java.lang.IllegalStateException: You need to use a Theme.AppCompat theme (or descendant) with this activity.AtMainActivity.displayCreateCategoryDialog

Question

I wrote the code for alert dialog for the event listener of the floating button but whenever i click on the floating button it always shows this error.

My MainActivity.java is as:

```package com.akashsoam.favlistapp;

import android.app.Activity;
import android.content.DialogInterface;
import android.os.Bundle;
import com.google.android.material.floatingactionbutton.FloatingActionButton;
import androidx.appcompat.app.AlertDialog;
import android.text.InputType;
import android.widget.EditText;
import androidx.appcompat.app.AppCompatActivity;
import androidx.recyclerview.widget.LinearLayoutManager;
import androidx.recyclerview.widget.RecyclerView;
import com.akashsoam.favlistapp.databinding.ActivityMainBinding;
public class MainActivity extends Activity {

    private ActivityMainBinding binding;
    private RecyclerView categoryRecyclerView;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
binding = ActivityMainBinding.inflate(getLayoutInflater());
        setContentView(binding.getRoot());
//        setContentView(R.layout.activity_main);

        categoryRecyclerView = findViewById(R.id.category_recyclerview);
        categoryRecyclerView.setAdapter(new CategoryRecyclerAdapter());
        categoryRecyclerView.setLayoutManager(new LinearLayoutManager(this));

        FloatingActionButton floatingActionButton = findViewById(R.id.fab);
        floatingActionButton.setOnClickListener(view -> {
            displayCreateCategoryDialog();
        });
    }

    private void displayCreateCategoryDialog() {
        String alertTitle = getString(R.string.create_category);
        String positiveButtonTitle = getString(R.string.positive_button_title);
        AlertDialog.Builder builder = new AlertDialog.Builder(getApplicationContext());
        EditText categoryEditText = new EditText(this);
        categoryEditText.setInputType(InputType.TYPE_CLASS_TEXT);


//        TODO:debug below code it is showing errors
        builder.setTitle(alertTitle).setPositiveButton(positiveButtonTitle, new DialogInterface.OnClickListener() {
            @Override
            public void onClick(DialogInterface dialog, int which) {
                dialog.dismiss();

            }
        }).setView(categoryEditText).create().show();
    }

} ```

AndroidManifest.xml ```

    <application
        android:allowBackup="true"
        android:dataExtractionRules="@xml/data_extraction_rules"
        android:fullBackupContent="@xml/backup_rules"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/Theme.AppCompat.Light"
        tools:targetApi="31">
        <activity
            android:name=".MainActivity"
            android:exported="true"
            android:theme="@style/Theme.AppCompat.Light">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

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

</manifest>```

**The error always popus up I have tried many solutions to the similar questions already asked before on stackoverflow but the don't work **

Like

1. I tried to give it a non Appcompat theme- that doesn't work

2. I tried extending MainActivity with Activity instead of AppCompatActivity but that doesn't work either. Please review the code by running it in your android studio.

Answer 1

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

This line is the issue for without even testing the code,you should use your activity context instead as so:

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