Android - Change app Theme on onClick [duplicate]

Following blog can solve your problem:

http://mrbool.com/how-to-change-the-layout-theme-of-an-android-application/25837

Copying the blog code for quick reference:

Assuming that you already defined following three themes in the XML file R.style.FirstTheme, R.style.SecondTheme and R.style.ThirdTheme

import android.app.Activity;import android.os.Bundle;import android.view.View;import android.view.View.OnClickListener;public class ChangeThemeActivity extends Activity implements OnClickListener{    /** Called when the activity is first created. */    @Override    public void onCreate(Bundle savedInstanceState)    {        super.onCreate(savedInstanceState);        Utils.onActivityCreateSetTheme(this);        setContentView(R.layout.main);                    findViewById(R.id.button1).setOnClickListener(this);          findViewById(R.id.button2).setOnClickListener(this);          findViewById(R.id.button3).setOnClickListener(this);    }     @Override     public void onClick(View v)     {          // TODO Auto-generated method stub          switch (v.getId())          {          case R.id.button1:          Utils.changeToTheme(this, Utils.THEME_DEFAULT);          break;          case R.id.button2:          Utils.changeToTheme(this, Utils.THEME_WHITE);          break;          case R.id.button3:          Utils.changeToTheme(this, Utils.THEME_BLUE);          break;          }     }}

Let us write the below code in the "Utils" file:

import android.app.Activity;import android.content.Intent;public class Utils{     private static int sTheme;     public final static int THEME_DEFAULT = 0;     public final static int THEME_WHITE = 1;     public final static int THEME_BLUE = 2;     /**      * Set the theme of the Activity, and restart it by creating a new Activity of the same type.      */     public static void changeToTheme(Activity activity, int theme)     {          sTheme = theme;          activity.finish();activity.startActivity(new Intent(activity, activity.getClass()));     }     /** Set the theme of the activity, according to the configuration. */     public static void onActivityCreateSetTheme(Activity activity)     {          switch (sTheme)          {          default:          case THEME_DEFAULT:              activity.setTheme(R.style.FirstTheme);              break;          case THEME_WHITE:              activity.setTheme(R.style.SecondTheme);              break;          case THEME_BLUE:              activity.setTheme(R.style.Thirdheme);              break;          }     }}

Hope it helps...

EDIT 1:

following is the reason AlertDialog does not take custom theme:

Implementation in Builder.create() is:

public AlertDialog create() {    final AlertDialog dialog = new AlertDialog(P.mContext);    P.apply(dialog.mAlert);    [...]}

which calls the "not-theme-aware" constructor of AlertDialog, which looks like this:

protected AlertDialog(Context context) {    this(context, com.android.internal.R.style.Theme_Dialog_Alert);}

There is a second constructor in AlertDialog for changing themes:

protected AlertDialog(Context context, int theme) {    super(context, theme);    [...]}

that the Builder just doesn't call.

Check out following post for more relevant fixes..

How to change theme for AlertDialog

Following is the most voted answer:

  new AlertDialog.Builder(  new ContextThemeWrapper(context, android.R.style.Theme_Dialog))