我在Android开发者网站上找到了一个教程，用于使用Google Play服务查找位置。 链接：http://developer.android.com/training/location/retrieve-current.html
它工作得很好。但是有一部分代码需要检查设备上是否有谷歌播放服务。但我不知道如何在我的代码中使用它。例如有一个方法如下：
private boolean servicesConnected() {
// Check that Google Play services is available
int resultCode =
GooglePlayServicesUtil.
isGooglePlayServicesAvailable(this);
// If Google Play services is available
if (ConnectionResult.SUCCESS == resultCode) {
// In debug mode, log the status
Log.d("Location Updates",
"Google Play services is available.");
// Continue
return true;
// Google Play services was not available for some reason.
// resultCode holds the error code.
} else {
// Get the error dialog from Google Play services
Dialog errorDialog = GooglePlayServicesUtil.getErrorDialog(
resultCode,
this,
CONNECTION_FAILURE_RESOLUTION_REQUEST);
// If Google Play services can provide an error dialog
if (errorDialog != null) {
// Create a new DialogFragment for the error dialog
ErrorDialogFragment errorFragment =
new ErrorDialogFragment();
// Set the dialog in the DialogFragment
errorFragment.setDialog(errorDialog);
// Show the error dialog in the DialogFragment
errorFragment.show(getSupportFragmentManager(),
"Location Updates");
}
return false;
}
}
还有其他方法，我不明白。喜欢以下内容：
public static class ErrorDialogFragment extends DialogFragment {
// Global field to contain the error dialog
private Dialog mDialog;
// Default constructor. Sets the dialog field to null
public ErrorDialogFragment() {
super();
mDialog = null;
}
// Set the dialog to display
public void setDialog(Dialog dialog) {
mDialog = dialog;
}
// Return a Dialog to the DialogFragment.
@Override
public Dialog onCreateDialog(Bundle savedInstanceState) {
return mDialog;
}
}
/*
* Handle results returned to the FragmentActivity
* by Google Play services
*/
@Override
protected void onActivityResult(
int requestCode, int resultCode, Intent data) {
// Decide what to do based on the original request code
switch (requestCode) {
case CONNECTION_FAILURE_RESOLUTION_REQUEST :
/*
* If the result code is Activity.RESULT_OK, try
* to connect again
*/
switch (resultCode) {
case Activity.RESULT_OK :
/*
* Try the request again
*/
break;
}
}
}
第一个错误对话框，如果用于显示错误。可能在
时使用onactivityresultconnectionResult.startResolutionForResult(this,ONNECTION_FAILURE_RESOLUTION_REQUEST);
被召唤。
我的问题是应该调用servicesConnected()吗？
完整代码：
package com.example.locationdocseg;
import com.google.android.gms.common.ConnectionResult;
import com.google.android.gms.common.GooglePlayServicesClient;
import com.google.android.gms.common.GooglePlayServicesUtil;
import com.google.android.gms.location.LocationClient;
import com.google.android.gms.location.LocationRequest;
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.GoogleMap.InfoWindowAdapter;
import com.google.android.gms.maps.model.LatLng;
import com.google.android.gms.maps.model.Marker;
import com.google.android.gms.maps.model.MarkerOptions;
import android.location.Location;
import android.location.LocationListener;
import android.os.Bundle;
import android.app.Activity;
import android.app.Dialog;
import android.content.Context;
import android.content.Intent;
import android.content.IntentSender;
import android.content.SharedPreferences;
import android.support.v4.app.DialogFragment;
import android.support.v4.app.FragmentActivity;
import android.util.Log;
import android.view.Menu;
import android.view.View;
import android.widget.TextView;
import android.widget.Toast;
public class MainActivity extends FragmentActivity implements
GooglePlayServicesClient.ConnectionCallbacks,
GooglePlayServicesClient.OnConnectionFailedListener,LocationListener, com.google.android.gms.location.LocationListener {
// Global constants
/*
* Define a request code to send to Google Play services
* This code is returned in Activity.onActivityResult
*/
private GoogleMap googleMap;
private final static int
CONNECTION_FAILURE_RESOLUTION_REQUEST = 9000;
LocationClient mLocationClient;
Location mCurrentLocation;
double current_latitude,current_longitude;
// Milliseconds per second
private static final int MILLISECONDS_PER_SECOND = 1000;
// Update frequency in seconds
public static final int UPDATE_INTERVAL_IN_SECONDS = 5;
// Update frequency in milliseconds
private static final long UPDATE_INTERVAL =
MILLISECONDS_PER_SECOND * UPDATE_INTERVAL_IN_SECONDS;
// The fastest update frequency, in seconds
private static final int FASTEST_INTERVAL_IN_SECONDS = 1;
// A fast frequency ceiling in milliseconds
private static final long FASTEST_INTERVAL =
MILLISECONDS_PER_SECOND * FASTEST_INTERVAL_IN_SECONDS;
// Define an object that holds accuracy and frequency parameters
LocationRequest mLocationRequest;
SharedPreferences mPrefs;
SharedPreferences.Editor mEditor;
boolean mUpdatesRequested,isplayservice=false;
// Define a DialogFragment that displays the error dialog
public static class ErrorDialogFragment extends DialogFragment {
// Global field to contain the error dialog
private Dialog mDialog;
// Default constructor. Sets the dialog field to null
public ErrorDialogFragment() {
super();
mDialog = null;
}
// Set the dialog to display
public void setDialog(Dialog dialog) {
mDialog = dialog;
}
// Return a Dialog to the DialogFragment.
