Android:How to programmatically set an Activity's theme to Theme.Dialog

Question

So I have an Activity (say TestActivity) which needs to act as a normal unthemed Activity as well as a Theme.Dialog at other place. I am trying to reuse same TestActivity for both the tasks.

All I am looking for setting the theme dynamically. The code is simple: Here is my activity's onCreate that works with a black background

public void onCreate(Bundle icicle) {
    if (Utility.isDialog == true)
        setTheme(android.R.style.Theme_Dialog);
    super.onCreate(icicle);
    requestWindowFeature(Window.FEATURE_NO_TITLE);
.....

and here is the Manifest Entry

<activity android:name=".TestActivity"/>

And in the meantime I found a post that says it can't be done here is the post http://code.google.com/p/android/issues/detail?id=4394 .But there is a strong feeling that it can be done.

All suggestions are welcome.

Solution 1

Would like to give a work around for this problem.

Problem : How to use the same activity as both dialog and full screen based.

Solution :

1. Define your activity in your AndroidManifest.xml with the theme @android:style/Theme.Dialog
   
2. In your respective .Java file, check for an intent extra that defines dialog mode.
   
3. If it does not exist, set the Theme to android.R.style.Theme. This is the default theme which is applied if you do not define any theme.

Code :

boolean fDialogMode = getIntent().hasExtra("dialog_mode");

if( ! fDialogMode ) {
    super.setTheme(android.R.style.Theme);
}

Alternate Solution:

A more complex solution is to use AlertDialog as below:

1. Define a ListAdapter class extended from ArrayAdapter.

2. return 1 in getCount function

   @Override
   public int getCount() { return 1; }
   

3. In the getView function, inflate the layout of the activity you need and do any customization before returning the view.

   @Override
   public View getView( int position, View view, ViewGroup group ) {
       View v = view;
       if( v == null ) {
           v = getSystemService(Context.LAYOUT_INFLATER_SERVICE).inflate( <layout res id>, null );
       }
   
   ... Do any customization here    ....
   
         return v;
   }
   

This is definitely a second choice option by if you are not doing too much processing in the activity class this could be an option.

Only reason to consider this solution could be that the logic to show it in a dialog is isolated to the places where it is used as a dialog.

Both the options worked for me but for obvious reasons I am taking the first option. :-)

Solution 2

you can use setTheme(..) before calling setContentView(...)and super.oncreate() and it should work fine

Solution 3

Like several others, calls to setTheme in onCreate (before or after my call to super.onCreate) did not work. However, by overriding setTheme, I was able to specify a theme other than that stated in Manifest.xml. Specifically, the following worked without issue:

@Override
public void setTheme(int resid) {
    boolean changeTheme = true;
    super.setTheme(changeTheme ? android.R.style.Theme_Dialog : resid);
}

I found the above in the discussion at: https://code.google.com/p/android/issues/detail?id=4394

Solution 4

Call Activity.setTheme() in onCreate() before you call setContentView().

Solution 5

use setTheme before calling super.onCreate(savedInstance)

View more solutions

Comments

[100rabh]

Reuben though it works (& I have tried that earlier too)but I see Black Background instead of the calling Activity

[Reuben Scratton]

Then your theme properties are incorrect. What is your android:windowBackground set to?

[100rabh]

Reuben I have not defined a custom style.But I will now implement a custom style with windowBackground to color/transparent

[100rabh]

Reuben even the custom style didn't worked.For your answer to windowBackgound see this post stackoverflow.com/questions/2176922/…

[100rabh]

see the updated post with the code.Do let me know for more details.

[Ahmed Salem]

you are not calling setContentView , and i know that it can be done because i did it in my activity

[Bradley Uffner]

Moving the call to setTheme before the super.onCreate made it work for me, thank you!

[Joris Weimar]

Just a FYI: This does work, but it creates an enormous lag in creating a new activity for some reason (on Kindle Fire) and it makes my app crash unexpectedly on the Nook Color.

[Ahmed Salem]

i never tried it on Kindle before , thx for the info , will have to test it when i get one

[Cookster]

This solution doesn't work for all devices. Consider the Motorola Xoom, the result is a dialog on top of a black background rather than a transparent one.

[Ahmed Salem]

@user933237 that is interesting , i also found out that what you described happens on ACER iconia tablet

[Dmitry Zaytsev]

Great explanation, thanks! If someone don't get it at the first time (like me :D) - read @mozarty solution first to understand where exactly you should put this code.

[android developer]

is it possible to call the setTheme after setContentView, if i call setContentView again (this time after setTheme) ? example of a scenario: user sees the activity, press a button, and it changes the theme by calling setTheme and then setContentView.

[Steve B]

However, with Android invoking setTheme() before the onCreate() call, one can't use the data normally sent to an activity to decide whether to change the theme. Some additional hack is needed to make that decision.

[Regolith]

please take some time to explain how this solves the problem so that other with similar problem can know the issue clearly.