Android AsyncTask [无法在未调用Looper.prepare()的线程内创建处理程序

时间:2021-05-04 20:44:54

I've created an image upload asynctask based on a function. And after uploading, I get this error on onPostExecute. I read up some * answers on Runnable yet i kept getting the error over and over again despite implementing different solution.

我已经基于一个函数创建了一个图像上传asynctask。上传后,我在onPostExecute上收到此错误。我在Runnable上读了一些*的答案,但我仍然不断地一遍又一遍地得到错误,尽管实现了不同的解决方案。

My code :

我的代码:

class uploadFile extends AsyncTask<String, String, String> {
        private ProgressDialog pDialog;

        /**
         * --------------------------------------------------------------------
         * --------------------------------- Before starting background thread
         * Show Progress Dialog
         * */
        @Override
        protected void onPreExecute() {
            super.onPreExecute();
            pDialog = new ProgressDialog(MainActivity.this);
            pDialog.setMessage("Uploading file");
            pDialog.setIndeterminate(false);
            pDialog.setCancelable(false);
            pDialog.show();
        }

        /**
         * --------------------------------------------------------------------
         * --------------------------------- getting all recent articles and
         * showing them in listview
         * */
        @Override
        protected String doInBackground(String... args) {
            HttpURLConnection conn = null;
            DataOutputStream dos = null;
            DataInputStream inStream = null;
            String existingFileName = Environment.getExternalStorageDirectory()
                    .getAbsolutePath() + "/mypic.png";
            String lineEnd = "\r\n";
            String twoHyphens = "--";
            String boundary = "*****";
            int bytesRead, bytesAvailable, bufferSize;
            byte[] buffer;
            int maxBufferSize = 1 * 1024 * 1024;
            String serverResponseMessage = "";
            String urlString = "http://google.info/imgupl/index.php";
            try {
                // ------------------ CLIENT REQUEST
                FileInputStream fileInputStream = new FileInputStream(new File(
                        existingFileName));
                // open a URL connection to the Servlet
                URL url = new URL(urlString);
                // Open a HTTP connection to the URL
                conn = (HttpURLConnection) url.openConnection();
                // Allow Inputs
                conn.setDoInput(true);
                // Allow Outputs
                conn.setDoOutput(true);
                // Don't use a cached copy.
                conn.setUseCaches(false);
                // Use a post method.
                conn.setRequestMethod("POST");
                conn.setRequestProperty("Connection", "Keep-Alive");
                conn.setRequestProperty("Content-Type",
                        "multipart/form-data;boundary=" + boundary);
                dos = new DataOutputStream(conn.getOutputStream());
                dos.writeBytes(twoHyphens + boundary + lineEnd);
                dos.writeBytes("Content-Disposition: form-data; name=\"uploadedfile\";filename=\""
                        + existingFileName + "\"" + lineEnd);
                dos.writeBytes(lineEnd);
                // create a buffer of maximum size
                bytesAvailable = fileInputStream.available();
                bufferSize = Math.min(bytesAvailable, maxBufferSize);
                buffer = new byte[bufferSize];
                // read file and write it into form...
                bytesRead = fileInputStream.read(buffer, 0, bufferSize);
                while (bytesRead > 0) {
                    dos.write(buffer, 0, bufferSize);
                    bytesAvailable = fileInputStream.available();
                    bufferSize = Math.min(bytesAvailable, maxBufferSize);
                    bytesRead = fileInputStream.read(buffer, 0, bufferSize);
                }
                // send multipart form data necesssary after file data...
                dos.writeBytes(lineEnd);
                dos.writeBytes(twoHyphens + boundary + twoHyphens + lineEnd);
                // close streams
                Integer serverResponseCode = conn.getResponseCode();
                serverResponseMessage = conn.getResponseMessage();
                Toast.makeText(getApplicationContext(), serverResponseMessage,
                        Toast.LENGTH_SHORT).show();
                Toast.makeText(getApplicationContext(),
                        serverResponseCode.toString(), Toast.LENGTH_SHORT)
                        .show();
                Log.e("Debug", "File is written");
                fileInputStream.close();
                dos.flush();
                dos.close();
            } catch (MalformedURLException ex) {
                Log.e("Debug", "error: " + ex.getMessage(), ex);
            } catch (IOException ioe) {
                Log.e("Debug", "error: " + ioe.getMessage(), ioe);
            }
            // ------------------ read the SERVER RESPONSE
            try {
                inStream = new DataInputStream(conn.getInputStream());

                while ((str = inStream.readLine()) != null) {
                    Log.e("Debug", "Server Response " + str);
                }
                inStream.close();

            } catch (IOException ioex) {
                Log.e("Debug", "error: " + ioex.getMessage(), ioex);
            }
            return null;
        }

        /**
         * --------------------------------------------------------------------
         * --------------------------------- After completing background task
         * Dismiss the progress dialog
         * **/
        protected void onPostExecute(String args) {
            // dismiss the dialog after getting all products
            pDialog.dismiss();
            MainActivity.this.runOnUiThread(new Runnable() {
                  public void run() {
                    Toast.makeText(MainActivity.this, "Hello", Toast.LENGTH_SHORT).show();
                  }
                });

        }
    }

My logcat :

我的logcat:

08-13 22:13:32.627: E/AndroidRuntime(9554): FATAL EXCEPTION: AsyncTask #1
08-13 22:13:32.627: E/AndroidRuntime(9554): java.lang.RuntimeException: An error occured while executing doInBackground()
08-13 22:13:32.627: E/AndroidRuntime(9554):     at android.os.AsyncTask$3.done(AsyncTask.java:200)
08-13 22:13:32.627: E/AndroidRuntime(9554):     at java.util.concurrent.FutureTask$Sync.innerSetException(FutureTask.java:274)
08-13 22:13:32.627: E/AndroidRuntime(9554):     at java.util.concurrent.FutureTask.setException(FutureTask.java:125)
08-13 22:13:32.627: E/AndroidRuntime(9554):     at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:308)
08-13 22:13:32.627: E/AndroidRuntime(9554):     at java.util.concurrent.FutureTask.run(FutureTask.java:138)
08-13 22:13:32.627: E/AndroidRuntime(9554):     at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1088)
08-13 22:13:32.627: E/AndroidRuntime(9554):     at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:581)
08-13 22:13:32.627: E/AndroidRuntime(9554):     at java.lang.Thread.run(Thread.java:1019)
08-13 22:13:32.627: E/AndroidRuntime(9554): Caused by: java.lang.RuntimeException: Can't create handler inside thread that has not called Looper.prepare()
08-13 22:13:32.627: E/AndroidRuntime(9554):     at android.os.Handler.<init>(Handler.java:121)
08-13 22:13:32.627: E/AndroidRuntime(9554):     at android.widget.Toast.<init>(Toast.java:68)
08-13 22:13:32.627: E/AndroidRuntime(9554):     at android.widget.Toast.makeText(Toast.java:231)
08-13 22:13:32.627: E/AndroidRuntime(9554):     at dev.google.imageupload.MainActivity$uploadFile.doInBackground(MainActivity.java:128)
08-13 22:13:32.627: E/AndroidRuntime(9554):     at dev.google.imageupload.MainActivity$uploadFile.doInBackground(MainActivity.java:1)
08-13 22:13:32.627: E/AndroidRuntime(9554):     at android.os.AsyncTask$2.call(AsyncTask.java:185)
08-13 22:13:32.627: E/AndroidRuntime(9554):     at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:306)
08-13 22:13:32.627: E/AndroidRuntime(9554):     ... 4 more

EDITED after zapl's suggestion :

在zapl的建议之后编辑:

08-13 22:38:06.297: E/AndroidRuntime(11511): FATAL EXCEPTION: AsyncTask #1
08-13 22:38:06.297: E/AndroidRuntime(11511): java.lang.RuntimeException: An error occured while executing doInBackground()
08-13 22:38:06.297: E/AndroidRuntime(11511):    at android.os.AsyncTask$3.done(AsyncTask.java:200)
08-13 22:38:06.297: E/AndroidRuntime(11511):    at java.util.concurrent.FutureTask$Sync.innerSetException(FutureTask.java:274)
08-13 22:38:06.297: E/AndroidRuntime(11511):    at java.util.concurrent.FutureTask.setException(FutureTask.java:125)
08-13 22:38:06.297: E/AndroidRuntime(11511):    at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:308)
08-13 22:38:06.297: E/AndroidRuntime(11511):    at java.util.concurrent.FutureTask.run(FutureTask.java:138)
08-13 22:38:06.297: E/AndroidRuntime(11511):    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1088)
08-13 22:38:06.297: E/AndroidRuntime(11511):    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:581)
08-13 22:38:06.297: E/AndroidRuntime(11511):    at java.lang.Thread.run(Thread.java:1019)
08-13 22:38:06.297: E/AndroidRuntime(11511): Caused by: java.lang.RuntimeException: Can't create handler inside thread that has not called Looper.prepare()
08-13 22:38:06.297: E/AndroidRuntime(11511):    at android.os.Handler.<init>(Handler.java:121)
08-13 22:38:06.297: E/AndroidRuntime(11511):    at android.widget.Toast.<init>(Toast.java:68)
08-13 22:38:06.297: E/AndroidRuntime(11511):    at android.widget.Toast.makeText(Toast.java:231)
08-13 22:38:06.297: E/AndroidRuntime(11511):    at dev.google.imageupload.MainActivity$uploadFile.doInBackground(MainActivity.java:128)
08-13 22:38:06.297: E/AndroidRuntime(11511):    at dev.google.imageupload.MainActivity$uploadFile.doInBackground(MainActivity.java:1)
08-13 22:38:06.297: E/AndroidRuntime(11511):    at android.os.AsyncTask$2.call(AsyncTask.java:185)
08-13 22:38:06.297: E/AndroidRuntime(11511):    at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:306)
08-13 22:38:06.297: E/AndroidRuntime(11511):    ... 4 more

