Develop Reference

How to increment arch length in custom view with OnClick?

I have a custom view(Circle) which is partly filled with arch(red color). Here is the picture https://gyazo.com/72e19cb97fd9f2adac2259c3855cf136.
I want to divide my custom view into sections, and when the button is clicked I draw an arch. 1 click 1/5 is covered with arch, 2nd click 2/5, etc...till 5.
How do I fill my view with red Arch when i press Increment button?(I don't understand the drawing part)
Here is what I have already tried - My CustomView class:
public class MySimpleView extends View {
private static final int PAINT_FLAGS = Paint.ANTI_ALIAS_FLAG | Paint.DITHER_FLAG;
private static final int STROKE_WIDTH = 40;
private static final int SECTIONS = 5;
private Paint basePaint, degreesPaint, centerPaint, rectPaint;
private RectF rect;
private int centerX, centerY, radius;
private int fullArchSliceLength;
private int colorArchLineLength;
public MySimpleView(Context context) {
super(context);
init();
}
public MySimpleView(Context context, AttributeSet attrs) {
super(context, attrs);
init();
}
public MySimpleView(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
init();
}
private void init() {
rectPaint = new Paint(PAINT_FLAGS);
rectPaint.setColor(ContextCompat.getColor(getContext(), R.color.white));
rectPaint.setStyle(Paint.Style.FILL);
centerPaint = new Paint(PAINT_FLAGS);
centerPaint.setColor(ContextCompat.getColor(getContext(), R.color.white));
centerPaint.setStyle(Paint.Style.FILL);
basePaint = new Paint(PAINT_FLAGS);
basePaint.setStyle(Paint.Style.STROKE);
basePaint.setStrokeWidth(STROKE_WIDTH);
basePaint.setColor(ContextCompat.getColor(getContext(), R.color.darkGrey));
degreesPaint = new Paint(PAINT_FLAGS);
degreesPaint.setStyle(Paint.Style.STROKE);
degreesPaint.setStrokeCap(Paint.Cap.ROUND);
degreesPaint.setStrokeJoin(Paint.Join.ROUND);
degreesPaint.setStrokeWidth(STROKE_WIDTH);
degreesPaint.setColor(Color.RED);
fullArchSliceLength = 360 / SECTIONS;
colorArchLineLength = fullArchSliceLength - 2;
}
public void swapColor() {
degreesPaint.setColor(degreesPaint.getColor() == Color.RED ? Color.GREEN :
Color.RED);
postInvalidate();
}
#Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
if (rect == null) {
centerX = getMeasuredWidth() / 2;
centerY = getMeasuredHeight() / 2;
radius = Math.min(centerX, centerY);
int startTop = STROKE_WIDTH / 2;
int startLeft = STROKE_WIDTH / 2;
int endBottom = 2 * radius - startTop;
int endRight = 2 * radius - startTop;
rect = new RectF(startTop, startLeft, endRight, endBottom);
}
canvas.drawRect(rect, rectPaint);
canvas.drawCircle(centerX, centerY, radius - STROKE_WIDTH / 2, basePaint);
// TODO: 2019-04-26 LOOK HERE
for (int i = 3; i < SECTIONS; i++) {
canvas.drawArc(rect, i * fullArchSliceLength,colorArchLineLength,
false, degreesPaint);
}
// TODO: 2019-04-26 LOOK HERE
// canvas.drawArc(rect, 0F, 90F, false, degreesPaint);
canvas.drawCircle(centerX, centerY, radius - STROKE_WIDTH, centerPaint);
}
}

