我遇到了下载图像和更新ImageView的问题，我正在使用ExecutorServices下载图像，但我遇到的问题是，在场景中，我使用基本适配器在列表中显示Imageview。图像被下载但两个图像仅在firstImage View中更新。
所以Bitmap在同一个imageView中得到更新，任何人都面临类似的问题
例如，我正在下载2个图像，它正在创建2个ImageDownloader实例，所有运行良好，直到该类的Run（）在下载部分之前的行中，一旦Image下载，我得到的对象参考第一个Image Downloader类的ImageView，我不知道为什么？我认为它与listview或者适配器无关，它与Executor和Runnable Implementation更相关，
public class ImageLoader {
ExecutorService mExecutorService = null;
static ImageLoader mLoader = null;
Handler mImageHandler = null ;
DisplayMetrics mDisplayMetrics = null;
int mRequiredWidth =0 , mRequiredHeight = 0;
Map<String,ImageView> mToLoadObjects = Collections.synchronizedMap(
new WeakHashMap<String, ImageView>());
ArrayList<String> toloadURL = new ArrayList<String>();
protected Resources mResources = null;
MyImageCache mMemoryCache;
Activity activity;
public static final String LOGGER = "ImageLoader";
public ImageLoader(Activity context){
mExecutorService = Executors.newFixedThreadPool(5);
mImageHandler = new Handler();
mResources = context.getResources();
activity = context;
mMemoryCache = new MyImageCache();
mDisplayMetrics = context.getResources().getDisplayMetrics();
mRequiredWidth = mDisplayMetrics.widthPixels;
mRequiredHeight = mDisplayMetrics.heightPixels;
}
public void loadImage (String url,ImageView imageView){
try {
if (imageView != null) {
if (!toloadURL.contains(url)) {
toloadURL.add(url);
mExecutorService.execute(new ImageDownloader(url,imageView));
}
}
}catch (Exception e){
Log.v("Exception Occurs>>",""+e.getMessage());
}
}
class ImageDownloader implements Runnable{
String imageUrl;
ImageView downloadableImageView;
ImageDownloader loader;
ImageDownloader(String url,ImageView view){
Log.v(LOGGER,"Within ImageDownloader "+url +"this>>>"+this);
loader = this;
imageUrl = url;
downloadableImageView = view;
Log.v(LOGGER,"Within ImageDownloader "+downloadableImageView.getTag()+"this>>>"+this);
}
@Override
public void run() {
Log.v(LOGGER, "run" + downloadableImageView.getTag()+"this>>>>>"+this);
Bitmap tempBitmap = null;
tempBitmap = (mMemoryCache.getBitmapFromMemCache(imageUrl));
try{
if(tempBitmap!=null){
Log.v(LOGGER,"ImageBitmap Wid>>>>>>"+downloadableImageView.getTag()+"this>>>>"+this+""+tempBitmap.getWidth());
Log.v(LOGGER,"ImageBitmap Ht>>>>>>"+downloadableImageView.getTag()+ "this>>>>"+this+""+tempBitmap.getHeight());
downloadableImageView.setImageBitmap(tempBitmap);
}else{
Log.v(LOGGER, "else to download Tag is" + downloadableImageView.getTag()+"this>>>>>"+this);//Works till this point
final Bitmap tempBitmap1 = getBitmap(imageUrl);
Log.v(LOGGER, "else to download Tag is " + downloadableImageView.getTag() + "After Download>>>" + tempBitmap1.getWidth() + "this>>>>>" + this);//Issue happens here
mMemoryCache.addBitmapToMemoryCache(imageUrl, tempBitmap1);
Log.v("LOGGER, else to download Tag is "+downloadableImageView.getTag()+"After Cache>>>", "" + downloadableImageView.getTag()+"this>>>>"+this);
if(tempBitmap1!=null){
activity.runOnUiThread(new Runnable() {
@Override
public void run() {
Log.v("LOGGER, else to download Tag is "+downloadableImageView.getTag()+"RunOnUIThread>>>", "" + downloadableImageView.getTag()+"this>>>>"+loader);
