我正在嘗試在我的項目中使用Volley，我曾經從PHP中獲取JSON數組編碼并將其改編為.我遵循了此頁面的教程：https://www.androidhive.info/2014/07/android-custom-listview-with-image-and-text-using-volley/JsonArrayRequest()ListView我的應用程序崩潰了，下面是錯誤。2019-03-18 15:34:51.706 14999-14999/com.example.smartparkingapp E/AndroidRuntime: FATAL EXCEPTION: main Process: com.example.smartparkingapp, PID: 14999 java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.Object android.app.Activity.getSystemService(java.lang.String)' on a null object reference at com.example.smartparkingapp.adapter.CarListAdapter.getView(CarListAdapter.java:48) at android.widget.AbsListView.obtainView(AbsListView.java:3180) at android.widget.ListView.makeAndAddView(ListView.java:2197) at android.widget.ListView.fillDown(ListView.java:824) at android.widget.ListView.fillFromTop(ListView.java:885) at android.widget.ListView.layoutChildren(ListView.java:1924) at android.widget.AbsListView.onLayout(AbsListView.java:2952) at android.view.View.layout(View.java:21054) at android.view.ViewGroup.layout(ViewGroup.java:6440) at android.support.constraint.ConstraintLayout.onLayout(ConstraintLayout.java:1915) at android.view.View.layout(View.java:21054) at android.view.ViewGroup.layout(ViewGroup.java:6440) at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1791) at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1635) at android.widget.LinearLayout.onLayout(LinearLayout.java:1544) at android.view.View.layout(View.java:21054) at android.view.ViewGroup.layout(ViewGroup.java:6440) at android.widget.FrameLayout.layoutChildren(FrameLayout.java:323) at android.widget.FrameLayout.onLayout(FrameLayout.java:261)
1 回答
楊魅力
TA貢獻1811條經驗 獲得超6個贊
您正在嘗試在適配器中使用空值。將活動對象從調用活動傳遞到 CarListAdapter 構造函數中activity
類似的東西：在你的家庭碎片
carListAdapter = new CarListAdapter(this, carList, getActivity());
并在您的 CarListAdapter 中：
public class CarListAdapter extends BaseAdapter {
private Activity activity;
private Fragment fragment;
private LayoutInflater layoutInflater;
private List<Car> carItems;
public CarListAdapter(Fragment fragment, List<Car> carItems, Activity activity) {
this.fragment = fragment;
this.carItems = carItems;
this.activity = activity;
}
.....
這是根據您顯示的錯誤
添加回答
舉報
0/150
提交
取消