You need to use a Theme.AppCompat theme (or descendant) with this activity

The reason you are having this problem is because the activity you are trying to apply the dialog theme to is extending ActionBarActivity which requires the AppCompat theme to be applied.

Update: Extending AppCompatActivity would also have this problem

In this case, change the Java inheritance from ActionBarActivity to Activity and leave the dialog theme in the manifest as it is, a non Theme.AppCompat value

---

The general rule is that if you want your code to support older versions of Android, it should have the AppCompat theme and the java code should extend AppCompatActivity. If you have *an activity that doesn't need this support, such as you only care about the latest versions and features of Android, you can apply any theme to it but the java code must extend plain old Activity.

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NOTE: When change from AppCompatActivity (or a subclass, ActionBarActivity), to Activity, must also change the various calls with "support" to the corresponding call without "support". So, instead of getSupportFragmentManager, call getFragmentManager.

All you need to do is add android:theme="@style/Theme.AppCompat.Light" to your application tag in the AndroidManifest.xml file.

Copying answer from @MarkKeen in the comments above as I had the same problem.

I had the error stated at the top of the post and happened after I added an alert dialog. I have all the relevant style information in the manifest. My problem was cured by changing a context reference in the alert builder - I changed:

new android.support.v7.app.AlertDialog.Builder(getApplicationContext())

to:

new android.support.v7.app.AlertDialog.Builder(this)

And no more problems.

If you are using the application context, like this:

final AlertDialog.Builder builder = new AlertDialog.Builder(getApplicationContext());

change it to an activity context like this:

final AlertDialog.Builder builder = new AlertDialog.Builder(MainActivity.this);

min sdk is 10. ActionBar is available from api level 11. So for 10 you would be using AppCompat from the support library for which you need to use Theme.AppCompat or descendant of the same.

Use

android:theme="@style/Theme.AppCompat" >

Or if you dont want action bar at the top

android:theme="@style/Theme.AppCompat.NoActionBar">

More info @

http://developer.android.com/guide/topics/ui/actionbar.html

Edit:

I might have misread op post.

Seems op wants a Dialog with a Activity Theme. So as already suggested by Bobbake4 extend Activity instead of ActionBarActivity.

Also have a look @ Dialog Attributes in the link below

http://grepcode.com/file/repository.grepcode.com/java/ext/com.google.android/android/4.4_r1/frameworks/base/core/res/res/values/themes.xml/

I was experiencing this problem even though my Theme was an AppCompat Theme and my Activity was an AppCompatActivity (or Activity, as suggested on other's answers). So I cleaned, rebuild and rerun the project.

(Build -> Clean Project ; Build -> Rebuild Project ; Run -> Run)

It may seem dumb, but now it works great!

Just hope it helps!

This is what fixed it for me: instead of specifying the theme in manifest, I defined it in onCreate for each activity that extends ActionBarActivity:

@Override
protected void onCreate(Bundle savedInstanceState) {
    setTheme(R.style.MyAppTheme);
    super.onCreate(savedInstanceState);
    setContentView(R.layout.my_activity_layout);
...
}

Here MyAppTheme is a descendant of Theme.AppCompat, and is defined in xml. Note that the theme must be set before super.onCreate and setContentView.

go to your styles and put the parent

parent="Theme.AppCompat"

instead of

parent="@android:style/Theme.Holo.Light"

In my case i have no values-v21 file in my res directory. Then i created it and added in it following codes:

  <style name="AppTheme" parent="Theme.AppCompat.Light.NoActionBar">
    <!-- Customize your theme here. -->
    <item name="colorPrimary">@color/colorPrimary</item>
    <item name="colorPrimaryDark">@color/colorPrimaryDark</item>
    <item name="colorAccent">@color/colorAccent</item>
</style>

Change the theme of the desired Activity. This works for me:

<activity
            android:name="HomeActivity"
            android:screenOrientation="landscape"
            android:theme="@style/Theme.AppCompat.Light"
            android:windowSoftInputMode="stateHidden" />

Just Do

new AlertDialog.Builder(this)

Instead of

new AlertDialog.Builder(getApplicationContext())

I had such crash on Samsung devices even though the activity did use Theme.AppCompat. The root cause was related to weird optimizations on Samsung side:

