我是Android新手。我在使用AsyncTask时遇到了麻烦。
我正在尝试创建一个图片库。在我的图库中有小尺寸图片，当您点击其中一张图片时，该图片的大尺寸会显示在下面的ImageView中。我使用了两个不同的AsyncTask类。其中一个是从主机获取小尺寸图片，另一个是当您点击图库中的一张图片时从主机获取大尺寸图片。
我可以加载图库图片但是当我点击其中一个图库图片时，我无法在ImageView中显示大尺寸图片。
如果您帮助我或提供任何建议，我将不胜感激......
我的代码是：
public class GalleryView extends Activity{
String[] smallpicsURL ={
"http://egtxxxxx.com/jImages/antartica1.jpg",
"http://egtxxxxx.com/jImages/antartica2.jpg",
"http://egtxxxxx.com/jImages/antartica3.jpg",
"http://egtxxxxx.com/jImages/antartica4.jpg",
"http://egtxxxxx.com/jImages/antartica5.jpg",
"http://egtxxxxx.com/jImages/antartica6.jpg",
"http://egtxxxxx.com/jImages/antartica7.jpg",
"http://egtxxxxx.com/jImages/antartica8.jpg",
"http://egtxxxxx.com/jImages/antartica9.jpg",
"http://egtxxxxx.com/jImages/antartica10.jpg"
};
String[] bigpicsURL ={
"http://egtxxxxx.com/jImages/b_antartica1.jpg",
"http://egtxxxxx.com/jImages/b_antartica2.jpg",
"http://egtxxxxx.com/jImages/b_antartica3.jpg",
"http://egtxxxxx.com/jImages/b_antartica4.jpg",
"http://egtxxxxx.com/jImages/b_antartica5.jpg",
"http://egtxxxxx.com/jImages/b_antartica6.jpg",
"http://egtxxxxx.com/jImages/b_antartica7.jpg",
"http://egtxxxxx.com/jImages/b_antartica8.jpg",
"http://egtxxxxx.com/jImages/b_antartica9.jpg",
"http://egtxxxxx.com/jImages/b_antartica10.jpg"
};
Bitmap pics[];
Bitmap bigPic;
ImageView imageView;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.gallery);
Gallery ga = (Gallery)findViewById(R.id.galleryKBU);
pics=new Bitmap[smallpicsURL.length];
new FetchSmallBitmap().execute();
ga.setAdapter(new ImageAdapter(this));
try {
Thread.sleep(700);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
imageView = (ImageView)findViewById(R.id.ivKBU);
ga.setOnItemClickListener(new OnItemClickListener() {
public void onItemClick(AdapterView<?> arg0, View arg1, int arg2,
long arg3) {
Toast.makeText(getBaseContext(),"Çağdaş Eğitim Yuvası", Toast.LENGTH_SHORT).show();
new FetchBigBitmap().execute(arg2);
//imageView.setImageBitmap(bigPic);
}
});
}
private Bitmap downloadPictures(int i) {
String urlStr=smallpicsURL[i];
try {
URL url = new URL(urlStr);
final URLConnection conn = url.openConnection();
conn.connect();
final BufferedInputStream bis = new BufferedInputStream(conn.getInputStream());
final Bitmap bm = BitmapFactory.decodeStream(bis);
bis.close();
return bm;
} catch (IOException e) {
Log.d("DEBUGTAG",". Resim indirmede hata...");
}
return null;
}
private Bitmap downloadBigPictures(int i) {
String urlStr=bigpicsURL[i];
try {
URL url = new URL(urlStr);
final URLConnection conn = url.openConnection();
conn.connect();
final BufferedInputStream bis = new BufferedInputStream(conn.getInputStream());
final Bitmap bm = BitmapFactory.decodeStream(bis);
bis.close();
return bm;
} catch (IOException e) {
Log.d("DEBUGTAG",". Resim indirmede hata...");
}
return null;
}
private class FetchSmallBitmap extends AsyncTask<Void, Integer, Bitmap[]> {
private ProgressDialog dialog = new ProgressDialog(GalleryView.this);
protected void onPreExecute(){
dialog.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL);
dialog.setMax(100);
dialog.setMessage("Resimler yükleniyor");
dialog.show();
}
@Override
protected Bitmap[] doInBackground (Void ...params) {
for(int i=0;i<10;i++){
pics[i]=downloadPictures(i);
publishProgress(10);
}
return pics;
}
protected void onProgressUpdate(Integer ...progress){
dialog.incrementProgressBy(progress[0]);
}
protected void onPostExecute(Bitmap[] mbitmap) {
dialog.dismiss();
}
}
public class ImageAdapter extends BaseAdapter {
private Context ctx;
int imageBackground;
public ImageAdapter(Context c) {
ctx = c;
TypedArray ta = obtainStyledAttributes(R.styleable.gallery_KBU);
imageBackground = ta.getResourceId(R.styleable.gallery_KBU_android_galleryItemBackground, 1);
ta.recycle();
}
public int getCount() {
