問題描述
我有一個在我的應用程序中實現 LocationListener 的活動，并且我的 onLocationChanged 方法直到最近一直運行良好.由于某種原因，傳遞給該方法的 Location 對象為空.我的問題是，為什么它是空的?如果無法獲取位置，是否傳入一個空對象?
I have an activity that implements LocationListener in my application and my onLocationChanged method has been working perfectly up until recently. For some reason the Location object being passed into the method is null. My question is, why is it null? Does it pass in a null object if it cannot acquire a location?
我的 GPS 已打開，我已將其設置為從 GPS 中提取位置，并且我知道我的 GPS 可以在我使用地圖時找到我并讓它定位我.
My GPS is on and I have it set to pull a location from the GPS, and I know my GPS can get a fix on me as I used Maps and had it locate me.
另外，我的應用權限設置為:
Also, I have the permission for my app set as:
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.CAMERA" />
<uses-permission android:name="android.permission.ACCESS_GPS" />
<uses-permission android:name="android.permission.ACCESS_LOCATION" />
<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
但我不認為權限是問題，因為我的活動是事先進行的，并且從那時起我沒有更改權限.
I don't believe permissions is the issue though, as my activity was working beforehand and I have not altered the permissions since then.
這里是確定位置對象提供者的代碼:
Here is the code that determines the provider of the location object:
String locationProvider = this.mLocationManager.getBestProvider(mLocationCriteria, true);
this.onLocationChanged(this.mLocationManager.getLastKnownLocation(locationProvider));
這是錯誤的 LogCat 輸出:
Here is the LogCat output of the error:
08-08 18:25:26.310: ERROR/MapActivity(6447): Couldn't get connection factory client
08-08 18:26:18.771: ERROR/AndroidRuntime(6447): Uncaught handler: thread main exiting due to uncaught exception
08-08 18:26:18.880: ERROR/AndroidRuntime(6447): java.lang.IllegalStateException: Could not execute method of the activity
08-08 18:26:18.880: ERROR/AndroidRuntime(6447): at android.view.View$1.onClick(View.java:2031)
08-08 18:26:18.880: ERROR/AndroidRuntime(6447): at android.view.View.performClick(View.java:2364)
08-08 18:26:18.880: ERROR/AndroidRuntime(6447): at android.view.View.onTouchEvent(View.java:4179)
08-08 18:26:18.880: ERROR/AndroidRuntime(6447): at android.view.View.dispatchTouchEvent(View.java:3709)
08-08 18:26:18.880: ERROR/AndroidRuntime(6447): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:884)
08-08 18:26:18.880: ERROR/AndroidRuntime(6447): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:884)
08-08 18:26:18.880: ERROR/AndroidRuntime(6447): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:884)
08-08 18:26:18.880: ERROR/AndroidRuntime(6447): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:884)
08-08 18:26:18.880: ERROR/AndroidRuntime(6447): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:884)
08-08 18:26:18.880: ERROR/AndroidRuntime(6447): at com.android.internal.policy.impl.PhoneWindow$DecorView.superDispatchTouchEvent(PhoneWindow.java:1659)
08-08 18:26:18.880: ERROR/AndroidRuntime(6447): at com.android.internal.policy.impl.PhoneWindow.superDispatchTouchEvent(PhoneWindow.java:1107)
08-08 18:26:18.880: ERROR/AndroidRuntime(6447): at android.app.Activity.dispatchTouchEvent(Activity.java:2061)
08-08 18:26:18.880: ERROR/AndroidRuntime(6447): at com.android.internal.policy.impl.PhoneWindow$DecorView.dispatchTouchEvent(PhoneWindow.java:1643)
08-08 18:26:18.880: ERROR/AndroidRuntime(6447): at android.view.ViewRoot.handleMessage(ViewRoot.java:1691)
08-08 18:26:18.880: ERROR/AndroidRuntime(6447): at android.os.Handler.dispatchMessage(Handler.java:99)
08-08 18:26:18.880: ERROR/AndroidRuntime(6447): at android.os.Looper.loop(Looper.java:123)
08-08 18:26:18.880: ERROR/AndroidRuntime(6447): at android.app.ActivityThread.main(ActivityThread.java:4363)
08-08 18:26:18.880: ERROR/AndroidRuntime(6447): at java.lang.reflect.Method.invokeNative(Native Method)
08-08 18:26:18.880: ERROR/AndroidRuntime(6447): at java.lang.reflect.Method.invoke(Method.java:521)
08-08 18:26:18.880: ERROR/AndroidRuntime(6447): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:860)
08-08 18:26:18.880: ERROR/AndroidRuntime(6447): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:618)
08-08 18:26:18.880: ERROR/AndroidRuntime(6447): at dalvik.system.NativeStart.main(Native Method)
08-08 18:26:18.880: ERROR/AndroidRuntime(6447): Caused by: java.lang.reflect.InvocationTargetException
08-08 18:26:18.880: ERROR/AndroidRuntime(6447): at com.proto.screens.MyMapActivity.onLocateUserClick(MyMapActivity.java:147)
08-08 18:26:18.880: ERROR/AndroidRuntime(6447): at java.lang.reflect.Method.invokeNative(Native Method)
08-08 18:26:18.880: ERROR/AndroidRuntime(6447): at java.lang.reflect.Method.invoke(Method.java:521)
08-08 18:26:18.880: ERROR/AndroidRuntime(6447): at android.view.View$1.onClick(View.java:2026)
08-08 18:26:18.880: ERROR/AndroidRuntime(6447): ... 21 more
08-08 18:26:18.880: ERROR/AndroidRuntime(6447): Caused by: java.lang.NullPointerException
08-08 18:26:18.880: ERROR/AndroidRuntime(6447): at com.proto.screens.MyMapActivity.onLocationChanged(MyMapActivity.java:135)
08-08 18:26:18.880: ERROR/AndroidRuntime(6447): ... 25 more
[UPDATE] 我已經在另一臺設備(確切地說是 HTC MyTouch 3G)上測試了相同的代碼，它與 GPS 完美配合，但是在我的 Motorola Droid 上它崩潰了.
[UPDATE] I have tested the same code on another device (an HTC MyTouch 3G to be precise) and it works flawlessly with the GPS, however on my Motorola Droid it crashes.
推薦答案
我已經解決了這個問題，但我不確定為什么會這樣.
I have fixed the problem, though I'm not sure why this worked.
我所做的是將我的活動設置為向最佳位置提供者(在本例中為 GPS)請求位置更新，并將其設置為在其位置精確到 50 米時觸發我的功能.我之前所做的只是嘗試檢索最后一個已知位置，但現在我將其設置為等到 GPS 可以得到修復.
What I did is I set my activity to request location updates from the best location provider (in this case the GPS) and set it to trigger my function onces it has a location accurate down to 50 meters. What I was doing before was just attempting to retrieve the last known location, but now I have it set to wait until the GPS can get a fix.
也許它沒有存儲我最后一個已知位置，因此返回 null.
Perhaps it wasn't storing my last known location and thus was returning null.
這篇關于傳遞給 onLocationChanged 的??位置對象為空?的文章就介紹到這了，希望我們推薦的答案對大家有所幫助，也希望大家多多支持html5模板網！