Java 为什么我的倒计时好像在倒计时？

我正在尝试制作一个应用程序，如果手机暂时不用，它会提醒你给手机充电。它的工作原理是这样的：你输入手机在提醒你之前应该空闲多长时间。然后它启动计时器，并在结束时提醒您

下面是我的MainActivity.Java：

public class MainActivity extends AppCompatActivity {
    //Defining UI elements
    public Button changeAppStateButton;
    public TextView minsEditText;

    //App variables
    boolean isAppRunning = false;
    public int secondsPhoneIsAsleep;

    public int timerDuration = secondsPhoneIsAsleep * 1000; //multiplying seconds by 100 to get milliseconds
    public int tickDuration = 60000; //multiplying seconds (1) by 100 to get milliseconds

    //Called when button is pressed
    public void changeAppState(View view) {
        Button changeAppStateButton = (Button) view;
        if (isAppRunning) { //If the app is running, stop app
            isAppRunning = false;
            changeAppStateButton.setBackgroundColor(getColor(R.color.colorPurple));
            changeAppStateButton.setText("Start Reminder");
            timer.cancel();
            Log.i("TIMER", "Timer interrupted");

        } else { //If the app is not running, start app
            secondsPhoneIsAsleep = Integer.parseInt(minsEditText.getText().toString()) * 60;
            isAppRunning = true;
            changeAppStateButton.setBackgroundColor(getColor(R.color.colorRed));
            changeAppStateButton.setText("Stop Reminder");
            timer.start();
            Log.i("TIMER", "Timer started");

        }
    }

    public CountDownTimer timer = new CountDownTimer(timerDuration, tickDuration) {
        @Override
        public void onTick(long millisUntilFinished) {
            Log.i("TIMER", "tick");
        }

        @Override
        public void onFinish() {
            isAppRunning = false;
            changeAppStateButton.setBackgroundColor(getColor(R.color.colorPurple));
            changeAppStateButton.setText("Start Reminder");
            Log.i("TIMER", "Timer finished");
        }
    };

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

        //Setting values for UI elements
        changeAppStateButton = findViewById(R.id.changeAppStateButton);
        minsEditText = findViewById(R.id.minEditText);

    }

这是我的XML的一部分：

    <EditText
        android:id="@+id/minEditText"
        android:layout_width="59dp"
        android:layout_height="42dp"
        android:layout_marginTop="14dp"
        android:ems="10"
        android:foregroundTint="#FF0000"
        android:inputType="number"
        android:text="30"
        android:textAlignment="center"
        android:textColor="#000000"
        android:textSize="20sp"
        app:layout_constraintStart_toEndOf="@+id/whenUntouched"
        app:layout_constraintTop_toBottomOf="@+id/numberEditText" />

    <Button
        android:id="@+id/changeAppStateButton"
        android:layout_width="0dp"
        android:layout_height="45dp"
        android:layout_marginStart="16dp"
        android:layout_marginEnd="16dp"
        android:layout_marginBottom="110dp"
        android:background="#9C27B0"
        android:fontFamily="@font/alegreya_sans_sc"
        android:onClick="changeAppState"
        android:text="Start Reminder"
        android:textAlignment="center"
        android:textColor="#FFFFFF"
        android:textSize="25sp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.0"
        app:layout_constraintStart_toStartOf="parent" />

为什么计时器似乎在倒计时？为什么它不每“滴答”一次就记录一条消息？

---

如能作出解释，将不胜感激。我对Android和Java没有太多经验。

因为在

MainActivity.Java

不初始化变量

secondsphoneissleep

，因此默认值为

0

因此，

timerDuration

将是

0

因此，将创建

计时器

，以在

0

的持续时间内计数

因此，当单击该按钮时，即使您读取了

secondsphoneissleep

的新值，调用

timer.start（）

也将使其根据先前初始化的值仅计数到

0

因此，

onFinish（）

被调用为记录

计时器完成

，然后

计时器启动

被记录为按钮单击代码的一部分

解决方案

如果在单击按钮时创建

timer

实例，则它应使用正确的

secondsphoneissleep

值并正常工作。如下图所示：

maintactivity.java

public class MainActivity extends AppCompatActivity {
    //Defining UI elements
    public Button changeAppStateButton;
    public TextView minsEditText;

    //App variables
    boolean isAppRunning = false;
    public int secondsPhoneIsAsleep;

    public CountDownTimer timer;

    public int timerDuration;
    public int tickDuration = 1000; //multiplying 1 second by 1000 to get milliseconds

