解决关于图片过大而造成OutOfMemoryError方法

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1.首先在Activity中获得屏幕分辨率
final DisplayMetrics dm = new DisplayMetrics();
getWindowManager().getDefaultDisplay().getMetrics(dm);
int height = dm.heightPixels;
int width = dm.widthPixels;
2.当图片过大,或图片数量较多时使用BitmapFactory解码图片会出java.lang.OutOfMemoryError: bitmap size exceeds VM budget,要想正常使用则需分配更少的内存,具体的解决办法是修改采样值BitmapFactory.Options.inSampleSize,例如:www.2cto.comBitmapFactory.Options opts = new BitmapFactory.Options();
opts.inSampleSize = 4;

Bitmap bitmap = BitmapFactory.decodeFile(imageFile, opts);如何设置恰当的inSampleSize

设置恰当的inSampleSize是解决该问题的关键之一。BitmapFactory.Options提供了另一个成员inJustDecodeBounds。

BitmapFactory.Options opts = new BitmapFactory.Options();
opts.inJustDecodeBounds = true;
Bitmap bitmap = BitmapFactory.decodeFile(imageFile, opts);

设置inJustDecodeBounds为true后,decodeFile并不分配空间,但可计算出原始图片的长度和宽度,即opts.width和opts.height。有了这两个参数,再通过一定的算法,即可得到一个恰当的inSampleSize。

查看Android源码,Android提供了一种动态计算的方法。

创建ImageTools类(参照原文http://www.2cto.com/kf/201206/136907.html)

/*** */package com.cmdi.util;import android.graphics.BitmapFactory;/*** @author wu*为了避免导入图片过大而造成内存溢出*/public class ImgTools {public static int computeSampleSize(BitmapFactory.Options options,int minSideLength, int maxNumOfPixels) {int initialSize = computeInitialSampleSize(options, minSideLength,maxNumOfPixels);int roundedSize;if (initialSize <= 8 ) {roundedSize = 1;while (roundedSize < initialSize) {roundedSize <<= 1;}} else {roundedSize = (initialSize + 7) / 8 * 8;}return roundedSize;}private static int computeInitialSampleSize(BitmapFactory.Options options,int minSideLength, int maxNumOfPixels) {double w = options.outWidth;double h = options.outHeight;int lowerBound = (maxNumOfPixels == -1) ? 1 :(int) Math.ceil(Math.sqrt(w * h / maxNumOfPixels));int upperBound = (minSideLength == -1) ? 128 :(int) Math.min(Math.floor(w / minSideLength),Math.floor(h / minSideLength));if (upperBound < lowerBound) {// return the larger one when there is no overlapping zone.return lowerBound;}if ((maxNumOfPixels == -1) &&(minSideLength == -1)) {return 1;} else if (minSideLength == -1) {return lowerBound;} else {return upperBound;}}}

3.调用ImgTools

// 通过图片的路径获得Bitmappublic void setImage(String path,int height,int width) {File f = new File(path);if (f != null && f.isFile()) {BitmapFactory.Options opts = new BitmapFactory.Options();opts.inJustDecodeBounds = true;BitmapFactory.decodeFile(path, opts);opts.inSampleSize = ImgTools.computeSampleSize(opts, -1, height*width);opts.inJustDecodeBounds = false;try {mBitmap = BitmapFactory.decodeFile(path,opts).copy(Bitmap.Config.ARGB_8888, true);} catch (OutOfMemoryError err) {}// 从资源中获取Bitmap并根据该位图的大小产生一个新位图/*mBitmap = BitmapFactory.decodeFile(path,opts).copy(Bitmap.Config.ARGB_8888, true);*/calculateAspectQuotient();// 刷新View,把之前的旧的view从主UI线程队列中pop掉invalidate();} else {;}}
注:同时需要通过onDestory()及时回收内存

@Overrideprotected void onDestroy(){super.onDestroy();//及时回收内存if (mBitmap != null){mBitmap.recycle();}}

	
				
		
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