downloadableImageView.setImageBitmap(tempBitmap1);
downloadableImageView.requestLayout();
}
});
}
}
}catch(Exception e){
Log.v("ExceptionBitmap",""+e.getMessage());
}
}
public Bitmap getBitmap(String imageUrl){
Bitmap bitmap=null;
try {
Log.v("Within getBitmap ","run");
URL uri = new URL(imageUrl);
HttpURLConnection connection = (HttpURLConnection)uri.openConnection();
connection.setInstanceFollowRedirects(true);
//bitmap = BitmapFactory.decodeStream(connection.getInputStream());
bitmap = decodeSampledBitmapFromInputStream(connection.getInputStream(), mRequiredWidth, mRequiredHeight);
} catch (Exception e) {
Log.v("ExceptionLoad",""+e.getMessage());
}
return bitmap;
}
}
public Bitmap decodeSampledBitmapFromInputStream(InputStream in
, int reqWidth, int reqHeight) {
InputStream copyiInputStream1 = null;
InputStream copyiInputStream2 = null;
try {
byte[] data = InputStreamTOByte(in);
copyiInputStream1 = byteTOInputStream(data);
copyiInputStream2 = byteTOInputStream(data);
} catch (Exception e) {
e.printStackTrace();
}
final BitmapFactory.Options options = new BitmapFactory.Options();
options.inJustDecodeBounds = true;
BitmapFactory.decodeStream(copyiInputStream1, null, options);
// Calculate inSampleSize
options.inSampleSize = calculateInSampleSize(options, reqWidth, reqHeight);
// Decode bitmap with inSampleSize set
options.inJustDecodeBounds = false;
return BitmapFactory.decodeStream(copyiInputStream2, null, options);
}
public static int calculateInSampleSize(
BitmapFactory.Options options, int reqWidth, int reqHeight) {
// Raw height and width of image
final int height = options.outHeight;
final int width = options.outWidth;
int inSampleSize = 1;
if (height > reqHeight || width > reqWidth) {
final int halfHeight = height / 2;
final int halfWidth = width / 2;
// Calculate the largest inSampleSize value that is a power of 2 and keeps both
// height and width larger than the requested height and width.
while ((halfHeight / inSampleSize) > reqHeight
&& (halfWidth / inSampleSize) > reqWidth) {
inSampleSize *= 2;
}
}
return inSampleSize;
}
public InputStream byteTOInputStream(byte[] in) throws Exception{
ByteArrayInputStream is = new ByteArrayInputStream(in);
return is;
}
public byte[] InputStreamTOByte(InputStream in) throws IOException {
ByteArrayOutputStream outStream = new ByteArrayOutputStream();
byte[] data = new byte[1024*16];
int count = -1;
while((count = in.read(data,0,1024*16)) != -1)
outStream.write(data, 0, count);
data = null;
return outStream.toByteArray();
}
class BitmapUpdater implements Runnable
{
Bitmap bitmap;
ImageView imageView;
public BitmapUpdater(Bitmap bitmap, ImageView imageView){
bitmap=bitmap;
imageView =imageView;
}
public void run()
{
// Show bitmap on UI
if(bitmap!=null){
activity.runOnUiThread(new Runnable() {
@Override
public void run() {
imageView.setImageBitmap(bitmap);
}
});
}
else
imageView.setImageResource(R.drawable.account_photo_book_detail2);
}
}
}
我已附上日志以供参考，请帮助解决此问题
Image Tag(0,1)--> I applied Tag for ImageView to sort out the Image View instance
