How to find its first non-repeating character in a given string in android?

This example demonstrate about How to find its first non-repeating character in a given string 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: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">
   <TextView
      android:id="@+id/text"
      android:textSize="30sp"
      android:layout_width="match_parent"
      android:layout_height="match_parent" />
</LinearLayout>

In the above code, we have taken text view to show first non-repeating character.

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

package com.example.myapplication;

import android.os.Build;
import android.os.Bundle;
import android.support.annotation.RequiresApi;
import android.support.v7.app.AppCompatActivity;
import android.util.Log;
import android.widget.TextView;

import java.lang.reflect.Array;
import java.util.ArrayList;
import java.util.Collections;
import java.util.HashMap;
import java.util.HashSet;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.stream.Collectors;

public class MainActivity extends AppCompatActivity {
   TextView textView;
   String strArray = "tutorialspoint";

   @RequiresApi(api = Build.VERSION_CODES.P)
   @Override
   protected void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      setContentView(R.layout.activity_main);
      LinkedHashMap<Character, Integer> hashMap = new LinkedHashMap<>();
      char[] chars=strArray.toCharArray();
      for (int i = 0; i < chars.length; i++) {
         if (hashMap.containsKey(strArray.charAt(i))) {
            hashMap.put(strArray.charAt(i), chars[i] + 1);
         } else {
            hashMap.put(strArray.charAt(i), 1);
         }
      }
      ArrayList<String> values=new ArrayList<>();
      for (Character name : hashMap.keySet()) {
         String key = name.toString();
         int value = hashMap.get(name);
         if(value==1) {
            values.add(key);
         }
      }
      TextView textView = findViewById(R.id.text);
      textView.setText(values.get(0));
   }
}

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 −

Click here to download the project code