public class MySimpleView extends View {
private static final int PAINT_FLAGS = Paint.ANTI_ALIAS_FLAG | Paint.DITHER_FLAG;
private static final int STROKE_WIDTH = 40;
private static final int SECTIONS = 5;
private Paint basePaint, degreesPaint, centerPaint, rectPaint;
private RectF rect;
private int centerX, centerY, radius;
private int fullArchSliceLength;
private int colorArchLineLength;
private int currentSections = 1;
public MySimpleView(Context context) {
super(context);
init();
}
public MySimpleView(Context context, AttributeSet attrs) {
super(context, attrs);
init();
}
public MySimpleView(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
init();
}
private void init() {
rectPaint = new Paint(PAINT_FLAGS);
rectPaint.setColor(ContextCompat.getColor(getContext(), R.color.white));
rectPaint.setStyle(Paint.Style.FILL);
centerPaint = new Paint(PAINT_FLAGS);
centerPaint.setColor(ContextCompat.getColor(getContext(), R.color.white));
centerPaint.setStyle(Paint.Style.FILL);
basePaint = new Paint(PAINT_FLAGS);
basePaint.setStyle(Paint.Style.STROKE);
basePaint.setStrokeWidth(STROKE_WIDTH);
basePaint.setColor(ContextCompat.getColor(getContext(), android.R.color.darker_gray));
degreesPaint = new Paint(PAINT_FLAGS);
degreesPaint.setStyle(Paint.Style.STROKE);
degreesPaint.setStrokeCap(Paint.Cap.ROUND);
degreesPaint.setStrokeJoin(Paint.Join.ROUND);
degreesPaint.setStrokeWidth(STROKE_WIDTH);
degreesPaint.setColor(Color.RED);
fullArchSliceLength = 360 / SECTIONS;
colorArchLineLength = fullArchSliceLength - 2;
}
//just a simple increment function
public void increment() {
if (currentSections < SECTIONS) {
currentSections++;
postInvalidate();
}
}
public void swapColor() {
degreesPaint.setColor(degreesPaint.getColor() == Color.RED ? Color.GREEN :
Color.RED);
postInvalidate();
}
#Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
if (rect == null) {
centerX = getMeasuredWidth() / 2;
centerY = getMeasuredHeight() / 2;
radius = Math.min(centerX, centerY);
int startTop = STROKE_WIDTH / 2;
int startLeft = STROKE_WIDTH / 2;
int endBottom = 2 * radius - startTop;
int endRight = 2 * radius - startTop;
rect = new RectF(startTop, startLeft, endRight, endBottom);
}
canvas.drawRect(rect, rectPaint);
canvas.drawCircle(centerX, centerY, radius - STROKE_WIDTH / 2, basePaint);
/*
startAngle is set to 270 so it will start at the top.
0 is right
90 bottom
180 left
270 top
*/
canvas.drawArc(rect, 270, currentSections * colorArchLineLength, false, degreesPaint);
canvas.drawCircle(centerX, centerY, radius - STROKE_WIDTH, centerPaint);
}
}
Basically your logic was a bit wrong. When calling drawArc the first parameter will be the startAngle of your line (meaning does the line start on top, left, right, bottom of the circle). I have written in comments what each degree corresponds to. The sweepAngle is how many degrees you are drawing (which you had already calculated correctly). Hope it works as you would expect it!

