Android: Using onStart() method in Bluetooth application
- by Nii
Hello,
I am getting a nullpointer exception when my onStart() method is called. Here is the breakdown of my Android app:
Opening the app brings a user to the homescreen:
The user is then presented with the first 6 icons to choose from. When the user presses the "Sugar" icon it takes them to the SugarTabActivity.
The SugarTabActivity is a Tabbed layout with two tabs. I'm concerned with the first tab. The first tab calls the getDefaultAdapter() method in its onCreate() method. Once it calls this, it checks if the bluetooth adapter is null on the phone, and if its null it shows a toast saying "Bluetooth is not available". This works just fine. Then I call the onStart() method. In the onStart() method I check if bluetooth is enabled, and if it isnt, then I start a new activity from the BluetoothAdapter enable bluetooth intent; otherwise, I start my bluetooth service.
The exact error I'm getting is 04-19 00:44:45.674: ERROR/AndroidRuntime(225): Caused by: java.lang.NullPointerException
04-19 00:44:45.674: ERROR/AndroidRuntime(225): at com.nii.glucose.Glucose.onStart(Glucose.java:313).
Heading
Override
public void onCreate(Bundle icicle) {
super.onCreate(icicle);
if(D) Log.d(TAG, "+++ ON CREATE +++");
setContentView(R.layout.glucose_layout);
mBluetoothAdapter = BluetoothAdapter.getDefaultAdapter();
if(mBluetoothAdapter==null){
Toast.makeText(this, "Bluetooth not available", Toast.LENGTH_LONG).show();
//finish();
return;
}
}
Override
public void onStart() {
super.onStart();
if(D) Log.e(TAG, "++ ON START ++");
// If BT is not on, request that it be enabled.
// setupChat() will then be called during onActivityResult
if (!mBluetoothAdapter.isEnabled()) {
Intent enableIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);
startActivityForResult(enableIntent, REQUEST_ENABLE_BT);
// Otherwise, setup the chat session
} else {
if (mGlucoseService == null)
mGlucoseService = new BluetoothService(this, mHandler);
}
}
@Override
public synchronized void onResume(){
super.onResume();
if(D) Log.e(TAG,"==== ON RESUME ======");
// Performing this check in onResume() covers the case in which BT was
// not enabled during onStart(), so we were paused to enable it...
// onResume() will be called when ACTION_REQUEST_ENABLE activity returns.
if (mGlucoseService != null) {
// Only if the state is STATE_NONE, do we know that we haven't started already
if (mGlucoseService.getState() == BluetoothService.STATE_NONE) {
// Start the Bluetooth chat services
mGlucoseService.start();
}
}
}
@Override
public synchronized void onPause(){
super.onPause();
//isActive.set(false);
if(D) Log.e(TAG,"==== ON PAUSE ======");
}
@Override
public void onDestroy() {
super.onDestroy();
// Stop the Bluetooth chat services
if (mGlucoseService != null) mGlucoseService.stop();
if(D) Log.e(TAG, "--- ON DESTROY ---");
}
