android图片处理方法（转） / 憋错料

//压缩图片大小
public static Bitmap compressImage(Bitmap image) {
ByteArrayOutputStream baos = new ByteArrayOutputStream();
image.compress(Bitmap.CompressFormat.JPEG, 100, baos);//质量压缩方法，这里100表示不压缩，把压缩后的数据存放到baos中
int options = 100;
while ( baos.toByteArray().length / 1024>100) { //循环判断如果压缩后图片是否大于100kb,大于继续压缩
baos.reset();//重置baos即清空baos
image.compress(Bitmap.CompressFormat.JPEG, options, baos);//这里压缩options%，把压缩后的数据存放到baos中
options -= 10;//每次都减少10
}
ByteArrayInputStream isBm = new ByteArrayInputStream(baos.toByteArray());//把压缩后的数据baos存放到ByteArrayInputStream中
Bitmap bitmap = BitmapFactory.decodeStream(isBm, null, null);//把ByteArrayInputStream数据生成图片
return bitmap;
}

/**
* 将彩色图转换为灰度图
* @param img 位图
* @return 返回转换好的位图
*/
public Bitmap convertGreyImg(Bitmap img) {
int width = img.getWidth(); //获取位图的宽
int height = img.getHeight(); //获取位图的高
int []pixels = new int[width * height]; //通过位图的大小创建像素点数组
img.getPixels(pixels, 0, width, 0, 0, width, height);
int alpha = 0xFF << 24;
for(int i = 0; i < height; i++) {
for(int j = 0; j < width; j++) {
int grey = pixels[width * i + j];
int red = ((grey & 0x00FF0000 ) >> 16);
int green = ((grey & 0x0000FF00) >> 8);
int blue = (grey & 0x000000FF);
grey = (int)((float) red * 0.3 + (float)green * 0.59 + (float)blue * 0.11);
grey = alpha | (grey << 16) | (grey << 8) | grey;
pixels[width * i + j] = grey;
}
}
Bitmap result = Bitmap.createBitmap(width, height, Config.RGB_565);
result.setPixels(pixels, 0, width, 0, 0, width, height);
return result;
}

将一个图片切割成多个图片
有种场景，我们想将一个图片切割成多个图片。比如我们在开发一个拼图的游戏，就首先要对图片进行切割。
以下是封装好的两个类，可以实现图片的切割。仅供参考和学习。
一个是ImagePiece类，此类保存了一个Bitmap对象和一个标识图片的顺序索引的int变量。

import android.graphics.Bitmap;
public class ImagePiece {
public int index = 0;
public Bitmap bitmap = null;
}

一个是ImageSplitter类，有一个静态方法split，传入的参数是要切割的Bitmap对象，和横向和竖向的切割片数。比如传入的是3、3，则横竖向都切割成3片，最终会将整个图片切割成3X3=9片。

import java.util.ArrayList;
import java.util.List;
import android.graphics.Bitmap;
public class ImageSplitter {
public static List<ImagePiece> split(Bitmap bitmap, int xPiece, int yPiece) {
List<ImagePiece> pieces = new ArrayList<ImagePiece>(xPiece * yPiece);
int width = bitmap.getWidth();
int height = bitmap.getHeight();
int pieceWidth = width / 3;
int pieceHeight = height / 3;
for (int i = 0; i < yPiece; i++) {
for (int j = 0; j < xPiece; j++) {
ImagePiece piece = new ImagePiece();
piece.index = j + i * xPiece;
int xValue = j * pieceWidth;
int yValue = i * pieceHeight;
piece.bitmap = Bitmap.createBitmap(bitmap, xValue, yValue,
pieceWidth, pieceHeight);
pieces.add(piece);
}
}
return pieces;
}
}

1、图标加灰色过滤；
2、android的图片资源默认是静态的，单实例；如果两个IM好友的头像一样，最简单的都是用的软件自带头像，有一个在线，一个离线，直接改变头像的灰度，则两个用户的头像都会变灰或者在线，答案是：Drawable.mutate()。

Drawable mDrawable = context.getResources().getDrawable(R.drawable.face_icon);
//Make this drawable mutable.
//A mutable drawable is guaranteed to not share its state with any other drawable.
mDrawable.mutate();
ColorMatrix cm = new ColorMatrix();
cm.setSaturation(0);
ColorMatrixColorFilter cf = new ColorMatrixColorFilter(cm);
mDrawable.setColorFilter(cf);

