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서버에서 이미지를 표시하는 응용 프로그램이 있습니다. 이제는 내 이미지를 게으른로드합니다. 처음에는 진행률 표시 줄이 표시됩니다. 이미지로드가 완료되면 속성을 View.INVISIBLE으로 설정하여 진행률 표시 줄을 제거하고 이미지가 나타납니다. 이것은 진행률 표시 줄이 이미지를 화면에 표시하지만 손상을 사라 이미지진행률 막대가있는 이미지로드 지연 이미지가 표시 될 때 이미지가 손상됩니다.
<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:layout_gravity="center" >
<ImageView
android:id="@+id/imageView1"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:layout_gravity="center"
android:contentDescription="@string/app_name"
android:scaleType="centerInside"
android:src="@drawable/ic_launcher" />
<RelativeLayout
android:id="@+id/loading_layout"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:background="@android:color/white" >
<ProgressBar
android:id="@+id/progressBar1"
style="?android:attr/progressBarStyleSmall"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerHorizontal="true"
android:layout_centerVertical="true"
android:background="@android:color/white" />
</RelativeLayout>
</FrameLayout>
문제 에 내가 사용하는 레이아웃 파일입니다. 이 이미지처럼
캐시 디렉토리에서로드 된 이미지가 목록을 새로 고칠 때 화면에 표시 될 때 손상없이 올바르게 표시됩니다.
하여 ImageLoader 클래스 내가해서 ProgressDialog 대신하여 ProgressBar를 사용하는 게으른로드 이미지에
public class ImageLoader {
// @@ JUST FOR THIS PROJECT
BaseAdapter mAdapter;
// @@
MemoryCache memoryCache = new MemoryCache();
FileCache fileCache;
private Map<ImageView, String> imageViews = Collections
.synchronizedMap(new WeakHashMap<ImageView, String>());
ExecutorService executorService;
boolean addRoundCournerAndStroke = false;
boolean scale = false;
boolean localfile = false;
int default_image;
public ImageLoader(Context context, boolean flag, boolean scale,
boolean localfile) {
fileCache = new FileCache(context);
this.addRoundCournerAndStroke = flag;
executorService = Executors.newFixedThreadPool(5);
this.scale = scale;
this.localfile = localfile;
}
public ImageLoader(Context context, boolean flag, boolean scale,
boolean localfile, int default_image_id) {
this(context, flag, scale, localfile);
this.default_image = default_image_id;
}
public ImageLoader(Context context, boolean flag, boolean scale,
boolean localfile, int default_image_id, BaseAdapter adapter) {
this(context, flag, scale, localfile);
this.default_image = default_image_id;
this.mAdapter = adapter;
}
public void DisplayImage(String url, ImageView imageView) {
imageViews.put(imageView, url);
Bitmap bitmap = memoryCache.get(url);
if (bitmap != null) {
changeProgressBarVisibilty(imageView, false);
imageView.setImageBitmap(bitmap);
}
else {
queuePhoto(url, imageView);
imageView.setImageResource(this.default_image);
}
}
private void queuePhoto(String url, ImageView imageView) {
PhotoToLoad p = new PhotoToLoad(url, imageView);
executorService.submit(new PhotosLoader(p));
}
private Bitmap getBitmap(String url) {
File f = null;
if (localfile)
f = new File(url);
else
f = fileCache.getFile(url);
// Log.d("bytes", "decode");
// 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);
conn.setInstanceFollowRedirects(true);
InputStream is = conn.getInputStream();
OutputStream os = new FileOutputStream(f);
Utils.CopyStream(is, os);
os.close();
bitmap = decodeFile(f);
// //Log.d("bytes", "decode");
return bitmap;
} catch (Exception ex) {
ex.printStackTrace();
return null;
}
}
private Bitmap decodeFileWithoutScaling(File f) {
try {
BitmapFactory.Options o2 = new BitmapFactory.Options();
o2.inSampleSize = 1;
//o2.inPurgeable = true;
if (this.localfile)
return BitmapFactory.decodeFile(f.getAbsolutePath(), o2);
else
return BitmapFactory.decodeStream(new FileInputStream(f), null,
o2);
} catch (FileNotFoundException e) {
}
return null;
}
private Bitmap decodeFile(File f) {
if (this.scale) {
return decodeFileWithScalling(f);
} else {
return decodeFileWithoutScaling(f);
}
}
// decodes image and scales it to reduce memory consumption
private Bitmap decodeFileWithScalling(File f) {
try {
// decode image size
BitmapFactory.Options o = new BitmapFactory.Options();
o.inJustDecodeBounds = true;
// o.inPurgeable = true;
if (this.localfile)
BitmapFactory.decodeFile(f.getAbsolutePath(), o);
else
BitmapFactory.decodeStream(new FileInputStream(f), null, o);
// Find the correct scale value. It should be the power of 2.
final int REQUIRED_SIZE = 70;
int width_tmp = o.outWidth, height_tmp = o.outHeight;
// Log.d("width", width_tmp + "");
// Log.d("height", height_tmp + "");
int scale = 1;
while (true) {
if (width_tmp/2 < REQUIRED_SIZE
|| height_tmp/2 < REQUIRED_SIZE)
break;
width_tmp /= 2;
height_tmp /= 2;
scale *= 2;
}
// decode with inSampleSize
BitmapFactory.Options o2 = new BitmapFactory.Options();
o2.inSampleSize = scale;
// o2.inPurgeable = true;
// Log.d("after shave width", o2.outWidth + "");
// Log.d("after shave height", o2.outHeight + "");
if (this.localfile)
return BitmapFactory.decodeFile(f.getAbsolutePath(), o2);
else
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;
}
}
class PhotosLoader implements Runnable {
PhotoToLoad photoToLoad;
PhotosLoader(PhotoToLoad photoToLoad) {
this.photoToLoad = photoToLoad;
}
public void run() {
if (imageViewReused(photoToLoad)) {
return;
}
Bitmap bmp = getBitmap(photoToLoad.url);
// if (addRoundCournerAndStroke) {
// // bmp = ImageHelper.rotateAndFrame(bmp, 10);
// bmp = ImageHelper.getRoundedCornerBitmap(bmp, 10);
// }
memoryCache.put(photoToLoad.url, bmp);
if (imageViewReused(photoToLoad))
return;
BitmapDisplayer bd = new BitmapDisplayer(bmp, photoToLoad);
Activity a = (Activity) photoToLoad.imageView.getContext();
a.runOnUiThread(bd);
}
}
boolean imageViewReused(PhotoToLoad photoToLoad) {
String tag = imageViews.get(photoToLoad.imageView);
if (tag == null || !tag.equals(photoToLoad.url))
return true;
return false;
}
// Used to display bitmap in the UI thread
class BitmapDisplayer implements Runnable {
Bitmap bitmap;
PhotoToLoad photoToLoad;
public BitmapDisplayer(Bitmap b, PhotoToLoad p) {
bitmap = b;
photoToLoad = p;
}
public void run() {
if (imageViewReused(photoToLoad))
return;
changeProgressBarVisibilty(photoToLoad.imageView, false);
if (bitmap != null) {
photoToLoad.imageView.setImageBitmap(bitmap);
} else {
photoToLoad.imageView
.setImageResource(ImageLoader.this.default_image);
}
if (mAdapter != null) {
mAdapter.notifyDataSetChanged();
}
}
}
private void changeProgressBarVisibilty(ImageView image, boolean visible) {
ViewGroup layout = (ViewGroup) image.getParent();
try {
View v = layout.findViewById(R.id.loading_layout);
v.setVisibility(visible ? View.VISIBLE : View.GONE);
} catch (Exception ex) {
ex.printStackTrace();
}
}
public void clearCache() {
memoryCache.clear();
fileCache.clear();
}
}
이미지 로딩을 위해 [Universal Image Loader] (https://github.com/nostra13/Android-Universal-Image-Loader) 라이브러리를 사용해보십시오. 어쩌면이 문제가 없다. – NOSTRA
이미지가로드 될 때 진행 막대를 숨기는 대신 이미지보기를 표시합니다. 로드하기 전에 숨기기 ... – Ronnie