Thread Runnable Tutorial

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:layout_height="match_parent"
    android:gravity="center"
    android:orientation="vertical"
    tools:context="com.codinginflow.threadexample.MainActivity">

    <Switch
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginBottom="16dp" />

    <Button
        android:id="@+id/button_start_thread"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:onClick="startThread"
        android:text="Start" />

    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:onClick="stopThread"
        android:text="Stop" />

</LinearLayout>

MainActivity.java

package com.codinginflow.threadexample;

import android.os.Handler;
import android.os.Looper;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;

public class MainActivity extends AppCompatActivity {
    private static final String TAG = "MainActivity";

    private Button buttonStartThread;

    private Handler mainHandler = new Handler();

    private volatile boolean stopThread = false;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        buttonStartThread = findViewById(R.id.button_start_thread);
    }

    public void startThread(View view) {
        stopThread = false;
        ExampleRunnable runnable = new ExampleRunnable(10);
        new Thread(runnable).start();
        /*
        ExampleThread thread = new ExampleThread(10);
        thread.start();
        */
        /*
        new Thread(new Runnable() {
            @Override
            public void run() {
                //work
            }
        }).start();
        */
    }

    public void stopThread(View view) {
        stopThread = true;
    }

    class ExampleThread extends Thread {
        int seconds;

        ExampleThread(int seconds) {
            this.seconds = seconds;
        }

        @Override
        public void run() {
            for (int i = 0; i < seconds; i++) {
                Log.d(TAG, "startThread: " + i);
                try {
                    Thread.sleep(1000);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
        }
    }

    class ExampleRunnable implements Runnable {
        int seconds;

        ExampleRunnable(int seconds) {
            this.seconds = seconds;
        }

        @Override
        public void run() {
            for (int i = 0; i < seconds; i++) {
                if (stopThread)
                    return;
                if (i == 5) {
                    /*
                    Handler threadHandler = new Handler(Looper.getMainLooper());
                    threadHandler.post(new Runnable() {
                        @Override
                        public void run() {
                            buttonStartThread.setText("50%");
                        }
                    });
                    */
                    /*
                    buttonStartThread.post(new Runnable() {
                        @Override
                        public void run() {
                            buttonStartThread.setText("50%");
                        }
                    });
                    */
                    runOnUiThread(new Runnable() {
                        @Override
                        public void run() {
                            buttonStartThread.setText("50%");
                        }
                    });
                }
                Log.d(TAG, "startThread: " + i);
                try {
                    Thread.sleep(1000);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
        }
    }
}

Thanks! Helped me a lot to understand the concept!

I am currently working on an Android app with heavy operations using openCV. This helped me get an idea how to resolve my issue on why my app keeps on crashing randomly. Thank you so much!