空指针异常,同时运行doInBackground方法 [英] null pointer exception while running doInBackground method
问题描述
我试图将文件上传到Dropbox的,我有一个还可以创建一个进度条来检查它的状态,但在执行它抛出异常。
我创建UploadFile类的一个对象,并调用UploadFile的功能,哪些是合格的UploadData.this,MAPI FILE_DIR,文件中的参数。
公共类UploadFile扩展的AsyncTask<无效,龙,布尔> {
私人DropboxAPI<> MAPI;
私人字符串的mpath;
私人文件MFILE;
私人长期mFileLen;
私人UploadRequest mRequest;
私人语境mContext;
私人最终ProgressDialog支持mDialog;
私人字符串mErrorMsg;
公共UploadFile(上下文的背景下,DropboxAPI<> API,弦乐dropboxPath,
档案文件)
{
mContext = context.getApplicationContext();
mFileLen = file.length();
MAPI = API;
的mpath = dropboxPath;
MFILE =文件; 支持mDialog =新ProgressDialog(背景);
mDialog.setMax(100);
mDialog.setMessage(上传+ file.getName());
mDialog.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL);
mDialog.setProgress(0);
mDialog.setButton(取消,新OnClickListener(){
公共无效的onClick(DialogInterface对话,诠释它){
//这将取消PUTFILE操作
mRequest.abort();
}
});
mDialog.show();
}@覆盖
保护布尔doInBackground(虚空...... PARAMS){
尝试{
FIS的FileInputStream =新的FileInputStream(MFILE);
字符串路径= +的mpath mFile.getName();
mRequest = mApi.putFileOverwriteRequest(路径,FIS,mFile.length()
新ProgressListener(){
@覆盖
众长progressInterval(){
返回500;
}
公共无效onProgress(长字节,长的总数){
publishProgress(字节);
}
}); 如果(mRequest!= NULL){
mRequest.upload();
返回true;
} }赶上(DropboxUnlinkedException E){
mErrorMsg =这个程序没有正确验证。
}赶上(DropboxFileSizeException E){
mErrorMsg =该文件是太大,无法上传;
}赶上(DropboxPartialFileException E){
mErrorMsg =上传取消;
}赶上(DropboxServerException E){
如果(e.error == DropboxServerException._401_UNAUTHORIZED){
}否则如果(e.error == DropboxServerException._403_FORBIDDEN){
}否则如果(e.error == DropboxServerException._404_NOT_FOUND){ }否则如果(e.error == DropboxServerException._507_INSUFFICIENT_STORAGE){
// 用户超出配额
}其他{
//别的东西
}
//这得到Dropbox的错误,翻译成用户的语言
mErrorMsg = e.body.userError;
如果(mErrorMsg == NULL){
mErrorMsg = e.body.error;
}
}赶上(DropboxIOException E){ mErrorMsg =网络错误重试。
}赶上(DropboxParseException E){
mErrorMsg =Dropbox的错误重试。
}赶上(DropboxException E){
mErrorMsg =未知错误,请重试。
}赶上(FileNotFoundException异常五){
}
返回false;
}@覆盖
保护无效onProgressUpdate(长...进度){
INT百分比=(INT)(100.0 *(双)进展[0] / mFileLen + 0.5);
mDialog.setProgress(百分比);
}@覆盖
保护无效onPostExecute(布尔结果){
mDialog.dismiss();
如果(结果){
showToast(图片上传成功);
}其他{
showToast(mErrorMsg);
}
}私人无效showToast(弦乐味精){
吐司错误= Toast.makeText(mContext,味精,Toast.LENGTH_LONG);
error.show();
}
}
下面是日志(我是新来这个,我不正确地理解日志)
6月6日至三十○日:18:34.400:W / dalvikvm(422):主题ID = 7:螺纹未捕获的异常退出(组= 0x4001d800)
6月6日至30日:18:34.410:E / AndroidRuntime(422):致命异常:AsyncTask的#1
6月6日至30日:18:34.410:E / AndroidRuntime(422):了java.lang.RuntimeException:执行doInBackground发生错误()
6月6日至30日:18:34.410:E / AndroidRuntime(422):在android.os.AsyncTask $ 3.done(AsyncTask.java:200)
6月6日至30日:18:34.410:E / AndroidRuntime(422):在java.util.concurrent.FutureTask中$ Sync.innerSetException(FutureTask.java:273)
6月6日至30日:18:34.410:E / AndroidRuntime(422):在java.util.concurrent.FutureTask.setException(FutureTask.java:124)
6月6日至30日:18:34.410:E / AndroidRuntime(422):在java.util.concurrent.FutureTask中$ Sync.innerRun(FutureTask.java:307)
6月6日至30日:18:34.410:E / AndroidRuntime(422):在java.util.concurrent.FutureTask.run(FutureTask.java:137)
6月6日至30日:18:34.410:E / AndroidRuntime(422):在java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1068)
6月6日至30日:18:34.410:E / AndroidRuntime(422):在java.util.concurrent.ThreadPoolExecutor中的$ Worker.run(ThreadPoolExecutor.java:561)
6月6日至30日:18:34.410:E / AndroidRuntime(422):在java.lang.Thread.run(Thread.java:1096)
6月6日至30日:18:34.410:E / AndroidRuntime(422):致:显示java.lang.NullPointerException
6月6日至30日:18:34.410:E / AndroidRuntime(422):在com.sachin.UploadFile.doInBackground(UploadFile.java:59)
6月6日至30日:18:34.410:E / AndroidRuntime(422):在com.sachin.UploadFile.doInBackground(UploadFile.java:1)
6月6日至30日:18:34.410:E / AndroidRuntime(422):在android.os.AsyncTask $ 2.call(AsyncTask.java:185)
6月6日至30日:18:34.410:E / AndroidRuntime(422):在java.util.concurrent.FutureTask中$ Sync.innerRun(FutureTask.java:305)
请确保您正确初始化
UploadRequest MAPI;
不这样做将导致一个 NullPointerException异常
在的onClick
方法被调用。
i am trying to upload a file to dropbox, i have a also create a progress bar to check its status but while executing it throws exception . i created a object of UploadFile class and call the UploadFile function and the argument which are pass are UploadData.this, mApi,FILE_DIR ,file.