@Override
public Dialog onCreateDialog(Bundle savedInstanceState) {
return mDialog;
}
}
/*
* Handle results returned to the FragmentActivity
* by Google Play services
*/
@Override
protected void onActivityResult(
int requestCode, int resultCode, Intent data) {
// Decide what to do based on the original request code
switch (requestCode) {
case CONNECTION_FAILURE_RESOLUTION_REQUEST :
/*
* If the result code is Activity.RESULT_OK, try
* to connect again
*/
switch (resultCode) {
case Activity.RESULT_OK :
/*
* Try the request again
*/
break;
}
}
}
private boolean servicesConnected() {
// Check that Google Play services is available
int resultCode =
GooglePlayServicesUtil.
isGooglePlayServicesAvailable(this);
// If Google Play services is available
if (ConnectionResult.SUCCESS == resultCode) {
// In debug mode, log the status
Log.d("Location Updates",
"Google Play services is available.");
// Continue
return true;
// Google Play services was not available for some reason.
// resultCode holds the error code.
} else {
// Get the error dialog from Google Play services
Dialog errorDialog = GooglePlayServicesUtil.getErrorDialog(
resultCode,
this,
CONNECTION_FAILURE_RESOLUTION_REQUEST);
// If Google Play services can provide an error dialog
if (errorDialog != null) {
// Create a new DialogFragment for the error dialog
ErrorDialogFragment errorFragment =
new ErrorDialogFragment();
// Set the dialog in the DialogFragment
errorFragment.setDialog(errorDialog);
// Show the error dialog in the DialogFragment
errorFragment.show(getSupportFragmentManager(),
"Location Updates");
}
return false;
}
}
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// Open the shared preferences
// isplayservice=true;
mLocationRequest = LocationRequest.create();
// Use high accuracy
mLocationRequest.setPriority(
LocationRequest.PRIORITY_HIGH_ACCURACY);
// Set the update interval to 5 seconds
mLocationRequest.setInterval(UPDATE_INTERVAL);
// Set the fastest update interval to 1 second
mLocationRequest.setFastestInterval(FASTEST_INTERVAL);
mPrefs = getSharedPreferences("SharedPreferences",
Context.MODE_PRIVATE);
// Get a SharedPreferences editor
mEditor = mPrefs.edit();
/*
* Create a new location client, using the enclosing class to
* handle callbacks.
*/
// Start with updates turned off
mUpdatesRequested = false;
mLocationClient = new LocationClient(this, this, this);
// mLocationClient.connect();
try {
// Loading map
initilizeMap();
} catch (Exception e) {
e.printStackTrace();
}
googleMap.setInfoWindowAdapter(new InfoWindowAdapter() {
@Override
public View getInfoWindow(Marker arg0) {
View v = getLayoutInflater().inflate(R.layout.info_window_layout, null);
// Getting the position from the marker
LatLng latLng = arg0.getPosition();
// Getting reference to the TextView to set latitude
TextView tvLat = (TextView) v.findViewById(R.id.tv_lat);
// Getting reference to the TextView to set longitude
TextView tvLng = (TextView) v.findViewById(R.id.tv_lng);
// Setting the latitude
tvLat.setText("Latitude:" + 8.505439);
// Setting the longitude
tvLng.setText("Longitude:"+ 76.971293);
// Returning the view containing InfoWindow contents
return v;
}
@Override
public View getInfoContents(Marker arg0) {
return null;
}
});
}
@Override
protected void onPause() {
// Save the current setting for updates
mEditor.putBoolean("KEY_UPDATES_ON", mUpdatesRequested);
mEditor.commit();
super.onPause();
}
@Override
protected void onResume() {
/*
* Get any previous setting for location updates
* Gets "false" if an error occurs
*/
if (mPrefs.contains("KEY_UPDATES_ON")) {
mUpdatesRequested =
mPrefs.getBoolean("KEY_UPDATES_ON", false);
// Otherwise, turn off location updates
} else {
mEditor.putBoolean("KEY_UPDATES_ON", false);
mEditor.commit();
}
super.onResume();
}
protected void onStart() {
super.onStart();
// Connect the client.
