安卓：内存错误的使用了位图时 [英] Android: out of memory error when using bitmaps
本文介绍了安卓：内存错误的使用了位图时的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
我经常收到内存不足的错误在我的应用程序。我相信这与我从服务器上下载的位图的事情。任何想法，为什么？
**在我的活性的方法，设置了ListView的：**私有类NewsFeedArrayAdapter扩展ArrayAdapter＆LT; AnimalLocationLog＆GT; { ArrayList的＆LT; AnimalLocationLog＆GT;物体;
上下文语境;
ArrayList的＆LT;串GT;网址;
ImageDownloader下载; 公共NewsFeedArrayAdapter（上下文的背景下，INT textViewResourceId，ArrayList的＆LT; AnimalLocationLog＆GT;对象的ArrayList＆LT;串GT;的网址）{
超（背景下，textViewResourceId，对象）;
this.context =背景;
this.objects =物体;
this.urls =网址;
下载=新ImageDownloader（）;
} @覆盖
公共查看getView（INT位置，查看convertView，父母的ViewGroup）{
LayoutInflater吹气=（LayoutInflater）context.getSystemService（Context.LAYOUT_INFLATER_SERVICE）;
查看rowView = inflater.inflate（R.layout.list_single，父母，假）; AnimalLocationLog电流= objects.get（位置）; ImageView的图像=（ImageView的）rowView.findViewById（R.id.icon）;
TextView的FIRSTLINE =（TextView中）rowView.findViewById（R.id.firstline）;
TextView的secondline =（TextView中）rowView.findViewById（R.id.secondline）; //下载外部图像
downloader.download（urls.get（仓位14％），图像）; firstline.setText（current.getSpecies（））;
secondline.setText（花斑+ current.getDateTime（）的toString（YYYY-MM-DD H：M））; 返回rowView;
}
** ImageDownloader.java：** 公共类ImageDownloader { 地图＆LT;弦乐，位图＆GT; imageCache; 公共ImageDownloader（）{
imageCache =新的HashMap＆LT;弦乐，位图＆GT;（）; } //下载功能
公共无效下载（字符串URL，ImageView的ImageView的）{
如果（cancelPotentialDownload（URL，ImageView的））{ //缓存code就在这里
字符串文件名=将String.valueOf（url.hash code（））;
文件f =新的文件（getCacheDirectory（imageView.getContext（）），文件名）; //是在我们的记忆缓存中的位图？
位图位图= NULL; 位=（位图）imageCache.get（f.getPath（））; 如果（位图== NULL）{ 位= BitmapFactory.de codeFILE（f.getPath（））; 如果（位图！= NULL）{
imageCache.put（f.getPath（），位图）;
} }
//没有？下载它
如果（位图== NULL）{
BitmapDownloaderTask任务=新BitmapDownloaderTask（ImageView的）;
DownloadedDrawable downloadedDrawable =新DownloadedDrawable（任务）;
imageView.setImageDrawable（downloadedDrawable）;
task.execute（URL）;
}其他{
//是？设置图像
imageView.setImageBitmap（位图）;
}
}
} //取消下载（仅供内部使用）
私有静态布尔cancelPotentialDownload（字符串URL，ImageView的ImageView的）{
BitmapDownloaderTask bitmapDownloaderTask = getBitmapDownloaderTask（ImageView的）; 如果（bitmapDownloaderTask！= NULL）{
字符串bitmapUrl = bitmapDownloaderTask.url;
如果（（bitmapUrl == NULL）||（！bitmapUrl.equals（URL）））{
bitmapDownloaderTask.cancel（真）;
}其他{
//相同的URL已经被下载。
返回false;
}
}
返回true;
} //如果存在的ImageView的得到现有下载
私有静态BitmapDownloaderTask getBitmapDownloaderTask（ImageView的ImageView的）{
如果（ImageView的！= NULL）{
可绘制可绘制= imageView.getDrawable（）;
如果（绘制的instanceof DownloadedDrawable）{
DownloadedDrawable downloadedDrawable =（DownloadedDrawable）绘制;
返回downloadedDrawable.getBitmapDownloaderTask（）;
}
}
返回null;
} //我们的缓存功能
//查找目录保存缓存图像
私有静态文件getCacheDirectory（上下文的背景下）{
串sdState = android.os.Environment.getExternalStorageState（）;
文件cacheDir; 如果（sdState.equals（android.os.Environment.MEDIA_MOUNTED））{
文件sdDir = android.os.Environment.getExternalStorageDirectory（）; // TODO：在此处更改diretcory
cacheDir =新的文件（sdDir，数据/ TAC / imagess）;
}
其他
cacheDir = context.getCacheDir（）; 如果（！cacheDir.exists（））
cacheDir.mkdirs（）;
