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POClassCastException causes my program to crash
 

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  1. POClassCastException causes my program to crash
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    <p>I have two Activities along with one Application class, and whenever I call my Application class in one of the Activities the program crashes. Here are the onCreate() methods for the two Activities:</p> <p>MainMenu:</p> <pre><code>protected BluetoothApplication myBt; private TextView bluetoothText; /** Called when the activity is first created. */ @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); customTitleSupported = requestWindowFeature( Window.FEATURE_CUSTOM_TITLE ); setContentView(R.layout.main); myBt = ((BluetoothApplication)getApplicationContext()); bluetoothText = new TextView(this); customTitleBar( getText( R.string.app_name).toString(), bluetoothText.getText().toString() ); } </code></pre> <p>DeviceList:</p> <pre><code>protected BluetoothApplication myBt; protected void onCreate( Bundle savedInstanceState ) { super.onCreate( savedInstanceState ); // Setup the window //requestWindowFeature( Window.FEATURE_INDETERMINATE_PROGRESS ); setContentView( R.layout.device_list ); myBt = (BluetoothApplication)getApplicationContext(); // Set result CANCELED in case the use backs out //setResult( Activity.RESULT_CANCELED ); // Initialize the button to perform device discovery Button scanButton = (Button) findViewById( R.id.button_scan ); scanButton.setOnClickListener( new OnClickListener() { public void onClick( View v ) { doDiscovery(); v.setVisibility( View.GONE ); } }); // Initialize array adapters. One for already paired devices and one // for newly discovered devices mPairedDevicesArrayAdapter = new ArrayAdapter&lt;String&gt;( this, R.layout.device_name ); mNewDevicesArrayAdapter = new ArrayAdapter&lt;String&gt;( this, R.layout.device_name ); // Find and set up the ListView for paired devices ListView pairedListView = (ListView) findViewById( R.id.paired_devices ); pairedListView.setAdapter( mPairedDevicesArrayAdapter ); pairedListView.setOnItemClickListener( mDeviceClickListener ); // Find and set up the ListView for newly discovered devices ListView newDevicesListView = (ListView) findViewById( R.id.new_devices ); newDevicesListView.setAdapter( mNewDevicesArrayAdapter ); // Register for broadcasts when a device is discovered IntentFilter filter = new IntentFilter( BluetoothDevice.ACTION_FOUND ); this.registerReceiver( mReceiver, filter ); // Register for broadcasts when discovery has finished filter = new IntentFilter( BluetoothAdapter.ACTION_DISCOVERY_FINISHED ); this.registerReceiver( mReceiver, filter ); // Get a set of currently paired devices Set&lt;BluetoothDevice&gt; pairedDevices = myBt.getMyBtAdapter().getBondedDevices(); if( pairedDevices.size() &gt; 0 ) { findViewById( R.id.title_paired_devices ).setVisibility( View.VISIBLE ); for ( BluetoothDevice device : pairedDevices ) { mPairedDevicesArrayAdapter.add( device.getName() + "\n" + device.getAddress() ); } } else { String noDevices = getResources().getText( R.string.none_paired ).toString(); mPairedDevicesArrayAdapter.add( noDevices ); } } </code></pre> <p>Both of these Activities load fine when I remove the lines involving the BluetoothApplication. I have tried changing getApplicationContext() to getApplication(). </p> <p>BluetoothApplication:</p> <pre><code>public class BluetoothApplication extends Application { // Debugging private static final String TAG = "BluetoothApplication"; private static final boolean D = true; // Member fields private BluetoothAdapter myAdapter; private Handler myHandler; private BluetoothDevice myBtDevice; private BluetoothSocket mySocket; private ArrayAdapter&lt;String&gt; mPairedDevicesArrayAdapter; private ArrayAdapter&lt;String&gt; mNewDevicesArrayAdapter; private ConnectThread myConnectThread; private ConnectedThread myConnectedThread; private int myState; // Constants that indicate the current connection state public static final int STATE_NONE = 0; public static final int STATE_LISTEN = 1; public static final int STATE_CONNECTING = 2; public static final int STATE_CONNECTED = 3; //In SDK15 (4.0.3) this method is now public as //Bluetooth.fetchUuisWithSdp() and BluetoothDevice.getUuids() public ParcelUuid[] servicesFromDevice(BluetoothDevice device) { try { Class cl = Class.forName("android.bluetooth.BluetoothDevice"); Class[] par = {}; Method method = cl.getMethod("getUuids", par); Object[] args = {}; ParcelUuid[] retval = (ParcelUuid[]) method.invoke(device, args); return retval; } catch (Exception e) { e.printStackTrace(); return null; } } public void onCreate( ) { myAdapter = BluetoothAdapter.getDefaultAdapter(); myAdapter.enable(); } public BluetoothAdapter getMyBtAdapter() { return myAdapter; } /** * Set the