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

问题描述

如何使用 Android 支持设计库 (v23.2.1) 将扩展 BottomSheetDialogFragment 的片段的状态设置为使用 BottomSheetBehavior#setState(STATE_EXPANDED) 扩展?

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/问题/详细信息?id=202396 说:

底部工作表首先设置为 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.

建议的做法需要首先要膨胀的视图，但我不确定如何将 BottomSheetBehaviour 设置为片段 (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

请注意，您不能在视图布局之前调用该方法."

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

以上文字为线索.

对话框有一个监听器，一旦对话框显示就会被触发.如果没有布局，则无法显示对话框.

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，在模态底部表单 (BottomSheetFragment) 的 onCreateDialog() 中，就在返回对话框之前(或任何地方，一旦您引用了对话框)，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 结果是:

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;
    }
}

如果这有帮助，请告诉我.

Let me know if this helps.

更新

请注意，您还可以将 BottomSheetDialogFragment 覆盖为:

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会想要这样做，因为基础 BottomSheetFragment 除了返回 BottomSheetDialog 之外什么都不做.

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

Android 更新

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

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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