Question

I want to draw a stack which should raise from the bottom. For example the stack height is 400, from the height 10 it should grow till it reaches 400.

I want to do this using paint and canvas.

I don’t want to do it with image view/bitmap and scale animation.

Is it possible to do this with canvas and paint? if so how to achieve it?

Thanks in advance.

Answer 1

What ever you do with canvas, even if you try for loop or invalidate, sleep, after all its drawing the shape in single stretch. I found the result in following way. May be it would be helpful for someone else, so adding the code here.

import android.os.Bundle;
import android.os.CountDownTimer;
import android.app.Activity;
import android.graphics.Color;
import android.util.Log;
import android.view.Menu;

public class AndroidDraw extends Activity {

private DrawView drawView;
private int height = 300;

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



    CountDownTimer timer = new CountDownTimer(2000, 50) {

        @Override
        public void onTick(long millisUntilFinished) {

            height = height - 10;
            drawView = new DrawView(AndroidDraw.this, height);
            drawView.setBackgroundColor(Color.WHITE);
            setContentView(drawView);
        }

        @Override
        public void onFinish() {

        }
    };
    timer.start();
}

}




import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.view.View;

public class DrawView extends View {
Paint paint = new Paint();
private int height;

public DrawView(Context context, int height) {
    super(context); 
    this.height = height;
}

@Override
public void onDraw(Canvas canvas) {
paint.setColor(Color.RED);
    canvas.drawRect(30, height, 60, 300, paint );

}
}