How to bring canvas on top of other views

I am using magnifier view for my application which is a library I got from here :
https://github.com/nomanr/android-image-magnifier
I have modified this class to extend FrameLayout (It was ImageView before) to work on my FrameLayout.
It's working well except the painted canvas view stays back of all the views which are added in that custom view.
How to bring that canvas on front of those added views?
Custom view class that i am using :
public class ImageMagnifier extends FrameLayout {
private PointF zoomPos;
private boolean zooming = false;
private Matrix matrix;
private Paint paint;
private Bitmap bitmap;
private BitmapShader shader;
private int sizeOfMagnifier = 300;
int cheight, cwidth;
Context con;
C c = C.getInstance();
public ImageMagnifier(Context context) {
super(context);
init();
con=context;
}
public ImageMagnifier(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
init();
con=context;
}
public ImageMagnifier(Context context, AttributeSet attrs) {
super(context, attrs);
init();
con=context;
}
private void init() {
zoomPos = new PointF(0, 0);
matrix = new Matrix();
paint = new Paint();
cwidth = c.Width * 109 / 1280;
cheight = cwidth * 134 / 109;
}
public void otherTouch(int x, int y) {
if (x > c.getwidth1(28) && x < c.getwidth1(921) && y > c.getheight1(135) && y < c.getheight1(560)) {
zoomPos.x = x - 10;
zoomPos.y = y - 75;
zooming = true;
this.invalidate();
} else {
RemoveMagnifire();
}
}
public void RemoveMagnifire() {
zooming = false;
this.invalidate();
}
#Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
if (!zooming) {
buildDrawingCache();
} else {
bitmap = getDrawingCache();
shader = new BitmapShader(bitmap, Shader.TileMode.CLAMP,Shader.TileMode.CLAMP);
paint.setShader(shader);
matrix.reset();
matrix.postScale(2f, 2f, zoomPos.x-10, zoomPos.y+60);
paint.getShader().setLocalMatrix(matrix);
int width = c.Width;
int height = c.Height;
float leftX = zoomPos.x - ((width * 100) / 1280);
float topY = zoomPos.y - ((height * 250) / 720);
float rightX = zoomPos.x + ((width * 100) / 1280);
float bottomY = zoomPos.y - ((height * 100) / 720);
canvas.drawRect(leftX , topY, rightX, bottomY, paint);
}
}
}

A ViewGroup draws its child Views in the dispatchDraw() method. We just need to move the magnifier drawing to after that happens.
The fix is simple. Move everything after the super call in onDraw() to after the super call in dispatchDraw().
...
#Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
// Removed
}
#Override
protected void dispatchDraw(Canvas canvas) {
super.dispatchDraw(canvas);
if (!zooming) {
buildDrawingCache();
}
else {
bitmap = getDrawingCache();
shader = new BitmapShader(bitmap, Shader.TileMode.CLAMP, Shader.TileMode.CLAMP);
paint.setShader(shader);
matrix.reset();
matrix.postScale(2f, 2f, zoomPos.x - 10, zoomPos.y + 60);
paint.getShader().setLocalMatrix(matrix);
int width = c.Width;
int height = c.Height;
float leftX = zoomPos.x - ((width * 100) / 1280);
float topY = zoomPos.y - ((height * 250) / 720);
float rightX = zoomPos.x + ((width * 100) / 1280);
float bottomY = zoomPos.y - ((height * 100) / 720);
canvas.drawRect(leftX , topY, rightX, bottomY, paint);
}
}
...
You can just remove the onDraw() override, if you no longer need it for anything else.

Custom Progress as Step - Android

I need to make something like this:
I'd try to draw this using Canvas.drawArc(...) but I failed.
Can anyone help me?

