Question

我正在为大学工作开发Android应用程序。在这项工作中，我想用计时器创建一个后台服务，当我关闭应用程序时，计时器仍在运行。当我打开应用程序时，我可以看到自我开始服务以来的时间。好吧，我的问题是当我关闭应用程序时，后台计时器会停止而不会增加更多。

你能帮帮我吗？非常感谢

我的发射器课程

    import android.app.Activity;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;

public class MainActivity extends Activity {

    private Button startButton;
    private Button pauseButton;

    private TextView timerValue;

    Intent intent;
    long timeSwapBuff = 0L;
    long updatedTime = 0L;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        timerValue = (TextView) findViewById(R.id.timerValue);

        startButton = (Button) findViewById(R.id.startButton);
        startButton.setOnClickListener(new View.OnClickListener() {

            public void onClick(View view) {
                intent = new Intent(MainActivity.this, CounterService.class);
                startService(intent);
                registerReceiver(broadcastReceiver, new IntentFilter(CounterService.BROADCAST_ACTION));
            }
        });

        pauseButton = (Button) findViewById(R.id.pauseButton);

        pauseButton.setOnClickListener(new View.OnClickListener() {

            public void onClick(View view) {
                unregisterReceiver(broadcastReceiver);
                stopService(intent);
            }
        });

    }

    private BroadcastReceiver broadcastReceiver = new BroadcastReceiver() {
        @Override
        public void onReceive(Context context, Intent intent) {

            updateUI(intent);       
        }
    };    

    private void updateUI(Intent intent) {
        int time = intent.getIntExtra("time", 0);

        Log.d("Hello", "Time " + time);

        int mins = time / 60;
        int secs = time % 60;
        timerValue.setText("" + mins + ":"
                + String.format("%02d", secs));
    }


}

这里是服务类

import android.app.Service;
import android.content.Intent;
import android.os.Handler;
import android.os.IBinder;
import android.os.SystemClock;

public class CounterService  extends Service {

    private Intent intent;
    public static final String BROADCAST_ACTION = "com.javacodegeeks.android.androidtimerexample.MainActivity";

    private Handler handler = new Handler();
    private long initial_time;
    long timeInMilliseconds = 0L;

    @Override
    public void onCreate() {
        super.onCreate();
        initial_time = SystemClock.uptimeMillis();
        intent = new Intent(BROADCAST_ACTION);  
        handler.removeCallbacks(sendUpdatesToUI);
        handler.postDelayed(sendUpdatesToUI, 1000); // 1 second

    }

    private Runnable sendUpdatesToUI = new Runnable() {
        public void run() {
            DisplayLoggingInfo();           
            handler.postDelayed(this, 1000); // 1 seconds
        }
    };    

    private void DisplayLoggingInfo() {

        timeInMilliseconds = SystemClock.uptimeMillis() - initial_time; 

        int timer = (int) timeInMilliseconds / 1000;
        intent.putExtra("time", timer);
        sendBroadcast(intent);

    }

    @Override
    public void onDestroy() {   
        super.onDestroy();
        handler.removeCallbacks(sendUpdatesToUI);   

    }



    @Override
    public IBinder onBind(Intent intent) {
        // TODO Auto-generated method stub
        return null;
    }


}

Answer 1

您需要在活动的onStop()方法中启动服务，如下所示：

@Override
    protected void onStop() {
        super.onStop();
       //write your code here to start your service
    }

Answer 2

为我工作

public void onResume() {
    super.onResume();

   //write your code here to start your service

    registerReceiver(broadcastReceiver, new IntentFilter(ServiceClass.BROADCAST_ACTION));
}

Answer 3

@Override
protected void onStop() {
    super.onStop();
   //write your code here to start your service
}

我认为这应该适合你。

Answer 4

请仔细查看链接，希望对后台运行 Timer in background

有帮助

activity_main.xml

<RelativeLayout android:layout_width="match_parent"
 android:layout_height="match_parent"
 xmlns:android="http://schemas.android.com/apk/res/android">