connection state of the device. * @param state */ public synchronized void setState( int state ) { if( D ) Log.d(TAG, " setState() " + myState + " -&gt; " + state ); myState = state; myHandler.obtainMessage( MainMenu.MESSAGE_STATE_CHANGE, state, -1 ).sendToTarget(); } /** * Get the connection state. */ public synchronized int getState() { return myState; } /** * Indicate that the connection attempt failed and notify the UI Activity. */ private void connectionFailed() { setState( STATE_NONE ); // Send failure message back to the Activity Message msg = myHandler.obtainMessage( MainMenu.MESSAGE_TOAST ); Bundle bundle = new Bundle(); bundle.putString( " ", "unable to connect to device" ); msg.setData( bundle ); myHandler.sendMessage( msg ); } /** * Indicate that the connection was lost and notify the UI Activity. */ private void connectionLost() { setState( STATE_NONE ); Message msg = myHandler.obtainMessage( MainMenu.MESSAGE_TOAST ); Bundle bundle = new Bundle(); bundle.putString( "ASdasd", "Device connection was lost" ); msg.setData( bundle ); myHandler.sendMessage( msg ); } public synchronized void start() { if (D) Log.d(TAG, "start" ); if( myConnectThread != null ) { myConnectThread.cancel(); myConnectThread = null; } if( myConnectedThread != null ) { myConnectedThread.cancel(); myConnectedThread = null; } setState( STATE_NONE ); } public synchronized void connect( BluetoothDevice device ) { if( D ) Log.d(TAG, "connect to: " + device ); if( myState == STATE_CONNECTING ) { if( myConnectThread != null ) { myConnectThread.cancel(); myConnectThread = null;} } // Cancel any thread currently running a connection if( myConnectedThread != null ) {myConnectedThread.cancel(); myConnectedThread = null;} // Start the thread to connect with the given device myConnectThread = new ConnectThread( device ); myConnectThread.start(); setState( STATE_CONNECTING ); } /** * Start the ConnectedThread to begin managin a Bluetooth connection */ public synchronized void connected( BluetoothSocket socket, BluetoothDevice device ) { if( D ) Log.d(TAG, "connected" ); // Cancel the thread that completed the connection if( myConnectThread != null ) { myConnectThread.cancel(); myConnectThread = null; } // Cancel any thread currently running a connection if( myConnectedThread != null ) { myConnectedThread.cancel(); myConnectedThread = null; } // Start the thread to manage the connection and perform transmissions myConnectedThread = new ConnectedThread( socket ); myConnectedThread.start(); // Send the name of the connected device back to the UI Activity Message msg = myHandler.obtainMessage( MainMenu.MESSAGE_DEVICE_NAME ); Bundle bundle = new Bundle(); bundle.putString( MainMenu.DEVICE_NAME, device.getName() ); msg.setData( bundle ); myHandler.sendMessage( msg ); setState( STATE_CONNECTED ); } /** * Stop ALL threads */ public synchronized void stop() { if(D) Log.d( TAG, "stop" ); if( myConnectThread != null ) { myConnectThread.cancel(); myConnectThread = null; } if( myConnectedThread != null ) { myConnectedThread.cancel(); myConnectedThread = null; } setState( STATE_NONE ); } /** * Write to the ConnectedThread in an unsynchronized manner */ public void write( byte[] out ) { ConnectedThread r; synchronized( this ) { if( myState != STATE_CONNECTED ) return; r = myConnectedThread; } r.write( out ); } public class ConnectThread extends Thread { private final BluetoothSocket mmSocket; private final BluetoothDevice mmDevice; public ConnectThread( BluetoothDevice device ) { mmDevice = device; BluetoothSocket tmp = null; ParcelUuid[] uuids = servicesFromDevice( myBtDevice ); try { tmp = device.createRfcommSocketToServiceRecord( uuids[0].getUuid() ); } catch (IOException e ) { Log.e( TAG, "create() failed", e ); } mmSocket = tmp; } public void run() { Log.i( TAG, "BEGIN mConnectThread" ); setName( "ConnectThread" ); // Always cancel discovery because it will slow down a connection myAdapter.cancelDiscovery(); try { mmSocket.connect(); } catch ( IOException e ) { connectionFailed(); try { mmSocket.close(); } catch ( IOException e2 ) { Log.e( TAG, "Unable to close() socket during connection failure", e2 ); } BluetoothApplication.this.start(); return; } synchronized ( BluetoothApplication.this ) { myConnectThread = null; } connected( mmSocket, mmDevice ); } public void cancel() { try { mmSocket.close(); } catch (IOException e ) { Log.e( TAG, "close() of connect socket failed", e ); } } } /** * This thread runs during a connection with a remote device. * It handles all incoming and outgoing transmissions. */ public class ConnectedThread extends Thread { private final BluetoothSocket mmSocket; private final InputStream mmInStream; private final OutputStream mmOutStream; public ConnectedThread( BluetoothSocket socket ) { Log.d( TAG, "create ConnectedThread" ); mmSocket = socket; InputStream tmpIn = null; OutputStream tmpOut = null; // Get the BluetoothSocket input and output streams try { tmpIn = socket.getInputStream(); tmpOut = socket.getOutputStream(); } catch ( IOException e ) { Log.e(TAG, "temp sockets not created", e ); } mmInStream = tmpIn; mmOutStream = tmpOut; } public void run() { Log.i(TAG, "BEGIN mConnectedThread" ); byte[] buffer = new byte[1024]; int bytes; while( true ){ try { bytes = mmInStream.read( buffer ); myHandler.obtainMessage( MainMenu.MESSAGE_READ, bytes, -1, buffer ).sendToTarget(); } catch (IOException e ) { Log.e( TAG, "disconnected", e ); connectionLost(); break; } } } /** * Write to connected OutStream. * */ public void write( byte[] buffer ) { try { mmOutStream.write( buffer ); myHandler.obtainMessage( MainMenu.MESSAGE_WRITE, buffer.length, -1, buffer ).sendToTarget(); } catch ( IOException e ) { Log.e( TAG, "Exception during write", e ); } } public void cancel() { try { mmSocket.close(); } catch (IOException e ) { Log.e( TAG, "close() of connect socket failed", e ); } } } } </code></pre> <p>I also think there may be something wrong with how I entered the Application class into my Manifest file:</p> <p>MODIFIED MANIFEST:</p> <pre><code>&lt;?xml version="1.0" encoding="utf-8"?&gt; &lt;manifest xmlns:android="http://schemas.android.com/apk/res/android" package="my.eti.commander" android:versionCode="1" android:versionName="1.0" &gt; &lt;uses-sdk android:minSdkVersion="10" /&gt; &lt;application android:icon="@drawable/ic_launcher" android:label="@string/app_name" android:name = ".BluetoothApplication" &gt; &lt;activity android:name=".MainMenu" android:label="@string/app_name" &gt; &lt;intent-filter&gt; &lt;action android:name="android.intent.action.MAIN" /&gt; &lt;category android:name="android.intent.category.LAUNCHER" /&gt; &lt;/intent-filter&gt; &lt;/activity&gt; &lt;activity android:name=".DeviceList" android:theme="@android:style/Theme.Dialog" android:label="@string/devices"&gt; &lt;intent-filter&gt; &lt;action android:name="android.intent.action.MAIN" /&gt; &lt;/intent-filter&gt; &lt;/activity&gt; &lt;/application&gt; &lt;/manifest&gt; </code></pre> <p>this is the LogCat:</p> <pre><code>06-18 09:09:26.625: I/Process(2097): Sending signal. PID: 2097 SIG: 9 06-18 09:17:32.241: D/AndroidRuntime(2304): Shutting down VM 06-18 09:17:32.241: W/dalvikvm(2304): threadid=1: thread exiting with uncaught exception (group=0x40015560) 06-18 09:17:32.241: E/AndroidRuntime(2304): FATAL EXCEPTION: main 06-18 09:17:32.241: E/AndroidRuntime(2304): java.lang.RuntimeException: Unable to start activity ComponentInfo{my.eti.commander/my.eti.commander.MainMenu}: java.lang.ClassCastException: android.app.Application 06-18 09:17:32.241: E/AndroidRuntime(2304): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1647) 06-18 09:17:32.241: E/AndroidRuntime(2304): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1663) 06-18 09:17:32.241: E/AndroidRuntime(2304): at android.app.ActivityThread.access$1500(ActivityThread.java:117) 06-18 09:17:32.241: E/AndroidRuntime(2304): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:931) 06-18 09:17:32.241: E/AndroidRuntime(2304): at android.os.Handler.dispatchMessage(Handler.java:99) 06-18 09:17:32.241: E/AndroidRuntime(2304): at android.os.Looper.loop(Looper.java:130) 06-18 09:17:32.241: E/AndroidRuntime(2304): at android.app.ActivityThread.main(ActivityThread.java:3683) 06-18 09:17:32.241: E/AndroidRuntime(2304): at java.lang.reflect.Method.invokeNative(Native Method) 06-18 09:17:32.241: E/AndroidRuntime(2304): at java.lang.reflect.Method.invoke(Method.java:507) 06-18 09:17:32.241: E/AndroidRuntime(2304): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839) 06-18 09:17:32.241: E/AndroidRuntime(2304): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597) 06-18 09:17:32.241: E/AndroidRuntime(2304): at dalvik.system.NativeStart.main(Native Method) 06-18 09:17:32.241: E/AndroidRuntime(2304): Caused by: java.lang.ClassCastException: android.app.Application 06-18 09:17:32.241: E/AndroidRuntime(2304): at my.eti.commander.MainMenu.onCreate(MainMenu.java:47) 06-18 09:17:32.241: E/AndroidRuntime(2304): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047) 06-18 09:17:32.241: E/AndroidRuntime(2304): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1611) 06-18 09:17:32.241: E/AndroidRuntime(2304): ... 11 more </code></pre>
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    1. COit would be easier to find error if you post your stacktrace instead
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    2. COPost your modified manifest file.
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      1. USuser370305
    3. CONow, your code looks fine, just only one assumption, put complete application name with package in application tag in manifest fiel like, my.eti.commander.BluetoothApplication and try it.
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