Question

I’m making a simple painting app, and it’s my first time using the canvas. I already have the SurfaceView in my layout xml, and the id is correct. Anyways, here is my code:

package com.example.paint;

import android.app.Activity;
import android.graphics.Canvas;
import android.os.Bundle;
import android.view.SurfaceHolder;
import android.view.SurfaceView;

public class Paint extends Activity {
/** Called when the activity is first created. */

SurfaceView v;
SurfaceHolder holder;
Canvas c;

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);

    v = (SurfaceView) findViewById(R.id.svDraw);
    holder = v.getHolder();

    while (true) {
        try {
            Thread.sleep(1000);
        } catch (InterruptedException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }

        if (!holder.getSurface().isValid())
            continue;

        c = holder.lockCanvas();
        c.drawARGB(255, 0, 255, 0);
        holder.unlockCanvasAndPost(c);
    }
}
}

Thanks.

Answer 1

You need to remove the while(true), its an infinite loop that prevents anything from happening.

The drawing code belongs in the onDraw method of your View that contains your canvas object