I created a view that can draw the shape that you want.
It starts by creating a path for one of the quarters, and rotating the canvas by 90 degrees to draw the path 4 times. The Paint used to draw the Path is determined by the progress / maxProgress.
I used a second path to denote the region of the canvas to clip out when drawing, so that there are empty spaces between the quarters.
Finally, the text can be drawn in the middle after restoring the canvas rotation and clipping.
public class CustomProgressView extends View {
private int progress;
private int maxProgress;
private float arcWidth;
private float arcPadding;
private Paint paintPositive;
private Paint paintNegative;
private Paint paintText;
private Path path;
private Path clipPath;
private ProgressListener listener;
public CustomProgressView(Context context) {
super(context);
init();
}
public CustomProgressView(Context context, AttributeSet attrs) {
super(context, attrs);
init();
}
public CustomProgressView(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
init();
}
private void init() {
arcWidth = TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, 25, getResources().getDisplayMetrics());
arcPadding = TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, 6, getResources().getDisplayMetrics());
paintPositive = new Paint();
paintPositive.setColor(Color.RED);
paintPositive.setStyle(Paint.Style.FILL_AND_STROKE);
paintPositive.setAntiAlias(true);
paintNegative = new Paint();
paintNegative.setColor(Color.BLUE);
paintPositive.setStyle(Paint.Style.FILL_AND_STROKE);
paintNegative.setAntiAlias(true);
paintText = new Paint();
paintText.setColor(Color.BLACK);
paintText.setTextSize(TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_SP, 24, getResources().getDisplayMetrics()));
progress = 0;
maxProgress = 10;
}
#Override
protected void onLayout(boolean changed, int left, int top, int right, int bottom) {
super.onLayout(changed, left, top, right, bottom);
float diameter = Math.min(getWidth(), getHeight());
RectF ovalOuter = new RectF(0, 0, diameter, diameter);
RectF ovalInner = new RectF(ovalOuter.left + arcWidth, ovalOuter.top + arcWidth, ovalOuter.right - arcWidth, ovalOuter.bottom - arcWidth);
path = new Path();
path.moveTo(ovalOuter.centerX(), ovalOuter.top);
path.addArc(ovalOuter, 270, 90);
path.lineTo(ovalInner.right, ovalInner.centerY());
path.addArc(ovalInner, 0, -90);
path.lineTo(ovalOuter.centerX(), ovalOuter.top);
clipPath = new Path();
clipPath.addRect(ovalOuter.left, ovalOuter.centerY() - arcPadding / 2, ovalOuter.right, ovalOuter.centerY() + arcPadding / 2, Path.Direction.CW);
clipPath.addRect(ovalOuter.centerX() - arcPadding / 2, ovalOuter.top, ovalOuter.centerX() + arcPadding / 2, ovalOuter.bottom, Path.Direction.CW);
}
#Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
float perc = (float) progress / (float) maxProgress;
int state = 0;
if (perc < 0.25) {
state = 1;
} else if (perc < 0.5) {
state = 2;
} else if (perc < 0.75) {
state = 3;
} else {
state = 4;
}
RectF bounds = new RectF();
path.computeBounds(bounds, true);
// Draw Circle
canvas.save();
// Clip padding
canvas.clipPath(clipPath, Region.Op.DIFFERENCE);
canvas.drawPath(path, state == 1 ? paintPositive : paintNegative);
canvas.rotate(90, bounds.left, bounds.bottom);
canvas.drawPath(path, state == 2 ? paintPositive : paintNegative);
canvas.rotate(90, bounds.left, bounds.bottom);
canvas.drawPath(path, state == 3 ? paintPositive : paintNegative);
canvas.rotate(90, bounds.left, bounds.bottom);
canvas.drawPath(path, state == 4 ? paintPositive : paintNegative);
canvas.restore();
// Draw Progress
String text = String.valueOf(progress);
Rect textBounds = new Rect();
paintText.getTextBounds(text, 0, text.length(), textBounds);
float x = bounds.left - textBounds.width() / 2;
float y = bounds.bottom + textBounds.height() / 2;
canvas.drawText(text, x, y, paintText);
}
public int getProgress() {
return progress;
}
public void setProgress(int progress) {
int oldProgress = this.progress;
this.progress = progress;
if (listener != null) {
listener.onProgressChanged(oldProgress, progress);
}
invalidate();
}
public int getMaxProgress() {
return maxProgress;
}
public void setMaxProgress(int maxProgress) {
this.maxProgress = maxProgress;
invalidate();
}
public ProgressListener getListener() {
return listener;
}
public void setListener(ProgressListener listener) {
this.listener = listener;
}
public interface ProgressListener {
void onProgressChanged(int oldProgress, int newProgress);
}
}

