我是
Android编程的新手,并希望从创建一个非常基本的应用程序开始,该应用程序在屏幕上显示当前位置的纬度和经度.
我正在为我的三星galaxy S3开发并读取你需要kickstart the phone to return the GPS.
我已尝试在onConnected()方法中使用LocationManager上的requestLocationUpdates()方法调用.但是我发现LocationClient仍然返回一个空位置.
谁能告诉我我做错了什么？
这是我的MainActivity：
import android.content.Context;
import android.location.Location;
import android.location.LocationListener;
import android.location.LocationManager;
import android.os.Bundle;
import android.support.v4.app.FragmentActivity;
import android.view.Menu;
import android.widget.TextView;
import android.widget.Toast;
import com.google.android.gms.common.ConnectionResult;
import com.google.android.gms.common.GooglePlayServicesClient;
import com.google.android.gms.location.LocationClient;
public class MainActivity extends FragmentActivity implements
GooglePlayServicesClient.ConnectionCallbacks,GooglePlayServicesClient.OnConnectionFailedListener {
private LocationClient mLocationClient;
private Location mCurrentLocation;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mLocationClient = new LocationClient(this,this,this);
}
@Override
protected void onStart() {
super.onStart();
mLocationClient.connect();
}
@Override
protected void onStop() {
mLocationClient.disconnect();
super.onStop();
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main,menu);
return true;
}
@Override
public void onConnectionFailed(ConnectionResult arg0) {
// Todo Auto-generated method stub
}
@Override
public void onConnected(Bundle arg0) {
Toast.makeText(this,"Connected",Toast.LENGTH_SHORT).show();
LocationManager manager = (LocationManager) this
.getSystemService(Context.LOCATION_SERVICE);
manager.requestLocationUpdates(LocationManager.NETWORK_PROVIDER,new LocationListener() {
@Override
public void onStatusChanged(String provider,int status,Bundle extras) {
}
@Override
public void onProviderEnabled(String provider) {
}
@Override
public void onProviderdisabled(String provider) {
}
@Override
public void onLocationChanged(final Location location) {
}
});
mCurrentLocation = mLocationClient.getLastLocation();
TextView latTextView = (TextView) findViewById(R.id.latitude_text);
latTextView.setText(Double.toString(mCurrentLocation.getLatitude()));
TextView longTextView = (TextView) findViewById(R.id.longitude_text);
longTextView.setText(Double.toString(mCurrentLocation.getLongitude()));
}
@Override
public void ondisconnected() {
Toast.makeText(this,"disconnected. Please re-connect.",Toast.LENGTH_SHORT).show();
}
}
我的Android清单看起来像这样：
<uses-sdk
android:minSdkVersion="8"
android:targetSdkVersion="17" />
<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="com.google.android.providers.gsf.permission.READ_GSERVICES" />
<application
android:allowBackup="true"
android:icon="@drawable/ic_launcher"
android:label="@string/app_name"
android:theme="@style/AppTheme" >
<activity
android:name="com.example.willigetwet.MainActivity"
android:label="@string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
</manifest>
运行调试器时,我发现调用mLocationClient.getLastLocation()后mCurrentLocation为null.
我会非常感谢任何帮助！
解决方法
mLocationClient.getLastLocation();如果您没有设备保存的任何最后位置,则可能返回null.如果你读它的
documentation,它说;
它返回当前可用的最新位置.
如果某个位置不可用,这种情况很少发生,则返回null
同样在onLocationChanged方法中,当您的位置发生变化时,您可能希望将位置设置为最新位置.
@Override
public void onLocationChanged(final Location location) {
mCurrentLocation = location;
}