Question

我正在尝试遵循“材质设计” specification，使用Android Design支持库在模态底页中添加封闭式工具栏。

全屏显示时，可以在内部滚动底部的页面以显示其他内容。 应使用工具栏提供折叠或关闭功能以退出此视图。

我和BottomSheetBehavior.BottomSheetCallback一起根据BottomSheetBehavior的展开/折叠状态来切换工具栏的可见性。问题是，即使BottomSheetDialogFragment内容无法填满整个屏幕，当我尝试向上拖动时，也会出现工具栏。如何知道底部面板展开时底部面板是全屏的？

public class BottomSheetToolbarToggleCallback : BottomSheetBehavior.BottomSheetCallback
{
    public BottomSheetToolbarToggleCallback(BottomSheetDialogFragment bottomSheetDialogFragment)
    {
        this.bottomSheetDialogFragment = bottomSheetDialogFragment ?? throw new System.ArgumentNullException(nameof(bottomSheetDialogFragment));
    }

    public override void OnSlide(View bottomSheet, float slideOffset)
    {
    }

    public override void OnStateChanged(View bottomSheet, int newState)
    {
        switch (newState)
        {
            case BottomSheetBehavior.StateCollapsed:
                ShowToolbar(bottomSheet, ViewStates.Gone);
                break;
            case BottomSheetBehavior.StateExpanded:
                ShowToolbar(bottomSheet, ViewStates.Visible);
                break;
            case BottomSheetBehavior.StateHidden:
                bottomSheetDialogFragment.Dismiss();
                break;
        }
    }

    private void ShowToolbar(View bottomSheet, ViewStates viewState)
    {
        var toolbar = bottomSheet.FindViewById<Toolbar>(Resource.Id.toolbar);
        if (toolbar != null)
        {
            toolbar.Visibility = viewState;
        }
    }

    private readonly BottomSheetDialogFragment bottomSheetDialogFragment;
}

public abstract class BaseBottomSheetDialogFragment<TViewModel> : MvxBottomSheetDialogFragment<TViewModel> where TViewModel : BaseViewModel
{
    protected BaseBottomSheetDialogFragment()
    {
    }

    protected BaseBottomSheetDialogFragment(IntPtr javaReference, JniHandleOwnership transfer) : base(javaReference, transfer)
    {
    }

    public override void SetupDialog(Dialog dialog, int style)
    {
        base.SetupDialog(dialog, style);

        this.EnsureBindingContextIsSet(); // This is required to use this.BindingInflate()
        var view = this.BindingInflate(LayoutResourceId, null);
        dialog.SetContentView(view);

        // Add support to handle material design specification to dynamically show a toolbar with an 'X' button.
        var layoutParams = (CoordinatorLayout.LayoutParams)((View)view.Parent).LayoutParameters;
        var behavior = layoutParams.Behavior;
        if (behavior != null && behavior is BottomSheetBehavior)
        {
            var toolbar = view.FindViewById<Toolbar>(Droid.Resource.Id.toolbar);
            if (toolbar != null)
            {
                toolbar.SetNavigationIcon(Droid.Resource.Drawable.clear);
                ((BottomSheetBehavior)behavior).SetBottomSheetCallback(new BottomSheetToolbarToggleCallback(this));
                if (CloseCommand != null)
                {
                    toolbar.SetNavigationOnClickListener(new MvxAsyncCommandOnClickListener(CloseCommand));
                }
            }
        }
    }

    /// <summary>
    /// The Android layout resource id of the layout to show in the modal bottom sheet.
    /// </summary>
    protected abstract int LayoutResourceId { get; }

    /// <summary>
    /// Optional <see cref="MvxAsyncCommand"/> to call when the optional toolbar navigation button is clicked.
    /// </summary>
    protected abstract IMvxAsyncCommand CloseCommand { get; }
}

Answer 1

由于我不知道您的特定代码，因此以下是我尝试过的一个简单示例的片段：

public View mView;

public override void SetupDialog(Dialog dialog, int style)
{
    base.SetupDialog(dialog, style);

    this.EnsureBindingContextIsSet(); // This is required to use this.BindingInflate()
    mView = this.BindingInflate(LayoutResourceId, null);
    dialog.SetContentView(view);
        ...        
}

在BottomSheetCallback中：

public override void OnStateChanged(View bottomSheet, int newState)
        {
            switch (newState)
            {          
                case BottomSheetBehavior.StateExpanded:
                   var height = bottomSheetDialogFragment.mView.Height;//need you convert to your BottomSheetDialogFragment
                    break;              
            }
        }

Answer 2

这是我最终使用的解决方案。仅当BottomSheetDialogFragment占据窗口的整个高度时，它才会显示关闭能力。它已经过多窗口模式，切口/插入，横向和纵向方向的测试。

public class BottomSheetDialogFragmentCloseAffordanceCallback : BottomSheetBehavior.BottomSheetCallback
{
    public BottomSheetDialogFragmentCloseAffordanceCallback(BottomSheetDialogFragment bottomSheetDialogFragment)
    {
        this.bottomSheetDialogFragment = bottomSheetDialogFragment ?? throw new System.ArgumentNullException(nameof(bottomSheetDialogFragment));
    }

    public override void OnSlide(View bottomSheet, float slideOffset)
    {
    }

    public override void OnStateChanged(View bottomSheet, int newState)
    {
        switch (newState)
        {
            case BottomSheetBehavior.StateCollapsed:
                ShowToolbar(bottomSheet, ViewStates.Gone);
                break;
            case BottomSheetBehavior.StateExpanded:
                if (IsViewSameHeightAsWindow(bottomSheet))
                {
                    ShowToolbar(bottomSheet, ViewStates.Visible);
                }
                break;
            case BottomSheetBehavior.StateHalfExpanded:
                break;
            case BottomSheetBehavior.StateHidden:
                bottomSheetDialogFragment.Dismiss();
                break;
        }
    }

    private void ShowToolbar(View bottomSheet, ViewStates viewState)
    {
        var toolbar = bottomSheet.FindViewById<Toolbar>(Resource.Id.toolbar);
        if (toolbar != null)
        {
            toolbar.Visibility = viewState;
        }
    }

    private bool IsViewSameHeightAsWindow(View view)
    {
        int[] locationInWindow = new int[2];
        view.GetLocationInWindow(locationInWindow);
        return locationInWindow[1] == view.RootWindowInsets.StableInsetTop;
    }

    private readonly BottomSheetDialogFragment bottomSheetDialogFragment;
}

如何判断BottomSheetDialogFragment何时展开以填充屏幕？

2 个答案: