Question

I have this code that should move an object down but it stands still can someone say what is wrong??

First code

The view class were I display the object code.

import android.app.Activity;
import android.os.Bundle;

public class Game extends Activity {
    Play View;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        // TODO Auto-generated method stub
        super.onCreate(savedInstanceState);
        View = new Play(this);
        setContentView(View);   
    }
}

Secound code

This is the code were the object should move.

import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Color;
import android.view.View;


public class Play extends View  {

    int Y=0;
    Bitmap object;

    public Play(Context context) {
        super(context);
        // TODO Auto-generated constructor stub         object = BitmapFactory.decodeResource(getResources(), R.drawable.brid);
   }

    @Override
    protected void onDraw(Canvas canvas) {
        // TODO Auto-generated method stub
        super.onDraw(canvas);
        canvas.drawColor(Color.GRAY);
        canvas.drawBitmap(object, (canvas.getWidth()/2), Y, null);
        if (Y < canvas.getHeight()){
            Y +=10;
        }else {
            Y = 0;
        }
    }    

}

Answer 1

First off don’t call your Play object “View” since that refers to an Android class. Name it something like “playView”…

To answer your question, a View doesn’t redraw itself when the onDraw() completes. To make it do that you should call invalidate() at the end of onDraw().

To make the drawing smooth I would recommend putting this into a Thread and make a game loop to run the drawing. Look into SurfaceView as that is faster than drawing straight to a Canvas from a View.