Apply Multiple Permissions RunTime

How to  give and apply run time multiple permissions in android,

First yo have to add permissions in Manifest file like below.

<uses-permission android:name="android.permission.CAMERA"/>
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"/>

<uses-permission android:name="android.permission.READ_CONTACTS"/>

Then, you have to code for the check permissions,add button in activitymain.xml file

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout    
xmlns:android="http://schemas.android.com/apk/res/android"    
android:id="@+id/root_layout"    
android:layout_width="match_parent"    
android:layout_height="match_parent"    
android:padding="16dp"    
android:orientation="vertical"    
android:background="#e5ead3"   
android:gravity="center" >
    
<Button        
android:id="@+id/btn_do_task"        
android:layout_width="wrap_content"        
android:layout_height="wrap_content"        
android:text="Check Permissions"        
android:layout_gravity="center"/>
</LinearLayout>

After add button in xml file now add code in MainActivity.java file

import android.Manifest;
import android.app.Activity;
import android.app.AlertDialog;
import android.content.Context;
import android.content.DialogInterface;
import android.content.pm.PackageManager;
import android.os.Build;
import android.support.v4.app.ActivityCompat;
import android.support.v4.content.ContextCompat;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.LinearLayout;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity {

    private Context mContext;
    private Activity mActivity;

    private Button btn_checkpermi;

    private static final int MY_PERMISSIONS_REQUEST_CODE = 123;
    @Override    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        mContext = getApplicationContext();
        mActivity = MainActivity.this;
        
        btn_checkpermi = findViewById(R.id.btn_checkpermi);

        btn_checkpermi.setOnClickListener(new View.OnClickListener() {
            @Override            public void onClick(View view) {
                if(Build.VERSION.SDK_INT >= Build.VERSION_CODES.M){
                    checkPermission();
                }
            }
        });
    }

    protected void checkPermission(){
        if(ContextCompat.checkSelfPermission(mActivity,Manifest.permission.CAMERA)
                + ContextCompat.checkSelfPermission(
                mActivity,Manifest.permission.READ_CONTACTS)
                + ContextCompat.checkSelfPermission(
                mActivity,Manifest.permission.READ_EXTERNAL_STORAGE)
                != PackageManager.PERMISSION_GRANTED){

            // when permissions not granted            
             if(ActivityCompat.shouldShowRequestPermissionRationale(
                    mActivity,Manifest.permission.CAMERA)
                    || ActivityCompat.shouldShowRequestPermissionRationale(
                    mActivity,Manifest.permission.READ_CONTACTS)
                    || ActivityCompat.shouldShowRequestPermissionRationale(
                    mActivity,Manifest.permission.READ_EXTERNAL_STORAGE)){
                // If we should give explanation of requested permissions
                // Show an alert dialog for request explanation                
                AlertDialog.Builder builder = new AlertDialog.Builder(mActivity);
                builder.setMessage("Camera, Read Contacts and Read External" +
                        " Storage permissions are required to do the task.");
                builder.setTitle("Please grant those permissions");
                builder.setPositiveButton("OK", new DialogInterface.OnClickListener() 
                {
                    @Override                    
                public void onClick(DialogInterface dialogInterface, int i) {
                        ActivityCompat.requestPermissions(
                                mActivity,
                                new String[]{
                                        Manifest.permission.CAMERA,
                                        Manifest.permission.READ_CONTACTS,
                                        Manifest.permission.READ_EXTERNAL_STORAGE },
                                MY_PERMISSIONS_REQUEST_CODE  );
                    }
                });
                builder.setNeutralButton("Cancel",null);
                AlertDialog dialog = builder.create();
                dialog.show();
            }else{
                //  request directly required permissions                
                        ActivityCompat.requestPermissions(
                        mActivity,
                        new String[]{
                                Manifest.permission.CAMERA,
                                Manifest.permission.READ_CONTACTS,
                                Manifest.permission.READ_EXTERNAL_STORAGE},
                        MY_PERMISSIONS_REQUEST_CODE );
            }
        }else {
            // Do your stuff here, permissions are already granted            
     Toast.makeText(mContext,"Permissions already granted",Toast.LENGTH_SHORT).show();
        }
    }

    @Override    
public void onRequestPermissionsResult(int requestCode, String[] permissions, int[] grantResults){
        switch (requestCode){
            case MY_PERMISSIONS_REQUEST_CODE:{
                // When request is cancelled, the results array are empty                
                    if(
                        (grantResults.length >0) &&
                                (grantResults[0]
                                        + grantResults[1]
                                        + grantResults[2]
                                        == PackageManager.PERMISSION_GRANTED                                )
                ){
                    // Permissions are granted                    
                    Toast.makeText(mContext,"Permissions granted.",Toast.LENGTH_SHORT).show();
                }else {
                    // Permissions are denied                    
                   Toast.makeText(mContext,"Permissions denied.",Toast.LENGTH_SHORT).show();
                }
                return;
            }
        }
    }
}