android - Determine if app open first time

activity_main.xml

 <?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:id="@+id/root_layout"     android:layout_width="match_parent"     android:layout_height="match_parent"     android:padding="16dp"     android:orientation="vertical"     >     <TextView         android:id="@+id/text_view"         android:layout_width="match_parent"         android:layout_height="wrap_content"         android:textSize="25sp"         android:textStyle="bold"         /> </LinearLayout> 

MainActivity.java

 package com.cfsuman.me.androidcodesnippets;  import android.app.Activity; import android.content.Context; import android.content.SharedPreferences; import android.graphics.Color; import android.support.v7.app.AppCompatActivity; import android.os.Bundle; import android.widget.LinearLayout; import android.widget.TextView;   public class MainActivity extends AppCompatActivity {     private Context mContext;     private Activity mActivity;      private LinearLayout mRootLayout;     private TextView mTextView;      private static simpulan String IS_APP_FIRST_TIME_LAUNCH = "is_app_first_time_launch";      SharedPreferences mSharedPreferences;     SharedPreferences.Editor mEditor;      @Override     protected void onCreate(Bundle savedInstanceState) {         super.onCreate(savedInstanceState);         setContentView(R.layout.activity_main);          // Get the application context         mContext = getApplicationContext();         mActivity = MainActivity.this;          // Get the widget reference from xml layout         mRootLayout = findViewById(R.id.root_layout);         mTextView = findViewById(R.id.text_view);          // Initialize shared preference and editor         mSharedPreferences = getPreferences(Context.MODE_PRIVATE);         mEditor = mSharedPreferences.edit();          if(isAppFirstTimeLaunch()){             mRootLayout.setBackgroundColor(Color.RED);             mTextView.setText("APP is launch for first time.");         }else {             mRootLayout.setBackgroundColor(Color.GREEN);             mTextView.setText("App previously opened.");         }     }      // Custom method to check app is open first time or not     protected boolean isAppFirstTimeLaunch(){         if(mSharedPreferences.getBoolean(IS_APP_FIRST_TIME_LAUNCH,true)){             // App is open/launch for first time             // Update the preference             mEditor.putBoolean(IS_APP_FIRST_TIME_LAUNCH,false);             mEditor.commit();             mEditor.apply();              return true;         }else {             // App previously opened             return false;         }     } }