实现图片缓慢展开功能

//要用到clipdrawble，xml功能如下，在drawble目录下新建，类型选择为clip（注意AS不会提示）
<?xml version="1.0" encoding="utf-8"?>
<clip xmlns:android="http://schemas.android.com/apk/res/android"
    android:drawable="@drawable/a"
    android:clipOrientation="horizontal"
    android:gravity="center">
</clip>


//IMG的XML

<ImageView
    android:id="@+id/img"
    android:src="@drawable/clip"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content" />






//JAVA代码如下

import android.graphics.drawable.ClipDrawable;
import android.os.Handler;
import android.os.Message;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.widget.ImageView;

public class MainActivity extends AppCompatActivity {
    private ImageView img;
    private ClipDrawable clip;
    private MyHandler handler;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        init();
    }

    private void init() {
        img = (ImageView) findViewById(R.id.img);
        clip=(ClipDrawable) img.getDrawable();
        handler=new MyHandler();
        MyThread thread=new MyThread();
        new Thread(thread).start();

    }
    private class MyThread implements Runnable{

    @Override
    public void run() {
        while(true){
            try {
                Message msg=handler.obtainMessage();
                msg.what=0x123;
                msg.sendToTarget();
                Thread.sleep(1000);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
    }
}
    private class MyHandler extends Handler{
        @Override
        public void handleMessage(Message msg) {
            super.handleMessage(msg);
            if(msg.what==0x123){
                clip.setLevel(clip.getLevel()+100);
            }
        }
    }
}