How to draw Bitmap fast in onDraw() method in canvas android

Question

I am trying to draw a marker on single tap method in android. when i draw the marker it will draw but it will take more time to draw i.e 30-40 milliseconds some times it tak

Answer 1

You should initialize all bitmaps in Constructor. Decoding bitmap takes a long time. You can use a HashMap (key, value) to store them. Then in onDraw, get the matched bitmap and draw it directly.

For example

public class MyView extends View{

    private HashMap mStore = new HashMap();
    public MyView(Context context) {
        super(context);
        // TODO Auto-generated constructor stub

        init();
    }

    @Override
    protected void onDraw(Canvas canvas) {
        // TODO Auto-generated method stub

        int caller = getIntent().getIntExtra("button", 0);
        Bitmap bmp = null;
        switch (caller) {
        case R.id.btMap:
            bmp = mStore.get(R.id.btMap);
            canvas.drawBitmap(bmp, screenPts.x, screenPts.y - 50, null);
            bmp.recycle();
            bmp = null;
            break;
        case R.id.imageButton1:
            bmp = mStore.get(R.id.imageButton1);
            canvas.drawBitmap(bmp, screenPts.x, screenPts.y - 50, null);
            bmp1.recycle();
            bmp1 = null;
            break;
        }

        super.onDraw(canvas);
    }

    public void init() {
        Bitmap bmp = BitmapFactory.decodeResource(getResources(),
                R.drawable.pin_annotation_darkblue);
        mStore.put(R.id.btMap, bmp);

        bmp = BitmapFactory.decodeResource(getResources(),
                R.drawable.pin_annotation_green);
        mStore.put(R.id.imageButton1, bmp);
    }
}

Here is what I've done based on your code. You have to check some duplicated resource IDs.

private ArrayList overlayItemList = new ArrayList();
private HashMap mStore = new HashMap();

public MyItemizedOverlay(Drawable pDefaultMarker,
        ResourceProxy pResourceProxy) {
    super(pDefaultMarker, pResourceProxy);

    Bitmap bmp = BitmapFactory.decodeResource(getResources(),
            R.drawable.pin_annotation_darkblue);
    mStore.put(R.id.btMap, bmp);
    bmp = BitmapFactory.decodeResource(getResources(),
            R.drawable.pin_annotation_green);
    mStore.put(R.id.imageButton1, bmp);
    bmp = BitmapFactory.decodeResource(getResources(),
            R.drawable.pin_annotation_bue);
    mStore.put(R.id.imageButton2, bmp);
    bmp = BitmapFactory.decodeResource(getResources(),
            R.drawable.pin_annotation_light); 
    mStore.put(R.id.imageButton3, bmp);
    bmp = BitmapFactory.decodeResource(getResources(),
            R.drawable.pin_annotation_light); // check it
    mStore.put(R.id.imageButton4, bmp);
    bmp = BitmapFactory.decodeResource(getResources(),
            R.drawable.pin_annotation_light); // check it
    mStore.put(R.id.imageButton5, bmp);
    bmp = BitmapFactory.decodeResource(getResources(),
            R.drawable.pin_annotation_light); // check it
    mStore.put(R.id.imageButton6, bmp);

}

@Override
public void draw(Canvas canvas, MapView mapView, boolean arg2) {
    super.draw(canvas, mapView, arg2);

    // ---translate the GeoPoint to screen pixels---
    Point screenPts = new Point();
    mapView.getProjection().toPixels(p, screenPts);

    // ---add the marker---
    if (count == 1) {
        int caller = getIntent().getIntExtra("button", 0);
        Bitmap bmp = null;

        switch (caller) {
        case R.id.btMap:
            bmp = mStore.get(R.id.btMap);
            canvas.drawBitmap(bmp, screenPts.x, screenPts.y - 50, null);
            bmp.recycle();
            break;
        case R.id.imageButton1:
            bmp = mStore.get(R.id.imageButton1);
            canvas.drawBitmap(bmp1, screenPts.x, screenPts.y - 50, null);
            bmp.recycle();
            break;
        case R.id.imageButton2:
            bmp = mStore.get(R.id.imageButton2);
            canvas.drawBitmap(bmp, screenPts.x, screenPts.y - 50, null);
            bmp.recycle();
            break;
        case R.id.imageButton3:
            bmp = mStore.get(R.id.imageButton3);
            canvas.drawBitmap(bmp, screenPts.x, screenPts.y - 50, null);
            bmp.recycle();
            break;
        case R.id.imageButton4:
            bmp = mStore.get(R.id.imageButton4);
            canvas.drawBitmap(bmp, screenPts.x, screenPts.y - 50, null);
            bmp.recycle();
            break;
        case R.id.imageButton5:
            bmp = mStore.get(R.id.imageButton5);
            canvas.drawBitmap(bmp, screenPts.x, screenPts.y - 50, null);
            bmp.recycle();
            break;
        case R.id.imageButton6:
            bmp = mStore.get(R.id.imageButton6);
            canvas.drawBitmap(bmp, screenPts.x, screenPts.y - 50, null);
            bmp.recycle();
            break;
        }
    }
    // Bitmap bmp = BitmapFactory.decodeResource(getResources(),
    // R.drawable.pin_annotation_green);
    // if (count == 1) {
    // canvas.drawBitmap(bmp, screenPts.x, screenPts.y - 50, null);
    // }
}