Android is an open-source operating system, based on the Linux kernel and used in mobile devices like smartphones, tablets, etc. Further, it was developed for smartwatches and Android TV. In this article, we are going to see how we can implement static methods in Android. We will be creating static methods to display Toast, AlertDialog, and redirect to any other activity.
What we are going to build in this article?
Here is a sample video of what we are going to build in this article. Note that we are going to implement this project in the Java language.
Step by Step Implementation
Step 1: Create a New Project
- Open a new project.
- We will be working on Empty Activity with language as Java. Leave all other options unchanged.
- Name the application at your convenience.
- There will be two default files named activity_main.xml and MainActivity.java.
If you don’t know how to create a new project in Android Studio then you can refer to How to Create/Start a New Project in Android Studio?
Step 2. Working on XML files
Navigate to the app > res > layout > activity_main.xml and add the below code to that file. Below is the code for the activity_main.xml file.
XML
<?xml version="1.0" encoding="utf-8"?><LinearLayout android:layout_width="match_parent" android:layout_height="match_parent" android:orientation="vertical" android:padding="16dp" android:gravity="center" tools:context=".MainActivity"> <Button android:layout_width="wrap_content" android:layout_height="wrap_content" android:id="@+id/bt_alert" android:text="Show alert dialog"/> <Button android:layout_width="wrap_content" android:layout_height="wrap_content" android:id="@+id/bt_redirect" android:text="Redirect to activity"/> </LinearLayout> |
Navigate to app > right-click > new > activity > empty activity and name it as “MainActivity2”. Use the following code in activity_main2.xml file
XML
<?xml version="1.0" encoding="utf-8"?><LinearLayout android:layout_width="match_parent" android:orientation="vertical" android:padding="16dp" android:gravity="center" android:layout_height="match_parent" tools:context=".MainActivity2"> <Button android:layout_width="wrap_content" android:layout_height="wrap_content" android:id="@+id/btToast" android:text="Display Toast"/> <Button android:layout_width="wrap_content" android:layout_height="wrap_content" android:id="@+id/bt_alert" android:text="Display Alert Dialog"/> <Button android:layout_width="wrap_content" android:layout_height="wrap_content" android:id="@+id/bt_redirect" android:text="Redirect to activity with text"/> </LinearLayout> |
Step 3. Working on Java files
Navigate to the MainActivity.java file and use the following code in it. Comments are added to the code to have a better understanding.
Java
package com.example.staticmethod; import androidx.appcompat.app.AppCompatActivity; import android.os.Bundle;import android.view.View;import android.widget.Button; public class MainActivity extends AppCompatActivity { // Initialize variables Button btAlert,btRedirect; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); // Assign variable btAlert=findViewById(R.id.bt_alert); btRedirect=findViewById(R.id.bt_redirect); btAlert.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View view) { // call static method to display alert dialog StaticMethod.displayAlertDialog(MainActivity.this,getString(R.string.app_name),"Welcome to GFG"); } }); btRedirect.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View view) { // call static method to redirect activity StaticMethod.redirect2Activity(MainActivity.this,MainActivity2.class); } }); // Check condition if(getIntent().hasExtra("key0")) { // When intent has extra data // Initialize bundle Bundle bundle=getIntent().getExtras(); // Check Condition if(bundle!=null) { // When bundle is not equal to null // get all string String s1=bundle.getString("key0"); String s2=bundle.getString("key1"); // Call static method to display toast StaticMethod.displayToast(MainActivity.this,s1+" And "+s2); } } }} |
Navigate to app > new > class and name it as “StaticMethod”. Use the following code in the StaticMethod.java file
Java
package com.example.staticmethod; import android.app.Activity;import android.app.AlertDialog;import android.content.DialogInterface;import android.content.Intent;import android.widget.Toast; import java.util.ArrayList; public class StaticMethod { // Create static method to redirect public static void redirect2Activity(Activity activity1,Class activity2) { // Initialize intent Intent intent=new Intent(activity1,activity2); // set flag intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK); // Start activity activity1.startActivity(intent); } // Create static method to redirect public static void redirectWithText(Activity activity1,Class activity2, ArrayList<String> arrayList) { // Initialize intent Intent intent= new Intent(activity1,activity2); // Use for loop for(int i=0;i<arrayList.size();i++) { // Add extra value intent.putExtra("key"+i,arrayList.get(i)); } // Set flag intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK); // Start activity activity1.startActivity(intent); } // Create static method to display toast public static void displayToast(Activity activity,String message) { // Initialize toast Toast.makeText(activity,message,Toast.LENGTH_SHORT).show(); } // create a static method to display an alert dialog public static void displayAlertDialog(Activity activity,String title,String message) { // Initialize alert dialog AlertDialog.Builder builder=new AlertDialog.Builder(activity); // Set title builder.setTitle(title); // Set message builder.setMessage(message); // Set positive button builder.setPositiveButton("OK", new DialogInterface.OnClickListener() { @Override public void onClick(DialogInterface dialogInterface, int i) { // Dismiss dialog dialogInterface.dismiss(); } }); // show dialog builder.show(); } // Create static method to display alert dialog with button public static AlertDialog.Builder displayAlertWithButton(Activity activity,String title,String message) { // Initialize alert dialog AlertDialog.Builder builder=new AlertDialog.Builder(activity); // set title builder.setTitle(title); // set message builder.setMessage(message); // Return alert dialog builder return builder; };} |
Navigate to the MainActivity2.java file and use the following code in it. Comments are added to the code to have a better understanding.
Java
package com.example.staticmethod; import androidx.appcompat.app.AppCompatActivity; import android.app.AlertDialog;import android.content.DialogInterface;import android.os.Bundle;import android.view.View;import android.widget.Button; import java.util.ArrayList; public class MainActivity2 extends AppCompatActivity { // Initialize variables Button btToast,btAlertDialog,btRedirect; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main2); // Assign variable btToast=findViewById(R.id.btToast); btAlertDialog=findViewById(R.id.bt_alert); btRedirect=findViewById(R.id.bt_redirect); btToast.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View view) { // Call static method to display toast StaticMethod.displayToast(MainActivity2.this,"Welcome to GFG"); } }); btAlertDialog.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View view) { // Initialize alert dialog AlertDialog.Builder builder=StaticMethod.displayAlertWithButton( MainActivity2.this ,getString(R.string.app_name) ,"You want to close the activity?" ); // Set positive button builder.setPositiveButton("Yes", new DialogInterface.OnClickListener() { @Override public void onClick(DialogInterface dialogInterface, int i) { // finish activity finish(); } }); // Set negative button builder.setNegativeButton("Cancel", new DialogInterface.OnClickListener() { @Override public void onClick(DialogInterface dialogInterface, int i) { // Dismiss dialog dialogInterface.dismiss(); } }); // Show dialog builder.show(); } }); btRedirect.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View view) { // Initialize array list ArrayList<String> arrayList=new ArrayList<>(); // Add value in array list arrayList.add("Text1"); arrayList.add("Text2"); // call static method to redirect with text StaticMethod.redirectWithText(MainActivity2.this,MainActivity.class,arrayList); } }); }} |
Here is the final output of our application.
Output:
