How do I fix error open Bluetooth?

Question

I created an application with bluetooth, but when bluetooth is closed, apk close with toast and I have this error... java.lang.NullPointerException in io.webbt.Activity2.openBT

void findBT()
{
    mBluetoothAdapter = BluetoothAdapter.getDefaultAdapter();
    if(mBluetoothAdapter == null)
    {
        myLabel.setText("No bluetooth adapter available");
    }

    if(!mBluetoothAdapter.isEnabled())
    {
        Intent enableBluetooth = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);
        startActivityForResult(enableBluetooth, REQUEST_ENABLE_BT);
    }     
}

I have a message if I want open bluetooth I choise yes...but after not continue to my activity...Any help?How i come back to my activity if bluetooth is closed?

01-16 15:36:08.483: W/dalvikvm(3677): threadid=1: thread exiting with uncaught exception (group=0x2b542210)
01-16 15:36:08.483: E/AndroidRuntime(3677): FATAL EXCEPTION: main
01-16 15:36:08.483: E/AndroidRuntime(3677): java.lang.RuntimeException: Unable to start activity ComponentInfo{io.webbt/io.webbt.Activity2}: java.lang.NullPointerException
01-16 15:36:08.483: E/AndroidRuntime(3677):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1967)
01-16 15:36:08.483: E/AndroidRuntime(3677):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1992)
01-16 15:36:08.483: E/AndroidRuntime(3677):     at android.app.ActivityThread.access$600(ActivityThread.java:127)
01-16 15:36:08.483: E/AndroidRuntime(3677):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1158)
01-16 15:36:08.483: E/AndroidRuntime(3677):     at android.os.Handler.dispatchMessage(Handler.java:99)
01-16 15:36:08.483: E/AndroidRuntime(3677):     at android.os.Looper.loop(Looper.java:137)
01-16 15:36:08.483: E/AndroidRuntime(3677):     at android.app.ActivityThread.main(ActivityThread.java:4441)
01-16 15:36:08.483: E/AndroidRuntime(3677):     at java.lang.reflect.Method.invokeNative(Native Method)
01-16 15:36:08.483: E/AndroidRuntime(3677):     at java.lang.reflect.Method.invoke(Method.java:511)
01-16 15:36:08.483: E/AndroidRuntime(3677):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784)
01-16 15:36:08.483: E/AndroidRuntime(3677):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551)
01-16 15:36:08.483: E/AndroidRuntime(3677):     at dalvik.system.NativeStart.main(Native Method)
01-16 15:36:08.483: E/AndroidRuntime(3677): Caused by: java.lang.NullPointerException
01-16 15:36:08.483: E/AndroidRuntime(3677):     at io.webbt.Activity2.openBT(Activity2.java:192)
01-16 15:36:08.483: E/AndroidRuntime(3677):     at io.webbt.Activity2.onStart(Activity2.java:130)
01-16 15:36:08.483: E/AndroidRuntime(3677):     at android.app.Instrumentation.callActivityOnStart(Instrumentation.java:1133)
01-16 15:36:08.483: E/AndroidRuntime(3677):     at   android.app.Activity.performStart(Activity.java:4475)
01-16 15:36:08.483: E/AndroidRuntime(3677):     at   android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1940)
01-16 15:36:08.483: E/AndroidRuntime(3677):     ... 11 more

 void openBT() throws IOException
  {
  UUID uuid = UUID.fromString("00001101-0000-1000-8000-00805f9b34fb"); //Standar      
  mmSocket = mmDevice.createRfcommSocketToServiceRecord(uuid);       
  mmSocket.connect();
  mmOutputStream = mmSocket.getOutputStream();
  mmInputStream = mmSocket.getInputStream();

  myLabel.setText("Bluetooth Opened");

  protected void onStart() {
    super.onStart();

    try
    {         
        //findBT();
        openBT();                            
    }
    catch (IOException ex) { }

    runnable.run();

}

I don't understant.. when the bluetooth is disabled.. and you press yes to enable it then everything works fine.. and when you press no it's give you this error? — Elior, Jan 16 '13 at 13:32
can you provide us the logcat and explain more clearly what are you trying to do? — Elior, Jan 16 '13 at 13:34
give us your code for openBT function.. because this method cause the error — Elior, Jan 16 '13 at 13:47
I think 192 is my void Open Bluetooth look my code i updated... — user1977741, Jan 16 '13 at 13:48
My problem is apk stop after enable bluetooth i must restart the apk...no continue automatic... — user1977741, Jan 16 '13 at 13:51
no, i think it works like that: 1) when the application is started the onStart() method is called - to let the user enable the bluetooth 2) meanwhile your activity is on pause status, because it's unfocused. 3) when the user select his choice the onResume() method is called.. to let your activity to take focus.. take a look at this link -> it's a greate example for bluetooth in android https://github.com/luugiathuy/Remote-Bluetooth-Android — Elior, Jan 16 '13 at 14:11

score 0 · Answer 1 · edited May 23 '17 at 12:18

0

Do you have a BroadcastReceiver? i think it will help you to listen to the bluetooth status and the ability to do what you need in each status..

take a look here

edited May 23 '17 at 12:18

Community

1
1

answered Jan 16 '13 at 13:46

Elior

3,178
6
37
67

How do I fix error open Bluetooth?

1 Answers1