返回cacheDir;
} 私人无效WriteFile的（BMP位图，文件f）{
FileOutputStream中走出= NULL; 尝试{
OUT =新的FileOutputStream（F）;
bmp.com preSS（Bitmap.Com pressFormat.PNG，80出）;
}赶上（例外五）{
e.printStackTrace（）;
}
最后{
尝试{如果out.close（）（满分！= NULL）; }
赶上（例外前）{}
}
}
/////////////////////// //下载的AsyncTask
公共类BitmapDownloaderTask扩展的AsyncTask＆LT;弦乐，太虚，位图＆GT; {
私人字符串URL;
私人最终的WeakReference＆LT; ImageView的＆GT; imageViewReference; 公共BitmapDownloaderTask（ImageView的ImageView的）{
imageViewReference =新的WeakReference＆LT; ImageView的＆GT;（ImageView的）;
} @覆盖
//实际的下载方法，在任务线程中运行
保护位图doInBackground（字符串... PARAMS）{
// PARAMS来自execute（）调用：PARAMS [0]是的URL。
URL =（字符串）PARAMS [0];
返回downloadBitmap（PARAMS [0]）;
} @覆盖
//一旦图像被下载，它关联到的ImageView
保护无效onPostExecute（位图位图）{
如果（isCancelled（））{
位= NULL;
} 如果（imageViewReference！= NULL）{
ImageView的ImageView的= imageViewReference.get（）;
BitmapDownloaderTask bitmapDownloaderTask = getBitmapDownloaderTask（ImageView的）;
//改变位图只有在这个过程中仍与它相关联
如果（这种== bitmapDownloaderTask）{
imageView.setImageBitmap（位图）; //缓存图片
字符串文件名=将String.valueOf（url.hash code（））;
文件f =新的文件（getCacheDirectory（imageView.getContext（）），文件名）; imageCache.put（f.getPath（），位图）; 写文件（位图，F）;
}
}
}
} 静态类DownloadedDrawable扩展ColorDrawable {
私人最终的WeakReference＆LT; BitmapDownloaderTask＆GT; bitmapDownloaderTaskReference; 公共DownloadedDrawable（BitmapDownloaderTask bitmapDownloaderTask）{
超（Color.BLACK）;
bitmapDownloaderTaskReference =
新的WeakReference＆LT; BitmapDownloaderTask＆GT;（bitmapDownloaderTask）;
} 公共BitmapDownloaderTask getBitmapDownloaderTask（）{
返回bitmapDownloaderTaskReference.get（）;
}
} //实际的下载code
静态位图downloadBitmap（字符串URL）{
的HttpParams PARAMS =新BasicHttpParams（）;
params.setParameter（CoreProtocolPNames.PROTOCOL_VERSION，HttpVersion.HTTP_1_1）;
HttpClient的客户端=新DefaultHttpClient（PARAMS）;
最终HTTPGET调用getRequest =新HTTPGET（URL）; 尝试{
HTT presponse响应= client.execute（调用getRequest）;
。最终诠释状态code = response.getStatusLine（）的getStatus code（）;
如果（状态code！= HttpStatus.SC_OK）{
Log.w（ImageDownloader，错误+状态code +，同时检索从位图+网址）;
返回null;
} 最终HttpEntity实体= response.getEntity（）;
如果（实体！= NULL）{
为InputStream的InputStream = NULL;
尝试{
的InputStream = entity.getContent（）;
最后的位图位图= BitmapFactory.de codeStream（InputStream的）;
返回位图;
} {最后
如果（的InputStream！= NULL）{
inputStream.close（）;
}
entity.consumeContent（）;
}
}
}赶上（例外五）{
//可以提供IOException异常或IllegalStateException异常更明确的错误信息
getRequest.abort（）;
; Log.w（ImageDownloader+ URL + e.toString（）错误而来自检索的位图）
} {最后
如果（客户端！= NULL）{
//client.close（）;
}
}
返回null;
}
}
解决方案
如果您有高分辨率的图像，你应该扩展他们失望。参见下加载缩小版本到内存的话题。结果
http://developer.android.com/training/displaying-bitmaps/load -bitmap.html 结果
内存不足错误的Android 的
在如何避免它们：结果
<一href=\"http://stackoverflow.com/questions/19151719/how-to-avoid-out-of-memory-error-while-using-bitmap-in-android\">how以避免内存不足的错误，而在Android的使用位图
对于大略介绍：结果
的http://blogs.innovationm.com/android-out-of-memory-error-causes-solution-and-best-practices/
http://android-developers.blogspot.de/2009/01 /avoiding-memory-leaks.html
i often get out of memory errors in my app. I believe it has to do with the bitmaps i download from the server. Any ideas why?
