How to show Dialog Box from the class which extends Application in android?

Question

I want show a dialog box after specific condition , but for demo right now I want show a Dialog Box from the class which extends Application . here is my code

public class ControlApplication extends Application
{
    @Override
    {
    super.onCreate();
    final Dialog dialog = new Dialog ( getApplicationContext() ); 
    dialog.setTitle("zakasssssssssssssssssss");
    dialog.setCancelable(false);
    dialog.show();
}

}

but at the dialog.show() I am getting error like

Attempted to add window with non-application token WindowToken{4067a268 token=null}.  Aborting.
D/AndroidRuntime( 1923): Shutting down VM
W/dalvikvm( 1923): threadid=1: thread exiting with uncaught exception (group=0x40015560)
E/AndroidRuntime( 1923): FATAL EXCEPTION: main
E/AndroidRuntime( 1923): java.lang.RuntimeException: Unable to create application 
com.test.shrenik.ControlApplication: android.view.WindowManager$BadTokenException: 
Unable to add window -- token null is not for an application
E/AndroidRuntime( 1923):    at android.app.ActivityThread.handleBindApplication(ActivityThread.java:3275)
E/AndroidRuntime( 1923):    at android.app.ActivityThread.access$2200(ActivityThread.java:117)
E/AndroidRuntime( 1923):    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:969)
E/AndroidRuntime( 1923):    at android.os.Handler.dispatchMessage(Handler.java:99)
E/AndroidRuntime( 1923):    at android.os.Looper.loop(Looper.java:123)
E/AndroidRuntime( 1923):    at android.app.ActivityThread.main(ActivityThread.java:3683)
E/AndroidRuntime( 1923):    at java.lang.reflect.Method.invokeNative(Native Method)
E/AndroidRuntime( 1923):    at java.lang.reflect.Method.invoke(Method.java:507)
E/AndroidRuntime( 1923):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839)
E/AndroidRuntime( 1923):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597)
E/AndroidRuntime( 1923):    at dalvik.system.NativeStart.main(Native Method)
E/AndroidRuntime( 1923): Caused by: android.view.WindowManager$BadTokenException: Unable to add window -- token null is not for an application
E/AndroidRuntime( 1923):    at android.view.ViewRoot.setView(ViewRoot.java:531)
E/AndroidRuntime( 1923):    at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:177)
E/AndroidRuntime( 1923):    at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:91)
E/AndroidRuntime( 1923):    at android.app.Dialog.show(Dialog.java:241)
E/AndroidRuntime( 1923):    at com.andromeda.ui.pandora.ControlApplication.onCreate(ControlApplication.java:38)
E/AndroidRuntime( 1923):    at android.app.Instrumentation.callApplicationOnCreate(Instrumentation.java:969)
E/AndroidRuntime( 1923):    at android.app.Instrumentation.callApplicationOnCreate(Instrumentation.java:969)
E/AndroidRuntime( 1923):    at android.app.ActivityThread.handleBindApplication(ActivityThread.java:3272)
E/AndroidRuntime( 1923):    ... 10 more

can anybody suggest any solution ?

Answer 1

Your program may behave as you want!**

** Just remember that you need to think about the consequences of its actions.

public class MyApplication extends Application {
        /** 
        * show example alertdialog on context -method could be moved to other class 
        * (eg. MyClass) or marked as static & used by MyClas.showAlertDialog(Context)
        * context is obtained via getApplicationContext() 
        */
        public void showAlertDialog(Context context) {
            /** define onClickListener for dialog */
            DialogInterface.OnClickListener listener 
                  = new   DialogInterface.OnClickListener() {
                @Override
                public void onClick(DialogInterface dialog, int which) {
                // do some stuff eg: context.onCreate(super)
                }
            };

            /** create builder for dialog */
            AlertDialog.Builder builder = new AlertDialog.Builder(context)
                .setCancelable(false)
                .setMessage("Messag...")
                .setTitle("Title")
                .setPositiveButton("OK", listener);
            /** create dialog & set builder on it */
            Dialog dialog = builder.create();
            /** this required special permission but u can use aplication context */ 
            dialog.getWindow().setType(WindowManager.LayoutParams.TYPE_SYSTEM_ALERT);
            /** show dialog */
            dialog.show();
        }

        @Override
        public void onCreate() {
            showAlertDialog(getApplicationContext());
        }
}

imports for abowe:

import android.app.AlertDialog;
import android.app.Application;
import android.app.Dialog; 
import android.content.Context;
import android.content.DialogInterface; 
import android.view.WindowManager;

edity:

You cannot **display an application window/dialog through a Context that is not an Activity or Service. Try passing a valid activity reference

** u can use application context to create dialog by adding before call to Dialog.show();

Dialog.getWindow().setType(WindowManager.LayoutParams.TYPE_SYSTEM_ALERT); 

- but this requires permission:  

<uses-permission android:name="android.permission.SYSTEM_ALERT_WINDOW" />

Ref:

• Dialogs
• AlertDialog
• WindowType

Answer 2

You can't use an application [or service] context. If you really want to show you diallog from an application, you will have to pass an Activity context to it. You could also store the Activity context, but I do not recommend that. The activity context is voided on finish, so you will break your program. As @LeoLink said, just call it directly from your Activity.

EDIT For Example

class MyDialog {
    public Dialog show(Context context) {
        Dialog d = new Dialog(context);
        d.setTitle("I'm a dialog");
        d.setMessage("I'm a message");
        return d.show();
    }
}