效果如下：

理解：Xfermode的16总模式如图

第一步：

package com.rong.activity;import com.rong.test.R;import android.content.Context;
import android.graphics.Bitmap; import android.graphics.BitmapFactory; import android.graphics.Canvas; import android.graphics.Color; import android.graphics.Paint; import android.graphics.PorterDuff.Mode; import android.graphics.PorterDuffXfermode; import android.graphics.Rect; import android.graphics.RectF; import android.util.AttributeSet; import android.view.View; /**  * 改变图片颜色的自定义View  * @author 徐荣  *  */ public class ChangeImageColorView extends View { Paint mPaint; PorterDuffXfermode xfermode; Bitmap bitmap; int mBitWidth; int mBitHeight; int width; int height; Rect srcRect; Rect dstRect; RectF mRect; int i=0; public ChangeImageColorView(Context context, AttributeSet attrs) { super(context, attrs); initView(); } private void initView() { // 初始化画笔 mPaint = new Paint(); mPaint.setAntiAlias(true); mPaint.setColor(Color.BLUE); // 设置Xfermode xfermode = new PorterDuffXfermode(Mode.SRC_IN); // 获取图片源 bitmap = BitmapFactory.decodeResource(getResources(), R.drawable.robot); mBitWidth = bitmap.getWidth(); mBitHeight = bitmap.getHeight(); } @Override protected void onSizeChanged(int w, int h, int oldw, int oldh) { super.onSizeChanged(w, h, oldw, oldh); //获取控件的宽高 width = w; height = h; srcRect = new Rect(0, 0, width, height); dstRect = new Rect(0, 0, width, height); mRect = new RectF(0, 0, width, height); i=width; } @Override protected void onDraw(Canvas canvas) { super.onDraw(canvas); //相当于PS的新建图层 int num = canvas.saveLayer(0, 0, width, height, mPaint, Canvas.ALL_SAVE_FLAG); //绘制图片 canvas.drawBitmap(bitmap, srcRect, dstRect, mPaint); //设置图片混合模式 mPaint.setXfermode(xfermode); //绘制动态区域 canvas.drawRect(mRect, mPaint); //恢复混合模式 mPaint.setXfermode(null); //合并图层 canvas.restoreToCount(num); //更改区域的位置 i = i - 1; mRect.top = i; if (i == 0) { i = width; } //刷新UI,他会调用onDraw方法 invalidate(); } }

第二步

<?xml version="1.0" encoding="utf-8"?> <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"     android:id="@+id/main_touchlayout"     android:layout_width="match_parent"     android:layout_height="match_parent"     android:background="#ffffff"     android:orientation="vertical" >     <com.rong.activity.ChangeImageColorView         android:id="@+id/main_percentview"         android:layout_width="100dp"         android:layout_height="100dp"         android:layout_centerInParent="true" /> </RelativeLayout>