- if one activity of your app has theme not inherited from Theme.AppCompat
- and it has also `android:launchMode="singleTask"`
- then all the activities that are launched from it will share the same Theme

My solution was just removing android:launchMode="singleTask"

If you need to extend ActionBarActivity you need on your style.xml:

<!-- Base application theme. -->
<style name="AppTheme" parent="AppTheme.Base"/>

<style name="AppTheme.Base" parent="Theme.AppCompat.Light.DarkActionBar">
    <!-- Customize your theme here. -->

If you set as main theme of your application as android:Theme.Material.Light instead of AppTheme.Base then youll get an IllegalStateException:You need to use a Theme.AppCompat theme (or descendant) with this activity error.

I had the same problem, but it solved when i put this on manifest: android:theme="@style/Theme.AppCompat.

    <application
        android:allowBackup="true"
        android:icon="@drawable/icon"
        android:label="@string/app_name_test"
        android:supportsRtl="true"
        android:theme="@style/Theme.AppCompat">

        ...    

    </application>

for me a solution, after trying all solutions from here, was to change

    <activity
        android:name="com.github.cythara.MainActivity"
        android:label="Main">
    </activity>

to include a theme:

    <activity
        android:name="com.github.cythara.MainActivity"
        android:theme="@style/Theme.AppCompat.NoActionBar"
        android:label="Main">
    </activity>

In my case such issue was appear when i tried to show Dialog. The problem was in context, I've use getBaseContext() which theoretically should return Activity context, but appears its not, or it return context before any Theme applied.

So I just replaced getBaseContexts() with "this", and now it work as expected.

        Dialog.showAlert(this, title, message,....);

You have came to this because you want to apply Material Design in your theme style in previous sdk versions to 21. ActionBarActivity requires AppThemeso if you also want to prevent your own customization about your AppTheme, only you have to change in your styles.xml (previous to sdk 21) so this way, can inherit for an App Compat theme.

<style name="AppTheme" parent="android:Theme.Holo.Light.DarkActionBar">

for this:

<style name="AppTheme" parent="Theme.AppCompat.Light.DarkActionBar">

I had an activity with theme <android:theme="@android:style/Theme.Dialog"> used for showing dialog in my appWidget and i had same problem

i solved this error by changing activity code like below:

@Override
protected void onCreate(Bundle savedInstanceState) {
    setTheme(R.style.Theme_AppCompat_Dialog); //this line i added
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_dialog);
}

Make sure you are using an activity context while creating a new Alert Dialog and not an application or base context.

for me was solution to use ContextThemeWrapper:

private FloatingActionButton getFAB() {
Context context = new android.support.v7.view.ContextThemeWrapper(getContext(), R.style.AppTheme);
FloatingActionButton fab = new FloatingActionButton(context);
return fab;}

from Android - How to create FAB programmatically?

I had this problem as well and what I did to fix it, AND still use the Holo theme was to take these steps:

first I replaced this import:

import android.support.v7.app.AppCompatActivity;

with this one:

import android.app.Activity;

then changed my extension from:

public class MyClass extends AppCompatActivity {//...

to this:

public class MyClass extends Activity {//...

And also had to change this import:

import android.support.v7.app.AlertDialog;

to this import:

import android.app.AlertDialog;

and then you can use your theme tag in the manifest at the activity level:

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

and lastly, (unless you have other classes in your project that has to use v7 appCompat) you can either clean and rebuild your project or delete this entry in the gradle build file at the app level:

compile 'com.android.support:appcompat-v7:23.2.1'

if you have other classes in your project that has to use v7 appCompat then just clean and rebuild the project.

In case the AndroidX SplashScreen library brought you here ...

This is because Theme.SplashScreen also has no R.styleable.AppCompatTheme_windowActionBar:

if (!a.hasValue(R.styleable.AppCompatTheme_windowActionBar)) {
    a.recycle();
    throw new IllegalStateException(
            "You need to use a Theme.AppCompat theme (or descendant) with this activity.");
}

This requires switching the theme to the postSplashScreenTheme, before calling super():

@Override
protected void onCreate(Bundle savedInstanceState) {

    /* When switching the theme to dark mode. */
    if (savedInstanceState != null) {
        this.setTheme(R.style.AppTheme);
    }
    super.onCreate(savedInstanceState);
    
    /* When starting the Activity. */
    if (savedInstanceState == null) {
        SplashScreen.installSplashScreen(this);
    }
}

Then the Theme.SplashScreen from AndroidManifest.xml won't interfere.