 <EditText
 android:layout_width="match_parent"
 android:layout_height="wrap_content"
 android:id="@+id/et_hours"
 android:hint="Hours"
 android:inputType="time"
 android:layout_marginRight="5dp"
 />




 <Button
 android:layout_width="match_parent"
 android:layout_height="wrap_content"
 android:id="@+id/btn_timer"
 android:layout_above="@+id/btn_cancel"
 android:text="Start Timer"/>

 <Button
 android:layout_width="match_parent"
 android:layout_height="wrap_content"
 android:layout_alignParentBottom="true"
 android:id="@+id/btn_cancel"
 android:text="cancel timer"/>




 <TextView
 android:layout_width="wrap_content"
 android:layout_height="wrap_content"
 android:id="@+id/tv_timer"
 android:layout_centerInParent="true"
 android:textSize="25dp"
 android:textColor="#000000"
 android:text="00:00:00"/>


 </RelativeLayout>

MainActivity.java

package playstore.com.a02backgroundtimer;

import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.content.SharedPreferences;
import android.preference.PreferenceManager;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;

import java.text.SimpleDateFormat;
import java.util.Calendar;

public class MainActivity extends AppCompatActivity implements View.OnClickListener {

    private Button btn_start, btn_cancel;
    private TextView tv_timer;
    String date_time;
    Calendar calendar;
    SimpleDateFormat simpleDateFormat;
    EditText et_hours;

    SharedPreferences mpref;
    SharedPreferences.Editor mEditor;

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


    }

    private void init() {
        btn_start = (Button) findViewById(R.id.btn_timer);
        tv_timer = (TextView) findViewById(R.id.tv_timer);
        et_hours = (EditText) findViewById(R.id.et_hours);
        btn_cancel = (Button) findViewById(R.id.btn_cancel);



        mpref = PreferenceManager.getDefaultSharedPreferences(getApplicationContext());
        mEditor = mpref.edit();

        try {
            String str_value = mpref.getString("data", "");
            if (str_value.matches("")) {
                et_hours.setEnabled(true);
                btn_start.setEnabled(true);
                tv_timer.setText("");

            } else {

                if (mpref.getBoolean("finish", false)) {
                    et_hours.setEnabled(true);
                    btn_start.setEnabled(true);
                    tv_timer.setText("");
                } else {

                    et_hours.setEnabled(false);
                    btn_start.setEnabled(false);
                    tv_timer.setText(str_value);
                }
            }
        } catch (Exception e) {

        }



    }

    private void listener() {
        btn_start.setOnClickListener(this);
        btn_cancel.setOnClickListener(this);

    }

    @Override
    public void onClick(View v) {

        switch (v.getId()) {
            case R.id.btn_timer:


                if (et_hours.getText().toString().length() > 0) {

                    int int_hours = Integer.valueOf(et_hours.getText().toString());

                    if (int_hours<=24) {


                        et_hours.setEnabled(false);
                        btn_start.setEnabled(false);


                        calendar = Calendar.getInstance();
                        simpleDateFormat = new SimpleDateFormat("HH:mm:ss");
                        date_time = simpleDateFormat.format(calendar.getTime());

                        mEditor.putString("data", date_time).commit();
                        mEditor.putString("hours", et_hours.getText().toString()).commit();


                        Intent intent_service = new Intent(getApplicationContext(), Timer_Service.class);
                        startService(intent_service);
                    }else {
                        Toast.makeText(getApplicationContext(),"Please select the value below 24 hours",Toast.LENGTH_SHORT).show();
                    }
/*
                    mTimer = new Timer();
                    mTimer.scheduleAtFixedRate(new TimeDisplayTimerTask(), 5, NOTIFY_INTERVAL);*/
                } else {
                    Toast.makeText(getApplicationContext(), "Please select value", Toast.LENGTH_SHORT).show();
                }
                break;


            case R.id.btn_cancel:


                Intent intent = new Intent(getApplicationContext(),Timer_Service.class);
                stopService(intent);

                mEditor.clear().commit();

                et_hours.setEnabled(true);
                btn_start.setEnabled(true);
                tv_timer.setText("");


                break;