return pics.length;
}
public Object getItem(int arg0) {
return arg0;
}
public long getItemId(int arg0) {
return arg0;
}
public View getView(int arg0, View arg1, ViewGroup arg2) {
ImageView iv = new ImageView(ctx);
iv.setImageBitmap(pics[arg0]);
iv.setScaleType(ImageView.ScaleType.FIT_XY);
iv.setLayoutParams(new Gallery.LayoutParams(150,120));
iv.setBackgroundResource(imageBackground);
return iv;
}
}
private class FetchBigBitmap extends AsyncTask<Integer, Integer, Bitmap> {
private ProgressDialog dialog = new ProgressDialog(GalleryView.this);
protected void onPreExecute(){
dialog.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL);
dialog.setMax(100);
dialog.setMessage("Resimler yükleniyor");
dialog.show();
}
@Override
protected Bitmap doInBackground (Integer ...params) {
imageView.setImageBitmap(downloadBigPictures(params[0]));
return null;
}
protected void onProgressUpdate(Integer ...progress){
dialog.incrementProgressBy(progress[0]);
}
protected void onPostExecute(Bitmap x) {
dialog.dismiss();
}
}
}
我收到如下错误消息：
08-18 15:23:11.477: E/AndroidRuntime(15005): FATAL EXCEPTION: AsyncTask #2
08-18 15:23:11.477: E/AndroidRuntime(15005): java.lang.RuntimeException: An error occured while executing doInBackground()
08-18 15:23:11.477: E/AndroidRuntime(15005): at android.os.AsyncTask$3.done(AsyncTask.java:200)
08-18 15:23:11.477: E/AndroidRuntime(15005): at java.util.concurrent.FutureTask$Sync.innerSetException(FutureTask.java:273)
08-18 15:23:11.477: E/AndroidRuntime(15005): at java.util.concurrent.FutureTask.setException(FutureTask.java:124)
08-18 15:23:11.477: E/AndroidRuntime(15005): at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:307)
08-18 15:23:11.477: E/AndroidRuntime(15005): at java.util.concurrent.FutureTask.run(FutureTask.java:137)
08-18 15:23:11.477: E/AndroidRuntime(15005): at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1068)
08-18 15:23:11.477: E/AndroidRuntime(15005): at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:561)
08-18 15:23:11.477: E/AndroidRuntime(15005): at java.lang.Thread.run(Thread.java:1096)
08-18 15:23:11.477: E/AndroidRuntime(15005): Caused by: android.view.ViewRoot$CalledFromWrongThreadException: Only the original thread that created a view hierarchy can touch its views.
08-18 15:23:11.477: E/AndroidRuntime(15005): at android.view.ViewRoot.checkThread(ViewRoot.java:2812)
08-18 15:23:11.477: E/AndroidRuntime(15005): at android.view.ViewRoot.requestLayout(ViewRoot.java:594)
08-18 15:23:11.477: E/AndroidRuntime(15005): at android.view.View.requestLayout(View.java:8125)
08-18 15:23:11.477: E/AndroidRuntime(15005): at android.view.View.requestLayout(View.java:8125)
08-18 15:23:11.477: E/AndroidRuntime(15005): at android.view.View.requestLayout(View.java:8125)
08-18 15:23:11.477: E/AndroidRuntime(15005): at android.view.View.requestLayout(View.java:8125)
08-18 15:23:11.477: E/AndroidRuntime(15005): at android.view.View.requestLayout(View.java:8125)
08-18 15:23:11.477: E/AndroidRuntime(15005): at android.widget.ImageView.setImageDrawable(ImageView.java:310)
08-18 15:23:11.477: E/AndroidRuntime(15005): at android.widget.ImageView.setImageBitmap(ImageView.java:324)
08-18 15:23:11.477: E/AndroidRuntime(15005): at com.kbu.bilgisistemi.GalleryView$FetchBigBitmap.doInBackground(GalleryView.java:258)
08-18 15:23:11.477: E/AndroidRuntime(15005): at com.kbu.bilgisistemi.GalleryView$FetchBigBitmap.doInBackground(GalleryView.java:1)
08-18 15:23:11.477: E/AndroidRuntime(15005): at android.os.AsyncTask$2.call(AsyncTask.java:185)
08-18 15:23:11.477: E/AndroidRuntime(15005): at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:305)
08-18 15:23:11.477: E/AndroidRuntime(15005): ... 4 more
08-18 15:23:11.687: E/WindowManager(15005): Activity com.kbu.bilgisistemi.GalleryView has leaked window com.android.internal.policy.impl.PhoneWindow$DecorView@4a514158 that was originally added here
08-18 15:23:11.687: E/WindowManager(15005): android.view.WindowLeaked: Activity com.kbu.bilgisistemi.GalleryView has leaked window com.android.internal.policy.impl.PhoneWindow$DecorView@4a514158 that was originally added here
08-18 15:23:11.687: E/WindowManager(15005): at android.view.ViewRoot.<init>(ViewRoot.java:247)
08-18 15:23:11.687: E/WindowManager(15005): at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:148)
08-18 15:23:11.687: E/WindowManager(15005): at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:91)
08-18 15:23:11.687: E/WindowManager(15005): at android.view.Window$LocalWindowManager.addView(Window.java:424)
08-18 15:23:11.687: E/WindowManager(15005): at android.app.Dialog.show(Dialog.java:241)
08-18 15:23:11.687: E/WindowManager(15005): at com.kbu.bilgisistemi.GalleryView$FetchBigBitmap.onPreExecute(GalleryView.java:253)
08-18 15:23:11.687: E/WindowManager(15005): at android.os.AsyncTask.execute(AsyncTask.java:391)
08-18 15:23:11.687: E/WindowManager(15005): at com.kbu.bilgisistemi.GalleryView$1.onItemClick(GalleryView.java:102)
08-18 15:23:11.687: E/WindowManager(15005): at android.widget.AdapterView.performItemClick(AdapterView.java:284)
08-18 15:23:11.687: E/WindowManager(15005): at android.widget.Gallery.onSingleTapUp(Gallery.java:864)
08-18 15:23:11.687: E/WindowManager(15005): at android.view.GestureDetector.onTouchEvent(GestureDetector.java:557)
08-18 15:23:11.687: E/WindowManager(15005): at android.widget.Gallery.onTouchEvent(Gallery.java:839)
08-18 15:23:11.687: E/WindowManager(15005): at android.view.View.dispatchTouchEvent(View.java:3766)
08-18 15:23:11.687: E/WindowManager(15005): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:897)
08-18 15:23:11.687: E/WindowManager(15005): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:936)
08-18 15:23:11.687: E/WindowManager(15005): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:936)
08-18 15:23:11.687: E/WindowManager(15005): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:936)
08-18 15:23:11.687: E/WindowManager(15005): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:936)
08-18 15:23:11.687: E/WindowManager(15005): at com.android.internal.policy.impl.PhoneWindow$DecorView.superDispatchTouchEvent(PhoneWindow.java:1731)
08-18 15:23:11.687: E/WindowManager(15005): at com.android.internal.policy.impl.PhoneWindow.superDispatchTouchEvent(PhoneWindow.java:1120)
08-18 15:23:11.687: E/WindowManager(15005): at android.app.Activity.dispatchTouchEvent(Activity.java:2086)
08-18 15:23:11.687: E/WindowManager(15005): at com.android.internal.policy.impl.PhoneWindow$DecorView.dispatchTouchEvent(PhoneWindow.java:1715)
08-18 15:23:11.687: E/WindowManager(15005): at android.view.ViewRoot.handleMessage(ViewRoot.java:1787)
08-18 15:23:11.687: E/WindowManager(15005): at android.os.Handler.dispatchMessage(Handler.java:99)
08-18 15:23:11.687: E/WindowManager(15005): at android.os.Looper.loop(Looper.java:123)
08-18 15:23:11.687: E/WindowManager(15005): at android.app.ActivityThread.main(ActivityThread.java:4633)
08-18 15:23:11.687: E/WindowManager(15005): at java.lang.reflect.Method.invokeNative(Native Method)
08-18 15:23:11.687: E/WindowManager(15005): at java.lang.reflect.Method.invoke(Method.java:521)
08-18 15:23:11.687: E/WindowManager(15005): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:858)
08-18 15:23:11.687: E/WindowManager(15005): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
08-18 15:23:11.687: E/WindowManager(15005): at dalvik.system.NativeStart.main(Native Method)
答案 0 :(得分：1)
您无法在非UI线程上执行以下操作。你正在doinbackground做一个Ui操作。
imageView.setImageBitmap(downloadBigPictures(params[0]));
将上一行移至OnpostExecute。
您只需设置图像
就不需要Asynctask