Hello freind Today will be learn about how to take run time permission in android studio.
Before starting this project, I have already told manage_external_storage and call phone permission. Click here to see it.Manage_External_Storage and Call phone.
Let's start creating the project First of all we will create a project in Android Studio.After creating the project, we will use this code in Splash or MainActivity.

activity_main.xml
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    android:padding="10sp"
    tools:context=".MainActivity">

    <Button
        android:id="@+id/btn"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerInParent="true"
        android:gravity="center"
        android:text="Click Me"
        android:textSize="20sp" />

</RelativeLayout>

MainActivity.java. 
package com.ardeveloper.whatsdeleterecovery;

import androidx.appcompat.app.AppCompatActivity;
import androidx.core.app.ActivityCompat;
import androidx.core.content.ContextCompat;
import android.Manifest;
import android.content.pm.PackageManager;
import android.os.Bundle;
import android.view.View;
import android.widget.TextView;

public class MainActivity extends AppCompatActivity {
    private Button getPermission;
    private static final String permissions = Manifest.permission.POST_NOTIFICATIONS;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        getPermission = findViewById(R.id.btn);
        getPermission.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                if (ContextCompat.checkSelfPermission(MainActivity.this, permissions) == PackageManager.PERMISSION_GRANTED) {
                    /// Pemission granted here .....
                } else {
                    ActivityCompat.requestPermissions(MainActivity.this, new String[]{permissions}, 100);
                  
                }
            }
        });
    }
    @Override
    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
        super.onRequestPermissionsResult(requestCode, permissions, grantResults);
        if (requestCode==100)
        {
            if (grantResults.length>0 && grantResults[0]==PackageManager.PERMISSION_GRANTED)
            {
                if (ContextCompat.checkSelfPermission(this,
                        permissions)
                        == PackageManager.PERMISSION_GRANTED) {
                    /// Write logic here
                }

            } else {
                finish();
            }

        }
    }
}
After this give permission in Manifest Whose code given below

Manifest
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools">
    <uses-permission android:name="android.permission.INTERNET"/>
    <uses-permission android:name="android.permission.POST_NOTIFICATIONS"/>
    <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......Samples"/// write app name here
        tools:targetApi="34">
        <activity
            android:name=".MainActivity"
            android:exported="true">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

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

</manifest>
Thanks you...