Android使用Xfermode图形渲染方法实现自定义圆形、圆角和椭圆ImageView

<ScrollView 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"
     >

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:gravity="center_horizontal"
        android:layout_marginTop="10dp"
        android:layout_marginBottom="55dp"
        android:orientation="vertical" >

        <com.czm.myroundimageview.XCRoundImageViewByXfermode
            android:id="@+id/cicleImageView"
            android:layout_width="150dp"
            android:layout_height="150dp"
            android:src="@drawable/img1" />

        <com.czm.myroundimageview.XCRoundImageViewByXfermode
            android:id="@+id/roundRectImageView"
            android:layout_width="125dp"
            android:layout_height="145dp"
            android:layout_marginTop="15dp"
            android:src="@drawable/img2" />

        <com.czm.myroundimageview.XCRoundImageViewByXfermode
            android:id="@+id/ovalImageView"
            android:layout_width="140dp"
            android:layout_height="184dp"
            android:layout_marginTop="15dp"
            android:src="@drawable/img3" />
    </LinearLayout>

</ScrollView>

package com.czm.myroundimageview;

import android.app.Activity;
import android.os.Bundle;

public class MainActivity extends Activity {

    private XCRoundImageViewByXfermode circleImageView;//圆形图片
    private XCRoundImageViewByXfermode roundRectImageView;//圆角矩形图片
    private XCRoundImageViewByXfermode ovalImageView;//椭圆图片
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        initViews();
    }
    /**
     * 初始化Views
     */
    private void initViews(){
        circleImageView = (XCRoundImageViewByXfermode)findViewById(R.id.cicleImageView);
        roundRectImageView = (XCRoundImageViewByXfermode)findViewById(R.id.roundRectImageView);
        ovalImageView = (XCRoundImageViewByXfermode)findViewById(R.id.ovalImageView);
       
        roundRectImageView.setType(XCRoundImageViewByXfermode.TYPE_ROUND);
        roundRectImageView.setRoundBorderRadius(100);
       
        ovalImageView.setType(XCRoundImageViewByXfermode.TYPE_OVAL);
        ovalImageView.setRoundBorderRadius(50);
       
    }

}

View mTarget=null;//保存捕获Touch事件处理的View
    public boolean dispatchTouchEvent(MotionEvent ev) {

        //....其他处理，在此不管
       
        if(ev.getAction()==KeyEvent.ACTION_DOWN){
            //每次Down事件，都置为Null

            if(!onInterceptTouchEvent()){
            mTarget=null;
            View[] views=getChildView();
            for(int i=0;i<views.length;i++){
                if(views[i].dispatchTouchEvent(ev))
                    mTarget=views[i];
                    return true;
            }
          }
        }
        //当子View没有捕获down事件时，ViewGroup自身处理。这里处理的Touch事件包含Down、Up和Move
        if(mTarget==null){
            return super.dispatchTouchEvent(ev);
        }
        //...其他处理，在此不管
        if(onInterceptTouchEvent()){

         //...其他处理，在此不管   
         }
//这一步在Action_Down中是不会执行到的，只有Move和UP才会执行到。
        return mTarget.dispatchTouchEvent(ev);

    }

@Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        // TODO Auto-generated method stub
        super.onMeasure(widthMeasureSpec, heightMeasureSpec);
        // 如果是绘制圆形，则强制宽高大小一致
        if (mType == TYPE_CIRCLE) {
            mWidth = Math.min(getMeasuredWidth(), getMeasuredHeight());
            mRadius = mWidth / 2;
            setMeasuredDimension(mWidth, mWidth);
        }

    }

/**
     * 设置BitmapShader
     */
    private void setBitmapShader() {
        Drawable drawable = getDrawable();
        if (null == drawable) {
            return;
        }
        Bitmap bitmap = drawableToBitmap(drawable);
        // 将bitmap作为着色器来创建一个BitmapShader
        mBitmapShader = new BitmapShader(bitmap, TileMode.CLAMP, TileMode.CLAMP);
        float scale = 1.0f;
        if (mType == TYPE_CIRCLE) {
            // 拿到bitmap宽或高的小值
            int bSize = Math.min(bitmap.getWidth(), bitmap.getHeight());
            scale = mWidth * 1.0f / bSize;

