我越來越想在Eclipse中運行應用程序的餐廳時,下面的錯誤運行餐廳應用程序的模擬器時獲得空指針異常:在com.myrestaurant.app在Eclipse
顯示java.lang.NullPointerException .ui.MainMenuForm.lambda $ 0(MainMenuForm.java:73) at com.codename1.ui.util.EventDispatcher.fireSelectionSync(EventDispatcher.java:321) at com.codename1.ui.util.EventDispatcher.fireSelectionEvent(EventDispatcher。 java:402) at com.codename1.ui.list.DefaultListModel.setSelectedIndex(DefaultListModel.java:181) at com.codename1.ui.List.initComponentImpl(List.java:329) at com.co dename1.ui.Container.initComponentImpl(Container.java:979) at com.codename1.ui.Container.insertComponentAtImpl(Container.java:715) at com.codename1.ui.Container.insertComponentAt(Container.java:687) at com.codename1.ui.Container.addComponent(Container.java:641) at com.codename1.ui.Form.addComponent(Form.java:1207) at com.codename1.ui.Container.add(Container。 java:281) at com.myrestaurant.app.ui.BaseForm.init(BaseForm.java:102) at com.myrestaurant.app.ui.BaseForm。(BaseForm.java:34) at com.myrestaurant.app .ui.MainMenuForm。(MainMenuForm.java:43) at com.myrestaurant.app.ui.BaseForm.showMainMenuForm(BaseForm.java:156) at com.myrestaurant.app.MyRestaurant.start(MyResta urant.java:48) 在sun.reflect.NativeMethodAccessorImpl.invoke0(本機方法) 在sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) 在sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43 ) at com.lang.reflect.Method.invoke(Method.java:498) at com.codename1.impl.javase.Executor $ 1 $ 1.run(Executor.java:123) at com.codename1.ui.Display .processSerialCalls(Display.java:1154) at com.codename1.ui.Display.mainEDTLoop(Display.java:971) at com.codename1.ui.RunnableWrapper.run(RunnableWrapper.java:120) at com.codename1 .impl.CodenameOneThread.run(CodenameOneThread.java:176)
請幫忙嗎?
的方法如下:
@Override
protected List<String> createCategoryList() {
if(Restaurant.getInstance().
menu.get().
categories.size() == 0) {
categoryModel = new DefaultListModel<>("Loading...");
} else {
categoryModel = new DefaultListModel<>(
Restaurant.getInstance().
menu.get().
categories.asList());
}
List<String> l = new List<String>(categoryModel) {
@Override
protected boolean shouldRenderSelection() {
return true;
}
};
((DefaultListCellRenderer<String>)l.getRenderer()).setAlwaysRenderSelection(true);
l.setIgnoreFocusComponentWhenUnfocused(false);
l.setOrientation(List.HORIZONTAL);
l.setFixedSelection(List.FIXED_CENTER);
l.addSelectionListener((i, ii) -> {
if(currentCategory != l.getSelectedItem()) {
currentCategory = l.getSelectedItem();
for(Component c : dishesContainer) {
Dish d = (Dish)c.getClientProperty("dish");
***boolean hidden = d.category.get().equals(currentCategory);***
c.setHidden(hidden);
c.setVisible(!hidden);
}
dishesContainer.animateLayout(150);
}
});
return l;
}
這是MainMenuForm.java:73處的NullPointerException。我們沒有該應用程序,所以我們無法幫助您。提供有問題的代碼。 –
抱歉忘了添加代碼。我添加了該方法。謝謝 –