I can not draw a round edge at the progress bar

I create custom progress in my programm.
But i can't create Semi Circle parts. I want create parts similar progress which is selected in the pictire on the top box.
My code:
public class SemiCircleProgressBarView extends View {
private Path mClippingPath;
private float mPivotX;
private float mPivotY;
private Context context;
private float progress = 0.0f;
private float thickness;
public SemiCircleProgressBarView(Context context) {
super(context);
this.context = context;
initializeImage();
}
public SemiCircleProgressBarView(Context context, AttributeSet attrs) {
super(context, attrs);
this.context = context;
initializeImage();
}
private void initializeImage() {
mClippingPath = new Path();
mPivotX = 0;
mPivotY = 0;
}
public void setClipping(float progress) {
this.progress = progress;
mClippingPath.reset();
thickness = 0.25f * getHeight();
mClippingPath.setFillType(Path.FillType.INVERSE_WINDING);
mClippingPath.addCircle(0.5f * getWidth(), getHeight(), getHeight() - thickness, Path.Direction.CCW);
invalidate();
}
#Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
float angle = (progress * 180) / 100;
RectF oval = new RectF(mPivotX, mPivotY, mPivotX + getWidth(), mPivotY + 2.0f * getHeight());
Paint p = new Paint();
p.setColor(context.getResources().getColor(R.color.progress));
Paint pbg = new Paint();
pbg.setColor(context.getResources().getColor(R.color.progress_bg));
// Paint cr = new Paint();
// cr.setColor(Color.RED);
canvas.clipPath(mClippingPath);
canvas.drawArc(oval, 180, 360, true, pbg);
canvas.drawArc(oval, 180, angle, true, p);
// canvas.drawCircle(0.5f * thickness,getHeight(),30,cr);
double radAngle = Math.toRadians(angle);
float px = getWidth () - (float)Math.cos(radAngle) * ((float)getWidth() - thickness);
float py = getHeight() - (float)Math.sin(radAngle) * ((float)getHeight() - 0.5f * thickness);
canvas.drawCircle(0.5f * px, py, 0.5f * thickness, p);
}
}
part in the bottoms select rectangles will be simular progress on the top select rectangles

Customize a ProgressBar to become a Thermometer

How to customize a ProgressBar to look like a Thermometer ? with the possibility to change color.
My suggestion was to rotate the progressBar 90° to become vertical then have it overlay an image of an empty Thermometer but it's bad and messy solution.
I Think the best will be to either to extends View or ProgressBar class and customize the draw method but I have no idea how to draw Thermometer, any Help would be appreciated.

