CODEWITHSUNDEEP
javaandroiduser-interfacealertactionlistener
Kevik
Kevik

Reputation: 9371

alert dialog null inside of listener method, null pointer

i put an alert dialog inside a custom listener that i created, it is like a onClick listener. the listener is called when an event occurs in another class.

why the null pointer when i put the alert dialog code inside of the listener call back method? how can i fix this? and more importantly. why do i get the null pointer?

the listener calls the callback method onResultReturned in this Android java class, and when that happens i wanted the alert dialog to appear.

the strange thing is that this alert dialog code works fine outside of my callback method, like when i put it in the onCreate method

the activity i am in is StartActivity and the method onReturnResult is in this class, the other activity called, Synchronizer is where the interface for the listener is located.

stack trace;

09-27 16:08:42.300: E/AndroidRuntime(7195): FATAL EXCEPTION: main
09-27 16:08:42.300: E/AndroidRuntime(7195): java.lang.NullPointerException
09-27 16:08:42.300: E/AndroidRuntime(7195):     at android.content.ContextWrapper.getApplicationInfo(ContextWrapper.java:132)
09-27 16:08:42.300: E/AndroidRuntime(7195):     at android.view.ContextThemeWrapper.getTheme(ContextThemeWrapper.java:65)
09-27 16:08:42.300: E/AndroidRuntime(7195):     at android.app.AlertDialog.resolveDialogTheme(AlertDialog.java:142)
09-27 16:08:42.300: E/AndroidRuntime(7195):     at android.app.AlertDialog$Builder.<init>(AlertDialog.java:359)
09-27 16:08:42.300: E/AndroidRuntime(7195):     at .StartActivity.onResultReturned(StartActivity.java:100)
09-27 16:08:42.300: E/AndroidRuntime(7195):     at .Synchronizer$SendOutMsgAndPack$2.run(Synchronizer.java:159)
09-27 16:08:42.300: E/AndroidRuntime(7195):     at android.os.Handler.handleCallback(Handler.java:605)
09-27 16:08:42.300: E/AndroidRuntime(7195):     at android.os.Handler.dispatchMessage(Handler.java:92)
09-27 16:08:42.300: E/AndroidRuntime(7195):     at android.os.Looper.loop(Looper.java:137)
09-27 16:08:42.300: E/AndroidRuntime(7195):     at android.app.ActivityThread.main(ActivityThread.java:4424)
09-27 16:08:42.300: E/AndroidRuntime(7195):     at java.lang.reflect.Method.invokeNative(Native Method)
09-27 16:08:42.300: E/AndroidRuntime(7195):     at java.lang.reflect.Method.invoke(Method.java:511)
09-27 16:08:42.300: E/AndroidRuntime(7195):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784)

code for my onResultReturned callback method, which is called about 4 to 5 seconds after the activity is created usually

    @Override
public void onResultReturned(int result) {

     // build allertdialog
     AlertDialog.Builder alertDialogBuilder = new AlertDialog.Builder(StartActivity.this);


     // set title
     alertDialogBuilder.setTitle("update status"); 
    //set allert message
     alertDialogBuilder
     .setMessage("update success")
     .setCancelable(false)
     .setPositiveButton("OK",new DialogInterface.OnClickListener() {
            public void onClick(DialogInterface dialog,int id) {
                // if this button is clicked, close
                // current activity
                //StartActivity.this.finish();
            }
          });

        // create alert dialog
        AlertDialog alertDialog = alertDialogBuilder.create();

        // show it
        alertDialog.show();

}

Upvotes: 0

Views: 305

Answers (1)

Vovchik
Vovchik

Reputation: 244

Check your context - (StartActivity.this) in 

AlertDialog.Builder alertDialogBuilder = new AlertDialog.Builder(StartActivity.this);

Perhaps Context is null;

Upvotes: 1

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