Question

问题：应用程序是从设备中获取经度和纬度的读数。执行此功能的活动第一次运行良好...但是当第二次进入活动时应用程序崩溃，给出以下NullPointerException：

08-25 19:53:36.517: E/AndroidRuntime(26672): FATAL EXCEPTION: main
08-25 19:53:36.517: E/AndroidRuntime(26672): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.vaw.selfhelp/com.vaw.selfhelp.SmsActivity}: java.lang.NullPointerException
08-25 19:53:36.517: E/AndroidRuntime(26672):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1651)
08-25 19:53:36.517: E/AndroidRuntime(26672):    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1667)
08-25 19:53:36.517: E/AndroidRuntime(26672):    at android.app.ActivityThread.access$1500(ActivityThread.java:117)
08-25 19:53:36.517: E/AndroidRuntime(26672):    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:935)
08-25 19:53:36.517: E/AndroidRuntime(26672):    at android.os.Handler.dispatchMessage(Handler.java:99)
08-25 19:53:36.517: E/AndroidRuntime(26672):    at android.os.Looper.loop(Looper.java:130)
08-25 19:53:36.517: E/AndroidRuntime(26672):    at android.app.ActivityThread.main(ActivityThread.java:3687)
08-25 19:53:36.517: E/AndroidRuntime(26672):    at java.lang.reflect.Method.invokeNative(Native Method)
08-25 19:53:36.517: E/AndroidRuntime(26672):    at java.lang.reflect.Method.invoke(Method.java:507)
08-25 19:53:36.517: E/AndroidRuntime(26672):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:867)
08-25 19:53:36.517: E/AndroidRuntime(26672):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:625)
08-25 19:53:36.517: E/AndroidRuntime(26672):    at dalvik.system.NativeStart.main(Native Method)
08-25 19:53:36.517: E/AndroidRuntime(26672): Caused by: java.lang.NullPointerException
08-25 19:53:36.517: E/AndroidRuntime(26672):    at com.vaw.selfhelp.SmsActivity.onCreate(SmsActivity.java:85)
08-25 19:53:36.517: E/AndroidRuntime(26672):    at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
08-25 19:53:36.517: E/AndroidRuntime(26672):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1615)
08-25 19:53:36.517: E/AndroidRuntime(26672):    ... 11 more

代码：

lm = (LocationManager)getSystemService(Context.LOCATION_SERVICE);
        location = lm.getLastKnownLocation(LocationManager.GPS_PROVIDER);
        locationListener = new LocationListener() {

            @Override
            public void onLocationChanged(Location location) {
                // TODO Auto-generated method stub
                latitude = location.getLatitude();
                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

            }
        };

        lm.requestLocationUpdates(LocationManager.GPS_PROVIDER, 2000, 10, locationListener);

        longitude = location.getLongitude(); //this is line 85 which the logcat is referring to
        latitude = location.getLatitude();

有人可以帮忙！

Answer 1

代码可能正常工作，因为你说它只会在第二次返回活动时崩溃。您应该在活动onResume（）回调期间重新分配位置对象。

NullPointerException经度和纬度上的位置

1 个答案: