现在我有一个带标记的简单地图。我以为我已经死了，因为我无法识别问题（当我加载应用程序时“App意外崩溃”消息），但是当我连接到wifi 时我尝试了应用程序它就像一个魅力。如果我有数据连接，则会发生意外崩溃。
我已经完成了基本的Android培训（http://developer.android.com/training/location/index.html），我的桌面是没有wifi的地方，所以我只能访问数据连接。我知道我必须在try-catch块中检查互联网连接，但如果我连接到网络仍然不能正常工作？
如果需要，我可以发布我的源代码，但我相信这是我的一个基本的误解，而不是代码错误。所以，如果有人能够对这种情况有所了解，我会非常欢迎它。
MainActivity.java
package com.taveras.androidmapsv2;
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.maps.GoogleMap;
import com.google.android.gms.maps.MapFragment;
import com.google.android.gms.maps.model.LatLng;
import com.google.android.gms.maps.model.MarkerOptions;
import android.app.Activity;
import android.app.Dialog;
import android.app.DialogFragment;
import android.content.IntentSender;
import android.location.Location;
import android.os.Bundle;
import android.util.Log;
import android.widget.Toast;
public class MainActivity extends Activity implements
GooglePlayServicesClient.ConnectionCallbacks,
GooglePlayServicesClient.OnConnectionFailedListener{
private final static int CONNECTION_FAILURE_RESOLUTION_REQUEST = 9000;
private static final int GPS_ERRORDIALOG_REQUEST = 9001;
private GoogleMap mMap;
private LocationClient mLocationClient;
private Location mCurrentLocation;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
if (servicesOK()) {
Toast.makeText(this, "Ready to map!!", Toast.LENGTH_LONG).show();
setContentView(R.layout.activity_main);
setUpMapIfNeeded();
mLocationClient = new LocationClient(this, this, this);
} else {
Toast.makeText(this, "An error has occurred", Toast.LENGTH_LONG).show();
}
}
private void setUpMapIfNeeded() {
// Do a null check to confirm that we have not already instantiated the map.
if (mMap == null) {
mMap = ((MapFragment) getFragmentManager().findFragmentById(R.id.map))
.getMap();
// Check if we were successful in obtaining the map.
if (mMap != null) {
// The Map is verified. It is now safe to manipulate the map.
}
}
}
@Override
public void onConnectionFailed(ConnectionResult connectionResult) {
// TODO Auto-generated method stub
/*
* 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.
*/
//showErrorDialog(connectionResult.getErrorCode());
}
}
@Override
public void onConnected(Bundle arg0) {
// TODO Auto-generated method stub
Double lat = 0.0;
Double lon = 0.0;
Toast.makeText(this, "Connected", Toast.LENGTH_SHORT).show();
mCurrentLocation = mLocationClient.getLastLocation();
//lat = mCurrentLocation.getLatitude();
//lon = mCurrentLocation.getLongitude();
mMap.addMarker(new MarkerOptions()
.position(new LatLng(lat, lon))
.title("IM HERE"));
}
@Override
public void onDisconnected() {
// TODO Auto-generated method stub
Toast.makeText(this, "Disconnected. Please re-connect.",Toast.LENGTH_SHORT).show();
}
private void servicesConnected() {
int errorCode = GooglePlayServicesUtil.isGooglePlayServicesAvailable(this);
if (errorCode != ConnectionResult.SUCCESS) {
GooglePlayServicesUtil.getErrorDialog(errorCode, this, 0).show();
}
}
/*
* Called when the Activity becomes visible.
*/
protected void onStart() {
super.onStart();
// Connect the client.
mLocationClient.connect();
//
}
protected void onStop() {
// Disconnecting the client invalidates it.
