通过向下拖动关闭后，BottomSheetDialog 保持隐藏状态

我对对方的行为很好奇BottomSheetDialog当它被解除时：当用户将其向下拖动以隐藏它时，它将保持隐藏状态，即使bottomSheetDialog#show()之后被调用。这只发生在向下拖动时，而不是当用户触摸外部或当bottomSheetDialog#dismiss()以编程方式调用。

这真的很烦人，因为我有一个很大的bottomSheetDialog里面有一个 recyclerview，每次我想显示时都必须创建一个新的bottomSheetDialog.

因此，不要只这样做：

if(bottomSheetDialog != null){
   bottomSheetDialog.show();
else{
   createNewBottomSheetDialog();
}

我每次都必须创建一个。

我错过了什么还是这是正常行为？ （顺便说一句，我用appcompat-v7:23.2.1)

所以我最终通过直接查看来解决这个问题BottomSheetDialog实现，我发现它只不过是一个简单的Dialog包裹成常规的BottomSheet.
问题出在BottomSheetCallBack :

@Override
    public void onStateChanged(@NonNull View bottomSheet,
            @BottomSheetBehavior.State int newState) {
        if (newState == BottomSheetBehavior.STATE_HIDDEN) {
            dismiss();
        }
    }

当达到隐藏状态时会出现问题，当对话框被向下拖动而关闭时会发生这种情况。之后，即使对话框保持隐藏状态bottomSheetDialog.show()叫做。我发现的最简单的修复方法是删除此状态并将其替换为 COLLAPSED 状态。

我创建一个classCustomBottomSheetDialog，复制整个BottomSheetDialog类并添加一行来解决问题：

@Override
    public void onStateChanged(@NonNull View bottomSheet,
                               @BottomSheetBehavior.State int newState) {

        if (newState == CustomBottomSheetBehavior.STATE_HIDDEN) {

            dismiss();
            bottomSheetBehavior.setState(CustomBottomSheetBehavior.STATE_COLLAPSED);
        }
    }

这是最终的代码：

public class CustomBottomSheetDialog extends AppCompatDialog {

    public CustomBottomSheetDialog (@NonNull Context context) {
        this(context, 0);
    }

    public CustomBottomSheetDialog (@NonNull Context context, @StyleRes int theme) {
        super(context, getThemeResId(context, theme));
        // We hide the title bar for any style configuration. Otherwise, there will be a gap
        // above the bottom sheet when it is expanded.
        supportRequestWindowFeature(Window.FEATURE_NO_TITLE);
    }

    protected CustomBottomSheetDialog (@NonNull Context context, boolean cancelable,
            OnCancelListener cancelListener) {
        super(context, cancelable, cancelListener);
        supportRequestWindowFeature(Window.FEATURE_NO_TITLE);
    }

    @Override
    public void setContentView(@LayoutRes int layoutResId) {
        super.setContentView(wrapInBottomSheet(layoutResId, null, null));
    }

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        getWindow().setLayout(
                ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.MATCH_PARENT);
    }

    @Override
    public void setContentView(View view) {
        super.setContentView(wrapInBottomSheet(0, view, null));
    }

    @Override
    public void setContentView(View view, ViewGroup.LayoutParams params) {
        super.setContentView(wrapInBottomSheet(0, view, params));
    }

    private View wrapInBottomSheet(int layoutResId, View view, ViewGroup.LayoutParams params) {
        final CoordinatorLayout coordinator = (CoordinatorLayout) View.inflate(getContext(),
                R.layout.design_bottom_sheet_dialog, null);
        if (layoutResId != 0 && view == null) {
            view = getLayoutInflater().inflate(layoutResId, coordinator, false);
        }
        FrameLayout bottomSheet = (FrameLayout) coordinator.findViewById(R.id.design_bottom_sheet);
        BottomSheetBehavior.from(bottomSheet).setBottomSheetCallback(mBottomSheetCallback);
        if (params == null) {
            bottomSheet.addView(view);
        } else {
            bottomSheet.addView(view, params);
        }
        // We treat the CoordinatorLayout as outside the dialog though it is technically inside
        if (shouldWindowCloseOnTouchOutside()) {
            coordinator.findViewById(R.id.touch_outside).setOnClickListener(
                    new View.OnClickListener() {
                        @Override
                        public void onClick(View view) {
                            if (isShowing()) {
                                cancel();
                            }
                        }
                    });
        }
        return coordinator;
    }

    private boolean shouldWindowCloseOnTouchOutside() {
        if (Build.VERSION.SDK_INT < 11) {
            return true;
        }
        TypedValue value = new TypedValue();
        //noinspection SimplifiableIfStatement
        if (getContext().getTheme()
                .resolveAttribute(android.R.attr.windowCloseOnTouchOutside, value, true)) {
            return value.data != 0;
        }
        return false;
    }

    private static int getThemeResId(Context context, int themeId) {
        if (themeId == 0) {
            // If the provided theme is 0, then retrieve the dialogTheme from our theme
            TypedValue outValue = new TypedValue();
            if (context.getTheme().resolveAttribute(
                    R.attr.bottomSheetDialogTheme, outValue, true)) {
                themeId = outValue.resourceId;
            } else {
                // bottomSheetDialogTheme is not provided; we default to our light theme
                themeId = R.style.Theme_Design_Light_BottomSheetDialog;
            }
        }
        return themeId;
    }

    private BottomSheetBehavior.BottomSheetCallback mBottomSheetCallback
            = new BottomSheetBehavior.BottomSheetCallback() {
        @Override
        public void onStateChanged(@NonNull View bottomSheet,
                @BottomSheetBehavior.State int newState) {
            if (newState == BottomSheetBehavior.STATE_HIDDEN) {
                dismiss();
                bottomSheetBehavior.setState(CustomBottomSheetBehavior.STATE_COLLAPSED);
            }
        }

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

}