Android Alert dialog from inside an intent service

问题:

I want to display an alert dialog from inside an intent service.

   AlertDialog alertDialog = new AlertDialog.Builder(this).create();

This throws the following exception

   Unable to add window — token null is not for an application

I have tried IntentService.this and getApplicationContext() as well. Between i dont want to do it using an activity. I just want to show a simple alert dialog with a little text.

回答1:

Need Activity for display AlertDialog, because we can't display Dialog from any Service

Solution.

Create Activity as Dialog Theme and start that Activity from Service.

Just need to register you Activity in menifest.xml like as below

android:theme="@android:style/Theme.Dialog"

or

android:theme="@android:style/Theme.Translucent.NoTitleBar"

MyDialog.java

public class MyDialog extends Activity {
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        final AlertDialog alertDialog = new AlertDialog.Builder(this).create();
        alertDialog.setTitle("your title");
        alertDialog.setMessage("your message");
        alertDialog.setIcon(R.drawable.icon);

        alertDialog.show();
    }
}

回答2:

Only if you set your alertDialog type to TYPE_SYSTEM_ALERT it will be displayed from an intent service.

 AlertDialog alertDialog = new AlertDialog.Builder(this).create();

add these after your code:

alertDialog.getWindow().setType(WindowManager.LayoutParams.TYPE_SYSTEM_ALERT);
alertDialog.show();

But, it have a cost:

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

回答3:

Please visit

https://github.com/selmantayyar/Custom-SMS-Popup

it will surly help you!!

or what you can do is register anActivity in menifest.xml as follows

android:theme="@android:style/Theme.Dialog"

or

android:theme="@android:style/Theme.Translucent.NoTitleBar"

and work around it

回答4:

The problem is because of Context. You can't use this as Context in Intent Service. So need to pass a Context variable of your Intent Service to your Alert Dialog. Like,

AlertDialog alertDialog = new AlertDialog.Builder(context).create();