mLocationClient.disconnect();
super.onStop();
}
public boolean servicesOK() {
int isAvailable = GooglePlayServicesUtil
.isGooglePlayServicesAvailable(this);
if (isAvailable == ConnectionResult.SUCCESS) {
return true;
} else if (GooglePlayServicesUtil.isUserRecoverableError(isAvailable)) {
Dialog dialog = GooglePlayServicesUtil.getErrorDialog(isAvailable,
this, GPS_ERRORDIALOG_REQUEST);
dialog.show();
} else {
Toast.makeText(this, "Cant connect!!", Toast.LENGTH_SHORT).show();
}
return false;
}
}
manifest.xml：我知道这很懒，但我添加了所有权限，只是为了检查是否是问题
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.taveras.androidmapsv2"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk
android:minSdkVersion="11"
android:targetSdkVersion="18" />
<permission
android:name="com.taveras.androidmapsv2.permission.MAPS_RECEIVE"
android:protectionLevel="signature" />
<uses-permission android:name="com.taveras.androidmapsv2.permission.MAPS_RECEIVE" />
<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" />
<uses-permission android:name="android.permission.ACCESS_LOCATION_EXTRA_COMMANDS" />
<uses-permission android:name="android.permission.ACCESS_MOCK_LOCATION" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
<uses-permission android:name="android.permission.ACCESS_WIFI_STATE" />
<uses-permission android:name="android.permission.AUTHENTICATE_ACCOUNTS" />
<uses-permission android:name="android.permission.BATTERY_STATS" />
<uses-permission android:name="android.permission.BLUETOOTH" />
<uses-permission android:name="android.permission.BLUETOOTH_ADMIN" />
<uses-permission android:name="android.permission.BROADCAST_STICKY" />
<uses-permission android:name="android.permission.CALL_PHONE"/>
<uses-permission android:name="android.permission.CAMERA"/>
<uses-permission android:name="android.permission.CHANGE_CONFIGURATION" />
<uses-permission android:name="android.permission.CHANGE_NETWORK_STATE" />
<uses-permission android:name="android.permission.CHANGE_WIFI_MULTICAST_STATE" />
<uses-permission android:name="android.permission.CHANGE_WIFI_STATE" />
<uses-permission android:name="android.permission.CLEAR_APP_CACHE" />
<uses-permission android:name="android.permission.DISABLE_KEYGUARD" />
<uses-permission android:name="android.permission.EXPAND_STATUS_BAR" />
<uses-permission android:name="android.permission.FLASHLIGHT" />
<uses-permission android:name="android.permission.GET_ACCOUNTS" />
<uses-permission android:name="android.permission.GET_PACKAGE_SIZE" />
<uses-permission android:name="android.permission.GET_TASKS" />
<uses-permission android:name="android.permission.INTERNET"/>
<uses-permission android:name="android.permission.KILL_BACKGROUND_PROCESSES" />
<uses-permission android:name="android.permission.MANAGE_ACCOUNTS" />
<uses-permission android:name="android.permission.MODIFY_AUDIO_SETTINGS" />
<uses-permission android:name="android.permission.MOUNT_FORMAT_FILESYSTEMS" />
<uses-permission android:name="android.permission.MOUNT_UNMOUNT_FILESYSTEMS" />
<uses-permission android:name="android.permission.NFC" />
<uses-permission android:name="android.permission.PROCESS_OUTGOING_CALLS" />
<uses-permission android:name="android.permission.READ_CALENDAR" />
<uses-permission android:name="android.permission.READ_CONTACTS" />
<uses-permission android:name="android.permission.READ_HISTORY_BOOKMARKS" />
<uses-permission android:name="android.permission.READ_LOGS" />
<uses-permission android:name="android.permission.READ_PHONE_STATE" />
<uses-permission android:name="android.permission.READ_SMS" />
<uses-permission android:name="android.permission.READ_SYNC_SETTINGS" />
<uses-permission android:name="android.permission.READ_SYNC_STATS" />
<uses-permission android:name="android.permission.RECEIVE_BOOT_COMPLETED" />
<uses-permission android:name="android.permission.RECEIVE_MMS" />
<uses-permission android:name="android.permission.RECEIVE_SMS" />
<uses-permission android:name="android.permission.RECEIVE_WAP_PUSH" />
<uses-permission android:name="android.permission.RECORD_AUDIO" />
<uses-permission android:name="android.permission.REORDER_TASKS" />
<uses-permission android:name="android.permission.RESTART_PACKAGES" />
<uses-permission android:name="android.permission.SEND_SMS" />
<uses-permission android:name="android.permission.SET_ALARM" />
<uses-permission android:name="android.permission.SET_ALWAYS_FINISH" />
<uses-permission android:name="android.permission.SET_ANIMATION_SCALE" />
<uses-permission android:name="android.permission.SET_DEBUG_APP" />
<uses-permission android:name="android.permission.SET_PROCESS_LIMIT" />
<uses-permission android:name="android.permission.SET_TIME_ZONE" />