        }

    }

    private BroadcastReceiver broadcastReceiver = new BroadcastReceiver() {
        @Override
        public void onReceive(Context context, Intent intent) {
            String str_time = intent.getStringExtra("time");
            tv_timer.setText(str_time);

        }
    };

    @Override
    protected void onResume() {
        super.onResume();
        registerReceiver(broadcastReceiver,new IntentFilter(Timer_Service.str_receiver));

    }

    @Override
    protected void onPause() {
        super.onPause();
        unregisterReceiver(broadcastReceiver);
    }
}

Timer_Service.java

package playstore.com.a02backgroundtimer;

import android.app.Service;
import android.content.Intent;
import android.content.SharedPreferences;
import android.os.Handler;
import android.os.IBinder;
import android.preference.PreferenceManager;
import android.support.annotation.Nullable;
import android.util.Log;

import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;
import java.util.Timer;
import java.util.TimerTask;
import java.util.concurrent.TimeUnit;

public class Timer_Service extends Service {

    public static String str_receiver = "com.countdowntimerservice.receiver";

    private Handler mHandler = new Handler();
    Calendar calendar;
    SimpleDateFormat simpleDateFormat;
    String strDate;
    Date date_current, date_diff;
    SharedPreferences mpref;
    SharedPreferences.Editor mEditor;

    private Timer mTimer = null;
    public static final long NOTIFY_INTERVAL = 1000;
    Intent intent;

    @Nullable
    @Override
    public IBinder onBind(Intent intent) {
        return null;
    }

    @Override
    public void onCreate() {
        super.onCreate();

        mpref = PreferenceManager.getDefaultSharedPreferences(getApplicationContext());
        mEditor = mpref.edit();
        calendar = Calendar.getInstance();
        simpleDateFormat = new SimpleDateFormat("HH:mm:ss");

        mTimer = new Timer();
        mTimer.scheduleAtFixedRate(new TimeDisplayTimerTask(), 5, NOTIFY_INTERVAL);
        intent = new Intent(str_receiver);
    }


    class TimeDisplayTimerTask extends TimerTask {

        @Override
        public void run() {
            mHandler.post(new Runnable() {

                @Override
                public void run() {

                    calendar = Calendar.getInstance();
                    simpleDateFormat = new SimpleDateFormat("HH:mm:ss");
                    strDate = simpleDateFormat.format(calendar.getTime());
                    Log.e("strDate", strDate);
                    twoDatesBetweenTime();

                }

            });
        }

    }

    public String twoDatesBetweenTime() {


        try {
            date_current = simpleDateFormat.parse(strDate);
        } catch (Exception e) {

        }

        try {
            date_diff = simpleDateFormat.parse(mpref.getString("data",""));
        } catch (Exception e) {

        }

        try {


            long diff = date_current.getTime() - date_diff.getTime();
            int int_hours = Integer.valueOf(mpref.getString("hours", ""));

            long int_timer = TimeUnit.HOURS.toMillis(int_hours);
            long long_hours = int_timer - diff;
            long diffSeconds2 = long_hours / 1000 % 60;
            long diffMinutes2 = long_hours / (60 * 1000) % 60;
            long diffHours2 = long_hours / (60 * 60 * 1000) % 24;


            if (long_hours > 0) {
                String str_testing = diffHours2 + ":" + diffMinutes2 + ":" + diffSeconds2;

                Log.e("TIME", str_testing);

                fn_update(str_testing);
            } else {
                mEditor.putBoolean("finish", true).commit();
                mTimer.cancel();
            }
        } catch (Exception e) {
            mTimer.cancel();
            mTimer.purge();


        }

        return "";

    }

    @Override
    public void onDestroy() {
        super.onDestroy();
        Log.e("Service finish", "Finish");
    }

    private void fn_update(String str_time) {

        intent.putExtra("time", str_time);
        sendBroadcast(intent);
    }
}

应用程序启动后，您需要提及计时器的时间...然后在重新启动应用程序时终止该应用程序后，它也会显示计时器的开始时间...现在，您可以根据需要自定义应用程序了您的要求。

计时器在背景中

4 个答案: