Android动画Drawable Animation

Drawable Animation是逐帧动画，那么使用它之前必须先定义好各个帧。我们可以通过代码定义，也可以使用xml文件定义，一般使用后者。如下：

<?xml version="1.0" encoding="utf-8"?>
<animation-list xmlns:android="http://schemas.android.com/apk/res/android"
    android:oneshot="false">
    <item android:drawable="@drawable/icon_aboutus" android:duration="200" />
    <item android:drawable="@drawable/icon_join_menu" android:duration="200" />
    <item android:drawable="@drawable/icon_join_opinion" android:duration="200" />
</animation-list>

其中android:oneshot=“true”表示该动画只播放一次，等于false时则循环播放。<item/>标签定义各个帧显示的图片。显示顺序依照<item/>定义顺序。

再看主界面的activity:

public class MainActivity extends Activity {
    public ImageView iv_start;
    public ImageView iv_stop;
    public ImageView iv_animation;
    public AnimationDrawable drawableAnimation;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        iv_start = (ImageView) findViewById(R.id.iv_start);
        iv_stop = (ImageView) findViewById(R.id.iv_stop);
        iv_animation = (ImageView) findViewById(R.id.iv_animation);
        iv_start.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                startAnimation();
            }
        });
        iv_stop.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                stopAnimation();
            }
        });
        iv_animation.setBackgroundResource(R.drawable.animations);
        drawableAnimation = (AnimationDrawable) iv_animation.getBackground();
    }

    public void startAnimation(){
        drawableAnimation.start();
    }

    public void stopAnimation(){
        drawableAnimation.stop();
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        int id = item.getItemId();
        if (id == R.id.action_settings) {
            return true;
        }
        return super.onOptionsItemSelected(item);
    }
}