生成缩略图，抠自android launcher源码：

/*
* Copyright (C) 2008 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.android.launcher;
import android.graphics.drawable.BitmapDrawable;
import android.graphics.drawable.Drawable;
import android.graphics.drawable.PaintDrawable;
import android.graphics.Bitmap;
import android.graphics.PixelFormat;
import android.graphics.Canvas;
import android.graphics.PaintFlagsDrawFilter;
import android.graphics.Paint;
import android.graphics.Rect;
import android.content.res.Resources;
import android.content.Context;
/**
* Various utilities shared amongst the Launcher‘s classes.
*/
final class Utilities {
private static int sIconWidth = -1;
private static int sIconHeight = -1;
private static final Paint sPaint = new Paint();
private static final Rect sBounds = new Rect();
private static final Rect sOldBounds = new Rect();
private static Canvas sCanvas = new Canvas();
static {
sCanvas.setDrawFilter(new PaintFlagsDrawFilter(Paint.DITHER_FLAG,
Paint.FILTER_BITMAP_FLAG));
}
/**
* Returns a Drawable representing the thumbnail of the specified Drawable.
* The size of the thumbnail is defined by the dimension
* android.R.dimen.launcher_application_icon_size.
*
* This method is not thread-safe and should be invoked on the UI thread only.
*
* @param icon The icon to get a thumbnail of.
* @param context The application‘s context.
*
* @return A thumbnail for the specified icon or the icon itself if the
* thumbnail could not be created.
*/
static Drawable createIconThumbnail(Drawable icon, Context context) {
if (sIconWidth == -1) {
final Resources resources = context.getResources();
sIconWidth = sIconHeight = (int) resources.getDimension(android.R.dimen.app_icon_size);
}
int width = sIconWidth;
int height = sIconHeight;
float scale = 1.0f;
if (icon instanceof PaintDrawable) {
PaintDrawable painter = (PaintDrawable) icon;
painter.setIntrinsicWidth(width);
painter.setIntrinsicHeight(height);
} else if (icon instanceof BitmapDrawable) {
// Ensure the bitmap has a density.
BitmapDrawable bitmapDrawable = (BitmapDrawable) icon;
Bitmap bitmap = bitmapDrawable.getBitmap();
if (bitmap.getDensity() == Bitmap.DENSITY_NONE) {
bitmapDrawable.setTargetDensity(context.getResources().getDisplayMetrics());
}
}
int iconWidth = icon.getIntrinsicWidth();
int iconHeight = icon.getIntrinsicHeight();
if (width > 0 && height > 0) {
if (width < iconWidth || height < iconHeight || scale != 1.0f) {
final float ratio = (float) iconWidth / iconHeight;
if (iconWidth > iconHeight) {
height = (int) (width / ratio);
} else if (iconHeight > iconWidth) {
width = (int) (height * ratio);
}
final Bitmap.Config c = icon.getOpacity() != PixelFormat.OPAQUE ?
Bitmap.Config.ARGB_8888 : Bitmap.Config.RGB_565;
final Bitmap thumb = Bitmap.createBitmap(sIconWidth, sIconHeight, c);
final Canvas canvas = sCanvas;
canvas.setBitmap(thumb);
// Copy the old bounds to restore them later
// If we were to do oldBounds = icon.getBounds(),
// the call to setBounds() that follows would
// change the same instance and we would lose the
// old bounds
sOldBounds.set(icon.getBounds());
final int x = (sIconWidth - width) / 2;
final int y = (sIconHeight - height) / 2;
icon.setBounds(x, y, x + width, y + height);
icon.draw(canvas);
icon.setBounds(sOldBounds);
icon = new FastBitmapDrawable(thumb);
} else if (iconWidth < width && iconHeight < height) {
final Bitmap.Config c = Bitmap.Config.ARGB_8888;
final Bitmap thumb = Bitmap.createBitmap(sIconWidth, sIconHeight, c);
final Canvas canvas = sCanvas;
canvas.setBitmap(thumb);
sOldBounds.set(icon.getBounds());
final int x = (width - iconWidth) / 2;
final int y = (height - iconHeight) / 2;
icon.setBounds(x, y, x + iconWidth, y + iconHeight);
icon.draw(canvas);
icon.setBounds(sOldBounds);
icon = new FastBitmapDrawable(thumb);
}
}
return icon;
}
/**
* Returns a Bitmap representing the thumbnail of the specified Bitmap.
* The size of the thumbnail is defined by the dimension
* android.R.dimen.launcher_application_icon_size.
*
* This method is not thread-safe and should be invoked on the UI thread only.
*
* @param bitmap The bitmap to get a thumbnail of.
* @param context The application‘s context.
*
* @return A thumbnail for the specified bitmap or the bitmap itself if the
* thumbnail could not be created.
*/
static Bitmap createBitmapThumbnail(Bitmap bitmap, Context context) {
if (sIconWidth == -1) {
final Resources resources = context.getResources();
sIconWidth = sIconHeight = (int) resources.getDimension(
android.R.dimen.app_icon_size);
}
int width = sIconWidth;
int height = sIconHeight;
final int bitmapWidth = bitmap.getWidth();
final int bitmapHeight = bitmap.getHeight();
if (width > 0 && height > 0) {
if (width < bitmapWidth || height < bitmapHeight) {
final float ratio = (float) bitmapWidth / bitmapHeight;
if (bitmapWidth > bitmapHeight) {
height = (int) (width / ratio);
} else if (bitmapHeight > bitmapWidth) {
width = (int) (height * ratio);
}
final Bitmap.Config c = (width == sIconWidth && height == sIconHeight) ?
bitmap.getConfig() : Bitmap.Config.ARGB_8888;
final Bitmap thumb = Bitmap.createBitmap(sIconWidth, sIconHeight, c);
final Canvas canvas = sCanvas;
final Paint paint = sPaint;
canvas.setBitmap(thumb);
paint.setDither(false);
paint.setFilterBitmap(true);
sBounds.set((sIconWidth - width) / 2, (sIconHeight - height) / 2, width, height);
sOldBounds.set(0, 0, bitmapWidth, bitmapHeight);
canvas.drawBitmap(bitmap, sOldBounds, sBounds, paint);
return thumb;
} else if (bitmapWidth < width || bitmapHeight < height) {
final Bitmap.Config c = Bitmap.Config.ARGB_8888;
final Bitmap thumb = Bitmap.createBitmap(sIconWidth, sIconHeight, c);
final Canvas canvas = sCanvas;
final Paint paint = sPaint;
canvas.setBitmap(thumb);
paint.setDither(false);
paint.setFilterBitmap(true);
canvas.drawBitmap(bitmap, (sIconWidth - bitmapWidth) / 2,
(sIconHeight - bitmapHeight) / 2, paint);
return thumb;
}
}
return bitmap;
}
}