<uses-permission android:name="android.permission.SET_WALLPAPER" />
<uses-permission android:name="android.permission.SET_WALLPAPER_HINTS" />
<uses-permission android:name="android.permission.SIGNAL_PERSISTENT_PROCESSES" />
<uses-permission android:name="android.permission.SUBSCRIBED_FEEDS_READ" />
<uses-permission android:name="android.permission.SUBSCRIBED_FEEDS_WRITE" />
<uses-permission android:name="android.permission.SYSTEM_ALERT_WINDOW" />
<uses-permission android:name="android.permission.USE_CREDENTIALS" />
<uses-permission android:name="android.permission.USE_SIP" />
<uses-permission android:name="android.permission.VIBRATE" />
<uses-permission android:name="android.permission.WAKE_LOCK" />
<uses-permission android:name="android.permission.WRITE_CALENDAR" />
<uses-permission android:name="android.permission.WRITE_CONTACTS" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.WRITE_HISTORY_BOOKMARKS" />
<uses-permission android:name="android.permission.WRITE_SETTINGS" />
<uses-permission android:name="android.permission.WRITE_SMS" />
<uses-permission android:name="android.permission.WRITE_SYNC_SETTINGS" />
<uses-permission android:name="android.permission.BIND_ACCESSIBILITY_SERVICE"/>
<uses-permission android:name="android.permission.PERSISTENT_ACTIVITY"/>
<uses-permission android:name="android.permission.READ_CALL_LOG"/>
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"/>
<uses-permission android:name="com.android.browser.permission.READ_HISTORY_BOOKMARKS"/>
<uses-permission android:name="android.permission.READ_PROFILE"/>
<uses-permission android:name="android.permission.READ_SOCIAL_STREAM"/>
<uses-permission android:name="android.permission.READ_USER_DICTIONARY"/>
<uses-permission android:name="com.android.alarm.permission.SET_ALARM"/>
<uses-permission android:name="android.permission.WRITE_CALL_LOG"/>
<uses-permission android:name="com.android.browser.permission.WRITE_HISTORY_BOOKMARKS"/>
<uses-permission android:name="android.permission.WRITE_PROFILE"/>
<uses-permission android:name="android.permission.WRITE_SOCIAL_STREAM"/>
<uses-permission android:name="android.permission.WRITE_USER_DICTIONARY"/>
<uses-feature
android:glEsVersion="0x00020000"
android:required="true" />
<application
android:allowBackup="true"
android:icon="@drawable/ic_launcher"
android:label="@string/app_name"
android:theme="@style/AppTheme" >
<activity
android:name="com.taveras.androidmapsv2.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>
<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="AIzaSyDLKtTtTDxULNBvNLtGPvkEf6NNacs-42A" />
</application>
</manifest>
第二次更新 我试着在模拟器上运行并且出现了同样的“应用程序意外崩溃”。这是logcat红色消息
01-08 20:56:15.670: E/AndroidRuntime(1051): FATAL EXCEPTION: main
01-08 20:56:15.670: E/AndroidRuntime(1051): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.taveras.androidmapsv2/com.taveras.androidmapsv2.MainActivity}: java.lang.NullPointerException
01-08 20:56:15.670: E/AndroidRuntime(1051): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2180)
01-08 20:56:15.670: E/AndroidRuntime(1051): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230)
01-08 20:56:15.670: E/AndroidRuntime(1051): at android.app.ActivityThread.access$600(ActivityThread.java:141)
01-08 20:56:15.670: E/AndroidRuntime(1051): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1234)
01-08 20:56:15.670: E/AndroidRuntime(1051): at android.os.Handler.dispatchMessage(Handler.java:99)
01-08 20:56:15.670: E/AndroidRuntime(1051): at android.os.Looper.loop(Looper.java:137)
01-08 20:56:15.670: E/AndroidRuntime(1051): at android.app.ActivityThread.main(ActivityThread.java:5041)
01-08 20:56:15.670: E/AndroidRuntime(1051): at java.lang.reflect.Method.invokeNative(Native Method)
01-08 20:56:15.670: E/AndroidRuntime(1051): at java.lang.reflect.Method.invoke(Method.java:511)
01-08 20:56:15.670: E/AndroidRuntime(1051): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
01-08 20:56:15.670: E/AndroidRuntime(1051): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
01-08 20:56:15.670: E/AndroidRuntime(1051): at dalvik.system.NativeStart.main(Native Method)
01-08 20:56:15.670: E/AndroidRuntime(1051): Caused by: java.lang.NullPointerException
01-08 20:56:15.670: E/AndroidRuntime(1051): at com.taveras.androidmapsv2.MainActivity.onStart(MainActivity.java:119)
01-08 20:56:15.670: E/AndroidRuntime(1051): at android.app.Instrumentation.callActivityOnStart(Instrumentation.java:1164)
01-08 20:56:15.670: E/AndroidRuntime(1051): at android.app.Activity.performStart(Activity.java:5114)
01-08 20:56:15.670: E/AndroidRuntime(1051): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2153)
01-08 20:56:15.670: E/AndroidRuntime(1051): ... 11 more