**A method in my activity that sets up ListView:**
private class NewsFeedArrayAdapter extends ArrayAdapter<AnimalLocationLog> {
ArrayList<AnimalLocationLog> objects;
Context context;
ArrayList<String> urls;
ImageDownloader downloader;
public NewsFeedArrayAdapter(Context context, int textViewResourceId, ArrayList<AnimalLocationLog> objects, ArrayList<String> urls) {
super(context, textViewResourceId, objects);
this.context = context;
this.objects = objects;
this.urls = urls;
downloader = new ImageDownloader();
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
LayoutInflater inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
View rowView = inflater.inflate(R.layout.list_single, parent, false);
AnimalLocationLog current = objects.get(position);
ImageView image = (ImageView) rowView.findViewById(R.id.icon);
TextView firstline = (TextView) rowView.findViewById(R.id.firstline);
TextView secondline = (TextView) rowView.findViewById(R.id.secondline);
// Download external images
downloader.download(urls.get(position % 14), image);
firstline.setText(current.getSpecies());
secondline.setText("Spotted " + current.getDateTime().toString("yyyy-MM-dd H:m"));
return rowView;
}
**ImageDownloader.java:**
public class ImageDownloader {
Map<String,Bitmap> imageCache;
public ImageDownloader(){
imageCache = new HashMap<String, Bitmap>();
}
//download function
public void download(String url, ImageView imageView) {
if (cancelPotentialDownload(url, imageView)) {
//Caching code right here
String filename = String.valueOf(url.hashCode());
File f = new File(getCacheDirectory(imageView.getContext()), filename);
// Is the bitmap in our memory cache?
Bitmap bitmap = null;
bitmap = (Bitmap)imageCache.get(f.getPath());
if(bitmap == null){
bitmap = BitmapFactory.decodeFile(f.getPath());
if(bitmap != null){
imageCache.put(f.getPath(), bitmap);
}
}
//No? download it
if(bitmap == null){
BitmapDownloaderTask task = new BitmapDownloaderTask(imageView);
DownloadedDrawable downloadedDrawable = new DownloadedDrawable(task);
imageView.setImageDrawable(downloadedDrawable);
task.execute(url);
}else{
//Yes? set the image
imageView.setImageBitmap(bitmap);
}
}
}
//cancel a download (internal only)
private static boolean cancelPotentialDownload(String url, ImageView imageView) {
BitmapDownloaderTask bitmapDownloaderTask = getBitmapDownloaderTask(imageView);
if (bitmapDownloaderTask != null) {
String bitmapUrl = bitmapDownloaderTask.url;
if ((bitmapUrl == null) || (!bitmapUrl.equals(url))) {
bitmapDownloaderTask.cancel(true);
} else {
// The same URL is already being downloaded.
