android学习笔记34——ClipDrawable资源

ClipDrawable

ClipDrawable代表从其他位图上截取一个“图片片段”

在XML文件中定义ClipDrawable对象使用<clip.../>元素，该元素的语法为：

以上语法格式中可指定如下三个属性：

1.android:drawable:指定截取的源Drawable对象

2.android:clipOrientaton:指定截取方向，可设置水平或垂直截取

3.android:gravity:指定截取时的对齐方式

注：使用ClipDrawable对象是可调用setLevel(int levle)方法设置截取的区域大小，当level为0时，截取的图片片段为空；当level为10000时，截取整张图片。

实例如下：徐徐展开的风景

注意：实际开发中，可采用该种方式完成进度显示控制。

资源文件==》drawable文件夹下
<?xml version="1.0" encoding="utf-8"?>
<clip xmlns:android="http://schemas.android.com/apk/res/android"
    android:clipOrientation="horizontal"
    android:drawable="@drawable/people"
    android:gravity="center" >
 
</clip>
 
布局文件==》
<LinearLayout 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"
    android:orientation="vertical"
    tools:context=".MainActivity" >
 
     <ImageView  
        android:id="@+id/image" 
        android:layout_width="wrap_content" 
        android:layout_height="wrap_content" 
        android:src="@drawable/myclip" />  
 
</LinearLayout>
 
代码实现==》
package com.example.myclipdrawable;
 
import java.util.Timer;
import java.util.TimerTask;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.annotation.SuppressLint;
import android.app.Activity;
import android.graphics.drawable.ClipDrawable;
import android.view.Menu;
import android.widget.ImageView;
 
@SuppressLint("HandlerLeak")
public class MainActivity extends Activity
{
    @Override
    protected void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
 
        ImageView img = (ImageView) this.findViewById(R.id.image);
        final ClipDrawable drawable = (ClipDrawable) img.getDrawable();
        final Handler hanler = new Handler()
        {
            @Override
            public void handleMessage(Message msg)
            {
                if (msg.what == 1)
                {
                    int value=drawable.getLevel() + 200;
                    drawable.setLevel(value);
                }
            }
        };
 
        final Timer timer = new Timer();
        timer.schedule(new TimerTask()
        {
            @Override
            public void run()
            {
                Message msg = new Message();
                msg.what = 1;
                hanler.sendMessage(msg);
                // 取消定时器
                if (drawable.getLevel() >= 10000)
                {
                    timer.cancel();
                }
            }
        }, 0, 300);
    }
 
    @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;
    }
 
}