应用关闭时的CountDownTimer问题 [英] CountDownTimer problem when app is closed

问题描述

我制作了一个CountDownTimer代码，即使关闭了应用程序，我也想在倒计时完成后重新启动CountDownTimer，但只有在应用程序运行或重新启动时，它才能重新启动。因此，如果我在倒计时为00:10（min：sec）时关闭应用程序，并在30秒后重新打开应用程序，则计数器应为00:40，但从1分钟开始...但是如果我在00中关闭应用程序： 40，然后在10秒后重新打开，它从00:30开始，所以很好，但是问题仅在应用程序关闭时从1分钟重新启动....有人可以帮助我吗？

I made a CountDownTimer code, i would like to CountDownTimer restart when countdown finished even if app is closed, but it only restart if app running or when app is re-launched. So if i close the app when countdown is 00:10 (min:sec) and reopen the app after 30 sec, the counter should be 00:40, but it starts from 1 minute... But if i close app in 00:40 and reopen after 10 sec, it starts from 00:30 so its good, but the problem only with restart from 1 min when app closed.... can somebody help me?

我的代码：

package com.example.countdown_implement;

import android.content.SharedPreferences;
import android.os.CountDownTimer;
import android.os.Bundle;
import android.widget.TextView;

import androidx.appcompat.app.AppCompatActivity;

import java.util.Locale;

public class MainActivity extends AppCompatActivity {
    private static final long START_TIME_IN_MILLIS = 60000;
    private TextView mTextViewCountDown;
    private CountDownTimer mCountDownTimer;
    private boolean mTimerRunning;
    private long mTimeLeftInMillis;
    private long mEndTime;

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

    mTextViewCountDown = findViewById(R.id.text_view_countdown);

}

private void startTimer() {
    mEndTime = System.currentTimeMillis() + mTimeLeftInMillis;

    mCountDownTimer = new CountDownTimer(mTimeLeftInMillis, 1000) {
        @Override
        public void onTick(long millisUntilFinished) {
            mTimeLeftInMillis = millisUntilFinished;
            updateCountDownText();
        }

        @Override
        public void onFinish() {
            //mTimerRunning = false;
            //updateButtons();

            updateCountDownText();
            resetTimer();
            startTimer();

        }
    }.start();

    //mTimerRunning = true;

}


private void resetTimer() {
    mTimeLeftInMillis = START_TIME_IN_MILLIS;
    updateCountDownText();

}

private void updateCountDownText() {
    int minutes = (int) (mTimeLeftInMillis / 1000) / 60;
    int seconds = (int) (mTimeLeftInMillis / 1000) % 60;

    String timeLeftFormatted = String.format(Locale.getDefault(), "%02d:%02d", minutes, seconds);

    mTextViewCountDown.setText(timeLeftFormatted);
}


@Override
protected void onStop() {
    super.onStop();

    SharedPreferences prefs = getSharedPreferences("prefs", MODE_PRIVATE);
    SharedPreferences.Editor editor = prefs.edit();

    editor.putLong("millisLeft", mTimeLeftInMillis);
    editor.putBoolean("timerRunning", mTimerRunning);
    editor.putLong("endTime", mEndTime);

    editor.apply();

}

@Override
protected void onStart() {
    super.onStart();

    SharedPreferences prefs = getSharedPreferences("prefs", MODE_PRIVATE);

    mTimeLeftInMillis = prefs.getLong("millisLeft", START_TIME_IN_MILLIS);
    mTimerRunning = prefs.getBoolean("timerRunning", false);
    mEndTime = prefs.getLong("endTime", 0);
    mTimeLeftInMillis = mEndTime - System.currentTimeMillis();

    updateCountDownText();
    startTimer();
    if (mTimeLeftInMillis < 0) {
        updateCountDownText();
        startTimer();
    }
  }
}

推荐答案

已更新

下面是将您的代码转换为CountdownTimer的代码段，即使该应用程序运行，该代码段也将继续工作已关闭，推送到后台或重新启动。

设置 START_TIME_IN_MILLIS 作为计时器的开始时间，在以下示例将其设置为15秒。

set START_TIME_IN_MILLIS as the Timer start time, in the following example it is set to 15 seconds.

import android.content.SharedPreferences;
import android.os.CountDownTimer;
import android.os.Bundle;
import android.util.Log;
import android.widget.TextView;

import androidx.appcompat.app.AppCompatActivity;

import java.util.Locale;

public class MainActivity2 extends AppCompatActivity {
    private static final long START_TIME_IN_MILLIS = 15000;
    private TextView mTextViewCountDown;
    private CountDownTimer mCountDownTimer;
    private boolean mTimerRunning;
    private long mTimeLeftInMillis;
    private long mEndTime;
    private long remainingTimeInMillis;

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

        mTextViewCountDown = findViewById(R.id.tv);
    }

    private void startTimer() {
        mCountDownTimer = new CountDownTimer(remainingTimeInMillis, 1000) {
            @Override
            public void onTick(long millisUntilFinished) {
                remainingTimeInMillis = millisUntilFinished;
                mTimeLeftInMillis = millisUntilFinished;
                updateCountDownText();
            }

            @Override
            public void onFinish() {
                //mTimerRunning = false;
                //updateButtons();

                updateCountDownText();
                resetTimer();
                startTimer();

            }
        }.start();

        //mTimerRunning = true;

    }


    private void resetTimer() {
        remainingTimeInMillis = START_TIME_IN_MILLIS;
        updateCountDownText();

    }

    private void updateCountDownText() {


        int minutes = (int) (remainingTimeInMillis / 1000) / 60;
        int seconds = (int) (remainingTimeInMillis / 1000) % 60;

        String timeLeftFormatted = String.format(Locale.getDefault(), "%02d:%02d", minutes, seconds);

        mTextViewCountDown.setText(timeLeftFormatted);
    }


    @Override
    protected void onStop() {
        super.onStop();

        SharedPreferences prefs = getSharedPreferences("prefs", MODE_PRIVATE);
        SharedPreferences.Editor editor = prefs.edit();

        editor.putLong("millisLeft", mTimeLeftInMillis);
        editor.putBoolean("timerRunning", mTimerRunning);
        editor.putLong("endTime", System.currentTimeMillis());
        editor.apply();

    }

    @Override
    protected void onStart() {
        super.onStart();

        SharedPreferences prefs = getSharedPreferences("prefs", MODE_PRIVATE);

        mTimeLeftInMillis = prefs.getLong("millisLeft", START_TIME_IN_MILLIS);
        mTimerRunning = prefs.getBoolean("timerRunning", false);
        mEndTime = prefs.getLong("endTime", 0);
        if (mEndTime == 0L) {
            remainingTimeInMillis = (mTimeLeftInMillis);
        } else {
            Long timeDiff = (mEndTime - System.currentTimeMillis());
            //to convert into positive number
            timeDiff = Math.abs(timeDiff);

            long timeDiffInSeconds = (timeDiff / 1000) % 60;
           long timeDiffInMillis = timeDiffInSeconds * 1000;
            Long timeDiffInMillisPlusTimerRemaining = remainingTimeInMillis = mTimeLeftInMillis - timeDiffInMillis;

            if (timeDiffInMillisPlusTimerRemaining < 0) {
                timeDiffInMillisPlusTimerRemaining = Math.abs(timeDiffInMillisPlusTimerRemaining);
                remainingTimeInMillis = START_TIME_IN_MILLIS - timeDiffInMillisPlusTimerRemaining;
            }
        }
        updateCountDownText();
        startTimer();
    }
}

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