将BottomSheetDialogFragment的状态设置为展开 [英] Set state of BottomSheetDialogFragment to expanded

问题描述

如何设置使用 BottomSheetBehavior＃setState（STATE_EXPANDED）扩展 BottomSheetDialogFragment 的片段的状态Android支持设计库（v23.2.1）？

How do you set the state of a fragment extending BottomSheetDialogFragment to expanded using BottomSheetBehavior#setState(STATE_EXPANDED) using the Android Support Design Library (v23.2.1)?

https://code.google.com/p/android/issues/detail?id=202396 说：

首先将底页设置为STATE_COLLAPSED。如果要扩展它，请调用BottomSheetBehavior＃setState（STATE_EXPANDED）。请注意，您不能在视图布局之前调用该方法。

Bottom sheets are set to STATE_COLLAPSED at first. Call BottomSheetBehavior#setState(STATE_EXPANDED) if you want to expand it. Note that you cannot call the method before view layouts.

建议的练习要求先放大视图，但我不确定如何设置将BottomSheetBehaviour放到一个片段上（ BottomSheetDialogFragment ）。

The suggested practice requires a view to be inflated first, but I'm not sure how I'll set the BottomSheetBehaviour onto a fragment (BottomSheetDialogFragment).

View bottomSheet = coordinatorLayout.findViewById(R.id.bottom_sheet);  
BottomSheetBehavior behavior = BottomSheetBehavior.from(bottomSheet);  

推荐答案

无法在视图布局之前调用该方法。

"Note that you cannot call the method before view layouts."

上面的文字就是线索。

对话框具有一个监听器，一旦显示，该监听器便被触发。

Dialogs have a listener that is fired once the dialog is shown. The dialog cannot be shown if it isn't laid out.

因此，在您的 onCreateDialog（）中，该对话框无法显示。模态底部工作表（ BottomSheetFragment ），在返回对话框之前（或者在引用对话框后，在任何位置），调用：

So, in the onCreateDialog() of your modal bottom sheet (BottomSheetFragment), just before returning the dialog (or anywhere, once you have a reference to the dialog), call:

// This listener's onShow is fired when the dialog is shown
dialog.setOnShowListener(new DialogInterface.OnShowListener() {
    @Override
    public void onShow(DialogInterface dialog) {

        // In a previous life I used this method to get handles to the positive and negative buttons
        // of a dialog in order to change their Typeface. Good ol' days.

        BottomSheetDialog d = (BottomSheetDialog) dialog;

        // This is gotten directly from the source of BottomSheetDialog
        // in the wrapInBottomSheet() method
        FrameLayout bottomSheet = (FrameLayout) d.findViewById(android.support.design.R.id.design_bottom_sheet);

        // Right here!
        BottomSheetBehavior.from(bottomSheet)
            .setState(BottomSheetBehavior.STATE_EXPANDED);
    }
});

就我而言，我的自定义 BottomSheet

In my case, my custom BottomSheet turned out to be:

@SuppressWarnings("ConstantConditions")
public class ShareBottomSheetFragment extends AppCompatDialogFragment {

    @NonNull @Override
    public Dialog onCreateDialog(Bundle savedInstanceState) {

        BottomSheetDialog dialog =
                new BottomSheetDialog(getActivity(), R.style.Haute_Dialog_ShareImage);

        dialog.setContentView(R.layout.dialog_share_image);

        dialog.findViewById(R.id.cancel).setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                dismiss();
            }
        });

        dialog.setOnShowListener(new DialogInterface.OnShowListener() {
            @Override
            public void onShow(DialogInterface dialog) {
                BottomSheetDialog d = (BottomSheetDialog) dialog;

                FrameLayout bottomSheet = (FrameLayout) d.findViewById(android.support.design.R.id.design_bottom_sheet);
                BottomSheetBehavior.from(bottomSheet).setState(BottomSheetBehavior.STATE_EXPANDED);
            }
        });

        SwitchCompat switchview = (SwitchCompat) dialog.findViewById(R.id.switchview);
        switchview.setTypeface(FontCache.get(dialog.getContext(), lookup(muli, NORMAL)));

        return dialog;
    }
}

让我知道是否有帮助。

更新

请注意，您也可以覆盖 BottomSheetDialogFragment as：

Note that you can also override BottomSheetDialogFragment as:

public class SimpleInitiallyExpandedBottomSheetFragment extends BottomSheetDialogFragment {

    @NonNull @Override
    public Dialog onCreateDialog(Bundle savedInstanceState) {

        BottomSheetDialog dialog = (BottomSheetDialog) super.onCreateDialog(savedInstanceState);

        dialog.setOnShowListener(new DialogInterface.OnShowListener() {
            @Override
            public void onShow(DialogInterface dialog) {
                BottomSheetDialog d = (BottomSheetDialog) dialog;

                FrameLayout bottomSheet = (FrameLayout) d.findViewById(android.support.design.R.id.design_bottom_sheet);
                BottomSheetBehavior.from(bottomSheet).setState(BottomSheetBehavior.STATE_EXPANDED);
            }
        });

        // Do something with your dialog like setContentView() or whatever
        return dialog;
    }
}

但我真的不明白为什么有人愿意这样做作为基础 BottomSheetFragment 除了返回 BottomSheetDialog 之外不做任何事情。

But I really dont see why anyone would want to do that as the base BottomSheetFragment doesn't do anything other than return a BottomSheetDialog.

ANDROIDX更新

使用AndroidX时，以前在 android.support上找到的资源.design.R.id.design_bottom_sheet 现在可以在 com.google.android.material.R.id.design_bottom_sheet 中找到。

When using AndroidX, the resource previously found at android.support.design.R.id.design_bottom_sheet can now be found at com.google.android.material.R.id.design_bottom_sheet.

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