Question

当我的应用程序启动时，服务启动（它启动计时器）然后活动受限于此服务。当我杀死应用程序时，调用服务的onCreate（）方法，因此计时器重新启动。为什么调用onCreate（）方法？我不希望我的计时器重新启动，我希望它从它离开的地方继续。

MainActivity.java

public class MainActivity extends AppCompatActivity {
    BoundService mBoundService;
    boolean mServiceBound = false;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        final TextView timestampText = (TextView) findViewById(R.id.timestamp_text);
        Button printTimestampButton = (Button) findViewById(R.id.print_timestamp);
        Button stopServiceButon = (Button) findViewById(R.id.stop_service);
        Button startServiceButon = (Button) findViewById(R.id.start_service);
        printTimestampButton.setOnClickListener(new OnClickListener() {
            @Override
            public void onClick(View v) {
                if (mServiceBound) {
                    timestampText.setText(mBoundService.getTimestamp());
                }
            }
        });

        stopServiceButon.setOnClickListener(new OnClickListener() {
            @Override
            public void onClick(View v) {
                if (mServiceBound) {
                    unbindService(mServiceConnection);
                    mServiceBound = false;
                }
                Intent intent = new Intent(MainActivity.this,
                        BoundService.class);
                stopService(intent);
            }
        });

        startServiceButon.setOnClickListener(new OnClickListener(){
            @Override
            public void onClick(View v) {
                if (!mServiceBound) {
                    Intent intent = new Intent(MainActivity.this, BoundService.class);
                    startService(intent);
                    bindService(intent, mServiceConnection, Context.BIND_AUTO_CREATE);
                    mServiceBound = true;
                }

            }
        });
    }

    @Override
    protected void onStart() {
        super.onStart();
        Log.v("mainactivity", "in onStart");
        Intent intent = new Intent(this, BoundService.class);
        startService(intent);
        bindService(intent, mServiceConnection, Context.BIND_AUTO_CREATE);
        mServiceBound = true;
    }

    @Override
    protected void onStop() {
        super.onStop();
        if (mServiceBound) {
            unbindService(mServiceConnection);
            mServiceBound = false;
        }
    }

    private ServiceConnection mServiceConnection = new ServiceConnection() {
        @Override
        public void onServiceDisconnected(ComponentName name) {
            mServiceBound = false;
        }

        @Override
        public void onServiceConnected(ComponentName name, IBinder service) {
            MyBinder myBinder = (MyBinder) service;
            mBoundService = myBinder.getService();
            mServiceBound = true;
        }
    };
}

BoundService.java

public class BoundService extends Service {
    private static String LOG_TAG = "BoundService";
    private IBinder mBinder = new MyBinder();
    private Chronometer mChronometer;

    @Override
    public void onCreate() {
        super.onCreate();
        Log.v(LOG_TAG, "in onCreate");
        mChronometer = new Chronometer(this);
        mChronometer.setBase(SystemClock.elapsedRealtime());
        mChronometer.start();
    }

    @Override
    public IBinder onBind(Intent intent) {
        Log.v(LOG_TAG, "in onBind");
        return mBinder;
    }

    @Override
    public void onRebind(Intent intent) {
        Log.v(LOG_TAG, "in onRebind");
        super.onRebind(intent);
    }

    @Override
    public boolean onUnbind(Intent intent) {
        Log.v(LOG_TAG, "in onUnbind");
        return true;
    }

    @Override
    public void onDestroy() {
        super.onDestroy();
        Log.v(LOG_TAG, "in onDestroy");
        mChronometer.stop();
    }

    public String getTimestamp() {
        long elapsedMillis = SystemClock.elapsedRealtime()
                - mChronometer.getBase();
        int hours = (int) (elapsedMillis / 3600000);
        int minutes = (int) (elapsedMillis - hours * 3600000) / 60000;
        int seconds = (int) (elapsedMillis - hours * 3600000 - minutes * 60000) / 1000;
        int millis = (int) (elapsedMillis - hours * 3600000 - minutes * 60000 - seconds * 1000);
        return hours + ":" + minutes + ":" + seconds + ":" + millis;
    }

    public class MyBinder extends Binder {
        BoundService getService() {
            return BoundService.this;
        }
    }
}

activity_main.xml中

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="#FFFFFF"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="oiyioz.com.a13_local_bound_service_4.MainActivity" >

    <ImageView
        android:id="@+id/imageView1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentBottom="true"
        android:layout_centerHorizontal="true"
        android:layout_marginBottom="-40dp"
        android:src="@drawable/truiton_sq" />

    <Button
        android:id="@+id/print_timestamp"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentTop="true"
        android:layout_centerHorizontal="true"
        android:layout_marginTop="130dp"
        android:text="Print Timestamp" />

    <TextView
        android:id="@+id/timestamp_text"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@+id/print_timestamp"
        android:layout_centerHorizontal="true"
        android:layout_marginTop="120dp"
        android:text=""
        android:textAppearance="?android:attr/textAppearanceLarge" />

    <Button
        android:id="@+id/stop_service"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@+id/print_timestamp"
        android:layout_centerHorizontal="true"
        android:text="Stop Service" />

    <Button
        android:id="@+id/start_service"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@+id/stop_service"
        android:layout_centerHorizontal="true"
        android:text="Start Service" />

</RelativeLayout>

Answer 1

而不是onCreate（）使用onActivityCreated（）。有关详细信息，请使用Official link

Answer 2

当您终止应用程序时，您将终止整个过程，而不仅仅是活动。因此，您的服务也已消失，当您重新启动应用程序时，它不知道以前的状态。要解决这个问题，你应该以某种方式坚持你感兴趣的状态。

当应用程序被杀死时，将调用oncreate（）方法。为什么？

2 个答案: