Possible Duplicate:
Android Out of Memory error with Lazy Load images
Outofmemory error during scrolling the listview fastly
我正在使用 listview 来显示图像，来自 facebook api 的名称。我可以正确显示图像。我的问题是当我快速滚动列表时，我得到
11-15 18:41:29.841: E/dalvikvm-heap(32303): 786432-byte external allocation too large for this process.
11-15 18:41:29.887: I/dalvikvm-heap(32303): Clamp target GC heap from 32.095MB to 32.000MB
11-15 18:41:29.887: E/GraphicsJNI(32303): VM won't let us allocate 786432 bytes
11-15 18:41:29.887: D/dalvikvm(32303): GC_FOR_MALLOC freed 0K, 51% free 4380K/8903K, external 23826K/25864K, paused 31ms
11-15 18:41:29.887: D/skia(32303): --- decoder->decode returned false
11-15 18:41:29.887: W/dalvikvm(32303): threadid=18: thread exiting with uncaught exception (group=0x40018560)
11-15 18:41:29.887: E/AndroidRuntime(32303): FATAL EXCEPTION: Thread-29
11-15 18:41:29.887: E/AndroidRuntime(32303): java.lang.OutOfMemoryError: bitmap size exceeds VM budget
11-15 18:41:29.887: E/AndroidRuntime(32303): at android.graphics.BitmapFactory.nativeDecodeStream(Native Method)
11-15 18:41:29.887: E/AndroidRuntime(32303): at android.graphics.BitmapFactory.decodeStream(BitmapFactory.java:470)
11-15 18:41:29.887: E/AndroidRuntime(32303): at com.beerbro.utils.ImageLoader.decodeFile(ImageLoader.java:156)
11-15 18:41:29.887: E/AndroidRuntime(32303): at com.beerbro.utils.ImageLoader.getBitmap(ImageLoader.java:99)
11-15 18:41:29.887: E/AndroidRuntime(32303): at com.beerbro.utils.ImageLoader$PhotosLoader.run(ImageLoader.java:214)
但是当我慢慢滚动这个 ListView 时，我没有收到任何错误。
这是我的 Adapter 类，我在其中调用 Imageloader 类的 displayImage 方法将我的 url 转换为位图并将其设置为 imageview。
public class MySimpleArrayAdapter extends ArrayAdapter<String> {
private Activity context;
ArrayList<String> namear,msgar,idar,profimage,postimage,commentsnum,objectid,urlString;
ImageLoader imageLoader;
Bitmap[] bitdata;
public MySimpleArrayAdapter(Activity c,int i,ArrayList<String> postpic, ArrayList<String> names,ArrayList<String> msg,ArrayList<String> id,ArrayList<String> proimg,Bitmap[] bit,ArrayList<String> comment,ArrayList<String> objid,ArrayList<String> web) {
super(c, i, names);
Log.e("adapter","adap");
this.context = c;
this.namear = names;
this.msgar = msg;
this.idar = id;
this.profimage=proimg;
this.postimage=postpic;
this.bitdata=bit;
this.commentsnum=comment;
this.objectid=objid;
this.urlString=web;
this.imageLoader = new ImageLoader(context);
}
@Override
public View getView(final int position, View convertView, ViewGroup parent) {
View rowView=convertView ;
LayoutInflater inflator = getLayoutInflater();
rowView = inflator.inflate(R.layout.walldata, null);
TextView name1 = (TextView) rowView.findViewById(R.id.name);
TextView message1 = (TextView) rowView.findViewById(R.id.msg);
ImageView profimg= (ImageView) rowView.findViewById(R.id.profile_pic);
ImageView postimg= (ImageView) rowView.findViewById(R.id.picpost);
TextView comments = (TextView) rowView.findViewById(R.id.comment);
Log.e("user",idar.get(position));
Log.e("adapter","adap");
name1.setText(namear.get(position));
if(msgar.get(position)!=""){
message1.setText(msgar.get(position));
}
else
{
message1.setVisibility(View.GONE);
}
if(!postimage.get(position).equals(""))
{try{
imageLoader.DisplayImage(postimage.get(position).replace(" ", "%20"), postimg) ;
}
catch(Exception e){
e.printStackTrace();
}
}
else
{
postimg.setVisibility(View.GONE);
}
try{
imageLoader.DisplayImage(profimage.get(position).replace(" ", "%20"), profimg) ;
}
catch(Exception e){
e.printStackTrace();
}
comments.setText(commentsnum.get(position)+"\t"+"Comments");
comments.setOnClickListener(new OnClickListener() {
public void onClick(View v) {
Intent myintent=new Intent(Wall.this,Comments.class);
myintent.putExtra("name", namear.get(position));
myintent.putExtra("profimg", profimage.get(position));
myintent.putExtra("message", msgar.get(position));
myintent.putExtra("postpic", postimage.get(position));
myintent.putExtra("objectid", objectid.get(position));
myintent.putExtra("commentsnum",commentsnum.get(position));
myintent.putExtra("webservice", urlString.get(position));
startActivity(myintent);
}
});
return rowView;
}
这是我的 Imageloader 类
public class ImageLoader {
MemoryCache memoryCache=new MemoryCache();
FileCache fileCache;
private Map<ImageView, String> imageViews=Collections.synchronizedMap(new WeakHashMap<ImageView, String>());
public ImageLoader(Context context){
photoLoaderThread.setPriority(Thread.NORM_PRIORITY-1);
fileCache=new FileCache(context);
}
public void DisplayImage(String url,ImageView imageView)
{
imageViews.put(imageView, url);
Bitmap bitmap=memoryCache.get(url);
if(bitmap!=null)
{
imageView.setBackgroundDrawable(new BitmapDrawable(bitmap));
System.gc();
}
else
{
queuePhoto(url, imageView);
}
}
private Bitmap createScaledBitmap(Bitmap bitmap, int i, int j, int k) {
return null;
}
private void queuePhoto(String url, ImageView imageView)
{
//This ImageView may be used for other images before. So there may be some old tasks in the queue. We need to discard them.
photosQueue.Clean(imageView);
PhotoToLoad p=new PhotoToLoad(url, imageView);
synchronized(photosQueue.photosToLoad){
photosQueue.photosToLoad.push(p);
photosQueue.photosToLoad.notifyAll();
}
//start thread if it's not started yet
if(photoLoaderThread.getState()==Thread.State.NEW)
photoLoaderThread.start();
}
public Bitmap getBitmap(String url)
{
File f=fileCache.getFile(url);
//from SD cache
Bitmap b = decodeFile(f);
if(b!=null)
return b;
//from web
try {
Bitmap bitmap=null;
URL imageUrl = new URL(url);
HttpURLConnection conn = (HttpURLConnection)imageUrl.openConnection();
conn.setConnectTimeout(30000);
conn.setReadTimeout(30000);
InputStream is=conn.getInputStream();
OutputStream os = new FileOutputStream(f);
Utils.CopyStream(is, os);
os.close();
bitmap = decodeFile(f);
return bitmap;
} catch (Exception ex){
ex.printStackTrace();
return null;
}
}//Lalit
//decodes image and scales it to reduce memory consumption
private Bitmap decodeFile(File f){
try {
//decode image size
BitmapFactory.Options o = new BitmapFactory.Options();
o.inJustDecodeBounds = true;
BitmapFactory.decodeStream(new FileInputStream(f),null,o);
//Find the correct scale value. It should be the power of 2.
