Understand How Progress Bar Work

MainActiviy.java code is here:


package com.example.arafat.progressbar;

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

public class MainActivity extends AppCompatActivity {

    private ProgressBar progressBar;
    private int status = 0;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        progressBar = findViewById(R.id.progress_horizontal);
        progressBar.setProgress(0);
        progressBar.setMax(5);
        Button tabButton = findViewById(R.id.tab_btn);

        tabButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                status++;
                progressBar.setProgress(status);
            }
        });
    }
}

activity_main.xml code is here :

<?xml version="1.0" encoding="utf-8"?>

<RelativeLayout 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"

    tools:context=".MainActivity">

    <ProgressBar

        android:id="@+id/progress_horizontal"

        style="@android:style/Widget.ProgressBar.Horizontal"

        android:layout_width="match_parent"

        android:layout_height="wrap_content"

        android:layout_margin="10dp" />

    <Button

        android:id="@+id/tab_btn"

        android:layout_width="match_parent"

        android:layout_height="wrap_content"

        android:layout_below="@id/progress_horizontal"

        android:layout_marginTop="64dp"

        android:text="tab" />

</RelativeLayout>