public class UploadFile extends AsyncTask<Void, Long, Boolean> {
private DropboxAPI<?> mApi;
private String mPath;
private File mFile;
private long mFileLen;
private UploadRequest mRequest;
private Context mContext;
private final ProgressDialog mDialog;
private String mErrorMsg;
public UploadFile(Context context, DropboxAPI<?> api, String dropboxPath,
File file)
{
mContext = context.getApplicationContext();
mFileLen = file.length();
mApi = api;
mPath = dropboxPath;
mFile = file;
mDialog = new ProgressDialog(context);
mDialog.setMax(100);
mDialog.setMessage("Uploading " + file.getName());
mDialog.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL);
mDialog.setProgress(0);
mDialog.setButton("Cancel", new OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
// This will cancel the putFile operation
mRequest.abort();
}
});
mDialog.show();
}
@Override
protected Boolean doInBackground(Void... params) {
try {
FileInputStream fis = new FileInputStream(mFile);
String path = mPath + mFile.getName();
mRequest = mApi.putFileOverwriteRequest(path, fis, mFile.length(),
new ProgressListener() {
@Override
public long progressInterval() {
return 500;
}
public void onProgress(long bytes, long total) {
publishProgress(bytes);
}
});
if (mRequest != null) {
mRequest.upload();
return true;
}
} catch (DropboxUnlinkedException e) {
mErrorMsg = "This app wasn't authenticated properly.";
} catch (DropboxFileSizeException e) {
mErrorMsg = "This file is too big to upload";
} catch (DropboxPartialFileException e) {
mErrorMsg = "Upload canceled";
} catch (DropboxServerException e) {
if (e.error == DropboxServerException._401_UNAUTHORIZED) {
} else if (e.error == DropboxServerException._403_FORBIDDEN) {
} else if (e.error == DropboxServerException._404_NOT_FOUND) {
} else if (e.error == DropboxServerException._507_INSUFFICIENT_STORAGE) {
// user is over quota
} else {
// Something else
}
// This gets the Dropbox error, translated into the user's language
mErrorMsg = e.body.userError;
if (mErrorMsg == null) {
mErrorMsg = e.body.error;
}
} catch (DropboxIOException e) {
mErrorMsg = "Network error. Try again.";
} catch (DropboxParseException e) {
mErrorMsg = "Dropbox error. Try again.";
} catch (DropboxException e) {
mErrorMsg = "Unknown error. Try again.";
} catch (FileNotFoundException e) {
}
return false;
}
@Override
protected void onProgressUpdate(Long... progress) {
int percent = (int)(100.0*(double)progress[0]/mFileLen + 0.5);
mDialog.setProgress(percent);
}
@Override
protected void onPostExecute(Boolean result) {
mDialog.dismiss();
if (result) {
showToast("Image successfully uploaded");
} else {
showToast(mErrorMsg);
}
}
private void showToast(String msg) {
Toast error = Toast.makeText(mContext, msg, Toast.LENGTH_LONG);
error.show();
}
}
here is the log (i am new to this and i don't understand the log properly)
06-30 06:18:34.400: W/dalvikvm(422): threadid=7: thread exiting with uncaught exception (group=0x4001d800)
06-30 06:18:34.410: E/AndroidRuntime(422): FATAL EXCEPTION: AsyncTask #1
06-30 06:18:34.410: E/AndroidRuntime(422): java.lang.RuntimeException: An error occured while executing doInBackground()
06-30 06:18:34.410: E/AndroidRuntime(422): at android.os.AsyncTask$3.done(AsyncTask.java:200)
06-30 06:18:34.410: E/AndroidRuntime(422): at java.util.concurrent.FutureTask$Sync.innerSetException(FutureTask.java:273)
06-30 06:18:34.410: E/AndroidRuntime(422): at java.util.concurrent.FutureTask.setException(FutureTask.java:124)
06-30 06:18:34.410: E/AndroidRuntime(422): at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:307)
06-30 06:18:34.410: E/AndroidRuntime(422): at java.util.concurrent.FutureTask.run(FutureTask.java:137)
06-30 06:18:34.410: E/AndroidRuntime(422): at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1068)
06-30 06:18:34.410: E/AndroidRuntime(422): at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:561)
06-30 06:18:34.410: E/AndroidRuntime(422): at java.lang.Thread.run(Thread.java:1096)
06-30 06:18:34.410: E/AndroidRuntime(422): Caused by: java.lang.NullPointerException
06-30 06:18:34.410: E/AndroidRuntime(422): at com.sachin.UploadFile.doInBackground(UploadFile.java:59)
06-30 06:18:34.410: E/AndroidRuntime(422): at com.sachin.UploadFile.doInBackground(UploadFile.java:1)
06-30 06:18:34.410: E/AndroidRuntime(422): at android.os.AsyncTask$2.call(AsyncTask.java:185)
06-30 06:18:34.410: E/AndroidRuntime(422): at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:305)
Make sure you properly initialize
UploadRequest mApi;
as not doing so will cause a NullPointerException
when the onClick
method is called.
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