ImageView设置边框的两种方式

MainActivity如下:

package cc.testimageviewbounds;

import android.os.Bundle;
import android.app.Activity;
/**
 * Demo描述:
 * 给ImageView添加边框的两种实现方式
 * 
 * 方式一:
 * 利用自定义的shape-->即此处的imageviewboundshape.xml
 * 且为ImageView设置background,即代码:
 * android:background="@drawable/imageviewboundshape"
 * 
 * 方式二:
 * 自定义ImageView
 *
 */
public class MainActivity extends Activity {
	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.main);
	}
}

ImageViewSubClass如下:

package cc.testimageviewbounds;

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Rect;
import android.util.AttributeSet;
import android.widget.ImageView;

public class ImageViewSubClass extends ImageView {

	public ImageViewSubClass(Context context, AttributeSet attrs, int defStyle) {
		super(context, attrs, defStyle);
	}

	public ImageViewSubClass(Context context, AttributeSet attrs) {
		super(context, attrs);
	}

	public ImageViewSubClass(Context context) {
		super(context);
	}
	
	@Override
	protected void onDraw(Canvas canvas) {
		super.onDraw(canvas);
		
		//获取控件需要重新绘制的区域
		Rect rect=canvas.getClipBounds();
		rect.bottom--;
		rect.right--;
		Paint paint=new Paint();
		paint.setColor(Color.RED);
		paint.setStyle(Paint.Style.STROKE);
		paint.setStrokeWidth(3);
		canvas.drawRect(rect, paint);
	}
   
}

main.xml如下:

<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"
   >

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="给ImageView添加边框的两种方式"
        android:layout_centerHorizontal="true"
        android:layout_marginTop="65dip"
     />
    <ImageView 
        android:id="@+id/firstImageView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:src="@drawable/ic_launcher"
        android:layout_centerHorizontal="true"
        android:layout_marginTop="150dip"
        android:background="@drawable/imageviewboundshape"
        />
    <cc.testimageviewbounds.ImageViewSubClass
         android:id="@+id/secondImageView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:src="@drawable/ic_launcher"
        android:layout_centerHorizontal="true"
        android:layout_marginTop="250dip"
        />
    
</RelativeLayout>

imageviewboundshape.xml如下:

<?xml version="1.0" encoding="utf-8"?>
    <!-- 定义矩形rectangle -->
<shape xmlns:android="http://schemas.android.com/apk/res/android"
       android:shape="rectangle"  >
   
    <!-- 设置边框的大小和颜色 -->
    <stroke android:width="3dip" android:color="#ff0000" /> 
    
    <!-- 设置矩形内的颜色,此处为透明色 -->
    <solid android:color="@android:color/transparent"/>
    
    <!-- 定义圆角弧度 -->
    <corners
        android:bottomLeftRadius="4dp"
        android:bottomRightRadius="4dp"
        android:topLeftRadius="4dp"
        android:topRightRadius="4dp" 
    />
    
</shape>