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POTextView update crashes application
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copied!<p>This has been discussed many times before, but it is still a real pain for me. </p> <p>PROBLEM: App crashes whenever I try to update text it TextView</p> <p>CONTEXT: Im using bluetooth app with multi threads. The "listening" thread (ConnectedThread) sends Handler whenever new message is obtained. This handler is then resolved in main Activity, where the TextView is initialized.</p> <p>WHAT I HAVE TRIED/CHECKED SO FAR:</p> <ol> <li>I think I am not updating TextView from different activity/thread</li> <li>the TextView is initialized after setContentView(R.layout.main); (well, in other post, this was causing the trouble)</li> </ol> <p>CODE: (in short)</p> <p>MAIN ACTIVITY</p> <pre><code> public class BluetoothActivity extends Activity { private TextView mDisplay; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); mBluetoothAdapter = BluetoothAdapter.getDefaultAdapter(); ..... .. } private void setupApp() { // Initialize the BluetoothService to perform bluetooth connections // This is where the Handler is passed to "ConnectedThread" (it is part of mService) mService = new BluetoothService(this, mHandler); } // The Handler that gets information back from the BluetoothService private final Handler mHandler = new Handler() { @Override public void handleMessage(Message msg) { switch (msg.what) { ...... case MESSAGE_READ: byte[] readBuf = (byte[]) msg.obj; // construct a string from the valid bytes in the buffer String readMessage = new String(readBuf, 0, msg.arg1); if(D) Log.d(TAG, "Received: " + readMessage); mDisplay.setText(readMessage); <----- THIS IS THE ISSUE break; ....... .... } } }; </code></pre> <p>CONNECTED THREAD</p> <pre><code>private class ConnectedThread extends Thread { ...... public void run() { byte[] buffer = new byte[1024]; int bytes; // Keep listening to the InputStream while connected while (true) { try { // Read from the InputStream bytes = mmInStream.read(buffer); // Send the obtained bytes to the UI Activity mHandler.obtainMessage(BluetoothActivity.MESSAGE_READ, bytes, -1, buffer) .sendToTarget(); } catch ... } } } </code></pre> <p>Primarily this was the function respossible for showing incoming messages </p> <pre><code>Toast.makeText(getApplicationContext(), "Received: " + readMessage, Toast.LENGTH_SHORT).show(); </code></pre>

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