How to use string buffer in android?

Before getting into example, we should know what string buffer is. StringBuffer class is used to create mutable string and it is thread safe. This example demonstrate about How to use string buffer in android.

Step 1 − Create a new project in Android Studio, go to File ⇒ New Project and fill all required details to create a new project.

Step 2 − Add the following code to res/layout/activity_main.xml.

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 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:gravity="center_horizontal"
   android:layout_marginTop="100dp"
   tools:context=".MainActivity">
   <EditText
      android:id="@+id/edit_query"
      android:layout_width="match_parent"
      android:layout_height="wrap_content"
      android:hint="Enter string" />
   <Button
      android:id="@+id/click"
      android:layout_marginTop="50dp"
      style="@style/Base.TextAppearance.AppCompat.Widget.Button.Borderless.Colored"
      android:layout_width="wrap_content"
      android:background="#c1c1c1"
      android:textColor="#FFF"
      android:layout_height="wrap_content"
      android:text="Button" />
   <TextView
      android:id="@+id/text"
      android:layout_width="wrap_content"
      android:layout_height="wrap_content" />
   <TextView
      android:id="@+id/text1"
      android:layout_width="wrap_content"
      android:layout_height="wrap_content" />
   <TextView
      android:id="@+id/text2"
      android:layout_width="wrap_content"
      android:layout_height="wrap_content" />
   <TextView
      android:id="@+id/text3"
      android:layout_width="wrap_content"
      android:layout_height="wrap_content" />
   <TextView
      android:id="@+id/text4"
      android:layout_width="wrap_content"
      android:layout_height="wrap_content" />
</LinearLayout>

In the above code, we have taken edittext, button and textviews. When user click on button, it will take the data from edittext and manipulate with string buffer methods. The result of manipulation data append to textview’s

Step 3 − Add the following code to src/MainActivity.java

package com.example.myapplication;

import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.EditText;
import android.widget.TextView;

public class MainActivity extends AppCompatActivity {
   EditText edit_query;

   @Override
   protected void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      setContentView(R.layout.activity_main);
      edit_query = findViewById(R.id.edit_query);
      final TextView textView = findViewById(R.id.text);
      final TextView textView1 = findViewById(R.id.text1);
      final TextView textView2 = findViewById(R.id.text2);
      final TextView textView3 = findViewById(R.id.text3);
      final TextView textView4 = findViewById(R.id.text4);
      findViewById(R.id.click).setOnClickListener(new View.OnClickListener() {
         @Override
         public void onClick(View v) {
            if (!edit_query.getText().toString().isEmpty()) {
               StringBuffer stringBuffer = new StringBuffer(edit_query.getText().toString());
               textView.setText(" default String : " + stringBuffer);
               textView1.setText(stringBuffer.insert(0, "insert at 0 " + "tutorialspoint.com"));
               textView2.setText("Capacity is " + stringBuffer.capacity());
               textView3.setText("Delete : " + stringBuffer.delete(1, 3));
               textView4.setText("append : " + stringBuffer.append(" appended to string buffer"));
            }
         }
      });
   }
}

Let's try to run your application. I assume you have connected your actual Android Mobile device with your computer. To run the app from android studio, open one of your project's activity files and click Run  icon from the toolbar. Select your mobile device as an option and then check your mobile device which will display your default screen −

In the above result, it is showing string buffer text with different manipulation data.

Click here to download the project code