全部.我正在编写一个关于 GPS 位置的 android 应用程序.
all. I am writing an android app about GPS locations.
我在模拟器上试了一下，手动输入了经纬度，效果很好.但是，我的问题是:在真机上，在调试模式下，使用intent去下一个类只有在位置改变时才能实现.如果我直接启动应用程序，我可以看到闪烁的 GPS 图标，但应用程序只会停留在这里，不会启动下一个活动.看来 onLocationChanged() 中的变量永远不会改变.
I tried it on emulator and entered the latitude and longitude manually, and it worked fine. However, my problem is: on the real device, in debugging mode, to go the next class by using intent can only be achieved when location is changed. If I start the app directly, I can see the blinking GPS icon, but the app will only stay here, and won't start the next activity. It seems that the variables in the onLocationChanged() will never be changed.
我听说要立即获取位置是使用 getLastKnownLocation() 方法.但我没有找到我应该使用它的地方.
I have heard that to get the location instantly is to use the getLastKnownLocation() method. But I failed to get where I should use it.
这是我如何使用 LocationManager 获取位置的类.
Here is the class of how I use the LocationManager to get the locations.
有什么解决办法吗?我很困惑.非常感谢！！
Is there any solutions? I am quite confused. Thank you very much!!
public class mainMenu extends Activity{
private LocationManager locationManager = null;
public void onCreate(Bundle savedInstanceState){
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
Button button1 = (Button)findViewById(R.id.button1);
button1.setOnClickListener(new OnClickListener(){
public void onClick(View v){
Intent i3 = new Intent();
i3.setClass(mainMenu.this, police.class);
i3.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
mainMenu.this.startActivityForResult(i3,0);
}
});
Button button2 = (Button)findViewById(R.id.button2);
button2.setOnClickListener(new OnClickListener(){
public void onClick(View v){
Intent i3 = new Intent();
i3.setClass(mainMenu.this, ambulance.class);
i3.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
mainMenu.this.startActivityForResult(i3,0);
}
});
Button button3 = (Button)findViewById(R.id.button3);
button3.setOnClickListener(new OnClickListener(){
public void onClick(View v){
Intent i3 = new Intent();
i3.setClass(mainMenu.this, fire_station.class);
i3.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
mainMenu.this.startActivityForResult(i3,0);
}
});
locationManager = (LocationManager)mainMenu.this.getSystemService(Context.LOCATION_SERVICE);
locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 120000 , 0, new MyLocationUpdater());
String provider = LocationManager.GPS_PROVIDER;
Location location = locationManager.getLastKnownLocation(provider);
}
public class MyLocationUpdater implements LocationListener{ //change location interface
@Override
public void onLocationChanged(Location location) {
// TODO Auto-generated method stub
// store the location data
// get the best record
Double lat = location.getLatitude();
Double lon = location.getLongitude();
System.out.println("The latitude is " + lat + "and "
+ "the longitude is "+ lon);
Double lat11 = lat - 1/69.0;
Double lat12 = lat + 1/69.0;
Double lon11 = lon - 1/42.0;
Double lon12 = lon + 1/42.0;
StaticVariables.latS1 = lat11.toString();
StaticVariables.latN1 = lat12.toString();
StaticVariables.lonW1 = lon11.toString();
StaticVariables.lonE1 = lon12.toString();
Double lat111 = lat - 2/69.0;
Double lat121 = lat + 2/69.0;
Double lon111 = lon - 2/42.0;
Double lon121 = lon + 2/42.0;
StaticVariables.latS11 = lat111.toString();
StaticVariables.latN11 = lat121.toString();
StaticVariables.lonW11 = lon111.toString();
StaticVariables.lonE11 = lon121.toString();
// ==================================================
// ambulances
Double lat21 = lat - 3/69.0;
Double lat22 = lat + 3/69.0;
Double lon21 = lon - 3/42.0;
Double lon22 = lon + 3/42.0;
StaticVariables.latS2 = lat21.toString();
StaticVariables.latN2 = lat22.toString();
StaticVariables.lonW2 = lon21.toString();
StaticVariables.lonE2 = lon22.toString();
Double lat211 = lat - 5.5/69.0;
Double lat221 = lat + 5.5/69.0;
Double lon211 = lon - 5.5/42.0;
Double lon221 = lon + 5.5/42.0;
StaticVariables.latS21 = lat211.toString();
StaticVariables.latN21 = lat221.toString();
StaticVariables.lonW21 = lon211.toString();
StaticVariables.lonE21 = lon221.toString();
// ===================================================
// fire stations
Double lat31 = lat - 2/69.0;
Double lat32 = lat + 2/69.0;
Double lon31 = lon - 2/42.0;
Double lon32 = lon + 2/42.0;
StaticVariables.latS3 = lat31.toString();
StaticVariables.latN3 = lat32.toString();
StaticVariables.lonW3 = lon31.toString();
StaticVariables.lonE3 = lon32.toString();
Double lat311 = lat - 2/69.0;
Double lat321 = lat + 2/69.0;
Double lon311 = lon - 2/42.0;
Double lon321 = lon + 2/42.0;
StaticVariables.latS31 = lat311.toString();
StaticVariables.latN31 = lat321.toString();
StaticVariables.lonW31 = lon311.toString();
StaticVariables.lonE31 = lon321.toString();
Intent intent = new Intent();
intent.setClass(mainMenu.this, getPhoneNumber.class);
mainMenu.this.startActivity(intent);
}
@Override
public void onProviderDisabled(String arg0) {
// TODO Auto-generated method stub
}
@Override
public void onProviderEnabled(String arg0) {
// TODO Auto-generated method stub
}
@Override
public void onStatusChanged(String arg0, int arg1, Bundle arg2) {
// TODO Auto-generated method stub
}
}
}
getLastKnownLocation 方法不会触发 onLocationChanged 事件.重构代码的一种方法是将作用于 Location 的逻辑移动到单独的方法中，然后在调用 getLastKnownLocation 之后和从 getLastKnownLocation 调用该方法code>onLocationChanged 方法.
The getLastKnownLocation method does not trigger an onLocationChanged event. One way to refactor your code would be to move the logic that acts on a Location to a separate method and then call that method both after you call getLastKnownLocation, and from your onLocationChanged method.
请记住，不能保证 getLastKnownLocation 将提供有意义的 Location，因为您的设备可能在上次位置更新后已经移动.
Bear in mind that there is no guarantee that getLastKnownLocation will provide a meaningful Location, since you the device might have moved since the last location update.
示例代码:
public void onCreate(Bundle savedInstanceState){
....
String provider = LocationManager.GPS_PROVIDER;
Location location = locationManager.getLastKnownLocation(provider);
updateLocation(location);
}
public class MyLocationUpdater implements LocationListener{ //change location interface
@Override
public void onLocationChanged(Location location) {
updateLocation(location);
}
...
}
void updateLocation(Location location) {
Double lat = location.getLatitude();
Double lon = location.getLongitude();
// the rest of the code from onLocationChanged
}
这篇关于通过 Android 应用即时获取 GPS 位置的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持跟版网！