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; }