//Android Matrix类实现镜像方法
public void drawRegion(Image image_src,
int x_src, int y_src,
int width, int height,
int transform,
int x_dest, int y_dest,
int anchor){
if((anchor&VCENTER) != 0){
y_dest -= height/2;
}else if((anchor&BOTTOM) != 0){
y_dest -= height;
}
if((anchor&RIGHT) != 0){
x_dest -= width;
}else if((anchor&HCENTER) != 0){
x_dest -= width/2;
}
Bitmap newMap = Bitmap.createBitmap(image_src.getBitmap(), x_src, y_src, width, height);
Matrix mMatrix = new Matrix();
Matrix temp = new Matrix();
Matrix temp2 = new Matrix();
float[] mirrorY = {
-1, 0, 0,
0, 1, 0,
0, 0, 1
};
temp.setValues(mirrorY);
switch(transform){
case Sprite.TRANS_NONE:
break;
case Sprite.TRANS_ROT90:
mMatrix.setRotate(90,width/2, height/2);
break;
case Sprite.TRANS_ROT180:
mMatrix.setRotate(180,width/2, height/2);
break;
case Sprite.TRANS_ROT270:
mMatrix.setRotate(270,width/2, height/2);
break;
case Sprite.TRANS_MIRROR:
mMatrix.postConcat(temp);
break;
case Sprite.TRANS_MIRROR_ROT90:
mMatrix.postConcat(temp);
mMatrix.setRotate(90,width/2, height/2);
break;
case Sprite.TRANS_MIRROR_ROT180:
mMatrix.postConcat(temp);
mMatrix.setRotate(180,width/2, height/2);
break;
case Sprite.TRANS_MIRROR_ROT270:
mMatrix.postConcat(temp);
mMatrix.setRotate(270,width/2, height/2);
break;
}
mMatrix.setTranslate(x_dest, y_dest);
canvas.drawBitmap(newMap, mMatrix, mPaint);
}

