25);
String rotatedtext = "Rotated helloandroid :)";
//Draw bounding rect before rotating text:
Rect rect = new Rect();
paint.getTextBounds(rotatedtext, 0, rotatedtext.length(), rect);
canvas.translate(x, y);
paint.setStyle(Paint.Style.FILL);
canvas.drawText(rotatedtext , 0, 0, paint);
paint.setStyle(Paint.Style.STROKE);
canvas.drawRect(rect, paint);
canvas.translate(-x, -y);
paint.setColor(Color.RED);
canvas.rotate(-45, x + rect.exactCenterX(),y + rect.exactCenterY());
paint.setStyle(Paint.Style.FILL);
canvas.drawText(rotatedtext, x, y, paint);
A bit late to the party but I had to figure this one out and it's a bit simpler than what I found around. You'll already have the x and y for your text, use these to rotate the canvas
canvas.rotate(yourDegrees, x, y)
canvas.drawText(yourText, x, y, yourPaint)
canvas.rotate(-yourDegrees, x, y)
The negative sign negates the first rotation. You could swap it around to rotate in the opposite direction.
You could do this in a loop but the rotation cycle must be done each time either coordinate changes.
may be this will help you,,
here 39.5 is radius,, this will perfectly show result on mdpi screen
protected void onDraw(){
canvas.save();
PointF pf = PointOnCircle(35f, 45f, new PointF(39.5f, 39.5f));
canvas.rotate(-45, pf.x, pf.y);
canvas.drawText("67%", pf.x, pf.y, red);//23.5
canvas.restore();
canvas.save();
PointF pfa = PointOnCircle(35f, 135f, new PointF(39.5f, 39.5f));
canvas.rotate(45, pfa.x, pfa.y);
canvas.drawText("33%", pfa.x, pfa.y, red);//23.5
canvas.restore();
canvas.save();
pfa = PointOnCircle(27.5f, 225f, new PointF(39.5f, 39.5f));
canvas.rotate(-45, pfa.x, pfa.y);
canvas.drawText("45%", pfa.x, pfa.y, red);//23.5
canvas.restore();
canvas.save();
pfa = PointOnCircle(27.5f, 315f, new PointF(39.5f, 39.5f));
canvas.rotate(45, pfa.x, pfa.y);
canvas.drawText("55%", pfa.x, pfa.y, red);//23.5
canvas.restore();}
protected static final PointF PointOnCircle(float radius, float angleInDegrees, PointF origin) {
// Convert from degrees to radians via multiplication by PI/180
float x = (float) (radius * Math.cos(angleInDegrees * Math.PI / 180F)) + origin.x;
float y = (float) (radius * Math.sin(angleInDegrees * Math.PI / 180F)) + origin.y;
return new PointF(x, y);
}
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 your Layout:
<com.example.piecharts.PieChart
android:id="#+id/pieChart"
android:layout_width="match_parent"
android:layout_height="match_parent" >
</com.example.piecharts.PieChart>
This question is pretty old, but I figured I would write a general answer.Here I assume you want to draw your pie chart in the middle of the canvas and that you have your start and seep angles in an array.
x = canvas.getWidth/2 //Horizontal center of canvas view
y = canvas.getHeight/2 //Vertical center of canvas view
canvas.rotate(fStartAngle[i]+ fSweepAngle[i]/2, x ,y ); //Rotates canvas to a line in the middle
//of start and end of arc
canvas.translate(50f,0);//Moves the text a little out of the center of the circle (50f is arbitrary)
paintText.setStyle(Paint.Style.FILL);
canvas.drawText(rotatedtext, x, y, paintText);
//Undo the translations and rotations so that next arc can be drawn normally
canvas.translate(-50f,0);
canvas.rotate(-(temp+ value_degree[i]/2), x ,y );
it's 2023 there might be other answers out there but here is one that is sure to work
//the path where your text/paint will be drawn across
Path path = new Path();
path.addArc(mEventsRect, fStartAngle, fSweepAngle);//add this if you want your path to be drawn across the arc of your sector
//if you are using a text get the width
float textWidth = mTextPaint.measureText("text");
//this is the y co-ordinate your text will start from
int hOffset = 100;
//this is the x co-ordinate your text will start from
int vOffset = 100;
//we will be using the matrix to rotate the bunds of our current path
Matrix matrix = new Matrix();
//we will use this to get the bounds of our current path
RectF bounds = new RectF();
path.computeBounds(bounds,true);
//we are using the matrix to rotate the bound (with is the bound of the path) by 90 degrees
matrix.setRotate(90,bounds.centerX(),bounds.centerY());
the we transform the points in the path using the matrix
path.transform(matrix);
//you can now draw the text on the path
canvas.drawTextOnPath("text", path, hOffset, vOffset , mBgPaints);