How to draw Arcs in Android using canvas?

This is a simple example showing how to draw Arcs in android, You can use this to create piecharts or someother similar thing you want.

Here we have 3 classes.
1. GraphicsActivity.java
2. MainActivity.java
3. PictureLayout.java

GraphicsActivity.java

package com.coderzheaven.arcdrawing;

import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.view.ViewGroup;

class GraphicsActivity extends Activity {
    // set to true to test Picture
    private static final boolean TEST_PICTURE = false;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
    }

    @Override
    public void setContentView(View view) {
        if (TEST_PICTURE) {
            ViewGroup vg = new PictureLayout(this);
            vg.addView(view);
            view = vg;
        }

        super.setContentView(view);
    }
}

PictureLayout.java

package com.coderzheaven.arcdrawing;

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Picture;
import android.graphics.Rect;
import android.graphics.drawable.Drawable;
import android.util.AttributeSet;
import android.view.View;
import android.view.ViewGroup;
import android.view.ViewParent;

public class PictureLayout extends ViewGroup {
    private final Picture mPicture = new Picture();

    public PictureLayout(Context context) {
        super(context);
    }

    public PictureLayout(Context context, AttributeSet attrs) {
        super(context, attrs);
    }

    @Override
    public void addView(View child) {
        if (getChildCount() > 1) {
            throw new IllegalStateException("PictureLayout can host only one direct child");
        }

        super.addView(child);
    }

    @Override
    public void addView(View child, int index) {
        if (getChildCount() > 1) {
            throw new IllegalStateException("PictureLayout can host only one direct child");
        }

        super.addView(child, index);
    }

    @Override
    public void addView(View child, LayoutParams params) {
        if (getChildCount() > 1) {
            throw new IllegalStateException("PictureLayout can host only one direct child");
        }

        super.addView(child, params);
    }

    @Override
    public void addView(View child, int index, LayoutParams params) {
        if (getChildCount() > 1) {
            throw new IllegalStateException("PictureLayout can host only one direct child");
        }

        super.addView(child, index, params);
    }

    @Override
    protected LayoutParams generateDefaultLayoutParams() {
        return new LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT);
    }

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        final int count = getChildCount();

        int maxHeight = 0;
        int maxWidth = 0;

        for (int i = 0; i < count; i++) {
            final View child = getChildAt(i);
            if (child.getVisibility() != GONE) {
                measureChild(child, widthMeasureSpec, heightMeasureSpec);
            }
        }

        maxWidth += getPaddingLeft() + getPaddingRight();
        maxHeight += getPaddingTop() + getPaddingBottom();

        Drawable drawable = getBackground();
        if (drawable != null) {
            maxHeight = Math.max(maxHeight, drawable.getMinimumHeight());
            maxWidth = Math.max(maxWidth, drawable.getMinimumWidth());
        }

        setMeasuredDimension(resolveSize(maxWidth, widthMeasureSpec),
                resolveSize(maxHeight, heightMeasureSpec));
    }

    private void drawPict(Canvas canvas, int x, int y, int w, int h,
                          float sx, float sy) {
        canvas.save();
        canvas.translate(x, y);
        canvas.clipRect(0, 0, w, h);
        canvas.scale(0.5f, 0.5f);
        canvas.scale(sx, sy, w, h);
        canvas.drawPicture(mPicture);
        canvas.restore();
    }

    @Override
    protected void dispatchDraw(Canvas canvas) {
        super.dispatchDraw(mPicture.beginRecording(getWidth(), getHeight()));
        mPicture.endRecording();

        int x = getWidth()/2;
        int y = getHeight()/2;

        if (false) {
            canvas.drawPicture(mPicture);
        } else {
            drawPict(canvas, 0, 0, x, y,  1,  1);
            drawPict(canvas, x, 0, x, y, -1,  1);
            drawPict(canvas, 0, y, x, y,  1, -1);
            drawPict(canvas, x, y, x, y, -1, -1);
        }
    }

    @Override
    public ViewParent invalidateChildInParent(int[] location, Rect dirty) {
        location[0] = getLeft();
        location[1] = getTop();
        dirty.set(0, 0, getWidth(), getHeight());
        return getParent();
    }

    @Override
    protected void onLayout(boolean changed, int l, int t, int r, int b) {
        final int count = super.getChildCount();

        for (int i = 0; i < count; i++) {
            final View child = getChildAt(i);
            if (child.getVisibility() != GONE) {
                final int childLeft = getPaddingLeft();
                final int childTop = getPaddingTop();
                child.layout(childLeft, childTop,
                        childLeft + child.getMeasuredWidth(),
                        childTop + child.getMeasuredHeight());

            }
        }
    }
}

MainActivity.java

package com.coderzheaven.arcdrawing;

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Paint.Style;
import android.graphics.RectF;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.LinearLayout;

public class MainActivity extends GraphicsActivity implements OnClickListener {

	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);

		Button b1 = (Button) findViewById(R.id.button1);
		Button b2 = (Button) findViewById(R.id.button2);
		Button b3 = (Button) findViewById(R.id.button3);
		b1.setOnClickListener(this);
		b2.setOnClickListener(this);
		b3.setOnClickListener(this);
	}

	@Override
	public void onClick(View v) {
		int id = v.getId();
		Style sytle = null;
		boolean use_centre = false;
		final LinearLayout r1 = (LinearLayout) findViewById(R.id.l1);
		if (MainActivity.this.findViewById(1) != null)
			r1.removeView(MainActivity.this.findViewById(1));
		switch (id) {
		case R.id.button1:
			use_centre = true;
			sytle = Paint.Style.FILL;
			break;
		case R.id.button2:
			use_centre = false;
			sytle = Paint.Style.STROKE;
			break;
		case R.id.button3:
			use_centre = true;
			sytle = Paint.Style.STROKE;
			break;
		default:
			break;

		}
		SampleView s = new SampleView(MainActivity.this);
		s.setId(1);
		s.startDraw(sytle, use_centre);
		r1.addView(s);
	}

	private static class SampleView extends View {
		private Paint mPaint;
		private Paint mFramePaint;
		private RectF mBigOval;
		private float mStart;
		private float mSweep;
		private boolean use_centre = false;
		private static final float SWEEP_INC = 0.5f;
		private static final float START_INC = 15;

		public SampleView(Context context) {
			super(context);
			mPaint = new Paint();
			mPaint.setAntiAlias(true);
			mPaint.setColor(0x880000FF);
			mPaint.setStrokeWidth(4);

			mBigOval = new RectF(40, 10, 280, 250);

			mFramePaint = new Paint();
			mFramePaint.setAntiAlias(true);
			mFramePaint.setStrokeWidth(4);
		}

		public void startDraw(Style style, boolean use_centre) {
			this.use_centre = use_centre;
			mPaint.setStyle(style);
			mFramePaint.setStyle(style);
		}

		private void drawArcs(Canvas canvas, RectF oval, boolean useCenter,
				Paint paint) {
			// canvas.drawRect(oval, mFramePaint);
			canvas.drawArc(oval, mStart, mSweep, useCenter, paint);
		}

		@Override
		protected void onDraw(Canvas canvas) {
			canvas.drawColor(Color.WHITE);

			drawArcs(canvas, mBigOval, use_centre, mPaint);

			mSweep += SWEEP_INC;
			if (mSweep > 360) {
				mSweep -= 360;
				mStart += START_INC;
				if (mStart >= 360) {
					mStart -= 360;
				}
			}
			invalidate();
		}
	}
}

Download the complete source code from here.