content: package com.alexfu.countdownview.sample;
  
  import android.os.Bundle;
  import android.support.v7.app.AppCompatActivity;
  import android.view.View;
  import android.widget.Button;
  import android.widget.Toast;
  import com.alexfu.countdownview.CountDownView;
  import com.alexfu.countdownview.CountDownListener;
  
  public class MainActivity extends AppCompatActivity implements CountDownListener {
      private CountDownView countDownView;
      private Button startButton;
      private Button resetButton;
      private Button stopButton;
  
      @Override
      protected void onCreate(Bundle savedInstanceState) {
          super.onCreate(savedInstanceState);
          setContentView(R.layout.activity_main);
  
          countDownView = findViewById(R.id.view_count_down);
          startButton = findViewById(R.id.button_start);
          resetButton = findViewById(R.id.button_reset);
          stopButton = findViewById(R.id.button_stop);
  
          startButton.setOnClickListener(new View.OnClickListener() {
              @Override public void onClick(View view) {
                  countDownView.start();
              }
          });
  
          resetButton.setOnClickListener(new View.OnClickListener() {
              @Override public void onClick(View view) {
                  countDownView.reset();
              }
          });
  
          stopButton.setOnClickListener(new View.OnClickListener() {
              @Override public void onClick(View view) {
                  countDownView.stop();
              }
          });
          countDownView.setListener(this);
      }
  
      @Override
      public void onFinishCountDown() {
          Toast.makeText(this, "Time up!!!", Toast.LENGTH_LONG).show();
      }
  }
  