Question

我有这个活动拍照并发送到亚马逊，但如果我在上传时关闭互联网，APP崩溃。我需要暂停异步并将警告发送到下一个活动

活动：

public void takeASelfie() {
    selfieController.takeASelfie();
}

public void useCamera() {

    Intent takePictureIntent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
    if (takePictureIntent.resolveActivity(getPackageManager()) != null) {
        // Create the File where the photo should go
        try {
            photoFile = createImageFile();
        } catch (IOException ex) {
            // Error occurred while creating the File
        }
        // Continue only if the File was successfully created
        if (photoFile != null) {
            takePictureIntent.putExtra(MediaStore.EXTRA_OUTPUT,
                    Uri.fromFile(photoFile));
            startActivityForResult(takePictureIntent, REQUEST_IMAGE_CAPTURE);
        }
    }
}

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
    super.onActivityResult(requestCode, resultCode, data);
    if (requestCode == REQUEST_IMAGE_CAPTURE && resultCode == RESULT_OK) {
        if (photoFile != null) {
            imageUri = Uri.fromFile(photoFile);

            Intent intent = new Intent(SelfieUI.this, PicturePreview.class);
            Bundle bundle = new Bundle();
            bundle.putSerializable(PicturePreview.NAME, name);
            bundle.putSerializable(PicturePreview.STEP, 1);
            bundle.putSerializable(PicturePreview.URI_PHOTO, imageUri.toString());
            intent.putExtras(bundle);
            SelfieUI.this.startActivity(intent);
        }
    }
}

private File createImageFile() throws IOException {
    // Create an image file name
    String timeStamp = new SimpleDateFormat("yyyyMMdd_HHmmss").format(new Date());
    String imageFileName = "JPEG_" + timeStamp;
    File storageDir = Environment.getExternalStoragePublicDirectory(
            Environment.DIRECTORY_PICTURES);
    File image = File.createTempFile(
            imageFileName,  /* prefix */
            ".jpg",         /* suffix */
            storageDir      /* directory */
    );

    // Save a file: path for use with ACTION_VIEW intents
    mCurrentPhotoPath = "file:" + image.getAbsolutePath();
    return image;
}

public void sendPicture(Boolean shouldSend) {
    if (shouldSend) {
        amazon();
    }
}

@Override
protected void onNewIntent(Intent intent) {
    super.onNewIntent(intent);
    setIntent(intent);
    //now getIntent() should always return the last received intent
}

public void amazon() {
    String fileName = photoFile.getName();
    long mTotalFileBytes;

    ObjectMetadata metadata = new ObjectMetadata();

    metadata.setContentLength(mTotalFileBytes = photoFile.length());
    metadata.setContentType("image/".concat(fileName));

    CognitoCachingCredentialsProvider credentialsProvider = new CognitoCachingCredentialsProvider(
            getApplicationContext(),
            "us-east-1:d6932c78-dadd-45bc-98d0-f89673a13c31",
            Regions.US_EAST_1
    );

    amazonS3Client = new AmazonS3Client(credentialsProvider);
    amazonS3Client.setRegion(Region.getRegion(Regions.SA_EAST_1));
    try {
        por = new PutObjectRequest(bucket, fileName, new FileInputStream(photoFile), metadata);

        postImageAsyncTask = new PostImageAsyncTask(0);
        postImageAsyncTask.executeOnExecutor(AsyncTask.THREAD_POOL_EXECUTOR);
    } catch (FileNotFoundException e) {
        e.printStackTrace();
    }
    amazonUrl = amazonS3Client.getResourceUrl(bucket, fileName);
    Log.e(">>>>>URL", ">>>>>" + amazonUrl);


}

public void finishTakingASelfie(Picture picture) {
    if (picture != null) {
        Intent intent = new Intent(SelfieUI.this, InformationStatusUI.class);
        Bundle bundle = new Bundle();
        bundle.putSerializable(InformationStatusUI.NAME, name);
        bundle.putSerializable(InformationStatusUI.STAGE, 3);
        bundle.putSerializable(InformationStatusUI.SELF_URL, picture.getSelfieURL());
        intent.putExtras(bundle);
        SelfieUI.this.startActivity(intent);
    } else {
        Intent intent = new Intent(SelfieUI.this, InformationStatusUI.class);
        Bundle bundle = new Bundle();
        bundle.putSerializable(InformationStatusUI.NAME, name);
        bundle.putSerializable(InformationStatusUI.STAGE, 3);
        intent.putExtras(bundle);
        SelfieUI.this.startActivity(intent);
    }
}

异步任务：

public class PostImageAsyncTask extends AsyncTask<Object, Object, PutObjectResult> {
    int backoff = 0;

    public PostImageAsyncTask(Integer backoff) {
        super();
        this.backoff = backoff;

