How to exit Application when click on Back Button Android?

Hello,
This article is for Beginner and people who want to learn Android .This article is about How to exit Application when click on Back Button Android?
    import android.support.v7.app.AppCompatActivity;
    import android.os.Bundle;
    import android.view.View;
    import android.widget.Button;
    import android.widget.ImageView;
    import android.widget.Toast;


public class MainActivity extends AppCompatActivity {




        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_main);



        }
    @Override
    public void onBackPressed()
    {
        finish();
    }

    }

Image setOnclickListener Android Example

Hello,
This article is for Beginner and people who want to learn Android .This article is about image setOnClickListener Example. 

1. XML File .
activity_main -

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:gravity="center"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <ImageView
        android:id="@+id/img"
        android:background="@drawable/android_logo"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"/>

</LinearLayout>

2.Java File
MainActivity

import android.support.v7.app.AppCompatActivity;
    import android.os.Bundle;
    import android.view.View;
    import android.widget.Button;
    import android.widget.ImageView;
    import android.widget.Toast;


public class MainActivity extends AppCompatActivity {
    ImageView img;



        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_main);
            img=findViewById(R.id.img);
            img.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    Toast.makeText(MainActivity.this, "Image", Toast.LENGTH_SHORT).show();
                }
            });


        }
    }

How to display image in Imageview?

Hello,

This article is for Beginner and people who want to learn Android .This article is about How to display image in Imageview Example. 

1. XML File .

activity_main -

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:gravity="center"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <ImageView
        android:id="@+id/img"
        android:background="@drawable/android_logo"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"/>

</LinearLayout>

How to Show Toast on Button Click Android ?

Hello,

This article is for Beginner and people who want to learn Android .This article is about How to show Toast On Button Click . 

1. XML File .

activity_main -

<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:gravity="center"
    android:layout_height="match_parent"
    tools:context=".MainActivity">


<Button
    android:id="@+id/btnshow"
    android:text="Show"
    android:textColor="#fff"
    android:background="@color/colorAccent"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"/>

</LinearLayout>

2.Java File
MainActivity

    import android.support.v7.app.AppCompatActivity;
    import android.os.Bundle;
    import android.view.View;
    import android.widget.Button;
    import android.widget.Toast;


public class MainActivity extends AppCompatActivity {
    Button btnshow;


        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_main);
            btnshow=findViewById(R.id.btnshow);
            btnshow.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    Toast.makeText(MainActivity.this, "Heyyy", Toast.LENGTH_SHORT).show();
                }
            });

        }
    }