Java 如何防止新意图上的倒计时重复

我对倒计时有问题。我有2个活动，主要和商店。。。在商店里我有一个按钮，如果用户点击按钮，倒计时开始。。如果结束，用户可获得+50硬币。它可以工作，但如果我回到mainactivity，然后再回到store，计时器会重复，用户会得到两倍或三倍的硬币。。。。我修正了一半，但是代码中有一个小错误。。。。 因此，如果我取消对startTimer（）的注释；在onResume的storeactivity中，如果我转到mainactivity并返回store，则倒计时重复。。。如果我删除startTimer（）；从onResume进入storeactivity，然后倒计时不更新，如果我转到mainactivity并返回store。。。。它可以工作，但不会自动更新计数器文本。。。 在mainactivity中，计时器工作正常，没有任何问题。。。 我如何解决这个问题？ 我尝试使用make runnable to updateCountDownText（）；但它不起作用，也许我写错了代码。 有人能帮我吗？ 或者如何使updateCountDownText（）能够运行

主要活动：

import androidx.appcompat.app.AppCompatActivity;


import android.content.Context;
import android.content.Intent;
import android.content.SharedPreferences;
import android.os.Bundle;
import android.os.CountDownTimer;
import android.view.View;
import android.view.WindowManager;
import android.widget.Button;
import android.widget.ImageView;
import android.widget.TextView;
import android.widget.Toast;


import java.util.Locale;

import static com.game.game.variables.coin;
import static com.game.game.variables.life;


public class MainActivity extends AppCompatActivity {

public static final String PREFS_NAME_MAIN = "mainpref";

private static final long START_TIME_IN_MILLIS = 60000;

public static final String PREFS_NAME_TIME = "timepref";

private TextView mTextViewCountDown;


private CountDownTimer mCountDownTimer;

private boolean mTimerRunning;

private long mTimeLeftInMillis;
private long mEndTime;



TextView coinbarText, lifesbarText;
Button playButton, closeButton;
ImageView lifesbarButton, coinbarButton;


private final Context app = this;




@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN);
    setContentView(R.layout.activity_main);

    coinbarText = findViewById(R.id.coinbarText);

    lifesbarText = findViewById(R.id.lifesbarText);

    playButton = findViewById(R.id.playButton);
    closeButton = findViewById(R.id.closeButton);
    lifesbarButton = findViewById(R.id.lifesbarButton);
    coinbarButton = findViewById(R.id.coinbarButton);

    textupgrade();


    closeButton.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            //finishAffinity();
            startActivity(new Intent(MainActivity.this, ExitActivity.class));
        }
    });

    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;
            mTimerRunning = true;
            updateCountDownText();
        }
        @Override
        public void onFinish() {
            mTimerRunning = false;

            load();
            coin = coin + 50;
            coinbarText.setText("" + coin);
            resetTimer();
            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();
            save();
        }
    }.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);
}


public void store (View store){


    Intent newstore = new Intent(this, StoreActivity.class);
    this.startActivity(newstore);
}



public void exit (View exit){

    Intent newexit = new Intent(this, ExitActivity.class);
    this.startActivity(newexit);
}

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

    coinbarText.setText("" + coin);

}

protected void onResume()
{
    super.onResume();
    load();
    //textupgrade();
    textupgrade();
    SharedPreferences prefs = getSharedPreferences("prefs", MODE_PRIVATE);
    mTimeLeftInMillis = prefs.getLong("millisLeft", START_TIME_IN_MILLIS);
    mTimerRunning = prefs.getBoolean("timerRunning", false);
    updateCountDownText();

    if (mTimerRunning) {
        mEndTime = prefs.getLong("endTime", 0);
        mTimeLeftInMillis = mEndTime - System.currentTimeMillis();
        if (mTimeLeftInMillis < 0) {
            mTimeLeftInMillis = 0;
            mTimerRunning = false;
            updateCountDownText();

            coin = coin + 50;
            resetTimer();

        } else {
            startTimer();
        }
    }
    coinbarText.setText("" + coin);

}

@Override
protected void onRestart() {
    super.onRestart();
    load();
    textupgrade();
    coinbarText.setText("" + coin);

}

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();

    if (mCountDownTimer != null) {
        mCountDownTimer.cancel();
    }
    save();
}

private void load()
{
    SharedPreferences varReader = app.getSharedPreferences(PREFS_NAME_MAIN, MODE_PRIVATE);


    coin = varReader.getInt("coin", 100);
    life = varReader.getInt("life", 5);

}

private void save()
{
    SharedPreferences.Editor varReader = app.getSharedPreferences(PREFS_NAME_MAIN, 0).edit();


    varReader.putInt("coin", coin);
    varReader.putInt("life", life);
    varReader.apply();
}

private void textupgrade(){
    coinbarText.setText(""+coin);
    lifesbarText.setText(life + "/5");

}



}

导入androidx.appcompat.app.appcompat活动；
导入android.content.Context；
导入android.content.Intent；
导入android.content.SharedReferences；
导入android.os.Bundle；
导入android.os.CountDownTimer；
导入android.view.view；
导入android.view.WindowManager；
导入android.widget.Button；
导入android.widget.ImageView；
导入android.widget.TextView；
导入android.widget.Toast；
导入java.util.Locale；
导入静态com.game.game.variables.coin；
导入静态com.game.game.variables.life；
公共类MainActivity扩展了AppCompatActivity{
公共静态最终字符串PREFS\u NAME\u MAIN=“mainpref”；
专用静态最终长启动时间单位为60000；
公共静态最终字符串PREFS\u NAME\u TIME=“timepref”；
私有文本视图MTEXTVIEW倒计时；
专用倒数计时器mCountDownTimer；
私有布尔mTimerRunning；
私有长mtimelftinmillis；
私生活时间长；
TextView coinbarText，LifeBarText；
按钮播放按钮，关闭按钮；
ImageView生活按钮，共按钮；
私有最终上下文应用程序=此；
@凌驾
创建时受保护的void（Bundle savedInstanceState）{
super.onCreate（savedInstanceState）；
getWindow（）.setFlags（WindowManager.LayoutParams.FLAG_全屏，WindowManager.LayoutParams.FLAG_全屏）；
setContentView（R.layout.activity_main）；
coinbarText=findviewbyd（R.id.coinbarText）；
lifestbartext=findviewbyd（R.id.lifestbartext）；
playButton=findViewById（R.id.playButton）；
closeButton=findViewById（R.id.closeButton）；
LifeBarButton=findViewById（R.id.LifeBarButton）；
coinbarButton=findViewById（R.id.coinbarButton）；
textupgrade（）；
closeButton.setOnClickListener（新视图.OnClickListener（）{
@凌驾
公共void onClick（视图）{
//有限性（）；
startActivity（新意图（MainActivity.this、ExitActivity.class））；
}
});
mTextViewCountDown=findviewbyd（R.id.text\u view\u countdown）；
}
私有void startTimer（）{
mEndTime=System.currentTimeMillis（）+mTimeLeftInMillis；
mCountDownTimer=新的倒计时（mtimelftinmillis，1000）{
@凌驾
公共void onTick（长毫秒未完成）{
mTimeLeftInMillis=毫秒直至完成；
mTimerRunning=真；
updateCountDownText（）；
}
@凌驾
公共无效onFinish（）{
mTimerRunning=假；
加载（）；
硬币=硬币+50；
coinbarText.setText（“+硬币）；
重置计时器（）；
SharedReferences prefs=GetSharedReferences（“prefs”，模式\私有）；
SharedReferences.Editor=prefs.edit（）；
编辑：putLong（“millisLeft”，mTimeLeftInMillis）；
编辑器.putBoolean（“timerRunning”，mTimerRunning）；
编辑：putLong（“结束时间”，mEndTime）；
editor.apply（）；
save（）；
}
}.start（）；
mTimerRunning=真；
}
私有void resetTimer（）{
MTIMELFTINMILLIS=开始时间（单位：毫秒）；
updateCountDownText（）；
}
私有void updateCountDownText（）{
int分钟=（int）（mtimelftinmillis/1000）/60；
整数秒=（整数）（mTimeLeftInMillis/1000）%60；
String timeLeftFormatted=String.format（Locale.getDefault（），%02d:%02d），分，秒）；
mTextViewCountDown.setText（timeLeftFormatted）；
}
公共空存储（视图存储）{
Intent newstore=newintent（这个，StoreActivity.class）；
这是startActivity（新闻商店）；
}
公共无效出口（视图出口）{
Intent newexit=newintent（这是exitctivity.class）；
这个。startActivity（newexit）；
}
@凌驾
受保护的void onStart（）
{
super.onStart（）；
加载（）；
textupgrade（）；
coinbarText.setText（“+硬币）；
}
受保护的void onResume（）
{
super.onResume（）；
加载（）；
//textupgrade（）；
textupgrade（）；
SharedReferences prefs=GetSharedReferences（“prefs”，模式\私有）；
mtimelftinmillis=prefs.getLong（“millisLeft”，以毫秒为单位的开始时间）；
mTimerRunning=prefs.getBoolean（“timerRunning”，false）；
updateCountDownText（）；
如果（mTimerRunning）{
mEndTime=prefs.getLong（“endTime”，0）；
mtimelftinmillis=mEndTime-System.currentTimeMillis（）；
如果（MTIMELFTINMILLIS<0）{
mtimelftinmillis=0；
mTimerRunning=假；
updateCountDownText（）；
硬币=硬币+50；
重置计时器（）；
}否则{
startTimer（）；
}
}
coinbarText.setText（“+硬币）；
}
@凌驾
受保护的void onRestart（）{
super.onRestart（）；
加载（）；
textupgrade（）；
coinbarText.setText（“+硬币）；
}
受保护的void onStop（）
{
super.onStop（）；
SharedReferences prefs=GetSharedReferences（“prefs”，模式\私有）；
SharedReferences.Editor=prefs.edit（）；
编辑：putLong（“millisLeft”，mTimeLeftInMillis）；
编辑器.putBoolean（“timerRunning”，mTimerRunning）；
编辑：普特隆
import android.content.Context;
import android.content.SharedPreferences;
import android.os.Bundle;
import android.os.CountDownTimer;
import android.view.View;
import android.view.WindowManager;
import android.widget.Button;
import android.widget.ImageView;
import android.widget.TextView;

