问帧动画无限运行

EN

import android.app.Activity;
import android.graphics.drawable.AnimationDrawable;
import android.os.Bundle;
import android.widget.ImageView;
import de.vrallev.tutorial.dialer.R;

public class testanim extends Activity {
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        // TODO Auto-generated method stub
        super.onCreate(savedInstanceState);
        setContentView(R.layout.animtest);
        ImageView iv = (ImageView) findViewById(R.id.imageView1);
        iv.setImageBitmap(null);
        iv.setBackgroundResource(R.anim.animation);

        final AnimationDrawable mailAnimation = (AnimationDrawable) iv
                .getBackground();
        mailAnimation.isOneShot();
        mailAnimation.start();