final int REQUIRED_SIZE=Wall.width;
final int REQUIRED_SIZE1=Wall.height;
int width_tmp=o.outWidth, height_tmp=o.outHeight;
int scale=1;
while(true){
if((width_tmp/2<REQUIRED_SIZE)&&(height_tmp/2<REQUIRED_SIZE1))
break;
width_tmp/=2;
height_tmp/=2;
scale*=2;
}
//decode with inSampleSize
BitmapFactory.Options o2 = new BitmapFactory.Options();
o2.inJustDecodeBounds = true;
BitmapFactory.decodeStream(new FileInputStream(f), null, o2);
o2.inSampleSize=scale;
o2.inJustDecodeBounds = false;
return BitmapFactory.decodeStream(new FileInputStream(f), null, o2);
} catch (FileNotFoundException e) {}
return null;
}
//Task for the queue
private class PhotoToLoad
{
public String url;
public ImageView imageView;
public PhotoToLoad(String u, ImageView i){
url=u;
imageView=i;
}
}
PhotosQueue photosQueue=new PhotosQueue();
public void stopThread()
{
photoLoaderThread.interrupt();
}
//stores list of photos to download
class PhotosQueue
{
private Stack<PhotoToLoad> photosToLoad=new Stack<PhotoToLoad>();
//removes all instances of this ImageView
public void Clean(ImageView image)
{
for(int j=0 ;j<photosToLoad.size();){
if(photosToLoad.get(j).imageView==image)
photosToLoad.remove(j);
else
++j;
}
}
}
class PhotosLoader extends Thread {
public void run() {
try {
while(true)
{
//thread waits until there are any images to load in the queue
if(photosQueue.photosToLoad.size()==0)
synchronized(photosQueue.photosToLoad){
photosQueue.photosToLoad.wait();
}
if(photosQueue.photosToLoad.size()!=0)
{
PhotoToLoad photoToLoad;
synchronized(photosQueue.photosToLoad){
photoToLoad=photosQueue.photosToLoad.pop();
}
Bitmap bmp=getBitmap(photoToLoad.url);
memoryCache.put(photoToLoad.url, bmp);
String tag=imageViews.get(photoToLoad.imageView);
if(tag!=null && tag.equals(photoToLoad.url)){
BitmapDisplayer bd=new BitmapDisplayer(bmp, photoToLoad.imageView);
Activity a=(Activity)photoToLoad.imageView.getContext();
a.runOnUiThread(bd);
}
}
if(Thread.interrupted())
break;
}
} catch (InterruptedException e) {
//allow thread to exit
}
}
}
PhotosLoader photoLoaderThread=new PhotosLoader();
//Used to display bitmap in the UI thread
class BitmapDisplayer implements Runnable
{
Bitmap bitmap;
ImageView imageView;
public BitmapDisplayer(Bitmap b, ImageView i){bitmap=b;imageView=i;}
public void run()
{
if(bitmap!=null)
imageView.setBackgroundDrawable(new BitmapDrawable(bitmap));
}
}
public void clearCache() {
memoryCache.clear();
fileCache.clear();
}
public static Bitmap getRoundedCornerBitmap(Bitmap bitmap, int pixels,int width,int height) {
Bitmap output = Bitmap.createBitmap(width,height, 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);
final float roundPx = pixels;
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;
}
我将图像缩放到我的设备屏幕尺寸，即 480*854，您可以在 imageloader 类中找到它，我也在这里提到以便于理解
final int REQUIRED_SIZE=Wall.width;
final int REQUIRED_SIZE1=Wall.height;
int width_tmp=o.outWidth, height_tmp=o.outHeight;
int scale=1;
while(true){
if((width_tmp/2<REQUIRED_SIZE)&&(height_tmp/2<REQUIRED_SIZE1))
break;
width_tmp/=2;
height_tmp/=2;
scale*=2;
}
}
通过查看错误，我可以了解到内存不足以加载位图，我不知道如何在运行时释放内存。 请帮助我，我引用了 stackoverflow 和其他人中的许多链接，但无法解决此问题。
最佳答案
嗯，我能想到的解决问题的一种方法是使用 onScrollListener，并向适配器添加一个可由监听器设置的标志。
当列表滚动时(flag = true)让适配器跳过加载图像。当列表停止滚动(标志 = false)时，让适配器加载图像。您可以通过在适配器上调用 notifyDataSetChanged() 来触发图像加载。
如果我们在适配器中调用该标志 isScrolling，您的监听器可能如下所示:
listView.setOnScrollListener(new OnScrollListener() {
public void onScroll(AbsListView view, int firstVisible,
int visibleCount, int total) {
public void onScrollStateChanged(AbsListView view, int scrollState) {
if (scrollState != 0)
listView.getAdapter()).isScrolling = true;
else {
listView.getAdapter().isScrolling = false;
listView.getAdapter().notifyDataSetChanged();
}
}
});
在您的适配器中，只需用以下内容包围您的图像加载代码:
if (!isScrolling) {
// code to load images
}
关于android - 如何解决 ListView 滚动期间内存不足错误？，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/13398367/