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我在我的一個應用程序中使用Picasso下載大量圖像以備將來使用，因爲應用程序在登錄後將完全脫機。Picasso - java.lang.NullPointerException：key == null
所以後成功登錄，我試圖下載圖像中的AsyncTask與進展
爲了實現我寫了下面的代碼來下載一些圖片的目標
import java.util.ArrayList;
import java.util.Collections;
import java.util.Iterator;
import java.util.List;
import android.app.Activity;
import android.app.ProgressDialog;
import android.os.AsyncTask;
import android.os.Bundle;
import com.squareup.picasso.Picasso;
public class CacheActivity extends Activity {
int size = 0;
final List<String> urls = new ArrayList<String>();
int totalImageSize;
static Picasso picasso;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_cache);
Collections.addAll(urls, Data.URLS);
Collections.addAll(urls, Data.URLS);
Collections.addAll(urls, Data.URLS);
totalImageSize = urls.size();
picasso = Picasso.with(CacheActivity.this);
picasso.setDebugging(true);
new TestTask().execute();
}
public class TestTask extends AsyncTask<Void, Integer, Void>
{
ProgressDialog dialog;
@Override
protected void onPreExecute() {
dialog = new ProgressDialog(CacheActivity.this);
dialog.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL);
dialog.setMax(totalImageSize);
dialog.setMessage("1 - 100");
dialog.setCanceledOnTouchOutside(false);
dialog.show();
}
@Override
protected Void doInBackground(Void... params) {
for (Iterator iterator = urls.iterator(); iterator.hasNext();) {
final String url = (String) iterator.next();
try {
picasso.load(url).get();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
size = size + 1;
publishProgress(size);
System.out.println("CacheActivity.TestTask.doInBackground()");
}
return null;
}
@Override
protected void onPostExecute(Void result) {
dialog.dismiss();
}
}
}
但是，當我運行的應用程序，我收到以下錯誤
07-30 12:55:42.334: W/System.err(2369): java.lang.NullPointerException: key == null
07-30 12:55:42.334: W/System.err(2369): at com.squareup.picasso.LruCache.get(LruCache.java:50)
07-30 12:55:42.334: W/System.err(2369): at com.squareup.picasso.BitmapHunter.hunt(BitmapHunter.java:101)
07-30 12:55:42.334: W/System.err(2369): at com.squareup.picasso.RequestBuilder.get(RequestBuilder.java:305)
07-30 12:55:42.344: W/System.err(2369): at com.example.picasso.CacheActivity$TestTask.doInBackground(CacheActivity.java:61)
07-30 12:55:42.344: W/System.err(2369): at com.example.picasso.CacheActivity$TestTask.doInBackground(CacheActivity.java:1)
07-30 12:55:42.344: W/System.err(2369): at android.os.AsyncTask$2.call(AsyncTask.java:287)
07-30 12:55:42.344: W/System.err(2369): at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:305)
07-30 12:55:42.344: W/System.err(2369): at java.util.concurrent.FutureTask.run(FutureTask.java:137)
07-30 12:55:42.344: W/System.err(2369): at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:230)
07-30 12:55:42.344: W/System.err(2369): at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1076)
07-30 12:55:42.344: W/System.err(2369): at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:569)
07-30 12:55:42.344: W/System.err(2369): at java.lang.Thread.run(Thread.java:856)
07-30 12:55:42.334: W/System.err(2369): java.lang.NullPointerException: key == null
07-30 12:55:42.334: W/System.err(2369): at com.squareup.picasso.LruCache.get(LruCache.java:50)
07-30 12:55:42.334: W/System.err(2369): at com.squareup.picasso.BitmapHunter.hunt(BitmapHunter.java:101)
07-30 12:55:42.334: W/System.err(2369): at com.squareup.picasso.RequestBuilder.get(RequestBuilder.java:305)
07-30 12:55:42.344: W/System.err(2369): at com.example.picasso.CacheActivity$TestTask.doInBackground(CacheActivity.java:61)
07-30 12:55:42.344: W/System.err(2369): at com.example.picasso.CacheActivity$TestTask.doInBackground(CacheActivity.java:1)
07-30 12:55:42.344: W/System.err(2369): at android.os.AsyncTask$2.call(AsyncTask.java:287)
07-30 12:55:42.344: W/System.err(2369): at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:305)
07-30 12:55:42.344: W/System.err(2369): at java.util.concurrent.FutureTask.run(FutureTask.java:137)
07-30 12:55:42.344: W/System.err(2369): at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:230)
07-30 12:55:42.344: W/System.err(2369): at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1076)
07-30 12:55:42.344: W/System.err(2369): at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:569)
07-30 12:55:42.344: W/System.err(2369): at java.lang.Thread.run(Thread.java:856)
有什麼我做錯了嗎？
我在做類似的東西在這裏！HTTP：//stackoverflow.com/questions/18808114/picasso-loading-of-image-spawned-inside-asynctask – toobsco42