所以我在我的应用程序中有这个代码，它使用＆＃34; locationListenerFunc = new LocationListener＆＃34;在应用程序未处于焦点时收集信息。服务， 然后当应用程序恢复焦点时，它使用此信息在地图上显示一条线， 当我测试应用程序并最小化它时，然后打开应用程序备份，一切正常，应用程序处于与我离开时相同的状态，并执行它想要做的所有事情。 当我生成APK并以这种方式测试时，它可以正常工作，但当我关闭它时，然后将其打开，它会重新启动itseld，活动与我离开时的状态不同。（进一步的测试表明，我恢复应用程序，它再次进入onCreate，而不是恢复）
有谁知道为什么会这样？
这是我的主要活动代码＆gt;
package -----;
import android.content.Context;
import android.graphics.Color;
import android.location.Criteria;
import android.location.Location;
import android.location.LocationListener;
import android.location.LocationManager;
import android.os.Bundle;
import android.support.v4.app.FragmentActivity;
import android.text.format.Time;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
import com.google.android.gms.maps.CameraUpdateFactory;
import com.google.android.gms.maps.GoogleMap;
import com.google.android.gms.maps.SupportMapFragment;
import com.google.android.gms.maps.model.CameraPosition;
import com.google.android.gms.maps.model.LatLng;
import com.google.android.gms.maps.model.PolylineOptions;
import java.util.ArrayList;
import java.util.List;
public class MapsActivity extends FragmentActivity {
private GoogleMap mMap; // Might be null if Google Play services APK is not available.
private Button startTrackingButton;
private Button stopTrackingButton;
private TextView mainText;
private Boolean isInPause = false;
private List<LocationItems> locationItemsList = new ArrayList<LocationItems>();
private double ladHistory = 0;
private double logHistory = 0;
private LocationManager manager;
private LocationListener locationListenerFunc;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.map_fragment_layout);
//casting
startTrackingButton = (Button) findViewById(R.id.BTStartTracking);
stopTrackingButton = (Button) findViewById(R.id.BTStopTracking);
mainText = (TextView) findViewById(R.id.TVMainTextView);
stopTrackingButton.setEnabled(false);
//GPS LOCATION MANAGER
manager = (LocationManager) this.getSystemService(Context.LOCATION_SERVICE);
locationListenerFunc = new LocationListener() {
@Override
public void onLocationChanged(Location location) {
///
Log.d("myTag", "onlocation change ?");
mMap.animateCamera(CameraUpdateFactory.newLatLngZoom(
new LatLng(location.getLatitude(), location.getLongitude()), 13));
CameraPosition cameraPosition = new CameraPosition.Builder()
.target(new LatLng(location.getLatitude(), location.getLongitude())) // Sets the center of the map to location user
.zoom(17) // Sets the zoom
.bearing(90) // Sets the orientation of the camera to east
.tilt(30) // Sets the tilt of the camera to 30 degrees
.build(); // Creates a CameraPosition from the builder
mMap.animateCamera(CameraUpdateFactory.newCameraPosition(cameraPosition));
//sets text & lat, long>
Time today = new Time(Time.getCurrentTimezone());
today.setToNow();
double Lad = location.getLatitude();
double Long = location.getLongitude();
mainText.setText("lat: " + String.valueOf(Lad) + ", " + "long: " + String.valueOf(Long) + ", last update at: " + today.format("%k:%M:%S"));
//add a line on map
if ((ladHistory != 0) && (logHistory != 0)) {
PolylineOptions line =
new PolylineOptions().add(new LatLng(ladHistory,
logHistory),
new LatLng(location.getLatitude(),
location.getLongitude()))
.width(30).color(Color.RED);
mMap.addPolyline(line);
}
//updates veraibles
ladHistory = location.getLatitude();
logHistory = location.getLongitude();
//handles all polylines lost while application was offline:
if (isInPause == true) {
locationItemsList.add(new LocationItems(location.getLatitude(), location.getLongitude()));
}
///
}
@Override
public void onStatusChanged(String provider, int status, Bundle extras) {
}
@Override
public void onProviderEnabled(String provider) {
}
@Override
public void onProviderDisabled(String provider) {
}
};
//stops tracking button touch listener
stopTrackingButton.setOnClickListener(new Button.OnClickListener() {
public void onClick(View v) {
//handles the disabling and starting of buttons
stopTrackingButton.setEnabled(false);
startTrackingButton.setEnabled(true);
//removing locaion updates
manager.removeUpdates(locationListenerFunc);
manager = null;
mainText.setText("stopped location update");
}
});
//starts tracking button touch listener
startTrackingButton.setOnClickListener(new Button.OnClickListener() {
public void onClick(View v) {
//Do stuff here
Time today = new Time(Time.getCurrentTimezone());
today.setToNow();
mainText.setText("location update started at: " + today.format("%k:%M:%S"));
manager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
manager.requestLocationUpdates(LocationManager.NETWORK_PROVIDER,
1000, 0, locationListenerFunc);
//handles the disabling and starting of buttons
startTrackingButton.setEnabled(false);
stopTrackingButton.setEnabled(true);
}
});
//setting up map
setUpMapIfNeeded();
}
@Override
protected void onResume() {
super.onResume();
setUpMapIfNeeded();
isInPause = false;
//repaints all lost points
for (int i = 0; i < locationItemsList.size() - 1; i++) {
LocationItems sourceItem = (LocationItems) locationItemsList.get(i);
LocationItems destinationItem = (LocationItems) locationItemsList.get(i + 1);
PolylineOptions line =
new PolylineOptions().add(new LatLng(sourceItem.getLatiduteVar(),
sourceItem.getLongitudeVar()),
new LatLng(destinationItem.getLatiduteVar(),
destinationItem.getLongitudeVar()))
.width(30).color(Color.RED);
mMap.addPolyline(line);
//zeroes the lists
locationItemsList = new ArrayList<LocationItems>();
}
}
@Override
protected void onPause() {
super.onPause();
isInPause = true;
}
protected void onDestroy() {
super.onDestroy();
manager.removeUpdates(locationListenerFunc);
manager = null;
}
private void setUpMapIfNeeded() {
// Do a null check to confirm that we have not already instantiated the map.
if (mMap == null) {
// Try to obtain the map from the SupportMapFragment.
mMap = ((SupportMapFragment) getSupportFragmentManager().findFragmentById(R.id.map))
.getMap();
// Check if we were successful in obtaining the map.
if (mMap != null) {
centerMapOnMyLocation(); //centers the map on user location
}
}
}
private void centerMapOnMyLocation() {
LocationManager locationManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
Criteria criteria = new Criteria();
Location location = locationManager.getLastKnownLocation(locationManager.getBestProvider(criteria, false));
if (location != null) {
mMap.animateCamera(CameraUpdateFactory.newLatLngZoom(
new LatLng(location.getLatitude(), location.getLongitude()), 13));
CameraPosition cameraPosition = new CameraPosition.Builder()
.target(new LatLng(location.getLatitude(), location.getLongitude())) // Sets the center of the map to location user
.zoom(17) // Sets the zoom
.bearing(90) // Sets the orientation of the camera to east
.tilt(30) // Sets the tilt of the camera to 30 degrees
.build(); // Creates a CameraPosition from the builder
mMap.animateCamera(CameraUpdateFactory.newCameraPosition(cameraPosition));
//sets text >
double Lad = location.getLatitude();
double Long = location.getLongitude();
mainText.setText("lat: " + String.valueOf(Lad) + ", " + "long: " + String.valueOf(Long));
}
}
}
这是我的清单文件＆gt;
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="-----" >
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<uses-permission android:name="com.google.android.providers.gsf.permission.READ_GSERVICES" />
<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
<application
android:allowBackup="true"
android:icon="@mipmap/ic_launcher"
android:label="@string/app_name"
android:theme="@style/AppTheme" >
<meta-data
android:name="com.google.android.gms.version"
android:value="@integer/google_play_services_version" />
<meta-data
android:name="com.google.android.maps.v2.API_KEY"
android:value="-------" />
<activity
android:name=".MapsActivity"
android:screenOrientation="portrait"
android:label="@string/title_activity_maps" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
</manifest>