    }

    @Override
    protected void onPreExecute() {
        ConnectivityManager cm =
                (ConnectivityManager) SelfieUI.this.getSystemService(Context.CONNECTIVITY_SERVICE);

        NetworkInfo activeNetwork = cm.getActiveNetworkInfo();
        boolean isConnected = activeNetwork != null &&
                activeNetwork.isConnectedOrConnecting();

        if (!isConnected) {
            if (postImageAsyncTask != null && postImageAsyncTask.getStatus() != AsyncTask.Status.FINISHED)
                postImageAsyncTask.cancel(true);
            handler.postDelayed(new Runnable() {
                @Override
                public void run() {
                    RECONECT_TIME_DELAY = RECONECT_TIME_DELAY * 2;
                    postImageAsyncTask = new PostImageAsyncTask(0);
                    postImageAsyncTask.executeOnExecutor(AsyncTask.THREAD_POOL_EXECUTOR);
                }
            }, RECONECT_TIME_DELAY);
        }
    }

    @Override
    protected PutObjectResult doInBackground(Object... params) {
        return amazonS3Client.putObject(por);

    }

    @Override
    protected void onPostExecute(PutObjectResult result) {
        if (!isCancelled()) {
            Log.e(">>>>>result", ">>>>>" + result.getContentMd5());
            Toast toast = Toast.makeText(SelfieUI.this, result.getContentMd5(), Toast.LENGTH_LONG);
            toast.show();
            if (result != null) {
                selfieController.picturePostedToS3(amazonUrl);
            }
        } else {
            postImageAsyncTask.cancel(true);
        }
    }
}
}

堆栈追踪：

/AndroidRuntime: FATAL EXCEPTION: AsyncTask #1
                                                               Process: com.foregon.forid, PID: 30963
                                                               java.lang.RuntimeException: An error occured while executing doInBackground()
                                                                   at android.os.AsyncTask$3.done(AsyncTask.java:300)
                                                                   at java.util.concurrent.FutureTask.finishCompletion(FutureTask.java:355)
                                                                   at java.util.concurrent.FutureTask.setException(FutureTask.java:222)
                                                                   at java.util.concurrent.FutureTask.run(FutureTask.java:242)
                                                                   at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112)
                                                                   at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587)
                                                                   at java.lang.Thread.run(Thread.java:818)
                                                                Caused by: com.amazonaws.AmazonClientException: Unable to execute HTTP request: Write error: ssl=0xb8a8cc08: I/O error during system call, Connection timed out
                                                                   at com.amazonaws.http.AmazonHttpClient.executeHelper(AmazonHttpClient.java:421)
                                                                   at com.amazonaws.http.AmazonHttpClient.execute(AmazonHttpClient.java:196)
                                                                   at com.amazonaws.services.s3.AmazonS3Client.invoke(AmazonS3Client.java:4204)
                                                                   at com.amazonaws.services.s3.AmazonS3Client.putObject(AmazonS3Client.java:1618)
                                                                   at com.foregon.forid.pictureManagement.boundary.SelfieUI$PostImageAsyncTask.doInBackground(SelfieUI.java:432)
                                                                   at com.foregon.forid.pictureManagement.boundary.SelfieUI$PostImageAsyncTask.doInBackground(SelfieUI.java:402)

Answer 1

首先创建一个用于检查网络连接的类，如下所示：

public class ConnectionDetector {

    private Context context;

    public ConnectionDetector(Context context){
        this.context = context;
    }

    public boolean isConnectedToInternet(){

        ConnectivityManager connectivity = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
          if (connectivity != null) 
          {
              NetworkInfo[] info = connectivity.getAllNetworkInfo();
              if (info != null) 
                  for (int i = 0; i < info.length; i++) 
                      if (info[i].getState() == NetworkInfo.State.CONNECTED)
                      {
                          return true;
                      }

          }
          return false;
    }
}

然后在后台调用call方法以检查网络连接，如下所示：

@Override
protected PutObjectResult doInBackground(Object... params) {
   if(new ConnectionDetector.isConnectedToInternet()){
    return amazonS3Client.putObject(por);
   } else{
    return null;
   }
}

现在在onPostExecute()检查null。如果结果为null则表示没有网络连接。

Answer 2

做这样的事情

@Override
    protected PutObjectResult doInBackground(Object... params) {
        try{
            return amazonS3Client.putObject(por);

        } catch (AmazonServiceException e){
            //code
            return null;

        } catch (AmazonClientException f) {
            //code
            return null;
        }

    }

关闭互联网时，AsyncTask崩溃

2 个答案: