/*
* Copyright (c) 2019 Samsung Electronics Co., Ltd.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
*/
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Diagnostics;
using Tizen.NUI.BaseComponents;
using System.Linq;
namespace Tizen.NUI
{
///
/// [Draft] LayoutGroup class providing container functionality.
///
public class LayoutGroup : LayoutItem, ILayoutParent
{
///
/// [Draft] List of child layouts in this container.
///
/// 6
protected List LayoutChildren{ get;} // Children of this LayoutGroup
///
/// [Draft] Constructor
///
/// 6
public LayoutGroup()
{
LayoutChildren = new List();
}
///
/// From ILayoutParent.
///
/// 6
/// LayoutItem to add to the layout group.
public virtual void Add(LayoutItem childLayout)
{
LayoutChildren.Add(childLayout);
childLayout.SetParent(this);
// Child added to use a Add transition.
childLayout.ConditionForAnimation = ConditionForAnimation | TransitionCondition.Add;
// Child's parent sets all other children not being added to a ChangeOnAdd transition.
SetConditionsForAnimationOnLayoutGroup(TransitionCondition.ChangeOnAdd);
OnChildAdd(childLayout);
RequestLayout();
}
///
/// Remove all layout children.
///
/// 6
public void RemoveAll()
{
foreach( LayoutItem childLayout in LayoutChildren )
{
childLayout.ConditionForAnimation = ConditionForAnimation | TransitionCondition.Remove;
childLayout.Owner = null;
}
LayoutChildren.Clear();
// todo ensure child LayoutItems are still not parented to this group.
RequestLayout();
}
///
/// From ILayoutParent
///
/// LayoutItem to remove from the layout group.
/// 6
public virtual void Remove(LayoutItem layoutItem)
{
bool childRemoved = false;
foreach( LayoutItem childLayout in LayoutChildren.ToList() )
{
if( childLayout == layoutItem )
{
Window.Instance.LayoutController.AddToRemovalStack(childLayout);
LayoutChildren.Remove(childLayout);
childLayout.ConditionForAnimation = childLayout.ConditionForAnimation | TransitionCondition.Remove;
// Add LayoutItem to the transition stack so can animate it out.
Window.Instance.LayoutController.AddTransitionDataEntry(new LayoutData(layoutItem, ConditionForAnimation, 0,0,0,0));
// Reset condition for animation ready for next transition when required.
// SetFrame usually would do this but this LayoutItem is being removed.
childLayout.ConditionForAnimation = TransitionCondition.Unspecified;
childRemoved = true;
}
}
if (childRemoved)
{
// If child removed then set all siblings not being added to a ChangeOnRemove transition.
SetConditionsForAnimationOnLayoutGroup(TransitionCondition.ChangeOnRemove);
}
RequestLayout();
}
// Attaches to View ChildAdded signal so called when a View is added to a view.
private void AddChildToLayoutGroup(View child)
{
// Only give children a layout if their parent is an explicit container or a pure View.
// Pure View meaning not derived from a View, e.g a Legacy container.
// layoutSet flag is true when the View became a layout using the set Layout API opposed to automatically due to it's parent.
// First time the set Layout API is used by any View the Window no longer has layoutingDisabled.
// If child already has a Layout then don't change it.
if (! View.layoutingDisabled && (null == child.Layout))
{
// Only wrap View with a Layout if a child a pure View or Layout explicitly set on this Layout
if ((true == Owner.layoutSet || GetType() == typeof(View)))
{
// If child of this layout is a pure View then assign it a LayoutGroup
// If the child is derived from a View then it may be a legacy or existing container hence will do layouting itself.
if (child.GetType() == typeof(View))
{
child.Layout = new LayoutGroup();
}
else
{
// Adding child as a leaf, layouting will not propagate past this child.
// Legacy containers will be a LayoutItems too and layout their children how they wish.
child.Layout = new LayoutItem();
}
}
}
else
{
// Add child layout to this LayoutGroup (Setting parent in the process)
if(child.Layout != null)
{
Add(child.Layout);
}
}
// Parent transitions are not attached to children.
}
///
/// If the child has a layout then it is removed from the parent layout.