import androidx.appcompat.app.AppCompatActivity;

import com.google.android.gms.ads.AdRequest;
import com.google.android.gms.ads.MobileAds;
import com.google.android.gms.ads.reward.RewardItem;
import com.google.android.gms.ads.reward.RewardedVideoAd;
import com.google.android.gms.ads.reward.RewardedVideoAdListener;

import java.util.Locale;

import static com.game.game.variables.coin;
import static com.game.game.variables.life;


public class StoreActivity extends AppCompatActivity implements RewardedVideoAdListener  {


public static final String PREFS_NAME_MAIN = "mainpref";

private static final long START_TIME_IN_MILLIS = 60000;

public static final String PREFS_NAME_TIME = "timepref";

private TextView mTextViewCountDown;


private CountDownTimer mCountDownTimer;

private boolean mTimerRunning;

private long mTimeLeftInMillis;
private long mEndTime;


private final Context app = this;

Button storecloseButton, coin200, coin500, coin1000, adcoinloading, adcoin, timecoin;

TextView coinbarText, lifesbarText;
ImageView lifesbarButton, coinbarButton;
RewardedVideoAd rewardedVideoAd;


@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN);
    setContentView(R.layout.activity_store);

    storecloseButton = findViewById(R.id.storecloseButton);
    lifesbarButton = findViewById(R.id.lifesbarButton);
    coinbarButton = findViewById(R.id.coinbarButton);
    lifesbarText = findViewById(R.id.lifesbarText);
    coinbarText = findViewById(R.id.coinbarText);
    coin200 = findViewById(R.id.coin200);
    coin500 = findViewById(R.id.coin500);
    coin1000 = findViewById(R.id.coin1000);
    adcoinloading = findViewById(R.id.adcoinloading);
    adcoin = findViewById(R.id.adcoin);
    timecoin = findViewById(R.id.timecoin);


    rewardedVideoAd = MobileAds.getRewardedVideoAdInstance(this);
    rewardedVideoAd.setRewardedVideoAdListener(this);

     textupgrade();

    if (rewardedVideoAd.isLoaded()){
            adcoin.setVisibility(View.VISIBLE);
            adcoinloading.setVisibility(View.INVISIBLE);
            }
    else{
      //  adcoinloading.setVisibility(View.VISIBLE);
       loadAd();
    }


    adcoin.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            if (rewardedVideoAd.isLoaded()){

                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();
                rewardedVideoAd.show();
            }
        }
    });

    mTextViewCountDown = findViewById(R.id.text_view_countdown);

    timecoin.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            if (mTimerRunning) {
                //pauseTimer();
            } else {
                startTimer();

            }
        }
    });

}

private void startTimer() {
    mEndTime = System.currentTimeMillis() + mTimeLeftInMillis;
    mCountDownTimer = new CountDownTimer(mTimeLeftInMillis, 1000) {
        @Override
        public void onTick(long millisUntilFinished) {
            mTimeLeftInMillis = millisUntilFinished;
            mTimerRunning = true;
            updateCountDownText();
        }
        @Override
        public void onFinish() {
            load();
            mTimerRunning = false;
            updateButtons();
            coin = coin + 50;
            coinbarText.setText("" + coin);
            resetTimer();
            save();
        }
    }.start();
    mTimerRunning = true;
    updateButtons();
}
private void pauseTimer() {
    mCountDownTimer.cancel();
    mTimerRunning = false;
    updateButtons();
}
private void resetTimer() {
    mTimeLeftInMillis = START_TIME_IN_MILLIS;
    updateCountDownText();
    updateButtons();
}
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);
}
private void updateButtons() {
    if (mTimerRunning) {
        //mButtonReset.setVisibility(View.INVISIBLE);
        timecoin.setVisibility(View.INVISIBLE);
    } else {
        //mButtonStartPause.setText("Start");
        if (mTimeLeftInMillis < 1000) {
            timecoin.setVisibility(View.INVISIBLE);

