Android计时器练习

<?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"
    tools:context=".TimerTest"
    android:orientation="vertical">

    <Chronometer
        android:id="@+id/chronometer"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center"
        android:textColor="#ff0000"
        android:textSize="60dip"></Chronometer>

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginTop="10dp"
        android:orientation="horizontal"
        android:paddingTop="10dp"
        >
        <Button
            android:id="@+id/btn_start"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="开始计时"
            android:layout_weight="1"></Button>
        <Button
            android:id="@+id/btn_stop"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="停止计时"
            android:layout_weight="1"></Button>
        <Button
            android:id="@+id/btn_resert"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="重置"
            android:layout_weight="1"></Button>
        <Button
            android:id="@+id/btn_format"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="格式化"
            android:layout_weight="1"></Button>
    </LinearLayout>

</LinearLayout>

public class TimerTest extends AppCompatActivity implements View.OnClickListener, Chronometer.OnChronometerTickListener {

    private  Chronometer chronometer;
    private Button btn_start,btn_stop,btn_resert,btn_format;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_timer_test);
        //初始化数据，并设置监听器
        initView();
    }

    private void initView(){
        chronometer = findViewById(R.id.chronometer);
        btn_start = findViewById(R.id.btn_start);
        btn_stop = findViewById(R.id.btn_stop);
        btn_resert = findViewById(R.id.btn_resert);
        btn_format = findViewById(R.id.btn_format);

        //绑定事件监听器
        btn_start.setOnClickListener(this);
        btn_stop.setOnClickListener(this);
        btn_resert.setOnClickListener(this);
        btn_format.setOnClickListener(this);
    }

    @Override
    public void onClick(View view) {
        switch (view.getId()){
            case R.id.btn_start:
                chronometer.start();//开始计时
                break;
            case R.id.btn_stop:
                chronometer.stop();//停止计时
                break;
            case R.id.btn_resert:
                chronometer.setBase(SystemClock.elapsedRealtime());//复位
                break;
            case R.id.btn_format:
                chronometer.setFormat("Time: %s");//更改时间显示格式
                break;
        }
    }

    @Override
    public void onChronometerTick(Chronometer chronometer) {
        String time = chronometer.getText().toString();
        if (time.equals("00:00")){
            Toast.makeText(this, "时间到了一个永恒阶段", Toast.LENGTH_SHORT).show();
        }
    }
}