///
/// Child View to remove.
internal void RemoveChildFromLayoutGroup(View child)
{
Debug.Assert(child.Layout !=null);
Remove(child.Layout);
}
///
/// Set all children in a LayoutGroup to the supplied condition.
/// Children with Add or Remove conditions should not be changed.
///
private void SetConditionsForAnimationOnLayoutGroup( TransitionCondition conditionToSet)
{
foreach( LayoutItem childLayout in LayoutChildren )
{
switch( conditionToSet )
{
case TransitionCondition.ChangeOnAdd :
{
// If other children also being added (TransitionCondition.Add) then do not change their
// conditions, Continue to use their Add transitions.
if (childLayout.ConditionForAnimation.HasFlag(TransitionCondition.Add))
{
break; // Child being Added so don't update it's condition
}
else
{
// Set siblings for the child being added to use the ChangeOnAdd transition.
childLayout.ConditionForAnimation = TransitionCondition.ChangeOnAdd;
}
break;
}
case TransitionCondition.ChangeOnRemove :
{
if (childLayout.ConditionForAnimation.HasFlag(TransitionCondition.Remove))
{
break; // Child being Removed so don't update it's condition
}
else
{
childLayout.ConditionForAnimation = TransitionCondition.ChangeOnRemove;
}
break;
}
case TransitionCondition.LayoutChanged :
{
childLayout.ConditionForAnimation = TransitionCondition.LayoutChanged;
break;
}
}
}
}
///
/// Callback for View.ChildAdded event
///
/// The object triggering the event.
/// Arguments from the event.
void OnChildAddedToOwner(object sender, View.ChildAddedEventArgs childAddedEvent)
{
AddChildToLayoutGroup(childAddedEvent.Added);
}
///
/// Callback for View.ChildRemoved event
///
/// The object triggering the event.
/// Arguments from the event.
void OnChildRemovedFromOwner(object sender, View.ChildRemovedEventArgs childRemovedEvent)
{
RemoveChildFromLayoutGroup(childRemovedEvent.Removed);
}
///
/// Calculate the right measure spec for this child.
/// Does the hard part of MeasureChildren: figuring out the MeasureSpec to
/// pass to a particular child. This method figures out the right MeasureSpec
/// for one dimension (height or width) of one child view.
///
/// The requirements for this view. MeasureSpecification.
/// The padding of this view for the current dimension and margins, if applicable. LayoutLength.
/// How big the child wants to be in the current dimension. LayoutLength.
/// a MeasureSpec for the child.
public static MeasureSpecification GetChildMeasureSpecification(MeasureSpecification parentMeasureSpec, LayoutLength padding, LayoutLength childDimension)
{
MeasureSpecification.ModeType specMode = parentMeasureSpec.Mode;
MeasureSpecification.ModeType resultMode = MeasureSpecification.ModeType.Unspecified;
LayoutLength resultSize = new LayoutLength(Math.Max( 0.0f, (parentMeasureSpec.Size.AsDecimal() - padding.AsDecimal() ) )); // reduce available size by the owners padding
switch( specMode )
{
// Parent has imposed an exact size on us
case MeasureSpecification.ModeType.Exactly:
{
if ((int)childDimension.AsRoundedValue() == LayoutParamPolicies.MatchParent)
{
// Child wants to be our size. So be it.
resultMode = MeasureSpecification.ModeType.Exactly;
}
else if ((int)childDimension.AsRoundedValue() == LayoutParamPolicies.WrapContent)
{
// Child wants to determine its own size. It can't be
// bigger than us.
resultMode = MeasureSpecification.ModeType.AtMost;
}
else
{
resultSize = childDimension;
resultMode = MeasureSpecification.ModeType.Exactly;
}
break;
}
// Parent has imposed a maximum size on us
case MeasureSpecification.ModeType.AtMost:
{
if (childDimension.AsRoundedValue() == LayoutParamPolicies.MatchParent)
{
// Child wants to be our size, but our size is not fixed.
