大家好,這一節給大家分享的是Android中幾種圖像特效處理的小技巧,比如圓角,倒影,還有就是圖片縮放,Drawable轉化為Bitmap,Bitmap轉化為Drawable等等. 廢話少說了,直接講解今天的實例,本例主要是先獲取壁紙(getWallpaper()),然后對當前壁紙的一些特效處理.大家按步驟一步一步來: 第一步:新建一個Android工程命名為ImageDemo,工程結構如下:  第二步:新建一個.java文件,命名為ImageUtil.java,在里面定義一些圖片處理方法,代碼如下: ~~~ package com.android.tutor;import android.graphics.Bitmap;import android.graphics.Canvas;import android.graphics.LinearGradient;import android.graphics.Matrix;import android.graphics.Paint;import android.graphics.PixelFormat;import android.graphics.PorterDuffXfermode;import android.graphics.Rect;import android.graphics.RectF;import android.graphics.Bitmap.Config;import android.graphics.PorterDuff.Mode;import android.graphics.Shader.TileMode;import android.graphics.drawable.Drawable;public class ImageUtil { //放大縮小圖片 public static Bitmap zoomBitmap(Bitmap bitmap,int w,int h){ int width = bitmap.getWidth(); int height = bitmap.getHeight(); Matrix matrix = new Matrix(); float scaleWidht = ((float)w / width); float scaleHeight = ((float)h / height); matrix.postScale(scaleWidht, scaleHeight); Bitmap newbmp = Bitmap.createBitmap(bitmap, 0, 0, width, height, matrix, true); return newbmp; } //將Drawable轉化為Bitmap public static Bitmap drawableToBitmap(Drawable drawable){ int width = drawable.getIntrinsicWidth(); int height = drawable.getIntrinsicHeight(); Bitmap bitmap = Bitmap.createBitmap(width, height, drawable.getOpacity() != PixelFormat.OPAQUE ? Bitmap.Config.ARGB_8888 : Bitmap.Config.RGB_565); Canvas canvas = new Canvas(bitmap); drawable.setBounds(0,0,width,height); drawable.draw(canvas); return bitmap; } //獲得圓角圖片的方法 public static Bitmap getRoundedCornerBitmap(Bitmap bitmap,float roundPx){ Bitmap output = Bitmap.createBitmap(bitmap.getWidth(), bitmap .getHeight(), Config.ARGB_8888); Canvas canvas = new Canvas(output); final int color = 0xff424242; final Paint paint = new Paint(); final Rect rect = new Rect(0, 0, bitmap.getWidth(), bitmap.getHeight()); final RectF rectF = new RectF(rect); paint.setAntiAlias(true); canvas.drawARGB(0, 0, 0, 0); paint.setColor(color); canvas.drawRoundRect(rectF, roundPx, roundPx, paint); paint.setXfermode(new PorterDuffXfermode(Mode.SRC_IN)); canvas.drawBitmap(bitmap, rect, rect, paint); return output; } //獲得帶倒影的圖片方法 public static Bitmap createReflectionImageWithOrigin(Bitmap bitmap){ final int reflectionGap = 4; int width = bitmap.getWidth(); int height = bitmap.getHeight(); Matrix matrix = new Matrix(); matrix.preScale(1, -1); Bitmap reflectionImage = Bitmap.createBitmap(bitmap, 0, height/2, width, height/2, matrix, false); Bitmap bitmapWithReflection = Bitmap.createBitmap(width, (height + height/2), Config.ARGB_8888); Canvas canvas = new Canvas(bitmapWithReflection); canvas.drawBitmap(bitmap, 0, 0, null); Paint deafalutPaint = new Paint(); canvas.drawRect(0, height,width,height + reflectionGap, deafalutPaint); canvas.drawBitmap(reflectionImage, 0, height + reflectionGap, null); Paint paint = new Paint(); LinearGradient shader = new LinearGradient(0, bitmap.getHeight(), 0, bitmapWithReflection.getHeight() + reflectionGap, 0x70ffffff, 0x00ffffff, TileMode.CLAMP); paint.setShader(shader); // Set the Transfer mode to be porter duff and destination in paint.setXfermode(new PorterDuffXfermode(Mode.DST_IN)); // Draw a rectangle using the paint with our linear gradient canvas.drawRect(0, height, width, bitmapWithReflection.getHeight() + reflectionGap, paint); return bitmapWithReflection; } } ~~~ 第三步:修改main.xml布局文件,主要放了兩個ImageView控件,代碼如下: ~~~ <?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:orientation="vertical" android:layout_width="fill_parent" android:layout_height="fill_parent" > <ImageView android:id="@+id/image01" android:layout_width="wrap_content" android:layout_height="wrap_content" android:padding="10px" /> <ImageView android:id="@+id/image02" android:layout_width="wrap_content" android:layout_height="wrap_content" android:padding="10px" /></LinearLayout> ~~~ 第四步:修改主核心程序,ImageDemo.java,代碼如下: ~~~ package com.android.tutor;import android.app.Activity;import android.graphics.Bitmap;import android.graphics.drawable.Drawable;import android.os.Bundle;import android.widget.ImageView;public class Imagedemo extends Activity { private ImageView mImageView01,mImageView02; public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); setupViews(); } private void setupViews(){ mImageView01 = (ImageView)findViewById(R.id.image01); mImageView02 = (ImageView)findViewById(R.id.image02); //獲取壁紙返回值是Drawable Drawable drawable = getWallpaper(); //將Drawable轉化為Bitmap Bitmap bitmap = ImageUtil.drawableToBitmap(drawable); //縮放圖片 Bitmap zoomBitmap = ImageUtil.zoomBitmap(bitmap, 100, 100); //獲取圓角圖片 Bitmap roundBitmap = ImageUtil.getRoundedCornerBitmap(zoomBitmap, 10.0f); //獲取倒影圖片 Bitmap reflectBitmap = ImageUtil.createReflectionImageWithOrigin(zoomBitmap); //這里可以讓Bitmap再轉化為Drawable// Drawable roundDrawable = new BitmapDrawable(roundBitmap); // Drawable reflectDrawable = new BitmapDrawable(reflectBitmap); // mImageView01.setBackgroundDrawable(roundDrawable);// mImageView02.setBackgroundDrawable(reflectDrawable); mImageView01.setImageBitmap(roundBitmap); mImageView02.setImageBitmap(reflectBitmap); } } ~~~ 第五步:運行上述工程,查看效果如下:  ? OK大功告成了!! ? 本文參考文獻:http://wiki.impjq.net/doku.php?id=code:android-code:image-convert&rev=1275640889&mddo=print