I created something like this for a project
package com.janslab.thermometer.widgets;
import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.RectF;
import android.util.AttributeSet;
import android.view.View;
import android.view.animation.AccelerateDecelerateInterpolator;
import android.widget.Scroller;
import com.janslab.thermometer.R;
public class DummyThermometer extends View {
private Paint mInnerCirclePaint;
private Paint mOuterCirclePaint;
private Paint mFirstOuterCirclePaint;
//thermometer arc paint
private Paint mFirstOuterArcPaint;
//thermometer lines paints
private Paint mInnerLinePaint;
private Paint mOuterLinePaint;
private Paint mFirstOuterLinePaint;
//thermometer radii
private int mOuterRadius;
private int mInnerRadius;
private int mFirstOuterRadius;
//thermometer colors
private int mThermometerColor = Color.rgb(200, 115, 205);
//circles and lines variables
private float mLastCellWidth;
private int mStageHeight;
private float mCellWidth;
private float mStartCenterY; //center of first cell
private float mEndCenterY; //center of last cell
private float mStageCenterX;
private float mXOffset;
private float mYOffset;
// I 1st Cell I 2nd Cell I 3rd Cell I
private static final int NUMBER_OF_CELLS = 3; //three cells in all ie.stageHeight divided into 3 equal cells
//animation variables
private float mIncrementalTempValue;
private boolean mIsAnimating;
private Animator mAnimator;
public DummyThermometer(Context context) {
this(context, null);
}
public DummyThermometer(Context context, AttributeSet attrs) {
this(context, attrs, 0);
}
public DummyThermometer(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
if (attrs != null) {
final TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.Thermometer, defStyle, 0);
mThermometerColor = a.getColor(R.styleable.Thermometer_therm_color, mThermometerColor);
a.recycle();
}
init();
}
private void init() {
mInnerCirclePaint = new Paint(Paint.ANTI_ALIAS_FLAG);
mInnerCirclePaint.setColor(mThermometerColor);
mInnerCirclePaint.setStyle(Paint.Style.FILL);
mInnerCirclePaint.setStrokeWidth(17f);
mOuterCirclePaint = new Paint(Paint.ANTI_ALIAS_FLAG);
mOuterCirclePaint.setColor(Color.WHITE);
mOuterCirclePaint.setStyle(Paint.Style.FILL);
mOuterCirclePaint.setStrokeWidth(32f);
mFirstOuterCirclePaint = new Paint(Paint.ANTI_ALIAS_FLAG);
mFirstOuterCirclePaint.setColor(mThermometerColor);
mFirstOuterCirclePaint.setStyle(Paint.Style.FILL);
mFirstOuterCirclePaint.setStrokeWidth(60f);
mFirstOuterArcPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
mFirstOuterArcPaint.setColor(mThermometerColor);
mFirstOuterArcPaint.setStyle(Paint.Style.STROKE);
mFirstOuterArcPaint.setStrokeWidth(30f);
mInnerLinePaint = new Paint(Paint.ANTI_ALIAS_FLAG);
mInnerLinePaint.setColor(mThermometerColor);
mInnerLinePaint.setStyle(Paint.Style.FILL);
mInnerLinePaint.setStrokeWidth(17f);
mOuterLinePaint = new Paint(Paint.ANTI_ALIAS_FLAG);
mOuterLinePaint.setColor(Color.WHITE);
mOuterLinePaint.setStyle(Paint.Style.FILL);
mFirstOuterLinePaint = new Paint(Paint.ANTI_ALIAS_FLAG);
mFirstOuterLinePaint.setColor(mThermometerColor);
mFirstOuterLinePaint.setStyle(Paint.Style.FILL);
}
#Override
protected void onSizeChanged(int w, int h, int oldw, int oldh) {
super.onSizeChanged(w, h, oldw, oldh);
mStageCenterX = getWidth() / 2;
mStageHeight = getHeight();
mCellWidth = mStageHeight / NUMBER_OF_CELLS;
//center of first cell
mStartCenterY = mCellWidth / 2;
//move to 3rd cell
mLastCellWidth = (NUMBER_OF_CELLS * mCellWidth);
//center of last(3rd) cell
mEndCenterY = mLastCellWidth - (mCellWidth / 2);
// mOuterRadius is 1/4 of mCellWidth
mOuterRadius = (int) (0.25 * mCellWidth);
mInnerRadius = (int) (0.656 * mOuterRadius);
mFirstOuterRadius = (int) (1.344 * mOuterRadius);
mFirstOuterLinePaint.setStrokeWidth(mFirstOuterRadius);
mOuterLinePaint.setStrokeWidth(mFirstOuterRadius / 2);
mFirstOuterArcPaint.setStrokeWidth(mFirstOuterRadius / 4);
mXOffset = mFirstOuterRadius / 4;
mXOffset = mXOffset / 2;
//get the d/f btn firstOuterLine and innerAnimatedline
mYOffset = (mStartCenterY + (float) 0.875 * mOuterRadius) - (mStartCenterY + mInnerRadius);
mYOffset = mYOffset / 2;
}
#Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
drawFirstOuterCircle(canvas);
drawOuterCircle(canvas);
drawInnerCircle(canvas);
drawFirstOuterLine(canvas);
drawOuterLine(canvas);
animateInnerLine(canvas);
drawFirstOuterCornerArc(canvas);
}
#Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
//take care of paddingTop and paddingBottom