---

Also quite related: When using Theme.MaterialComponents, there's a bridge theme contained, which works as substitute for Theme.AppCompat: Theme.MaterialComponents.DayNight.NoActionBar.Bridge.

This Bridge theme works despite Theme.MaterialComponents not inherits from Theme.AppCompat:

<?xml version="1.0" encoding="utf-8"?>
<resources>    
    <style name="AppTheme" parent="Theme.MaterialComponents.DayNight.NoActionBar.Bridge" />   
    <style name="AppTheme.SplashScreen" parent="Theme.SplashScreen" />    
</resources>

You have many solutions to that error.

1. You should use Activity or FragmentActivity instead of ActionbarActivity or AppCompatActivity

2. If you want use ActionbarActivity or AppCompatActivity, you should change in styles.xml Theme.Holo.xxxx to Theme.AppCompat.Light (if necessary add to DarkActionbar)

If you don't need advanced attributes about action bar or AppCompat you don't need to use Actionbar or AppCompat.

In Android manifest just change theme of activity to AppTheme as follow code snippet

<activity
  android:name=".MainActivity"
  android:label="@string/app_name"
  android:theme="@style/AppTheme">
</activity>

In my experiences the problem was the context where I showed my dialog. Inside a button click I instantiate an AlertDialog in this way:

builder = new AlertDialog.Builder(getApplicationContext());

But the context was not correct and caused the error. I've changed it using the application context in this way:

In declare section:

Context mContext;

in the onCreate method

mContext = this;

And finally in the code where I need the AlertDialog:

start_stop = (Button) findViewById(R.id.start_stop);
start_stop.setOnClickListener( new View.OnClickListener()
     {
                @Override
                public void onClick(View v)
                {
                    if (!is_running)
                    {
                        builder = new AlertDialog.Builder(mContext);
                        builder.setMessage("MYTEXT")
                                .setCancelable(false)
                                .setPositiveButton("SI", new DialogInterface.OnClickListener() {
                                    public void onClick(DialogInterface dialog, int id) {
                                    Task_Started = false;
                                    startTask();
                                    }
                                })
                                .setNegativeButton("NO",
                                        new DialogInterface.OnClickListener() {
                                    public void onClick(DialogInterface dialog, int id) {
                                        dialog.cancel();
                                    }
                                });
                        AlertDialog alert = builder.create();
                        alert.show();
                    }
            }
        }

This is the solution for me.

I was getting this same problem. Because i was creating custom navigation drawer. But i forget to mention theme in my manifest like this

android:theme="@style/Theme.AppCompat.NoActionBar"

As soon i added the above the theme to my manifest it resolved the problem.

Change your theme style parent to

 parent="Theme.AppCompat"

This worked for me ...

This one worked for me:

<application
           android:allowBackup="true"
           android:icon="@mipmap/ic_launcher"
           android:label="@string/app_name"
           android:theme="@style/AppTheme" >
           <activity
               android:name=".MainActivity"
               android:label="@string/app_name"
               android:theme="@style/Theme.AppCompat.NoActionBar">

               <intent-filter>
                   <action android:name="android.intent.action.MAIN" />

                   <category android:name="android.intent.category.LAUNCHER" />
               </intent-filter>
           </activity>
</application>

Your Activity is extending ActionBarActivity which requires the AppCompat.theme to be applied. Change from ActionBarActivity to Activity or FragmentActivity, it will solve the problem.

If you use no Action bar then :

android:theme="@android:style/Theme.Light.NoTitleBar.Fullscreen" 

This is when you want a AlertDialog in a Fragment

            AlertDialog.Builder adb = new AlertDialog.Builder(getActivity());
            adb.setTitle("My alert Dialogue \n");
            adb.setPositiveButton("OK", new DialogInterface.OnClickListener() {
                public void onClick(DialogInterface dialog, int which) {

                  //some code

            } });
            adb.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
                public void onClick(DialogInterface dialog, int which) {

                 dialog.dismiss();

                } });
            adb.show();