有个知识大家要注意：

Clip类型的图片默认裁剪级别为0，此时是全部裁剪，图片看不见；
当级别为10000时，不裁剪图片，图片全部可见

程序运行结果：第一张为初始界面，第二张为点击5次界面，第三张为点击10的界面

程序结构目录：

activity_main.xml

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent">
    
    
   <ImageView
       android:id="@+id/gril_img"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:background="@drawable/clip"
        android:contentDescription="@string/app_name"
        />
    
    <Button 
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="@string/Clip"
        android:onClick="change"
        android:layout_alignParentBottom="true"
        android:layout_centerHorizontal="true"
        android:layout_marginBottom="20dp"/>
</RelativeLayout>

clip.xml

<?xml version="1.0" encoding="utf-8"?>
<clip xmlns:android="http://schemas.android.com/apk/res/android" 
    android:drawable="@drawable/girl"
    android:clipOrientation="horizontal"
    android:gravity="left"
    >
</clip>

strings.xml

<?xml version="1.0" encoding="utf-8"?>
<resources>

    <string name="app_name">ClipDrawable</string>
    <string name="hello_world">Hello world!</string>
    <string name="action_settings">Settings</string>
	<string name="Clip">clip</string>
</resources>

MainActivity.java

package com.shen.clipdrawable;

import android.support.v7.app.ActionBarActivity;
import android.graphics.drawable.ClipDrawable;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.ImageView;

public class MainActivity extends ActionBarActivity {

	private ImageView imageView;

	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);
		// 获取Imageview控件
		imageView = (ImageView) findViewById(R.id.gril_img);
	}

	@Override
	public boolean onCreateOptionsMenu(Menu menu) {
		// Inflate the menu; this adds items to the action bar if it is present.
		getMenuInflater().inflate(R.menu.main, menu);
		return true;
	}

	@Override
	public boolean onOptionsItemSelected(MenuItem item) {
		// Handle action bar item clicks here. The action bar will
		// automatically handle clicks on the Home/Up button, so long
		// as you specify a parent activity in AndroidManifest.xml.
		int id = item.getItemId();
		if (id == R.id.action_settings) {
			return true;
		}
		return super.onOptionsItemSelected(item);
	}

	public void change(View v) {
		// 获得ClipDrawable对象
		ClipDrawable clipDrawable = (ClipDrawable) imageView.getBackground();
		// 设置裁剪级别，Clip类型的图片默认裁剪级别为0，此时是全部裁剪，图片看不见；
		// 当级别为10000时，不裁剪图片，图片全部可见
		// 当全部显示后，设置不可见
		if (10000 == clipDrawable.getLevel()) {
			clipDrawable.setLevel(0);
		}
		else {
			clipDrawable.setLevel(clipDrawable.getLevel() + 1000);
		}

	}
}

程序中用的资源图片：

源码下载

Andorid Clip 实现自定义进度条效果实例