        } else {
            timecoin.setVisibility(View.VISIBLE);
        }
        if (mTimeLeftInMillis < START_TIME_IN_MILLIS) {
            //mButtonReset.setVisibility(View.VISIBLE);

        } else {
            //mButtonReset.setVisibility(View.INVISIBLE);
        }
    }
}


public void storeback (View storeback){


    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();
    if (mCountDownTimer != null) {
        mCountDownTimer.cancel();
    }
    save();


    finish();
}


private void loadAd() {
    if (!rewardedVideoAd.isLoaded()){
        rewardedVideoAd = null;
        rewardedVideoAd = MobileAds.getRewardedVideoAdInstance(this);
        rewardedVideoAd.setRewardedVideoAdListener(this);
        rewardedVideoAd.loadAd("ca-app-pub-3940256099942544/5224354917",new AdRequest.Builder().build());
    }
}




@Override
public void onRewardedVideoAdLoaded() {
    adcoin.setVisibility(View.VISIBLE);
    adcoinloading.setVisibility(View.INVISIBLE);
}

@Override
public void onRewardedVideoAdOpened() {

}

@Override
public void onRewardedVideoStarted() {

    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
public void onRewardedVideoAdClosed() {
    loadAd();
    adcoin.setVisibility(View.INVISIBLE);
    adcoinloading.setVisibility(View.VISIBLE);
    SharedPreferences prefs = getSharedPreferences("prefs", MODE_PRIVATE);
    mTimeLeftInMillis = prefs.getLong("millisLeft", START_TIME_IN_MILLIS);
    mTimerRunning = prefs.getBoolean("timerRunning", false);
    updateCountDownText();
    updateButtons();
    if (mTimerRunning) {
        mEndTime = prefs.getLong("endTime", 0);
        mTimeLeftInMillis = mEndTime - System.currentTimeMillis();
        if (mTimeLeftInMillis < 0) {
            mTimeLeftInMillis = 0;
            mTimerRunning = false;
            updateCountDownText();
            updateButtons();
            //coin = coin + 50;
            resetTimer();
            timecoin.setVisibility(View.VISIBLE);
        } else {
            //startTimer();
            updateCountDownText();
        }
    }



}


@Override
public void onRewarded(RewardItem rewardItem) {
    load();
    coin = coin + 50;
    save();
    textupgrade();

}


@Override
public void onRewardedVideoAdLeftApplication() {

}


@Override
public void onRewardedVideoAdFailedToLoad(int i) {

}


@Override
public void onRewardedVideoCompleted() {

}

@Override
protected void onPause() {
    super.onPause();
    rewardedVideoAd.pause(this);
    save();
}

@Override
protected void onResume() {
    super.onResume();
    loadAd();
    load();
    textupgrade();
    SharedPreferences prefs = getSharedPreferences("prefs", MODE_PRIVATE);
    mTimeLeftInMillis = prefs.getLong("millisLeft", START_TIME_IN_MILLIS);
    mTimerRunning = prefs.getBoolean("timerRunning", false);
    updateCountDownText();
    updateButtons();
    if (mTimerRunning) {
        mEndTime = prefs.getLong("endTime", 0);
        mTimeLeftInMillis = mEndTime - System.currentTimeMillis();
        if (mTimeLeftInMillis < 0) {
            mTimeLeftInMillis = 0;
            mTimerRunning = false;
            updateCountDownText();
            updateButtons();
            coin = coin + 50;
            resetTimer();
            timecoin.setVisibility(View.VISIBLE);
        } else {
            //startTimer();
            updateCountDownText();


        }
    }
    coinbarText.setText("" + coin);

}




@Override
protected void onRestart() {
    super.onRestart();
    loadAd();
    load();
    textupgrade();
    coinbarText.setText("" + coin);

}


@Override
protected void onDestroy() {
    //rewardedVideoAd.destroy(this);
    super.onDestroy();

}


@Override
protected void onStart() {
    super.onStart();
    loadAd();
    load();
    textupgrade();

    coinbarText.setText("" + coin);

}

@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();
    if (mCountDownTimer != null) {
        mCountDownTimer.cancel();
    }
    save();

}


private void load()
{
    SharedPreferences varReader = app.getSharedPreferences(PREFS_NAME_MAIN, MODE_PRIVATE);

    coin = varReader.getInt("coin", 100);
    life = varReader.getInt("life", 5);
}

private void save()
{
    SharedPreferences.Editor varReader = app.getSharedPreferences(PREFS_NAME_MAIN, 0).edit();

    varReader.putInt("coin", coin);
    varReader.putInt("life", life);
    varReader.apply();
}

private void textupgrade(){
    coinbarText.setText(""+ coin);
    lifesbarText.setText(life + "/5");

}

}