CODEWITHSUNDEEP
androidcanvassurfaceviewondraw
Cyril Horad
Cyril Horad

Reputation: 1565

Android: onDraw is too slow

I'm building a game using Android 2.2. The main game Activity uses a custom SurfaceView:

class GameView extends SurfaceView

From what I understand, the onDraw() method requires its own Thread to be executed. That in mind, I am planning to add a background image in onDraw():

canvas.drawBitmap(wallpaper, 0, 0, paint);
paint = new Paint();

But when I execute the game, it becomes very slow. If I comment out the new Paint() line, the game speeds up.

Is there something I am doing wrong, or is there a solution to my problem? For example, is there a way to reduce the number of calls to onDraw()? Or add an XML attribute to my custom SurfaceView class?

Here's the code how I load the drawable images.


public Bitmap loadBitmap(String image) {
        Bitmap bitmap = null;

        try {
            int id = R.drawable.class.getField(image).getInt(new Integer(0));
            bitmap = BitmapFactory.decodeResource(context.getResources(), id);
//          bitmap = Bitmap.createBitmap(bitmap.getWidth(), bitmap.getHeight(), Bitmap.Config.RGB_565); 
        } catch(Exception ex) {
            Log.e("loadBitmap", ex.getMessage());
        }

        return bitmap;
    }

Here's the code of the onDraw method. Unfortunately, I can't post everything. 

paint.setColor(Color.BLACK);
canvas.drawRect(0, 0, getWidth(), getHeight(), paint);
canvas.drawBitmap(gameLevel.getBitmap(), 0, 0, paint);
// draw object(1) 320x25
// draw object(5) 50x50 each
// draw object(n) 15x15 each, estimate
// draw object(n) 50x50 each
// collision check, draw hit tile on the image sheet



// draw game information using canvas.drawText()
timeLine++;

Thanks in advance!

Upvotes: 4

Views: 5513

Answers (2)

Carlos Silva
Carlos Silva

Reputation: 544

If the problem is only the "paint = new Paint();" line, why don't you create the Paint object only once? When the class is first created and make it a Class variable. Then just use the object everytime you want.

Upvotes: 3

mibollma
mibollma

Reputation: 15108

You could try to load the background as RGB_565 instead of ARGB_8888 in case you haven't already. Otherwise there is not much you can do except switching to OpenGL

EDIT:

Options options = new Options();
options.inDither = false;
options.inJustDecodeBounds = false;
options.inSampleSize = 1;
options.mCancel = false;
options.inPreferredConfig = Config.RGB_565;

bitmap = BitmapFactory.decodeResource(context.getResources(), id, options);

If that doesn't help other reasons may be:

  • You drawing code is wrong
  • You scale the background when you draw it
  • You run it on an emulator

Upvotes: 1

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