return false;
}
}
return true;
}
//gets an existing download if one exists for the imageview
private static BitmapDownloaderTask getBitmapDownloaderTask(ImageView imageView) {
if (imageView != null) {
Drawable drawable = imageView.getDrawable();
if (drawable instanceof DownloadedDrawable) {
DownloadedDrawable downloadedDrawable = (DownloadedDrawable)drawable;
return downloadedDrawable.getBitmapDownloaderTask();
}
}
return null;
}
//our caching functions
// Find the dir to save cached images
private static File getCacheDirectory(Context context){
String sdState = android.os.Environment.getExternalStorageState();
File cacheDir;
if (sdState.equals(android.os.Environment.MEDIA_MOUNTED)) {
File sdDir = android.os.Environment.getExternalStorageDirectory();
//TODO : Change your diretcory here
cacheDir = new File(sdDir,"data/tac/imagess");
}
else
cacheDir = context.getCacheDir();
if(!cacheDir.exists())
cacheDir.mkdirs();
return cacheDir;
}
private void writeFile(Bitmap bmp, File f) {
FileOutputStream out = null;
try {
out = new FileOutputStream(f);
bmp.compress(Bitmap.CompressFormat.PNG, 80, out);
} catch (Exception e) {
e.printStackTrace();
}
finally {
try { if (out != null ) out.close(); }
catch(Exception ex) {}
}
}
///////////////////////
//download asynctask
public class BitmapDownloaderTask extends AsyncTask<String, Void, Bitmap> {
private String url;
private final WeakReference<ImageView> imageViewReference;
public BitmapDownloaderTask(ImageView imageView) {
imageViewReference = new WeakReference<ImageView>(imageView);
}
@Override
// Actual download method, run in the task thread
protected Bitmap doInBackground(String... params) {
// params comes from the execute() call: params[0] is the url.
url = (String)params[0];
return downloadBitmap(params[0]);
}
@Override
// Once the image is downloaded, associates it to the imageView
protected void onPostExecute(Bitmap bitmap) {
if (isCancelled()) {
bitmap = null;
}
if (imageViewReference != null) {
ImageView imageView = imageViewReference.get();
BitmapDownloaderTask bitmapDownloaderTask = getBitmapDownloaderTask(imageView);
// Change bitmap only if this process is still associated with it
if (this == bitmapDownloaderTask) {
imageView.setImageBitmap(bitmap);
//cache the image
String filename = String.valueOf(url.hashCode());
File f = new File(getCacheDirectory(imageView.getContext()), filename);
imageCache.put(f.getPath(), bitmap);
writeFile(bitmap, f);
}
}
}
}
static class DownloadedDrawable extends ColorDrawable {
private final WeakReference<BitmapDownloaderTask> bitmapDownloaderTaskReference;
public DownloadedDrawable(BitmapDownloaderTask bitmapDownloaderTask) {
super(Color.BLACK);
bitmapDownloaderTaskReference =
new WeakReference<BitmapDownloaderTask>(bitmapDownloaderTask);
}
public BitmapDownloaderTask getBitmapDownloaderTask() {
return bitmapDownloaderTaskReference.get();
}
}
//the actual download code
static Bitmap downloadBitmap(String url) {
HttpParams params = new BasicHttpParams();
params.setParameter(CoreProtocolPNames.PROTOCOL_VERSION, HttpVersion.HTTP_1_1);
HttpClient client = new DefaultHttpClient(params);
final HttpGet getRequest = new HttpGet(url);
try {
HttpResponse response = client.execute(getRequest);
final int statusCode = response.getStatusLine().getStatusCode();
if (statusCode != HttpStatus.SC_OK) {
Log.w("ImageDownloader", "Error " + statusCode + " while retrieving bitmap from " + url);
return null;
}
final HttpEntity entity = response.getEntity();
if (entity != null) {
InputStream inputStream = null;
try {
inputStream = entity.getContent();
final Bitmap bitmap = BitmapFactory.decodeStream(inputStream);
return bitmap;
} finally {
if (inputStream != null) {
inputStream.close();
}
entity.consumeContent();
}
}
} catch (Exception e) {
// Could provide a more explicit error message for IOException or IllegalStateException
getRequest.abort();
Log.w("ImageDownloader", "Error while retrieving bitmap from " + url + e.toString());
} finally {
if (client != null) {
//client.close();
}
}
return null;
}
}
解决方案
If you have high resolution image , you should scale them down. See the topic under Load a Scaled Down Version into Memory.
http://developer.android.com/training/displaying-bitmaps/load-bitmap.html
Out of memory error android
On how to avoid them:
how to avoid out of memory error while using bitmap in android
For an oveview:
http://blogs.innovationm.com/android-out-of-memory-error-causes-solution-and-best-practices/
http://android-developers.blogspot.de/2009/01/avoiding-memory-leaks.html
这篇关于安卓：内存错误的使用了位图时的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
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