我正在尝试将GPS坐标发送到android中的服务器，但是我的应用程序在我运行它时就崩溃了，我是android的新手，所以我没有得到如何解决这个问题
这是我的logcat文件
01-23 14:03:40.220: E/AndroidRuntime(880): FATAL EXCEPTION: main
01-23 14:03:40.220: E/AndroidRuntime(880): Process: com.example.server2, PID: 880
01-23 14:03:40.220: E/AndroidRuntime(880): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.server2/com.example.server2.MainActivity}: java.lang.IllegalArgumentException: invalid provider: null
01-23 14:03:40.220: E/AndroidRuntime(880): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2195)
01-23 14:03:40.220: E/AndroidRuntime(880):at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2245)
01-23 14:03:40.220: E/AndroidRuntime(880): at android.app.ActivityThread.access$800(ActivityThread.java:135)
01-23 14:03:40.220: E/AndroidRuntime(880): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1196)
01-23 14:03:40.220: E/AndroidRuntime(880): at android.os.Handler.dispatchMessage(Handler.java:102)
01-23 14:03:40.220: E/AndroidRuntime(880): at android.os.Looper.loop(Looper.java:136)
01-23 14:03:40.220: E/AndroidRuntime(880): at android.app.ActivityThread.main(ActivityThread.java:5017)
01-23 14:03:40.220: E/AndroidRuntime(880): at java.lang.reflect.Method.invokeNative(Native Method)
01-23 14:03:40.220: E/AndroidRuntime(880): at java.lang.reflect.Method.invoke(Method.java:515)
01-23 14:03:40.220: E/AndroidRuntime(880): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779)
01-23 14:03:40.220: E/AndroidRuntime(880): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)
01-23 14:03:40.220: E/AndroidRuntime(880): at dalvik.system.NativeStart.main(Native Method)
01-23 14:03:40.220: E/AndroidRuntime(880): Caused by: java.lang.IllegalArgumentException: invalid provider: null
01-23 14:03:40.220: E/AndroidRuntime(880): at android.location.LocationManager.checkProvider(LocationManager.java:1623)
01-23 14:03:40.220: E/AndroidRuntime(880): at android.location.LocationManager.getLastKnownLocation(LocationManager.java:1167)
01-23 14:03:40.220: E/AndroidRuntime(880): at com.example.server2.MainActivity.onCreate(MainActivity.java:71)
01-23 14:03:40.220: E/AndroidRuntime(880): at android.app.Activity.performCreate(Activity.java:5231)
01-23 14:03:40.220: E/AndroidRuntime(880): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
01-23 14:03:40.220: E/AndroidRuntime(880): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2159)
这是我的MainActivity.java：
public class MainActivity extends Activity implements LocationListener {
private TextView latituteField;
private TextView longitudeField;
private LocationManager locationManager;
private String provider;
String lat,lng;
EditText etResponse;
TextView tvIsConnected;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
// get reference to the views
etResponse = (EditText) findViewById(R.id.etResponse);
tvIsConnected = (TextView) findViewById(R.id.tvIsConnected);
// check if you are connected or not
if(isConnected()){
tvIsConnected.setBackgroundColor(0xFF00CC00);
tvIsConnected.setText("You are conncted");
}
else{
tvIsConnected.setText("You are NOT conncted");
}
latituteField = (TextView) findViewById(R.id.TextView02);
longitudeField = (TextView) findViewById(R.id.TextView04);
// Get the location manager
locationManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
// Define the criteria how to select the locatioin provider -> use
// default
Criteria criteria = new Criteria();
provider = locationManager.getBestProvider(criteria, false);
Location location = locationManager.getLastKnownLocation(provider);
// Initialize the location fields
if (location != null) {
System.out.println("Provider " + provider + " has been selected.");
onLocationChanged(location);
} else {
latituteField.setText("Location not available");
longitudeField.setText("Location not available");
}
// call AsynTask to perform network operation on separate thread
new HttpAsyncTask().execute("http://182.18.144.140:80");
}
public static String GET(String url){
InputStream inputStream = null;
String result = "";
try {
// create HttpClient
HttpClient httpclient = new DefaultHttpClient();
// make GET request to the given URL
HttpResponse httpResponse = httpclient.execute(new HttpGet(url));
// receive response as inputStream
inputStream = httpResponse.getEntity().getContent();
// convert inputstream to string
if(inputStream != null)
result = convertInputStreamToString(inputStream);
else
result = "Did not work!";
} catch (Exception e) {
Log.d("InputStream", e.getLocalizedMessage());
}
return result;
}
private static String convertInputStreamToString(InputStream inputStream) throws IOException{
BufferedReader bufferedReader = new BufferedReader( new InputStreamReader(inputStream));
String line = "";
String result = "";
while((line = bufferedReader.readLine()) != null)
result += line;
inputStream.close();
return result;
}
public boolean isConnected(){
ConnectivityManager connMgr = (ConnectivityManager) getSystemService(this.CONNECTIVITY_SERVICE);
NetworkInfo networkInfo = connMgr.getActiveNetworkInfo();
if (networkInfo != null && networkInfo.isConnected())
return true;
else
return false;
}
@Override
public void onLocationChanged(Location location) {
lat = Double.toString(location.getLatitude());
lng = Double.toString (location.getLongitude());
latituteField.setText(String.valueOf(lat));
longitudeField.setText(String.valueOf(lng));
// TODO Auto-generated method stub
}
@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
}
private class HttpAsyncTask extends AsyncTask<String, Void, String> {
@Override
protected String doInBackground(String... urls) {
HttpClient httpclient = new DefaultHttpClient();
HttpPost httppost = new HttpPost("http://182.18.144.140:80");
try {
// Add your data
List<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>(1);
// nameValuePairs.add(new BasicNameValuePair("android", editText1.getText().toString()));
nameValuePairs.add(new BasicNameValuePair("LAT", lat));
nameValuePairs.add(new BasicNameValuePair("LON", lng));
httppost.setEntity(new UrlEncodedFormEntity(nameValuePairs));
try {
httpclient.execute(httppost);
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
}
} catch (IOException e) {
// TODO Auto-generated catch block
Log.i("HTTP Failed", e.toString());
}
return null;
}
// onPostExecute displays the results of the AsyncTask.
@Override
protected void onPostExecute(String result) {
Toast.makeText(getBaseContext(), "Received!", Toast.LENGTH_LONG).show();
etResponse.setText(result);
}
}
}
我的manifest.xml就像这样
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.server2"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk
android:minSdkVersion="8"
android:targetSdkVersion="18" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
<uses-permission android:name="android.permission.INTERNET" />
<application
android:allowBackup="true"
android:icon="@drawable/ic_launcher"
android:label="@string/app_name"
android:theme="@style/AppTheme" >
<activity
android:name="com.example.server2.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>
答案 0 :(得分：2)
provider是null。你在这里声明
private String provider;
但你永远不会正确地初始化它。
此行返回null
provider = locationManager.getBestProvider(criteria, false);
导致此行的初始异常
Location location = locationManager.getLastKnownLocation(provider);
你可以通过回溯堆栈跟踪来看到它。
调试并查看提供者为null的原因。
答案 1 :(得分：0)
我可以在这里看到一些可能有问题的事情：
provider = locationManager.getBestProvider(criteria, false);
Location location = locationManager.getLastKnownLocation(provider);
提供程序此时为空，您还需要设置权限以获得精细或粗略的用户位置。