In the below code I have created Runnable Thread program in android. Here first I have added TextView in activity_main.xml layout. In MainActivity I have used handler class then I have created a new Runnable interface , And I have also used onStart (),run() and update() method. You can see below example code it clearly describe you How to make Runnable Thread in android.

Step(1)activity_main.xml layout-

<?xml version="1.0" encoding="utf-8"?>
 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    >
    <TextView
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text=" Runnable Thread"
        android:textAlignment="center"
        android:textSize="20dp"/>
    <TextView
        android:id="@+id/one"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        />
</LinearLayout>

Step(2)- MainActivity-
 

public class MainActivity extends AppCompatActivity {
        int i = 0;
        TextView raj;

        Handler handler = new Handler(){

            @Override
            public void handleMessage(Message msg) {
                // TODO Auto-generated method stub
                update_i();
            }
        };

        /** Called when the activity is first created. */
        @Override
        public void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_main);

            raj =(TextView)findViewById(R.id.one);
        }

        @Override
        protected void onStart() {
            // TODO Auto-generated method stub
            super.onStart();

            Thread myThread=new Thread(new Runnable() {
                public void run() {
                    while(true){
                        try {
                            handler.sendMessage(handler.obtainMessage());
                            Thread.sleep(1000);
                        }
                        catch (Throwable t) {
                        }
                    }
                }
            });

            myThread.start();
        }

        private void update_i()
        {
            i++;
            raj.setText(String.valueOf(i));
        }
    }