//图片Url保存为位图并进行缩放操作
//通过传入图片url获取位图方法
public Bitmap returnBitMap(String url) {
URL myFileUrl = null;
Bitmap bitmap = null;
try {
myFileUrl = new URL(url);
} catch (MalformedURLException e) {
e.printStackTrace();
}
try {
HttpURLConnection conn = (HttpURLConnection) myFileUrl
.openConnection();
conn.setDoInput(true);
conn.connect();
InputStream is = conn.getInputStream();
bitmap = BitmapFactory.decodeStream(is);
is.close();
} catch (IOException e) {
e.printStackTrace();
}
Log.v(tag, bitmap.toString());
return bitmap;
}
//通过传入位图,新的宽.高比进行位图的缩放操作
public static Drawable resizeImage(Bitmap bitmap, int w, int h) {
// load the origial Bitmap
Bitmap BitmapOrg = bitmap;
int width = BitmapOrg.getWidth();
int height = BitmapOrg.getHeight();
int newWidth = w;
int newHeight = h;
Log.v(tag, String.valueOf(width));
Log.v(tag, String.valueOf(height));
Log.v(tag, String.valueOf(newWidth));
Log.v(tag, String.valueOf(newHeight));
// calculate the scale
float scaleWidth = ((float) newWidth) / width;
float scaleHeight = ((float) newHeight) / height;
// create a matrix for the manipulation
Matrix matrix = new Matrix();
// resize the Bitmap
matrix.postScale(scaleWidth, scaleHeight);
// if you want to rotate the Bitmap
// matrix.postRotate(45);
// recreate the new Bitmap
Bitmap resizedBitmap = Bitmap.createBitmap(BitmapOrg, 0, 0, width,
height, matrix, true);
// make a Drawable from Bitmap to allow to set the Bitmap
// to the ImageView, ImageButton or what ever
return new BitmapDrawable(resizedBitmap);
}

1.图片加载方法，方便用户加载图片
/***
* 加载本地图片
* @param context：主运行函数实例
* @param bitAdress：图片地址，一般指向R下的drawable目录
* @return
*/
public final Bitmap CreatImage(Context context, int bitAdress) {
Bitmap bitmaptemp = null;
bitmaptemp = BitmapFactory.decodeResource(context.getResources(),
bitAdress);
return bitmaptemp;
}
2.图片平均分割方法，将大图平均分割为N行N列，方便用户使用
/***
* 图片分割
*
* @param g
* ：画布
* @param paint
* ：画笔
* @param imgBit
* ：图片
* @param x
* ：X轴起点坐标
* @param y
* ：Y轴起点坐标
* @param w
* ：单一图片的宽度
* @param h
* ：单一图片的高度
* @param line
* ：第几列
* @param row
* ：第几行
*/
public final void cuteImage(Canvas g, Paint paint, Bitmap imgBit, int x,
int y, int w, int h, int line, int row) {
g.clipRect(x, y, x + w, h + y);
g.drawBitmap(imgBit, x – line * w, y – row * h, paint);
g.restore();
}
3.图片缩放，对当前图片进行缩放处理
/***
* 图片的缩放方法
*
* @param bgimage
* ：源图片资源
* @param newWidth
* ：缩放后宽度
* @param newHeight
* ：缩放后高度
* @return
*/
public Bitmap zoomImage(Bitmap bgimage, int newWidth, int newHeight) {
// 获取这个图片的宽和高
int width = bgimage.getWidth();
int height = bgimage.getHeight();
// 创建操作图片用的matrix对象
Matrix matrix = new Matrix();
// 计算缩放率，新尺寸除原始尺寸
float scaleWidth = ((float) newWidth) / width;
float scaleHeight = ((float) newHeight) / height;
// 缩放图片动作
matrix.postScale(scaleWidth, scaleHeight);
Bitmap bitmap = Bitmap.createBitmap(bgimage, 0, 0, width, height,
matrix, true);
return bitmap;
}
4.绘制带有边框的文字，一般在游戏中起文字的美化作用
/***
* 绘制带有边框的文字
*
* @param strMsg
* ：绘制内容
* @param g
* ：画布
* @param paint
* ：画笔
* @param setx
* ：：X轴起始坐标
* @param sety
* ：Y轴的起始坐标
* @param fg
* ：前景色
* @param bg
* ：背景色
*/
public void drawText(String strMsg, Canvas g, Paint paint, int setx,
int sety, int fg, int bg) {
paint.setColor(bg);
g.drawText(strMsg, setx + 1, sety, paint);
g.drawText(strMsg, setx, sety – 1, paint);
g.drawText(strMsg, setx, sety + 1, paint);
g.drawText(strMsg, setx – 1, sety, paint);
paint.setColor(fg);
g.drawText(strMsg, setx, sety, paint);
g.restore();
}
5.Android 图片透明度处理代码
/**
* 图片透明度处理
*
* @param sourceImg
* 原始图片
* @param number
* 透明度
* @return
*/
public static Bitmap setAlpha(Bitmap sourceImg, int number) {
int[] argb = new int[sourceImg.getWidth() * sourceImg.getHeight()];
sourceImg.getPixels(argb, 0, sourceImg.getWidth(), 0, 0,sourceImg.getWidth(), sourceImg.getHeight());// 获得图片的ARGB值
number = number * 255 / 100;
for (int i = 0; i < argb.length; i++) {
argb = (number << 24) | (argb & 0×00FFFFFF);// 修改最高2位的值
}
sourceImg = Bitmap.createBitmap(argb, sourceImg.getWidth(), sourceImg.getHeight(), Config.ARGB_8888);
return sourceImg;
}
6.图片翻转
Resources res = this.getContext().getResources();
img = BitmapFactory.decodeResource(res, R.drawable.slogo);
Matrix matrix = new Matrix();
matrix.postRotate(90); /*翻转90度*/
int width = img.getWidth();
int height = img.getHeight();
r_img = Bitmap.createBitmap(img, 0, 0, width, height, matrix, true);

