Help learning how custom Alert Boxes work


  1. Arehexes

    Arehexes Well-Known Member

    So I'm trying to figure out how to make a custom dialog pop up on a function call, yet my app crashes when I try to pop it up on the app.

    [HIGH] public void eventpopUpDialog(BluetoothAdapter bluetooth){
    //Sets up the layout for the popup box
    final Dialog dialog = new Dialog(this);
    dialog.requestWindowFeature(Window.FEATURE_NO_TITLE);
    dialog.setContentView(R.layout.bluetooth_popup_status);

    //Make the variables for each UI element on the pop up box
    TextView output = (TextView) findViewById(R.id.popupDialogTV);
    final Button close = (Button) findViewById(R.id.closePopUp);

    //testing to see what is crashing
    output.setText("test");

    //The Event to close the dialog
    close.setOnClickListener(new View.OnClickListener() {
    public void onClick(View v) {
    dialog.dismiss();
    }
    });

    dialog.show();
    }
    [/HIGH]

    This is the code in question, I'm at a lost for why it's not working >_>.

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  2. jonbonazza

    jonbonazza Well-Known Member

    Can you please post a copy of the logcat output?
  3. Arehexes

    Arehexes Well-Known Member

    Wow I'm sorry for this late response I was busy the last two weeks, here is the logcat file from debugging the app.

    PHP:
    1. 01-07 17:22:38.343: E/AndroidRuntime(14383): FATAL EXCEPTION: main
    2. 01-07 17:22:38.343: E/AndroidRuntime(14383): java.lang.NullPointerException
    3. 01-07 17:22:38.343: E/AndroidRuntime(14383):    at com.example.bluetooth.practice.MainActivity.eventpopUpDialog(MainActivity.java:122)
    4. 01-07 17:22:38.343: E/AndroidRuntime(14383):    at com.example.bluetooth.practice.MainActivity$3.onClick(MainActivity.java:50)
    5. 01-07 17:22:38.343: E/AndroidRuntime(14383):    at android.view.View.performClick(View.java:4084)
    6. 01-07 17:22:38.343: E/AndroidRuntime(14383):    at android.view.View$PerformClick.run(View.java:16966)
    7. 01-07 17:22:38.343: E/AndroidRuntime(14383):    at android.os.Handler.handleCallback(Handler.java:615)
    8. 01-07 17:22:38.343: E/AndroidRuntime(14383):    at android.os.Handler.dispatchMessage(Handler.java:92)
    9. 01-07 17:22:38.343: E/AndroidRuntime(14383):    at android.os.Looper.loop(Looper.java:137)
    10. 01-07 17:22:38.343: E/AndroidRuntime(14383):    at android.app.ActivityThread.main(ActivityThread.java:4745)
    11. 01-07 17:22:38.343: E/AndroidRuntime(14383):    at java.lang.reflect.Method.invokeNative(Native Method)
    12. 01-07 17:22:38.343: E/AndroidRuntime(14383):    at java.lang.reflect.Method.invoke(Method.java:511)
    13. 01-07 17:22:38.343: E/AndroidRuntime(14383):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786)
    14. 01-07 17:22:38.343: E/AndroidRuntime(14383):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
    15. 01-07 17:22:38.343: E/AndroidRuntime(14383):    at dalvik.system.NativeStart.main(Native Method)
    16.  
  4. jonbonazza

    jonbonazza Well-Known Member

    Whats on line 122 of MainActivity.java?
  5. Arehexes

    Arehexes Well-Known Member

    Again I'm super sorry for the late response last time.

    This is what was in line 122

    PHP:
    1. output.setText("test");
    I'm guessing it's not working cause it's trying to talk to a object that is null. But I'm setting the object on line 118

    PHP:
    1. TextView output = (TextView) findViewById(R.id.popupDialogTV);
  6. myrecek

    myrecek Active Member

    I am not sure if it helps but you could try dialog.findViewById

    [HIGH]TextView output = (TextView) dialog.findViewById(R.id.popupDialogTV); [/HIGH]
    Arehexes likes this.
  7. jonbonazza

    jonbonazza Well-Known Member

    This is what I was going to say. This should fix your problem.
  8. Arehexes

    Arehexes Well-Known Member

    Thanks this worked, wonder why it was so hard to find the answer too >_>.
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