        } else if (mType == TYPE_ROUND || mType == TYPE_OVAL) {
            // 如果图片的宽或者高与view的宽高不匹配，计算出需要缩放的比例；缩放后的图片的宽高，一定要大于我们view的宽高；所以我们这里取大值；
            scale = Math.max(getWidth() * 1.0f / bitmap.getWidth(), getHeight() * 1.0f / bitmap.getHeight());
        }
        // shader的变换矩阵，我们这里主要用于放大或者缩小
        mMatrix.setScale(scale, scale);
        // 设置变换矩阵
        mBitmapShader.setLocalMatrix(mMatrix);
        mPaint.setShader(mBitmapShader);

    }

@Override
    protected void onDraw(Canvas canvas) {

        if (null == getDrawable()) {
            return;
        }
        setBitmapShader();
        if (mType == TYPE_CIRCLE) {
            canvas.drawCircle(mRadius, mRadius, mRadius, mPaint);
        } else if (mType == TYPE_ROUND) {
            mPaint.setColor(Color.RED);
            canvas.drawRoundRect(mRect, mRoundRadius, mRoundRadius, mPaint);
        }else if(mType == TYPE_OVAL){
            canvas.drawOval(mRect, mPaint);
        }
    }

<ScrollView 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"
    tools:context=".MainActivity" >

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:gravity="center_horizontal"
        android:layout_marginTop="5dp"
        android:layout_marginBottom="25dp"
        android:orientation="vertical" >

        <com.czm.viewdrawtest.XCRoundAndOvalImageView
            android:id="@+id/cicleImageView"
            android:layout_width="200dp"
            android:layout_height="200dp"
            android:src="@drawable/img1" />

        <com.czm.viewdrawtest.XCRoundAndOvalImageView
            android:id="@+id/roundRectImageView"
            android:layout_width="200dp"
            android:layout_height="240dp"
            android:layout_marginTop="5dp"
            android:src="@drawable/img2" />

        <com.czm.viewdrawtest.XCRoundAndOvalImageView
            android:id="@+id/ovalImageView"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginTop="5dp"
            android:src="@drawable/img3" />
    </LinearLayout>

</ScrollView>

package com.czm.viewdrawtest;

import android.app.Activity;
import android.os.Bundle;
import android.view.Window;
import android.view.WindowManager;
/**
 * 使用自定义ImageView
 * @author caizhiming
 *
 */
public class MainActivity extends Activity {

    private XCRoundAndOvalImageView circleImageView;//圆形图片
    private XCRoundAndOvalImageView roundRectImageView;//圆角矩形图片
    private XCRoundAndOvalImageView ovalImageView;//椭圆图片
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        //设置无标题 
        requestWindowFeature(Window.FEATURE_NO_TITLE); 
        //设置全屏 
        getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,  
                WindowManager.LayoutParams.FLAG_FULLSCREEN); 
        setContentView(R.layout.activity_main);
       
        initViews();
    }
    /**
     * 初始化Views
     */
    private void initViews(){
        circleImageView = (XCRoundAndOvalImageView)findViewById(R.id.cicleImageView);
        roundRectImageView = (XCRoundAndOvalImageView)findViewById(R.id.roundRectImageView);
        ovalImageView = (XCRoundAndOvalImageView)findViewById(R.id.ovalImageView);
       
        roundRectImageView.setType(XCRoundAndOvalImageView.TYPE_ROUND);
        roundRectImageView.setRoundRadius(100);
       
        ovalImageView.setType(XCRoundAndOvalImageView.TYPE_OVAL);
        ovalImageView.setRoundRadius(50);
       
    }
}