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;
/**
*
* @author superdev
* @version 1.0
*
*/
public class ImageUtil {
/**
* 放大缩小图片
*/
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;
}
/**
* 将Drawable转化为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;
}
/**
* 获得圆角图片的方法
*/
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;
}
/**
* 获得带倒影的图片方法
*/
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;
}
}

private byte[] Bitmap2Bytes(Bitmap bm){
ByteArrayOutputStream baos = new ByteArrayOutputStream();
bm.compress(Bitmap.CompressFormat.PNG, 100, baos);
return baos.toByteArray();
}
private Bitmap Bytes2Bimap(byte[] b){
if(b.length!=0){
return BitmapFactory.decodeByteArray(b, 0, b.length);
}
else {
return null;
}
}
/**
* create the bitmap from a byte array
*生成水印图片
* @param src the bitmap object you want proecss
* @param watermark the water mark above the src
* @return return a bitmap object ,if paramter‘s length is 0,return null
*/
private Bitmap createBitmap( Bitmap src, Bitmap watermark )
{
String tag = "createBitmap";
Log.d( tag, "create a new bitmap" );
if( src == null )
{
return null;
}
int w = src.getWidth();
int h = src.getHeight();
int ww = watermark.getWidth();
int wh = watermark.getHeight();
//create the new blank bitmap
Bitmap newb = Bitmap.createBitmap( w, h, Config.ARGB_8888 );//创建一个新的和SRC长度宽度一样的位图
Canvas cv = new Canvas( newb );
//draw src into
cv.drawBitmap( src, 0, 0, null );//在 0，0坐标开始画入src
//draw watermark into
cv.drawBitmap( watermark, w - ww + 5, h - wh + 5, null );//在src的右下角画入水印
//save all clip
cv.save( Canvas.ALL_SAVE_FLAG );//保存
//store
cv.restore();//存储
return newb;
}
/** 重新编码Bitmap
*
* @param src
* 需要重新编码的Bitmap
*
* @param format
* 编码后的格式（目前只支持png和jpeg这两种格式）
*
* @param quality
* 重新生成后的bitmap的质量
*
* @return
* 返回重新生成后的bitmap
*/
private static Bitmap codec(Bitmap src, Bitmap.CompressFormat format,
int quality) {
ByteArrayOutputStream os = new ByteArrayOutputStream();
src.compress(format, quality, os);
byte[] array = os.toByteArray();
return BitmapFactory.decodeByteArray(array, 0, array.length);
}
//Stream转换成Byte
static byte[] streamToBytes(InputStream is) {
ByteArrayOutputStream os = new ByteArrayOutputStream(1024);
byte[] buffer = new byte[1024];
int len;
try {
while ((len = is.read(buffer)) >= 0) {
os.write(buffer, 0, len);
}
} catch (java.io.IOException e) {
}
return os.toByteArray();
}
//把View转换成Bitmap
/**
* 把一个View的对象转换成bitmap
*/
static Bitmap getViewBitmap(View v) {
v.clearFocus();
v.setPressed(false);
//能画缓存就返回false
boolean willNotCache = v.willNotCacheDrawing();
v.setWillNotCacheDrawing(false);
int color = v.getDrawingCacheBackgroundColor();
v.setDrawingCacheBackgroundColor(0);
if (color != 0) {
v.destroyDrawingCache();
}
v.buildDrawingCache();
Bitmap cacheBitmap = v.getDrawingCache();
if (cacheBitmap == null) {
Log.e(TAG, "failed getViewBitmap(" + v + ")", new RuntimeException());
return null;
}
Bitmap bitmap = Bitmap.createBitmap(cacheBitmap);
// Restore the view
v.destroyDrawingCache();
v.setWillNotCacheDrawing(willNotCache);
v.setDrawingCacheBackgroundColor(color);
return bitmap;
}