int paddingY = getPaddingBottom() + getPaddingTop();
//get height and width
int width = MeasureSpec.getSize(widthMeasureSpec);
int height = MeasureSpec.getSize(heightMeasureSpec);
height += paddingY;
setMeasuredDimension(width, height);
}
private void drawInnerCircle(Canvas canvas) {
drawCircle(canvas, mInnerRadius, mInnerCirclePaint);
}
private void drawOuterCircle(Canvas canvas) {
drawCircle(canvas, mOuterRadius, mOuterCirclePaint);
}
private void drawFirstOuterCircle(Canvas canvas) {
drawCircle(canvas, mFirstOuterRadius, mFirstOuterCirclePaint);
}
private void drawCircle(Canvas canvas, float radius, Paint paint) {
canvas.drawCircle(mStageCenterX, mEndCenterY, radius, paint);
}
private void drawOuterLine(Canvas canvas) {
float startY = mEndCenterY - (float) (0.875 * mOuterRadius);
float stopY = mStartCenterY + (float) (0.875 * mOuterRadius);
drawLine(canvas, startY, stopY, mOuterLinePaint);
}
private void drawFirstOuterLine(Canvas canvas) {
float startY = mEndCenterY - (float) (0.875 * mFirstOuterRadius);
float stopY = mStartCenterY + (float) (0.875 * mOuterRadius);
drawLine(canvas, startY, stopY, mFirstOuterLinePaint);
}
private void drawLine(Canvas canvas, float startY, float stopY, Paint paint) {
canvas.drawLine(mStageCenterX, startY, mStageCenterX, stopY, paint);
}
//simulate temperature measurement for now
private void animateInnerLine(Canvas canvas) {
if (mAnimator == null)
measureTemperature();
if (!mIsAnimating) {
mIncrementalTempValue = mEndCenterY + (float) (0.875 * mInnerRadius);
mIsAnimating = true;
} else {
mIncrementalTempValue = mEndCenterY + (float) (0.875 * mInnerRadius) - mIncrementalTempValue;
}
if (mIncrementalTempValue > mStartCenterY + mInnerRadius) {
float startY = mEndCenterY + (float) (0.875 * mInnerRadius);
drawLine(canvas, startY, mIncrementalTempValue, mInnerCirclePaint);
} else {
float startY = mEndCenterY + (float) (0.875 * mInnerRadius);
float stopY = mStartCenterY + mInnerRadius;
drawLine(canvas, startY, stopY, mInnerCirclePaint);
mIsAnimating = false;
stopMeasurement();
}
}
private void drawFirstOuterCornerArc(Canvas canvas) {
float y = mStartCenterY - (float) (0.875 * mFirstOuterRadius);
RectF rectF = new RectF(mStageCenterX - mFirstOuterRadius / 2 + mXOffset, y + mFirstOuterRadius, mStageCenterX + mFirstOuterRadius / 2 - mXOffset, y + (2 * mFirstOuterRadius) + mYOffset);
canvas.drawArc(rectF, -180, 180, false, mFirstOuterArcPaint);
}
public void setThermometerColor(int thermometerColor) {
this.mThermometerColor = thermometerColor;
mInnerCirclePaint.setColor(mThermometerColor);
mFirstOuterCirclePaint.setColor(mThermometerColor);
mFirstOuterArcPaint.setColor(mThermometerColor);
mInnerLinePaint.setColor(mThermometerColor);
mFirstOuterLinePaint.setColor(mThermometerColor);
invalidate();
}
//simulate temperature measurement for now
private void measureTemperature() {
mAnimator = new Animator();
mAnimator.start();
}
private class Animator implements Runnable {
private Scroller mScroller;
private final static int ANIM_START_DELAY = 1000;
private final static int ANIM_DURATION = 4000;
private boolean mRestartAnimation = false;
public Animator() {
mScroller = new Scroller(getContext(), new AccelerateDecelerateInterpolator());
}
public void run() {
if (mAnimator != this)
return;
if (mRestartAnimation) {
int startY = (int) (mStartCenterY - (float) (0.875 * mInnerRadius));
int dy = (int) (mEndCenterY + mInnerRadius);
mScroller.startScroll(0, startY, 0, dy, ANIM_DURATION);
mRestartAnimation = false;
}
boolean isScrolling = mScroller.computeScrollOffset();
mIncrementalTempValue = mScroller.getCurrY();
if (isScrolling) {
invalidate();
post(this);
} else {
stop();
}
}
public void start() {
mRestartAnimation = true;
postDelayed(this, ANIM_START_DELAY);
}
public void stop() {
removeCallbacks(this);
mAnimator = null;
}
}
private void stopMeasurement() {
if (mAnimator != null)
mAnimator.stop();
}
#Override
protected void onAttachedToWindow() {
super.onAttachedToWindow();
measureTemperature();
}
#Override
protected void onDetachedFromWindow() {
stopMeasurement();
super.onDetachedFromWindow();
}
#Override
public void setVisibility(int visibility) {
super.setVisibility(visibility);
switch (visibility) {
case View.VISIBLE:
measureTemperature();
break;
default:
stopMeasurement();
break;
}
}
}
attrs.xml file
<?xml version="1.0" encoding="utf-8"?>
<resources>
<declare-styleable name="Thermometer">
<attr name="therm_color" format="color" />
</declare-styleable>
</resources>