// Constrain child to not be bigger than us.
resultMode = MeasureSpecification.ModeType.AtMost;
}
else if (childDimension.AsRoundedValue() == LayoutParamPolicies.WrapContent)
{
// Child wants to determine its own size. It can't be
// bigger than us.
resultMode = MeasureSpecification.ModeType.AtMost;
}
else
{
// Child wants a specific size... so be it
resultSize = childDimension + padding;
resultMode = MeasureSpecification.ModeType.Exactly;
}
break;
}
// Parent asked to see how big we want to be
case MeasureSpecification.ModeType.Unspecified:
{
if ((childDimension.AsRoundedValue() == LayoutParamPolicies.MatchParent))
{
// Child wants to be our size... find out how big it should be
resultMode = MeasureSpecification.ModeType.Unspecified;
}
else if (childDimension.AsRoundedValue() == (LayoutParamPolicies.WrapContent))
{
// Child wants to determine its own size.... find out how big
// it should be
resultMode = MeasureSpecification.ModeType.Unspecified;
}
else
{
// Child wants a specific size... let him have it
resultSize = childDimension + padding;
resultMode = MeasureSpecification.ModeType.Exactly;
}
break;
}
} // switch
return new MeasureSpecification( resultSize, resultMode );
}
///
/// Measure the layout and its content to determine the measured width and the measured height.
/// If this method is overridden, it is the subclass's responsibility to make
/// sure the measured height and width are at least the layout's minimum height
/// and width.
///
/// horizontal space requirements as imposed by the parent.
/// vertical space requirements as imposed by the parent.
/// 6
protected override void OnMeasure(MeasureSpecification widthMeasureSpec, MeasureSpecification heightMeasureSpec)
{
LayoutLength measuredWidth = new LayoutLength(0.0f);
LayoutLength measuredHeight = new LayoutLength(0.0f);
// Layout takes size of largest child width and largest child height dimensions
foreach( LayoutItem childLayout in LayoutChildren )
{
if( childLayout != null )
{
MeasureChild( childLayout, widthMeasureSpec, heightMeasureSpec );
LayoutLength childWidth = new LayoutLength(childLayout.MeasuredWidth.Size);
LayoutLength childHeight = new LayoutLength( childLayout.MeasuredHeight.Size);
Extents childMargin = childLayout.Margin;
measuredWidth = new LayoutLength(Math.Max( measuredWidth.AsDecimal(), childWidth.AsDecimal() + childMargin.Start + childMargin.End));
measuredHeight = new LayoutLength(Math.Max( measuredHeight.AsDecimal(), childHeight.AsDecimal() + childMargin.Top + childMargin.Bottom));
}
}
if( 0 == LayoutChildren.Count )
{
// Must be a leaf as has no children
measuredWidth = GetDefaultSize( SuggestedMinimumWidth, widthMeasureSpec );
measuredHeight = GetDefaultSize( SuggestedMinimumHeight, heightMeasureSpec );
}
SetMeasuredDimensions( new MeasuredSize( measuredWidth, MeasuredSize.StateType.MeasuredSizeOK ),
new MeasuredSize( measuredHeight, MeasuredSize.StateType.MeasuredSizeOK ) );
}
///
/// Called from Layout() when this layout should assign a size and position to each of its children.
/// Derived classes with children should override this method and call Layout() on each of their children.
///
/// This is a new size or position for this layout.
/// Left position, relative to parent.
/// Top position, relative to parent.
/// Right position, relative to parent.
/// Bottom position, relative to parent.
/// 6
protected override void OnLayout(bool changed, LayoutLength left, LayoutLength top, LayoutLength right, LayoutLength bottom)
{
foreach( LayoutItem childLayout in LayoutChildren )
{
if( childLayout !=null )
{
// Use position if explicitly set to child otherwise will be top left.
var childLeft = new LayoutLength( childLayout.Owner.Position2D.X );
var childTop = new LayoutLength( childLayout.Owner.Position2D.Y );
View owner = Owner;
if ( owner )
{
// Margin and Padding only supported when child anchor point is TOP_LEFT.
if ( owner.PivotPoint == PivotPoint.TopLeft || ( owner.PositionUsesPivotPoint == false ) )
{
childLeft = childLeft + owner.Padding.Start + childLayout.Margin.Start;
childTop = childTop + owner.Padding.Top + childLayout.Margin.Top;
}
}
childLayout.Layout( childLeft, childTop, childLeft + childLayout.MeasuredWidth.Size, childTop + childLayout.MeasuredHeight.Size );
}
}
}
///
/// Overridden method called when the layout is attached to an owner.
///
/// 6
protected override void OnAttachedToOwner()
{
// Layout takes ownership of it's owner's children.
foreach (View view in Owner.Children)
{
AddChildToLayoutGroup(view);
}
// Connect to owner ChildAdded signal.
Owner.ChildAdded += OnChildAddedToOwner;
// Removing Child from the owners View will directly call the LayoutGroup removal API.
}
// Virtual Methods that can be overridden by derived classes.
///
/// Callback when child is added to container.
/// Derived classes can use this to set their own child properties on the child layout's owner.
///
/// The Layout child.
/// 6
protected virtual void OnChildAdd(LayoutItem child)
{
}
///
/// Callback when child is removed from container.
///
/// The Layout child.
/// 6
protected virtual void OnChildRemove(LayoutItem child)
{
}
///
/// Ask all of the children of this view to measure themselves, taking into
/// account both the MeasureSpec requirements for this view and its padding.
/// The heavy lifting is done in GetChildMeasureSpec.
///
/// The width requirements for this view.
/// The height requirements for this view.
/// 6
protected virtual void MeasureChildren(MeasureSpecification widthMeasureSpec, MeasureSpecification heightMeasureSpec)
{
foreach( LayoutItem childLayout in LayoutChildren )
{
MeasureChild( childLayout, widthMeasureSpec, heightMeasureSpec );
}
}
///
/// Ask one of the children of this view to measure itself, taking into
/// account both the MeasureSpec requirements for this view and its padding.
/// The heavy lifting is done in GetChildMeasureSpecification.
///
/// The child to measure.
/// The width requirements for this view.
/// The height requirements for this view.
/// 6
protected virtual void MeasureChild(LayoutItem child, MeasureSpecification parentWidthMeasureSpec, MeasureSpecification parentHeightMeasureSpec)
{
View childOwner = child.Owner;
Extents padding = child.Padding; // Padding of this layout's owner, not of the child being measured.
MeasureSpecification childWidthMeasureSpec = GetChildMeasureSpecification( parentWidthMeasureSpec,
new LayoutLength(padding.Start + padding.End ),
new LayoutLength(childOwner.WidthSpecification) );
MeasureSpecification childHeightMeasureSpec = GetChildMeasureSpecification( parentHeightMeasureSpec,
new LayoutLength(padding.Top + padding.Bottom),
new LayoutLength(childOwner.HeightSpecification) );
child.Measure( childWidthMeasureSpec, childHeightMeasureSpec );
}
///
/// Ask one of the children of this view to measure itself, taking into
/// account both the MeasureSpec requirements for this view and its padding.
/// and margins. The child must have MarginLayoutParams The heavy lifting is
/// done in GetChildMeasureSpecification.
///
/// The child to measure.
/// The width requirements for this view.
/// Extra space that has been used up by the parent horizontally (possibly by other children of the parent).
/// The height requirements for this view.
/// Extra space that has been used up by the parent vertically (possibly by other children of the parent).
/// 6
protected virtual void MeasureChildWithMargins(LayoutItem child, MeasureSpecification parentWidthMeasureSpec, LayoutLength widthUsed, MeasureSpecification parentHeightMeasureSpec, LayoutLength heightUsed)
{
View childOwner = child.Owner;
int desiredWidth = childOwner.WidthSpecification;
int desiredHeight = childOwner.HeightSpecification;
Extents padding = child.Padding; // Padding of this layout's owner, not of the child being measured.
MeasureSpecification childWidthMeasureSpec = GetChildMeasureSpecification( parentWidthMeasureSpec,
new LayoutLength( padding.Start + padding.End ) +
widthUsed, new LayoutLength(desiredWidth) );
MeasureSpecification childHeightMeasureSpec = GetChildMeasureSpecification( parentHeightMeasureSpec,
new LayoutLength( padding.Top + padding.Bottom )+
heightUsed, new LayoutLength(desiredHeight) );
child.Measure( childWidthMeasureSpec, childHeightMeasureSpec );
}
}
}