读取raw资源文件中的mp3文件，然后通过音乐播放器播放：
/**
* 把mp3文件写入卡
*
* @param fileName
* 输出的文件名（全路径）
* @param context
* context对象
*/
private void writeMP3ToSDcard(String fileName, Context context) {
byte[] buffer = new byte[1024 * 8];
int read;
BufferedInputStream bin = new BufferedInputStream(context.getResources().openRawResource(R.raw.ring));
try {
BufferedOutputStream bout = new BufferedOutputStream(new FileOutputStream(fileName));
while ((read = bin.read(buffer)) > -1) {
bout.write(buffer, 0, read);
}
bout.flush();
bout.close();
bin.close();
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
Intent intent = new Intent();
intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
intent.setAction(android.content.Intent.ACTION_VIEW);
intent.setDataAndType(Uri.fromFile(newFile("XXXXmp3的文件全路径")),"audio/*");
startActivity(intent);

绘制图像倒影

private void
_Init()
{
m_paint = new Paint(Paint.ANTI_ALIAS_FLAG);
LinearGradient lg = new LinearGradient(
0, 0, 0, m_nShadowH,
0xB0FFFFFF, 0x00000000,
Shader.TileMode.CLAMP);
m_paint.setShader(lg);
m_paint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.MULTIPLY));
}
@Override protected void
onDraw(Canvas canvas)
{
super.onDraw(canvas);
int nX = 0;
int nY = 20;
_DrawNormalImg(canvas, nX, nY);
_DrawMirror(canvas, nX, nY);
}
private void
_DrawNormalImg(Canvas canvas, int nX, int nY)
{
canvas.save(Canvas.MATRIX_SAVE_FLAG);
canvas.translate(nX, nY);
m_dw.draw(canvas);
canvas.restore();
}
private void
_DrawMirror(Canvas canvas, int nX, int nY)
{
int nW = m_dw.getIntrinsicWidth();
int nH = m_dw.getIntrinsicHeight();
///////////////////////////////////
//draw mirror image
canvas.save(Canvas.MATRIX_SAVE_FLAG);
canvas.scale(1.0f, -1.0f);
canvas.translate(nX, -(nY + nH * 2));
canvas.clipRect(0, nH, nW, nH - m_nShadowH);
m_dw.draw(canvas);
canvas.restore();
//////////////////////////////
//draw mask
canvas.save();
canvas.translate(nX, nY + nH);
canvas.drawRect(0, 0, nW, m_nShadowH, m_paint);
canvas.restore();
}

Android 繪圖座標體系預設的原點在左上角，X 軸往右是越來越大的正值，而 Y 軸往下，則是越來越大的正值。要畫出垂直翻轉的圖片，其實也就是要垂直翻轉整個繪圖座標體系。在 Android 中，要如何做？答案就是 canvas.scale(1.0f, -1.0f)。很簡單吧，沒想到給 scale() 函式一個負值，就可以翻轉相對應的軸。
在 Photoshop 中，做鏡像特效的第二步是要對這翻轉的圖片，加個由灰到黑的漸層 mask。
在 Android 中，要畫漸層色，那就一定得用 LinearGradient 這個類別。至於要對背景圖加上個 mask，就請參考一下 Paint 的 setXfermode() 函式。_Init() 這個函式，就是負責生成一個由灰到黑漸層 mask 的 m_paint 物件。