First I would provide 2 setters, one for color and one for the temperature value, normalized from 0 ... 1, where 0 means no visible bar, and 1 means a fully visible bar.
public void setColor(int color) {
mColor = color;
invalidate(); // important, this triggers onDraw
}
public void setValue(float value) {
mValue = -(value - 1);
invalidate(); // important, this triggers onDraw
}
Notice for value, I reverse the value, since we draw the bar from bottom up, instead from top down. It makes sense in the canvas.drawRect method.
If your CustomView may have custom sizes, set your size of the progressBar (I refer to the inner bar as progressBar) in onSizeChanged, as this gets called when the View has changed it's size.
If it is a fixed size, you can just provide those values statically in an init function or the constructor.
#Override
protected void onSizeChanged(int w, int h, int oldw, int oldh) {
super.onSizeChanged(w, h, oldw, oldh);
mProgressRect = new Rect(
/*your bar left offset relative to base bitmap*/,
/*your bar top offset relative to base bitmap*/,
/*your bar total width*/,
/*your max bar height*/
);
}
Then in ondraw, take these values into account and draw accordingly.
First draw the Bitmap, depending on your selected color (I would provide the thermometer base as a Bitmap, as long as it does not have to be completely dynamically drawn (special requirements)
Then draw the progress bar, with an height based on mValue * totalHeight of the bar, using the color provided in the setter.
For example:
#Override
protected void onDraw(Canvas canvas) {
// draw your thermometer base, bitmap based on color value
canvas.drawBitmap( /*your base thermometer bitmap here*/ );
// draw the "progress"
canvas.drawRect(mProgressRect.left, mProgressRect.top + (mValue * mProgressRect.bottom - mProgressRect.top), mProgressRect.right, mProgressRect.bottom, mPaint);
}
Hope that helps.
P.S.:
If you want to have the thermometer base image also dynamically drawn, it's a slightly different story, it would involve creating a path first and draw it with a Paint object, instead of drawing the bitmap.
EDIT:
Even better, if you want a simple solution for the "roundness" of the bar, draw a line instead a rect.
Define a line paint object like this:
mPaint = new Paint();
mPaint.setStyle(Paint.Style.STROKE);
mPaint.setStrokeCap(Paint.Cap.ROUND);
mPaint.setStrokeWidth(20); // thickness of your bar
then in onDraw, instead drawRect:
// draw the "progress"
canvas.drawLine(mProgressRect.left, mProgressRect.top + (mValue * mProgressRect.bottom - mProgressRect.top), mProgressRect.left, mProgressRect.bottom, mPaint);
Be sure to adjust your mProgressRectaccordingly.