2 个解决方案

#1


46  

You are attempting to update the UI from a background thread. Either move the toast to onPostExecute, which executes on the UI thread (recommended), or call runOnUiThread.

您正在尝试从后台线程更新UI。将toast移动到onPostExecute,它在UI线程上执行(推荐),或者调用runOnUiThread。

runOnUiThread(new Runnable() {
    public void run() {
        // runs on UI thread
    }
});

#2


6  

at dev.shaunidiot.imageupload.MainActivity$uploadFile.doInBackground(MainActivity.java:128)

You could use the progress mechanism of AsyncTasks to update UI from inside doInBackground while the task is running:

您可以使用AsyncTasks的进度机制在任务运行时从doInBackground内部更新UI:

replace

Toast.makeText(getApplicationContext(), serverResponseMessage,
        Toast.LENGTH_SHORT).show();
Toast.makeText(getApplicationContext(),
        serverResponseCode.toString(), Toast.LENGTH_SHORT)
        .show();

in doInBackground with

在doInBackground中

publishProgress(serverResponseMessage, serverResponseCode.toString());

and add the following to your AsyncTask implementation

并将以下内容添加到AsyncTask实现中

@Override
protected void onProgressUpdate(String... values) {
    if (values != null) {
        for (String value : values) {
            // shows a toast for every value we get
            Toast.makeText(MainActivity.this, value, Toast.LENGTH_SHORT).show();
        }
    }
}

You already have set String as progress type in AsyncTask<Params, Progress, Result> so in case you want to use progress for something different you can try to use runOnUiThread but I don't know if that will work.

您已经在AsyncTask 中将String设置为进度类型,因此如果您想使用不同的进度,可以尝试使用runOnUiThread,但我不知道这是否有效。 ,progress,result>

#1


46  

You are attempting to update the UI from a background thread. Either move the toast to onPostExecute, which executes on the UI thread (recommended), or call runOnUiThread.

您正在尝试从后台线程更新UI。将toast移动到onPostExecute,它在UI线程上执行(推荐),或者调用runOnUiThread。

runOnUiThread(new Runnable() {
    public void run() {
        // runs on UI thread
    }
});

#2


6  

at dev.shaunidiot.imageupload.MainActivity$uploadFile.doInBackground(MainActivity.java:128)

You could use the progress mechanism of AsyncTasks to update UI from inside doInBackground while the task is running:

您可以使用AsyncTasks的进度机制在任务运行时从doInBackground内部更新UI:

replace

Toast.makeText(getApplicationContext(), serverResponseMessage,
        Toast.LENGTH_SHORT).show();
Toast.makeText(getApplicationContext(),
        serverResponseCode.toString(), Toast.LENGTH_SHORT)
        .show();

in doInBackground with

在doInBackground中

publishProgress(serverResponseMessage, serverResponseCode.toString());

and add the following to your AsyncTask implementation

并将以下内容添加到AsyncTask实现中

@Override
protected void onProgressUpdate(String... values) {
    if (values != null) {
        for (String value : values) {
            // shows a toast for every value we get
            Toast.makeText(MainActivity.this, value, Toast.LENGTH_SHORT).show();
        }
    }
}

You already have set String as progress type in AsyncTask<Params, Progress, Result> so in case you want to use progress for something different you can try to use runOnUiThread but I don't know if that will work.

您已经在AsyncTask 中将String设置为进度类型,因此如果您想使用不同的进度,可以尝试使用runOnUiThread,但我不知道这是否有效。 ,progress,result>