04-06 17：05：57.662 20053-20053 / com.xxx.xxxxmobileapp V / ImageLoader：在ImageDownloader https://lh6.googleusercontent.com/-8HO-4vIFnlw/URquZnsFgtI/AAAAAAAAAbs/WT8jViTF7vw/s1024/Antelope%252520Hallway.jpgthis＆gt;＆gt;＆gt; com.xxx.xxxxmobileapp.Imagebook.network.ImageLoader $ ImageDownloader @ 435058b0 04-06 17：05：57.662 20053-20053 / com.xxx.xxxxmobileapp V / ImageLoader：在ImageDownloader 0（imageViewObjectTag）中，这是＆gt;＆gt;＆gt;＆gt;＆gt; com.xxx.xxxxmobileapp.Imagebook.network.ImageLoader $ ImageDownloader @
04-06 17：05：57.664 20053-20130 / com.xxx.xxxxmobileapp V / ImageLoader：否则下载Tag is0（imageViewObjectTag）这个＆gt;＆gt;＆gt;＆gt;＆gt; com.xxx.xxxxmobileapp.Imagebook。 network.ImageLoader$ImageDownloader@435058b0
04-06 17：05：57.666 20053-20053 / com.xxx.xxxxmobileapp V / ImageLoader：在ImageDownloader https://lh5.googleusercontent.com/-7qZeDtRKFKc/URquWZT1gOI/AAAAAAAAAbs/hqWgteyNXsg/s1024/Another%252520Rockaway%252520Sunset.jpgthis＆gt;＆gt;＆gt; com.xxx.xxxxmobileapp.Imagebook.network.ImageLoader $ ImageDownloader @ 431a5d58 04-06 17：05：57.666 20053-20053 / com.xxx.xxxxmobileapp V / ImageLoader：在ImageDownloader 1（imageView）中，这是＆gt;＆gt;＆gt;＆gt; com.xxx.xxxxmobileapp.Imagebook.network.ImageLoader$ImageDownloader@431a5d58
20053-20130 / com.xxx.xxxxmobileapp V / ImageLoader：运行0（imageViewObjectTag）这个＆gt;＆gt;＆gt;＆gt;＆gt; com.xxx.xxxxmobileapp.Imagebook.network.ImageLoader$ImageDownloader@435058b0 20053-20131 / com.xxx.xxxxmobileapp V / ImageLoader：运行1（imageViewObjectTag）这个＆gt;＆gt;＆gt;＆gt;＆gt; com.xxx.xxxxmobileapp.Imagebook.network.ImageLoader$ImageDownloader@431a5d58
否则下载Tag is1this＆gt;＆gt;＆gt;＆gt;＆gt; com.xxx.xxxxmobileapp.Imagebook.network.ImageLoader$ImageDownloader@431a5d58
否则下载标签为0（imageViewObjectTag）下载后＆gt;＆gt;＆gt;＆gt; 1024this＆gt;＆gt;＆gt;＆gt;＆gt; com.xxx.xxxxmobileapp.Imagebook.network.ImageLoader$ImageDownloader@435058b0 //（ImageDownloader1对象） ） 否则下载Tag为0（imageViewObjectTag）After Cache＆gt;＆gt;＆gt;：0这个＆gt;＆gt;＆gt;＆gt; com.xxx.xxxxmobileapp.Imagebook.network.ImageLoader$ImageDownloader@435058b0 //（ImageDownloader1 Object）） 否则下载标签为0（imageViewObjectTag）RunOnUIThread＆gt;＆gt;＆gt;：0这个＆gt;＆gt;＆gt;＆gt; com.xxx.xxxxmobileapp.Imagebook.network.ImageLoader$ImageDownloader@435058b0 //（ImageDownloader1对象））
一切都好，直到这一点
否则下载标签为0（imageViewObjectTag）下载＆gt;＆gt;＆gt; 1024this＆gt;＆gt;＆gt;＆gt;＆gt; com.xxx.xxxxmobileapp.Imagebook.network.ImageLoader$ImageDownloader@431a5d58 //（ImageDownloader2对象包含ImageView标签变为0不同，应该是tag1）） 否则下载Tag为0（imageViewObjectTag）After Cache＆gt;＆gt;＆gt;：0this＆gt;＆gt;＆gt;＆gt; com.xxx.xxxxmobileapp.Imagebook.network.ImageLoader$ImageDownloader@431a5d58 //（带有ImageView标签的ImageDownloader2对象来自0个不同的应该是tag1）） 否则下载标签为0（imageViewObjectTag）RunOnUIThread＆gt;＆gt;＆gt;：0这个＆gt;＆gt;＆gt;＆gt; com.xxx.xxxxmobileapp.Imagebook.network.ImageLoader$ImageDownloader@431a5d58 //（ImageDownloader2对象，ImageView标签为0不同的应该是tag1））
答案 0 :(得分：4)
为什么不使用Glide库进行图像下载？
它只需一行即可完成所有事情。
这是它的语法
Glide.with(context).load(URL).into(Imageview);
答案 1 :(得分：1)
我认为这是一个回收问题，问题是在下载完成后，初始ImageView可能代表列表中的另一个位置。你看到问题发生在getBitmap(imageUrl)调用之后，但从理论上讲，它也可能更早发生。我不确定您的代码中是否使用了BitmapUpdater，但初看起来，这与您的情况无关。
因此，为了解决此问题，您需要实现一种机制，以避免使用“旧”位图更新ImageView。您可以使用tag的{{1}}属性来保存需要显示的实际URL。如果图像ImageView中的URL与实际用于下载的URL不同，则只需缓存图像。你可以做点什么
tag和
public void loadImage (String url,ImageView imageView){
if(imageView != null) imageView.setTag(url);
[...]
}
另外，我建议避免使用if(tempBitmap1!=null){
activity.runOnUiThread(new Runnable() {
@Override
public void run() {
Log.v("LOGGER, else to download Tag is " + downloadableImageView.getTag()+"RunOnUIThread>>>", "" + downloadableImageView.getTag()+"this>>>>"+loader);
if(downloadableImageView.getTag().equals(imageUrl) {
downloadableImageView.setImageBitmap(tempBitmap1);
}
else Log.v(LOGGER, "the image no longer wants this URL, ignoring");
//downloadableImageView.requestLayout();
}
});
}
，因为它会导致整个布局被测量，在您的情况下，不需要它。
答案 2 :(得分：1)
是的，最终我通过我的朋友arunkumar
解决了问题感谢他：）
我尝试了两件事，
1）找出问题是列表视图或执行器服务实现。要找出我用线性布局替换列表视图并添加为成功工作的视图，这确认问题是listview而不是执行器服务实现。
2）图像在第一张图片中更新的真正问题是因为视图ID（ImageView.getID（））相同，
我设置了ID而不是设置标签，我将id传递给了图像加载器类，我通过findViewById（SetID）检索了图像，这是有用的
我正在添加一些有用的代码
final ImageView imageView = holder.jobImageView;
holder.jobImageView.setId(position);
loader.loadImage(object.getlargeImageUrl(),holder.jobImageView,position);
final Bitmap tempBitmap1 = getBitmap(imageUrl);
Log.v(LOGGER, "else to download Tag is " +imageViewId + "After Download>>>" + tempBitmap1.getWidth() + "this>>>>>" + this);
mMemoryCache.addBitmapToMemoryCache(imageUrl, tempBitmap1);
downloadableImageView = (ImageView)activity.findViewById(imageViewId);
Log.v("LOGGER, else to download Tag is "+downloadableImageView.getTag()+"After Cache>>>", "" + downloadableImageView.getTag()+"this>>>>"+this);
if(tempBitmap1!=null){
activity.runOnUiThread(new Runnable() {
@Override
public void run() {
Log.v("LOGGER, else to download Tag is " + downloadableImageView.getTag() + "RunOnUIThread>>>", "" + downloadableImageView.getTag() + "this>>>>" + loader);
downloadableImageView.setImageBitmap(tempBitmap1);
//downloadableImageView.requestLayout();
}
});
}
答案 3 :(得分：0)
您可以使用Picasso图像加载库 链接以获取Picasso
的文档答案 4 :(得分：0)
如果在本地存储或在线流中解码大位图这样繁重的工作，我们必须在工作线程中完成，问题是在完成解码后，imageview已被回收。解决它：
// In your adapter (onCreateView)
bitmap = yourBitmapCache.get(position);
if (bitmap != null)
yourImageView.setImageBitmap(bitmap);
else if (imageLoaderManager.isLoading.get(position) == false){
imagerLoaderManager.load(position, url);
}
// Create Callback interface
interface Callback {
void onFinishLoad(int position, Bitmap bm);
}
// Create inner class ImageLoaderManager
class ImageLoaderManager {
Hasmap<Integer, Boolean> isLoading = new Hasmap<>();
Callback callback = new Callback() {
@Override
void onFinishLoad(int position, Bitmap bitmap){
isLoading.put(position, false);
if (bitmap != null) {
yourBitmapCache.put(position, bitmap)
activity.runOnUiThread(new Runnable() {
@Override
public void run(){
notifyDataSetInvalidated();
// If you use recycler view adapter: notifyItemChanged(position)
}
});
}
}
};
public void load(int position, String url){
isLoading.put(position, true);
newYourImageLoader(url, position, callback).start();
// when loader finish job,
// it's must call back using callback.onFinishLoad(given position, bitmap result);
}
}
无需在我的解决方案中保留ImageView引用。只需记住position并要求适配器在解码任务完成后重新加载此位置的项目视图，现在yourBitmapCache中已存在位图。