//mLocationClient.connect();
}
/*
* Called when the Activity is no longer visible.
*/
@Override
protected void onStop() {
// If the client is connected
if (mLocationClient.isConnected()) {
/*
* Remove location updates for a listener.
* The current Activity is the listener, so
* the argument is "this".
*/
// removeLocationUpdates(MainActivity.this);
mLocationClient.removeLocationUpdates(this);
}
/*
* After disconnect() is called, the client is
* considered "dead".
*/
// Disconnecting the client invalidates it.
mLocationClient.disconnect();
super.onStop();
}
@Override
public void onConnectionFailed(ConnectionResult connectionResult) {
/*
* Google Play services can resolve some errors it detects.
* If the error has a resolution, try sending an Intent to
* start a Google Play services activity that can resolve
* error.
*/
if (connectionResult.hasResolution()) {
try {
// Start an Activity that tries to resolve the error
connectionResult.startResolutionForResult(
this,
CONNECTION_FAILURE_RESOLUTION_REQUEST);
/*
* Thrown if Google Play services canceled the original
* PendingIntent
*/
} catch (IntentSender.SendIntentException e) {
// Log the error
e.printStackTrace();
}
} else {
/*
* If no resolution is available, display a dialog to the
* user with the error.
*/
showDialog(connectionResult.getErrorCode());
}
}
@Override
public void onConnected(Bundle arg0) {
// Display the connection status
//Toast.makeText(this, "Connected", Toast.LENGTH_SHORT).show();
if (mUpdatesRequested) {
mLocationClient.requestLocationUpdates(mLocationRequest, this);
}
mCurrentLocation=mLocationClient.getLastLocation();
current_latitude=mCurrentLocation.getLatitude();
current_longitude=mCurrentLocation.getLongitude();
placemarkersonmap();
//Toast.makeText(getApplicationContext(),current_latitude+" "+current_longitude,Toast.LENGTH_LONG).show();
}
@Override
public void onDisconnected() {
// Display the connection status
Toast.makeText(this, "Disconnected. Please re-connect.",
Toast.LENGTH_SHORT).show();
}
@Override
public void onLocationChanged(Location location) {
// Report to the UI that the location was updated
// String msg = "Updated Location: " +
// Double.toString(location.getLatitude()) + "," +
// Double.toString(location.getLongitude());
// Toast.makeText(this, msg, Toast.LENGTH_SHORT).show();
current_latitude=location.getLatitude();
current_longitude=location.getLongitude();
}
@Override
public void onProviderDisabled(String provider) {
// TODO Auto-generated method stub
}
@Override
public void onProviderEnabled(String provider) {
// TODO Auto-generated method stub
}
@Override
public void onStatusChanged(String provider, int status, Bundle extras) {
// TODO Auto-generated method stub
}
private void initilizeMap() {
if (googleMap == null) {
googleMap = ((SupportMapFragment) getSupportFragmentManager().findFragmentById(R.id.map)).getMap();
// check if map is created successfully or not
if (googleMap == null) {
Toast.makeText(getApplicationContext(),"Sorry! unable to create maps", Toast.LENGTH_SHORT).show();
}
}
if(googleMap!=null)
{
mLocationClient.connect();
//placemarkersonmap();
}
}
public void placemarkersonmap()
{
googleMap.setMyLocationEnabled(true);
googleMap.getUiSettings().setMyLocationButtonEnabled(true);
LatLng latLng = new LatLng(current_latitude, current_longitude);
Toast.makeText(getApplicationContext(),current_latitude+" "+current_longitude,Toast.LENGTH_LONG).show();
googleMap.moveCamera(CameraUpdateFactory.newLatLngZoom(latLng, 12f));
googleMap.animateCamera(CameraUpdateFactory.newLatLngZoom(latLng, 12f));
MarkerOptions marker = new MarkerOptions().position(new LatLng(8.505439, 76.971293));
googleMap.addMarker(marker);
}
}
答案 0 :(得分：0)
首先，从onCreate()方法调用此方法。在调用此方法之后，以及您在何处获得此方法的回调，请检查它，是否可用。如果可用，则继续获取位置数据，否则显示错误对话框，说明您的设备无法使用Google Play服务，请从设置中启用。