ThreadPractice_android

Posted 2020-12-02 lingyaoyao

RandomService.java
public class RandomService extends Service {
    private Thread workThread;
    private static double random;
    @Nullable
    @Override
    public android.os.IBinder onBind(Intent intent) {
        return null;
    }
    @Override
    public void onCreate() {
        super.onCreate();
        workThread = new Thread(null, workRunnable, "work");
        Toast.makeText(this, "create()", Toast.LENGTH_LONG).show();
    }
    @Override
    public int onStartCommand(Intent intent, int flags, int startId) {
        Toast.makeText(this, "start()", Toast.LENGTH_LONG).show();
        if(!workThread.isAlive()){
            workThread.start();
        }
        return super.onStartCommand(intent, flags, startId);
    }

    @Override
    public void onDestroy() {
        super.onDestroy();
        Toast.makeText(this, "Destroy()", Toast.LENGTH_LONG).show();
    }
    Runnable workRunnable = new Runnable() {
        @Override
        public void run() {
                  while (!Thread.interrupted()){
                      try{
                          random = Math.round(Math.random()*100);
                          MainActivity.updateGUI(random);
                          Thread.sleep(1000);
                      }
                      catch (InterruptedException e){
                          e.printStackTrace();
                      }
                  }
        }
    };
}
////////////////////////////////////////////////////////////////////////
MainActivity.java

public class MainActivity extends AppCompatActivity {

    private static TextView textView = null;
    Button btn_start;
    Button btn_stop;
    private static Handler handler = new Handler();
    private static double random;

    @Override
        protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        textView = (TextView)findViewById(R.id.text);
        btn_start = (Button)findViewById(R.id.btn_start);
        btn_stop = (Button)findViewById(R.id.btn_stop);
        final Intent intent = new Intent(this, RandomService.class);
        btn_start.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                startService(intent);
            }
        });
        btn_stop.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                stopService(intent);
            }
        });
    }
    public static void updateGUI(double _random){
        random = _random;
        handler.post(new Runnable() {
            @Override
            public void run() {
                textView.setText(String.valueOf(random));
            }
        });
    }
}