    //Called when button is pressed
    public void changeAppState(View view) {
        Button changeAppStateButton = (Button) view;
        if (isAppRunning) { //If the app is running, stop app
            isAppRunning = false;
      changeAppStateButton.setBackgroundColor(getColor(R.color.colorPurple));
            changeAppStateButton.setText("Start Reminder");
            timer.cancel();
            Log.i("TIMER", "Timer interrupted");

        } else { //If the app is not running, start app
            secondsPhoneIsAsleep = Integer.parseInt(minsEditText.getText().toString()) * 60;
            timerDuration = secondsPhoneIsAsleep * 1000;
            timer = getNewTimer(); // Creates a new timer.
            isAppRunning = true;
         changeAppStateButton.setBackgroundColor(getColor(R.color.colorRed));
            changeAppStateButton.setText("Stop Reminder");
            timer.start();
            Log.i("TIMER", "Timer started");

        }
    }

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

        //Setting values for UI elements
        changeAppStateButton = findViewById(R.id.changeAppStateButton);
        minsEditText = findViewById(R.id.minEditText);

    }

    private CountdownTimer getNewTimer() {
      return new CountDownTimer(timerDuration, tickDuration) {
        @Override
        public void onTick(long millisUntilFinished) {
            Log.i("TIMER", "tick");
        }

        @Override
        public void onFinish() {
            isAppRunning = false;

changeAppStateButton.setBackgroundColor(getColor(R.color.colorPurple));
            changeAppStateButton.setText("Start Reminder");
            Log.i("TIMER", "Timer finished");
        }
    };
    }

---

你对tickDuration的评论似乎暗示一秒钟内有100毫秒而不是1000毫秒。滴答声多长时间发生一次？从你的代码中，我希望它每60000ms=60s=1minCan打勾一次。你发布了完整的

MainActivity.java

文件吗？@VivekSasidharan我发布了几乎所有的东西，除了onCreate（），但没问题。@ContinuousLoad-这是评论中的一个错误，抱歉。我现在用1000乘一次code@AmethystAurora请看我的答案。我确实初始化了

secondsphoneissleep

——就在

else

之后的一行。“我是不是误解了什么？”紫水晶极光是的，在点击按钮的过程中。但是到那时，当您使用

secondsPhoneIsAsleep

的初始值调用

new CountDownTimer（）

时，

计时器已初始化（未启动！但已创建）

请查看更新的答案。它包括一个更新的

MainActivity.java

文件，并对其进行了一些更改以使其正常工作。

public class MainActivity extends AppCompatActivity {
    //Defining UI elements
    public Button changeAppStateButton;
    public TextView minsEditText;

    //App variables
    boolean isAppRunning = false;
    public int secondsPhoneIsAsleep;

    public CountDownTimer timer;

    public int timerDuration;
    public int tickDuration = 1000; //multiplying 1 second by 1000 to get milliseconds

    //Called when button is pressed
    public void changeAppState(View view) {
        Button changeAppStateButton = (Button) view;
        if (isAppRunning) { //If the app is running, stop app
            isAppRunning = false;
      changeAppStateButton.setBackgroundColor(getColor(R.color.colorPurple));
            changeAppStateButton.setText("Start Reminder");
            timer.cancel();
            Log.i("TIMER", "Timer interrupted");

        } else { //If the app is not running, start app
            secondsPhoneIsAsleep = Integer.parseInt(minsEditText.getText().toString()) * 60;
            timerDuration = secondsPhoneIsAsleep * 1000;
            timer = getNewTimer(); // Creates a new timer.
            isAppRunning = true;
         changeAppStateButton.setBackgroundColor(getColor(R.color.colorRed));
            changeAppStateButton.setText("Stop Reminder");
            timer.start();
            Log.i("TIMER", "Timer started");

        }
    }

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

        //Setting values for UI elements
        changeAppStateButton = findViewById(R.id.changeAppStateButton);
        minsEditText = findViewById(R.id.minEditText);

    }

    private CountdownTimer getNewTimer() {
      return new CountDownTimer(timerDuration, tickDuration) {
        @Override
        public void onTick(long millisUntilFinished) {
            Log.i("TIMER", "tick");
        }

        @Override
        public void onFinish() {
            isAppRunning = false;

changeAppStateButton.setBackgroundColor(getColor(R.color.colorPurple));
            changeAppStateButton.setText("Start Reminder");
            Log.i("TIMER", "Timer finished");
        }
    };
    }