Question

在android studio中运行我的程序时遇到错误。这是以下消息错误：

public class ParentModel
{
    public string EnvironmentName { get; set; }
}

MainActivity.java的第103行如下：

[HttpPost]
    public ActionResult ParentClass(string submit, ParentModel model)
    {
        //omit
        var envName = model.EnvironmentName;
        //I am not seeing a value for model.EnvironmentName at this point
    }

这是AndroidManifest.xml中的权限代码：

10-22 19:13:54.831 3478-3478/com.example.natasya.myapplication E/AndroidRuntime: FATAL EXCEPTION: main
10-22 19:13:54.831 3478-3478/com.example.natasya.myapplication E/AndroidRuntime: Process: com.example.natasya.myapplication, PID: 3478
10-22 19:13:54.831 3478-3478/com.example.natasya.myapplication E/AndroidRuntime: java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.natasya.myapplication/com.example.natasya.myapplication.MainActivity}: java.lang.IllegalArgumentException: invalid provider: null
10-22 19:13:54.831 3478-3478/com.example.natasya.myapplication E/AndroidRuntime:     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2416)
10-22 19:13:54.831 3478-3478/com.example.natasya.myapplication E/AndroidRuntime:     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2476)
10-22 19:13:54.831 3478-3478/com.example.natasya.myapplication E/AndroidRuntime:     at android.app.ActivityThread.-wrap11(ActivityThread.java)
10-22 19:13:54.831 3478-3478/com.example.natasya.myapplication E/AndroidRuntime:     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1344)
10-22 19:13:54.831 3478-3478/com.example.natasya.myapplication E/AndroidRuntime:     at android.os.Handler.dispatchMessage(Handler.java:102)
10-22 19:13:54.831 3478-3478/com.example.natasya.myapplication E/AndroidRuntime:     at android.os.Looper.loop(Looper.java:148)
10-22 19:13:54.831 3478-3478/com.example.natasya.myapplication E/AndroidRuntime:     at android.app.ActivityThread.main(ActivityThread.java:5417)
10-22 19:13:54.831 3478-3478/com.example.natasya.myapplication E/AndroidRuntime:     at java.lang.reflect.Method.invoke(Native Method)
10-22 19:13:54.831 3478-3478/com.example.natasya.myapplication E/AndroidRuntime:     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
10-22 19:13:54.831 3478-3478/com.example.natasya.myapplication E/AndroidRuntime:     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
10-22 19:13:54.831 3478-3478/com.example.natasya.myapplication E/AndroidRuntime:  Caused by: java.lang.IllegalArgumentException: invalid provider: null
10-22 19:13:54.831 3478-3478/com.example.natasya.myapplication E/AndroidRuntime:     at android.location.LocationManager.checkProvider(LocationManager.java:1704)
10-22 19:13:54.831 3478-3478/com.example.natasya.myapplication E/AndroidRuntime:     at android.location.LocationManager.getLastKnownLocation(LocationManager.java:1194)
10-22 19:13:54.831 3478-3478/com.example.natasya.myapplication E/AndroidRuntime:     at com.example.natasya.myapplication.MainActivity.getlongilatifile(MainActivity.java:103)
10-22 19:13:54.831 3478-3478/com.example.natasya.myapplication E/AndroidRuntime:     at com.example.natasya.myapplication.MainActivity.onCreate(MainActivity.java:76)
10-22 19:13:54.831 3478-3478/com.example.natasya.myapplication E/AndroidRuntime:     at android.app.Activity.performCreate(Activity.java:6237)
10-22 19:13:54.831 3478-3478/com.example.natasya.myapplication E/AndroidRuntime:     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1107)
10-22 19:13:54.831 3478-3478/com.example.natasya.myapplication E/AndroidRuntime:     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2369)
10-22 19:13:54.831 3478-3478/com.example.natasya.myapplication E/AndroidRuntime:     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2476) 
10-22 19:13:54.831 3478-3478/com.example.natasya.myapplication E/AndroidRuntime:     at android.app.ActivityThread.-wrap11(ActivityThread.java) 
10-22 19:13:54.831 3478-3478/com.example.natasya.myapplication E/AndroidRuntime:     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1344) 
10-22 19:13:54.831 3478-3478/com.example.natasya.myapplication E/AndroidRuntime:     at android.os.Handler.dispatchMessage(Handler.java:102) 
10-22 19:13:54.831 3478-3478/com.example.natasya.myapplication E/AndroidRuntime:     at android.os.Looper.loop(Looper.java:148) 
10-22 19:13:54.831 3478-3478/com.example.natasya.myapplication E/AndroidRuntime:     at android.app.ActivityThread.main(ActivityThread.java:5417) 
10-22 19:13:54.831 3478-3478/com.example.natasya.myapplication E/AndroidRuntime:     at java.lang.reflect.Method.invoke(Native Method) 
10-22 19:13:54.831 3478-3478/com.example.natasya.myapplication E/AndroidRuntime:     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726) 
10-22 19:13:54.831 3478-3478/com.example.natasya.myapplication E/AndroidRuntime:     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)

我很困惑为什么会这样？请帮帮我。

这是MainActivity：

Location location = locationManager.getLastKnownLocation(bestProvider);

}

谢谢，阿贡

Answer 1

传递给getLastKnownLocation的提供程序应该是以下字符串常量之一：

GPS_PROVIDER，有价值＆＃34; gps＆＃34;;
NETWORK_PROVIDER，有价值＆＃34;网络＆＃34;;
PASSIVE_PROVIDER，有价值＆＃34;被动＆＃34;;

以下是source code of getLastKnownLocation：

public Location getLastKnownLocation(String provider) {
    checkProvider(provider);
    String packageName = mContext.getPackageName();
    LocationRequest request = LocationRequest.createFromDeprecatedProvider(
            provider, 0, 0, true);
    try {
        return mService.getLastLocation(request, packageName);
    } catch (RemoteException e) {
        Log.e(TAG, "RemoteException", e);
        return null;
    }
}

和方法checkProvider：

private static void checkProvider(String provider) {
    if (provider == null) {
        throw new IllegalArgumentException("invalid provider: " + provider);
    }
}

由此我们可以得出结论，你的参数bestProvider为空，而不是有效的提供者字符串。

当我在android studio中运行我的程序时，有一个错误“不幸的是，我的应用程序停止了”

1 个答案: