Android - 无法在Fragment中使用弹出窗口

Question

我是android的新手.现在我正在尝试创建一个滑块.现在我创建了一个滑块.现在我想在单击操作栏中的图标时显示弹出窗口.当我扩展活动时,弹出窗口工作正常.但是当我更改为范围片段时,我无法使用弹出窗口.请在Fragment页面中告诉我任何想法或弹出窗口的任何示例.

public void popup_window() {
    View menuItemView = findViewById(R.id.menu_popup);
    PopupMenu popupMenu = new PopupMenu(this, menuItemView);
    popupMenu.getMenuInflater().inflate(R.menu.list_, popupMenu.getMenu());

    popupMenu.setOnMenuItemClickListener(new PopupMenu.OnMenuItemClickListener() {
        public boolean onMenuItemClick(MenuItem item) {
            switch (item.getItemId()) {  
                case R.id.action_ticket:  
                    Intent intdn = new Intent(List_Activity.this,List_Activity.class);
                    intdn.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP | Intent.FLAG_ACTIVITY_CLEAR_TASK);                   
                    startActivity(intdn);
                  break;    

                case R.id.action_survey:  
                    Toast.makeText(getApplicationContext(),"Under Construction ",Toast.LENGTH_LONG).show();  
                    break;      
                case R.id.action_service_request:  
                    Toast.makeText(getApplicationContext(),"Under Construction ",Toast.LENGTH_LONG).show();  
                    break;  

                  default: 
                      break;  

            }  
             return true;
        }
    });
    popupMenu.show();
}

我收到错误: -

很多错误.请帮我解决这个问题.提前致谢.

LogCat错误消息: -

    FATAL EXCEPTION: main
java.lang.IllegalStateException: MenuPopupHelper cannot be used without an anchor
at com.android.internal.view.menu.MenuPopupHelper.show(MenuPopupHelper.java:101)
at android.widget.PopupMenu.show(PopupMenu.java:108)
at com.example.sample.Testing_Fragment1.popup_window(Testing_Fragment1.java:262)
at com.example.sample.Testing_Fragment1.onOptionsItemSelected(Testing_Fragment1.java:227)
at android.app.Fragment.performOptionsItemSelected(Fragment.java:1801)
at android.app.FragmentManagerImpl.dispatchOptionsItemSelected(FragmentManager.java:1959)
at android.app.Activity.onMenuItemSelected(Activity.java:2551)
at com.android.internal.policy.impl.PhoneWindow.onMenuItemSelected(PhoneWindow.java:980)
at com.android.internal.view.menu.MenuBuilder.dispatchMenuItemSelected(MenuBuilder.java:735)
at com.android.internal.view.menu.MenuItemImpl.invoke(MenuItemImpl.java:149)
at com.android.internal.view.menu.MenuBuilder.performItemAction(MenuBuilder.java:874)
at com.android.internal.view.menu.ActionMenuView.invokeItem(ActionMenuView.java:547)
at com.android.internal.view.menu.ActionMenuItemView.onClick(ActionMenuItemView.java:115)
at android.view.View.performClick(View.java:4204)
at android.view.View$PerformClick.run(View.java:17355)
at android.os.Handler.handleCallback(Handler.java:725)
at android.os.Handler.dispatchMessage(Handler.java:92)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:5041)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:511)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
at dalvik.system.NativeStart.main(Native Method)

Answer 1

当我扩展活动时,弹出窗口工作正常.但是当我更改为范围片段时,我无法使用弹出窗口.

您可以findViewById()直接调用Activity,但是当您使用a时Fragment,youo将需要一个视图对象来调用findViewById().例如..getView()findViewById();

1. 查看 - findViewById()

2. 活动 - findViewById()

   getView() - 这将返回片段的根视图,您可以调用它findViewById()

新的PopupMenu(this,menuItemView);

这里弹出菜单需要Context,作为第一个参数传递.你可以使用,this如果你在活动,但在Fragment中你需要使用getActivity()而不是this

PopupMenu(上下文上下文,查看锚点)

new Intent(List_Activity.this,List_Activity.class);

这是错误的,实际上它应该是包上下文和类

packageContext ---实现此类的应用程序包的上下文.

class ---用于intent的组件类.

使用getActivity().getApplicationContext()而不是仅仅getApplicationContext()只要你想显示Toast从Fragment

所以你的代码看起来像

public void popup_window() {

View menuItemView = getView().findViewById(R.id.menu_popup);
PopupMenu popupMenu = new PopupMenu(getActivity(), menuItemView);
popupMenu.getMenuInflater().inflate(R.menu.list_, popupMenu.getMenu());

popupMenu.setOnMenuItemClickListener(new PopupMenu.OnMenuItemClickListener() {
    public boolean onMenuItemClick(MenuItem item) {
        switch (item.getItemId()) {  
            case R.id.action_ticket:  
                Intent intdn = new Intent(getActivity(),List_Activity.class); // Your nxt activity name instead of List_Activity
                intdn.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP | Intent.FLAG_ACTIVITY_CLEAR_TASK);                   
                getActivity().startActivity(intdn);
              break;    

            case R.id.action_survey:  
                Toast.makeText(getActivity().getApplicationContext(),"Under Construction ",Toast.LENGTH_LONG).show();  
                break;      
            case R.id.action_service_request:  
                Toast.makeText(getActivity().getApplicationContext(),"Under Construction ",Toast.LENGTH_LONG).show();  
                break;  

              default: 
                  break;  

        }  
         return true;
    }
});
popupMenu.show();
}

更新:

java.lang.IllegalStateException:没有锚点,不能使用MenuPopupHelper

你得到这个异常,因为我猜这个弹出窗口的Anchor视图是null.因此,每当系统尝试显示弹出窗口时,它都会为您提供此异常.

只是检查tryShow()中 MenuPopupHelper

另请参阅Maxim Zaslavsky关于SO的这篇文章