任何人都可以在android中使用dropbox上传文件时找到空指针异常的原因。下面是我的代码。我给出的“uFilePath”值是“/mnt/sdcard/Download/myImg.jpg”，其中myImg。 jpg是我要上传的文件...
@Override
protected Boolean doInBackground(Void... params) {
// TODO Auto-generated method stub
FileInputStream fis=null;
File file= new File(uFilePath, "myImg.jpg");
uFileLen=file.length();
try {
fis = new FileInputStream(file);
System.out.println("file="+file.getName()+" "+fis.toString()+" "+file.getPath());
DropboxAPI.Entry newEntry = uDBApi.putFileOverwrite("myImg.jpg", fis, uFileLen, null);
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (DropboxException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}finally {
if (fis != null) {
try {
fis.close();
} catch (IOException e) {}
}
}
return null;
}
这是logcat消息----
09-22 03:27:17.335: E/AndroidRuntime(10331): FATAL EXCEPTION: AsyncTask #1
09-22 03:27:17.335: E/AndroidRuntime(10331): java.lang.RuntimeException: An error occured while executing doInBackground()
09-22 03:27:17.335: E/AndroidRuntime(10331): at android.os.AsyncTask$3.done(AsyncTask.java:278)
09-22 03:27:17.335: E/AndroidRuntime(10331): at java.util.concurrent.FutureTask$Sync.innerSetException(FutureTask.java:273)
09-22 03:27:17.335: E/AndroidRuntime(10331): at java.util.concurrent.FutureTask.setException(FutureTask.java:124)
09-22 03:27:17.335: E/AndroidRuntime(10331): at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:307)
09-22 03:27:17.335: E/AndroidRuntime(10331): at java.util.concurrent.FutureTask.run(FutureTask.java:137)
09-22 03:27:17.335: E/AndroidRuntime(10331): at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1076)
09-22 03:27:17.335: E/AndroidRuntime(10331): at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:569)
09-22 03:27:17.335: E/AndroidRuntime(10331): at java.lang.Thread.run(Thread.java:856)
09-22 03:27:17.335: E/AndroidRuntime(10331): Caused by: java.lang.NullPointerException
09-22 03:27:17.335: E/AndroidRuntime(10331): at com.example.downloadupload.UploadPicture.doInBackground(UploadPicture.java:63)
09-22 03:27:17.335: E/AndroidRuntime(10331): at com.example.downloadupload.UploadPicture.doInBackground(UploadPicture.java:1)
09-22 03:27:17.335: E/AndroidRuntime(10331): at android.os.AsyncTask$2.call(AsyncTask.java:264)
09-22 03:27:17.335: E/AndroidRuntime(10331): at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:305)
09-22 03:27:17.335: E/AndroidRuntime(10331): ... 4 more
09-22 03:27:25.343: E/WindowManager(10331): Activity com.example.downloadupload.MainActivity has leaked window com.android.internal.policy.impl.PhoneWindow$DecorView@41275178 that was originally added here
09-22 03:27:25.343: E/WindowManager(10331): android.view.WindowLeaked: Activity com.example.downloadupload.MainActivity has leaked window com.android.internal.policy.impl.PhoneWindow$DecorView@41275178 that was originally added here
09-22 03:27:25.343: E/WindowManager(10331): at android.view.ViewRootImpl.<init>(ViewRootImpl.java:383)
09-22 03:27:25.343: E/WindowManager(10331): at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:279)
09-22 03:27:25.343: E/WindowManager(10331): at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:215)
09-22 03:27:25.343: E/WindowManager(10331): at android.view.WindowManagerImpl$CompatModeWrapper.addView(WindowManagerImpl.java:140)
09-22 03:27:25.343: E/WindowManager(10331): at android.view.Window$LocalWindowManager.addView(Window.java:537)
09-22 03:27:25.343: E/WindowManager(10331): at android.app.Dialog.show(Dialog.java:278)
09-22 03:27:25.343: E/WindowManager(10331): at com.example.downloadupload.UploadPicture.<init>(UploadPicture.java:52)
09-22 03:27:25.343: E/WindowManager(10331): at com.example.downloadupload.MainActivity.onClick(MainActivity.java:66)
09-22 03:27:25.343: E/WindowManager(10331): at android.view.View.performClick(View.java:3558)
09-22 03:27:25.343: E/WindowManager(10331): at android.view.View$PerformClick.run(View.java:14157)
09-22 03:27:25.343: E/WindowManager(10331): at android.os.Handler.handleCallback(Handler.java:605)
09-22 03:27:25.343: E/WindowManager(10331): at android.os.Handler.dispatchMessage(Handler.java:92)
09-22 03:27:25.343: E/WindowManager(10331): at android.os.Looper.loop(Looper.java:137)
09-22 03:27:25.343: E/WindowManager(10331): at android.app.ActivityThread.main(ActivityThread.java:4514)
09-22 03:27:25.343: E/WindowManager(10331): at java.lang.reflect.Method.invokeNative(Native Method)
09-22 03:27:25.343: E/WindowManager(10331): at java.lang.reflect.Method.invoke(Method.java:511)
09-22 03:27:25.343: E/WindowManager(10331): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:790)
09-22 03:27:25.343: E/WindowManager(10331): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:557)
09-22 03:27:25.343: E/WindowManager(10331): at dalvik.system.NativeStart.main(Native Method)