click event on pie chart in android [closed]

Question

I have used to draw pie chart using canvas.. There are approximately 10 arcs in pie chart..i want to perform click event on each arc. Is there any way to do this? or any other way?

This is my pie chart view..

MyView.java

package android.piechart;
import java.util.ArrayList;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.RectF;
import android.util.AttributeSet;
import android.util.Log;
import android.view.View;

public class MyView extends View {

private Paint p;
private int startX;
private int startY;
private int radius;
private ArrayList<Integer> colors;
private ArrayList<Integer> values;

public MyView(Context context, AttributeSet attrs) {
    super(context, attrs);
    p = new Paint();
    p.setColor(Color.BLUE);
    p.setAntiAlias(true);

    colors = new ArrayList<Integer>();
    values = new ArrayList<Integer>();

    startX = 320 / 4;
    startY = 480 / 8;
    radius = 320 / 2;

    colors.add(Color.GREEN);
    colors.add(Color.CYAN);
    colors.add(Color.MAGENTA);
    colors.add(Color.BLUE);
    colors.add(Color.RED);

    values.add(0);
    values.add(1);
    values.add(3);
    values.add(0);
    values.add(2);

}

@Override
protected void onDraw(Canvas canvas) {
    super.onDraw(canvas);

    Log.e("", "onDraw() is called...");

    float offset = 0;
    float sum = 0;
    for (int a = 0; a < values.size(); a++) {
        sum += values.get(a);
    }

    float angle = (float) (360 / sum);

    Log.e("angle", "" + angle);

    RectF rectF = new RectF();
    rectF.set(getStartX(), getStartY(), getStartX() + getRadius(),
            getStartY() + getRadius());

    for (int i = 0; i < values.size(); i++) {

        p.setColor(colors.get(i));

        if (i == 0) {
            canvas.drawArc(rectF, 0, values.get(i) * angle, true, p);
        } else {
            canvas.drawArc(rectF, offset, values.get(i) * angle, true, p);
        }

        offset += (values.get(i) * angle);
    }

    canvas.save();
}

public int getStartX() {
    return startX;
}

public void setStartX(int startX) {
    this.startX = startX;
}

public int getStartY() {
    return startY;
}

public void setStartY(int startY) {
    this.startY = startY;
}

public int getRadius() {
    return radius;
}

public void setRadius(int radius) {
    this.radius = radius;
}

public ArrayList<Integer> getColors() {
    return colors;
}

public void setColors(ArrayList<Integer> colors) {
    this.colors = colors;
}

public ArrayList<Integer> getValues() {
    return values;
}

public void setValues(ArrayList<Integer> values) {
    this.values = values;
}
}

Thanks in advance..

Answer 1

I solved my question myself...

MyView.java

public class MyView extends View {

private Paint p;
private int startX;
private int startY;
private int radius;
private ArrayList<Integer> colors;
private ArrayList<Float> values;
Bitmap bitmap;
Context mContext;

public MyView(Context context, AttributeSet attrs) {
    super(context, attrs);

    mContext = context;

    p = new Paint();
    p.setAntiAlias(true);

    colors = new ArrayList<Integer>();
    values = new ArrayList<Float>();

    startX = 320 / 4;
    startY = 480 / 8;
    radius = 320 / 2;

    colors.add(Color.GREEN);
    colors.add(Color.CYAN);
    colors.add(Color.MAGENTA);
    colors.add(Color.BLUE);
    colors.add(Color.RED);

    values.add(5f);
    values.add(1f);
    values.add(3f);
    values.add(5f);
    values.add(2f);

}

@Override
protected void onDraw(Canvas canvas) {
    super.onDraw(canvas);
    bitmap = Bitmap.createBitmap(canvas.getWidth(), canvas.getHeight(),
            Bitmap.Config.ARGB_8888);

    Canvas c = new Canvas(bitmap);

    Log.e("", "onDraw() is called...");

    float offset = 0;
    float sum = 0;
    for (int a = 0; a < values.size(); a++) {
        sum += values.get(a);
    }

    float angle = (float) (360 / sum);

    Log.e("angle", "" + angle);

    RectF rectF = new RectF();
    rectF.set(getStartX(), getStartY(), getStartX() + getRadius(),
            getStartY() + getRadius());

    for (int i = 0; i < values.size(); i++) {

        p.setColor(colors.get(i));

        if (i == 0) {
            canvas.drawArc(rectF, 0, values.get(i) * angle, true, p);
            c.drawArc(rectF, 0, values.get(i) * angle, true, p);
        } else {
            canvas.drawArc(rectF, offset, values.get(i) * angle, true, p);
            c.drawArc(rectF, offset, values.get(i) * angle, true, p);
        }

        offset += (values.get(i) * angle);
    }

    canvas.save();

}

@Override
public boolean onTouchEvent(MotionEvent event) {

    int color = bitmap.getPixel((int) event.getX(), (int) event.getY());

    Log.e("", "" + color);

    if (colors.contains(color)) {
        Log.e("", "is matching");
        if (color == Color.RED) {
            Toast.makeText(mContext, "Is Red", Toast.LENGTH_SHORT).show();
        }

        if (color == Color.CYAN) {
            Toast.makeText(mContext, "Is Cyan", Toast.LENGTH_SHORT).show();
        }

        if (color == Color.MAGENTA) {
            Toast.makeText(mContext, "Is MAGENTA", Toast.LENGTH_SHORT)
                    .show();
        }
        if (color == Color.BLUE) {
            Toast.makeText(mContext, "Is BLUE", Toast.LENGTH_SHORT).show();
        }
        if (color == Color.GREEN) {
            Toast.makeText(mContext, "Is GREEN", Toast.LENGTH_SHORT).show();
        }
    }

    return super.onTouchEvent(event);
}

public int getStartX() {
    return startX;
}

public void setStartX(int startX) {
    this.startX = startX;
}

public int getStartY() {
    return startY;
}

public void setStartY(int startY) {
    this.startY = startY;
}

public int getRadius() {
    return radius;
}

public void setRadius(int radius) {
    this.radius = radius;
}

public ArrayList<Integer> getColors() {
    return colors;
}

public void setColors(ArrayList<Integer> colors) {
    this.colors = colors;
}

public ArrayList<Float> getValues() {
    return values;
}

public void setValues(ArrayList<Float> values) {
    this.values = values;
}

}

I hope it's useful to others...

piechart

Answer 2

If you've used a Canvas, you probably have a reference to its underlying Bitmap. You could use Bitmap.getPixel(int x, int y) and test the color it returns to decide which section the click was in.

Otherwise, you have to do the calculation manually to figure out which wedge contains the x,y coordinates of your click.