BottomSheetDialog get Behavour始终返回null [英] BottomSheetDialog get Behavour always returns null

问题描述

我正在与 BottomSheetDialog 一起工作，而且我必须获取Behavior，因此可以设置 setBottomSheetCallback()来处理一些事情.

I working with BottomSheetDialog and i have to get Behavior so can set setBottomSheetCallback() to handle some stuff.

如谷歌所说将Coordinator放在parentView上并为其添加行为.我在MainActivity(根活动)中定义了CoordinatorLayout，如下所示:

As google says i had to put Coordinator on parentView and add behavior to it. I defined CoordinatorLayout in MainActivity (root activity) like this:

<android.support.design.widget.CoordinatorLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:tag="coordinatorLayout"
    app:layout_behavior="android.support.design.widget.BottomSheetBehavior"

...

这是尝试从活动中获得的东西:

This is try to get from activity:

 public void setupDialog(final Dialog dialog, int style) {

 CoordinatorLayout coordinatorLayout = getActivity().getWindow().getDecorView();
 BottomSheetBehavior behavior = BottomSheetBehavior.from(coordinatorLayout);

我也尝试过:

CoordinatorLayout coordinatorLayout = getActivity().getWindow().getDecorView().findViewById(R.id.coordinatorLayout); 
//this is point to the coordinatorView 

BottomSheetBehavior behavior = BottomSheetBehavior.from(coordinatorLayout);
//But this returns same error that "The view is not a child of CoordinatorLayout"

如您所见，我通过了coordinator-layout，但是方法无法在其中找到行为. 我还应该提到使用 BottonSheetDialog 的要点:

As you see i passed the coordinator-layout but method can not find behavior in it. I also should mention to points in using BottonSheetDialog:

1. 我这样显示我的BottonSheetFragments:
2. 我在OnCreateView(不是在setupDialog()中)对 BottomSheetDialog 进行了夸大，以便能够在其中添加View Pager.如您所知，如果您在 onSetupDialog()中对视图进行充气，则ViewPager不会附加到BottonSheetDialog.

1. I show my BottonSheetFragments like this:
2. I inflated my BottomSheetDialog in OnCreateView (not in setupDialog()) for ability of adding View Pager inside. As you may know ViewPager wont attach to BottonSheetDialog if you inflate view in onSetupDialog().

无论如何，我都无法获得父级CoordinatorLayout的行为. 在我的bottonSheetDialog中，我尝试了这些方法，但都无法使用，并且出现视图不是CoordinatorLayout的子视图" 错误.

Any way i could not get behavior of CoordinatorLayout of parent. In my bottonSheetDialog i try these methods and non of them works and i get "The view is not a child of CoordinatorLayout" error.

点1 的代码:

MyFragment myFragment= MyFragment.getInstance(bundle);
myFragment.show(fragment.getChildFragmentManager(),"tag");

第2点的代码:

@Override
public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container,@Nullable Bundle savedInstanceState) {
rootView = inflater.inflate(R.layout.fragment_bottomsheet, null, false);  
return rootView;
}

推荐答案

BottomSheetDialog是一个非常奇特的Dialog实现.它不会添加到，也不会依赖Activity布局中的CoordinatorLayout ^* .它在内部设置自己的CoordinatorLayout，并在其中设置带有BottomSheetBehavior的FrameLayout，将View放入其中. BottomSheetDialog本身充满了整个屏幕，并具有透明的背景，因此它可以处理底部工作表的交互以及任何外部接触.

BottomSheetDialog is a rather peculiar Dialog implementation. It is not added to, nor does it rely on^*, a CoordinatorLayout in your Activity's layout. It sets up its own CoordinatorLayout internally, and within that, a FrameLayout with BottomSheetBehavior, into which your View is placed. The BottomSheetDialog itself fills the whole screen, and has a transparent background, so that it can handle the bottom sheet interaction, and any outside touches.

如果需要访问该底页及其BottomSheetBehavior，则需要从Dialog的View层次结构中获取它.这就像在Dialog上调用findViewById(R.id.design_bottom_sheet)一样简单，但是我们需要等到显示Dialog来修改BottomSheetBehavior.此外，由于BottomSheetDialog设置了自己的BottomSheetCallback，因此我们必须确保适当替换它.也就是说，当Dialog达到关闭状态时，我们必须注意取消它.例如:

If you need access to that bottom sheet and its BottomSheetBehavior, we'll need to get it from the Dialog's View hierarchy. That's as simple as calling findViewById(R.id.design_bottom_sheet) on the Dialog, but we'll need to wait until the Dialog is shown to modify the BottomSheetBehavior. Furthermore, since BottomSheetDialog sets its own BottomSheetCallback, we must ensure that we replace it appropriately. That is, we must take care of cancelling the Dialog when it hits the closed state. For example:

final BottomSheetDialog bsd = new BottomSheetDialog(MainActivity.this);
bsd.setContentView(R.layout.your_dialog_layout);
bsd.show();

FrameLayout bottomSheet = (FrameLayout) bsd.findViewById(R.id.design_bottom_sheet);
BottomSheetBehavior behavior = BottomSheetBehavior.from(bottomSheet);
behavior.setBottomSheetCallback(new BottomSheetBehavior.BottomSheetCallback() {
        @Override
        public void onStateChanged(View bottomSheet, int newState) {
            // This is the crucial bit.
            if (newState == BottomSheetBehavior.STATE_HIDDEN) {
                bsd.cancel();
            }
        }

        @Override
        public void onSlide(View bottomSheet, float slideOffset) {}
    }
);

如果您使用的是BottomSheetDialogFragment，则Dialog会显示在DialogFragment的onStart()中，并且在super调用之后，我们可以覆盖该方法以在此处进行修改.例如:

If you're using a BottomSheetDialogFragment, the Dialog is shown in DialogFragment's onStart(), and we can override that method to do our modifications there, after the super call. For example:

public class MyFragment extends BottomSheetDialogFragment {
    public MyFragment() {}

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        return inflater.inflate(R.layout.your_dialog_layout, container, false);
    }

    @Override
    public void onStart() {
        super.onStart();

        FrameLayout bottomSheet = getDialog().findViewById(R.id.design_bottom_sheet);
        BottomSheetBehavior behavior = BottomSheetBehavior.from(bottomSheet);
        behavior.setBottomSheetCallback(new BottomSheetBehavior.BottomSheetCallback() {
                @Override
                public void onStateChanged(View bottomSheet, int newState) {
                    // This is the crucial bit.
                    if (newState == BottomSheetBehavior.STATE_HIDDEN) {
                        getDialog().cancel();
                    }
                }

                @Override
                public void onSlide(View bottomSheet, float slideOffset) {}
            }
        );
    }
}

无论哪种情况，只要在newState == BottomSheetBehavior.STATE_HIDDEN中onStateChanged()中的cancel() Dialog，只要cancel()中的cancel().

In either case, you can do pretty much whatever you want in the BottomSheetCallback, as long as you cancel() the Dialog in onStateChanged() when newState == BottomSheetBehavior.STATE_HIDDEN.

^{**顺便说一句，这意味着您不必在Activity'布局中使用CoordinatorLayout即可使用BottomSheetDialog或BottomSheetDialogFragment，尽管我不确定在任何地方都清楚在文档或其他开发人员资源中.}

^{*Incidentally, this means that you do not have to have a CoordinatorLayout in your Activity'a layout to use BottomSheetDialog or BottomSheetDialogFragment, though I'm not sure that's made clear anywhere in the documentation or other developer resources.}

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