2 * Copyright (c) 2020 Samsung Electronics Co., Ltd.
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
8 * http://www.apache.org/licenses/LICENSE-2.0
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
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13 * See the License for the specific language governing permissions and
14 * limitations under the License.
18 using System.Collections.Generic;
19 using System.ComponentModel;
20 using System.Diagnostics;
21 using Tizen.NUI.BaseComponents;
27 /// [Draft] LayoutGroup class providing container functionality.
29 public class LayoutGroup : LayoutItem, ILayoutParent
32 /// [Draft] List of child layouts in this container.
34 /// <since_tizen> 6 </since_tizen>
35 protected List<LayoutItem> LayoutChildren{ get;} // Children of this LayoutGroup
38 /// [Draft] Constructor
40 /// <since_tizen> 6 </since_tizen>
43 LayoutChildren = new List<LayoutItem>();
47 /// From ILayoutParent.<br />
49 /// <since_tizen> 6 </since_tizen>
50 /// <param name="childLayout">LayoutItem to add to the layout group.</param>
51 public virtual void Add(LayoutItem childLayout)
53 LayoutChildren.Add(childLayout);
54 childLayout.SetParent(this);
55 // Child added to use a Add transition.
56 childLayout.ConditionForAnimation = ConditionForAnimation | TransitionCondition.Add;
57 // Child's parent sets all other children not being added to a ChangeOnAdd transition.
58 SetConditionsForAnimationOnLayoutGroup(TransitionCondition.ChangeOnAdd);
59 OnChildAdd(childLayout);
64 /// Remove all layout children.<br />
66 /// <since_tizen> 6 </since_tizen>
67 public void RemoveAll()
69 foreach( LayoutItem childLayout in LayoutChildren )
71 childLayout.ConditionForAnimation = ConditionForAnimation | TransitionCondition.Remove;
72 childLayout.Owner = null;
74 LayoutChildren.Clear();
75 // todo ensure child LayoutItems are still not parented to this group.
80 /// From ILayoutParent
82 /// <param name="layoutItem">LayoutItem to remove from the layout group.</param>
83 /// <since_tizen> 6 </since_tizen>
84 public virtual void Remove(LayoutItem layoutItem)
86 bool childRemoved = false;
87 foreach( LayoutItem childLayout in LayoutChildren.ToList() )
89 if( childLayout == layoutItem )
91 if (! childLayout.IsReplaceFlag())
93 Window.Instance.LayoutController.AddToRemovalStack(childLayout);
95 childLayout.ClearReplaceFlag();
96 LayoutChildren.Remove(childLayout);
97 childLayout.ConditionForAnimation = childLayout.ConditionForAnimation | TransitionCondition.Remove;
98 // Add LayoutItem to the transition stack so can animate it out.
99 Window.Instance.LayoutController.AddTransitionDataEntry(new LayoutData(layoutItem, ConditionForAnimation, 0,0,0,0));
100 // Reset condition for animation ready for next transition when required.
101 // SetFrame usually would do this but this LayoutItem is being removed.
102 childLayout.ConditionForAnimation = TransitionCondition.Unspecified;
108 // If child removed then set all siblings not being added to a ChangeOnRemove transition.
109 SetConditionsForAnimationOnLayoutGroup(TransitionCondition.ChangeOnRemove);
114 // Attaches to View ChildAdded signal so called when a View is added to a view.
115 private void AddChildToLayoutGroup(View child)
117 // Only give children a layout if their parent is an explicit container or a pure View.
118 // Pure View meaning not derived from a View, e.g a Legacy container.
119 // layoutSet flag is true when the View became a layout using the set Layout API opposed to automatically due to it's parent.
120 // First time the set Layout API is used by any View the Window no longer has layoutingDisabled.
122 // If child already has a Layout then don't change it.
123 if (! View.layoutingDisabled && (null == child.Layout))
125 // Only wrap View with a Layout if a child a pure View or Layout explicitly set on this Layout
126 if ((true == Owner.layoutSet || GetType() == typeof(View)))
128 // If child of this layout is a pure View then assign it a LayoutGroup
129 // If the child is derived from a View then it may be a legacy or existing container hence will do layouting itself.
130 if (child.GetType() == typeof(View))
132 child.Layout = new LayoutGroup();
136 // Adding child as a leaf, layouting will not propagate past this child.
137 // Legacy containers will be a LayoutItems too and layout their children how they wish.
138 child.Layout = new LayoutItem();
144 // Add child layout to this LayoutGroup (Setting parent in the process)
145 if(child.Layout != null)
150 // Parent transitions are not attached to children.
154 /// If the child has a layout then it is removed from the parent layout.
156 /// <param name="child">Child View to remove.</param>
157 internal void RemoveChildFromLayoutGroup(View child)
159 Debug.Assert(child.Layout !=null);
160 Remove(child.Layout);
164 /// Set all children in a LayoutGroup to the supplied condition.
165 /// Children with Add or Remove conditions should not be changed.
167 private void SetConditionsForAnimationOnLayoutGroup( TransitionCondition conditionToSet)
169 foreach( LayoutItem childLayout in LayoutChildren )
171 switch( conditionToSet )
173 case TransitionCondition.ChangeOnAdd :
175 // If other children also being added (TransitionCondition.Add) then do not change their
176 // conditions, Continue to use their Add transitions.
177 if (childLayout.ConditionForAnimation.HasFlag(TransitionCondition.Add))
179 break; // Child being Added so don't update it's condition
183 // Set siblings for the child being added to use the ChangeOnAdd transition.
184 childLayout.ConditionForAnimation = TransitionCondition.ChangeOnAdd;
188 case TransitionCondition.ChangeOnRemove :
190 if (childLayout.ConditionForAnimation.HasFlag(TransitionCondition.Remove))
192 break; // Child being Removed so don't update it's condition
196 childLayout.ConditionForAnimation = TransitionCondition.ChangeOnRemove;
200 case TransitionCondition.LayoutChanged :
202 childLayout.ConditionForAnimation = TransitionCondition.LayoutChanged;
211 /// Callback for View.ChildAdded event
213 /// <param name="sender">The object triggering the event.</param>
214 /// <param name="childAddedEvent">Arguments from the event.</param>
215 void OnChildAddedToOwner(object sender, View.ChildAddedEventArgs childAddedEvent)
217 AddChildToLayoutGroup(childAddedEvent.Added);
221 /// Callback for View.ChildRemoved event
223 /// <param name="sender">The object triggering the event.</param>
224 /// <param name="childRemovedEvent">Arguments from the event.</param>
225 void OnChildRemovedFromOwner(object sender, View.ChildRemovedEventArgs childRemovedEvent)
227 RemoveChildFromLayoutGroup(childRemovedEvent.Removed);
231 /// Calculate the right measure spec for this child.
232 /// Does the hard part of MeasureChildren: figuring out the MeasureSpec to
233 /// pass to a particular child. This method figures out the right MeasureSpec
234 /// for one dimension (height or width) of one child view.<br />
236 /// <param name="parentMeasureSpec">The requirements for this view. MeasureSpecification.</param>
237 /// <param name="padding">The padding of this view for the current dimension and margins, if applicable. LayoutLength.</param>
238 /// <param name="childDimension"> How big the child wants to be in the current dimension. LayoutLength.</param>
239 /// <returns>a MeasureSpec for the child.</returns>
240 public static MeasureSpecification GetChildMeasureSpecification(MeasureSpecification parentMeasureSpec, LayoutLength padding, LayoutLength childDimension)
242 MeasureSpecification.ModeType specMode = parentMeasureSpec.Mode;
243 MeasureSpecification.ModeType resultMode = MeasureSpecification.ModeType.Unspecified;
244 LayoutLength resultSize = new LayoutLength(Math.Max( 0.0f, (parentMeasureSpec.Size.AsDecimal() - padding.AsDecimal() ) )); // reduce available size by the owners padding
248 // Parent has imposed an exact size on us
249 case MeasureSpecification.ModeType.Exactly:
251 if ((int)childDimension.AsRoundedValue() == LayoutParamPolicies.MatchParent)
253 // Child wants to be our size. So be it.
254 resultMode = MeasureSpecification.ModeType.Exactly;
256 else if ((int)childDimension.AsRoundedValue() == LayoutParamPolicies.WrapContent)
258 // Child wants to determine its own size. It can't be
260 resultMode = MeasureSpecification.ModeType.AtMost;
264 resultSize = childDimension;
265 resultMode = MeasureSpecification.ModeType.Exactly;
271 // Parent has imposed a maximum size on us
272 case MeasureSpecification.ModeType.AtMost:
274 if (childDimension.AsRoundedValue() == LayoutParamPolicies.MatchParent)
276 // Child wants to be our size, but our size is not fixed.
277 // Constrain child to not be bigger than us.
278 resultMode = MeasureSpecification.ModeType.AtMost;
280 else if (childDimension.AsRoundedValue() == LayoutParamPolicies.WrapContent)
282 // Child wants to determine its own size. It can't be
284 resultMode = MeasureSpecification.ModeType.AtMost;
288 // Child wants a specific size... so be it
289 resultSize = childDimension + padding;
290 resultMode = MeasureSpecification.ModeType.Exactly;
296 // Parent asked to see how big we want to be
297 case MeasureSpecification.ModeType.Unspecified:
300 if ((childDimension.AsRoundedValue() == LayoutParamPolicies.MatchParent))
302 // Child wants to be our size... find out how big it should be
303 resultMode = MeasureSpecification.ModeType.Unspecified;
305 else if (childDimension.AsRoundedValue() == (LayoutParamPolicies.WrapContent))
307 // Child wants to determine its own size.... find out how big
309 resultMode = MeasureSpecification.ModeType.Unspecified;
313 // Child wants a specific size... let him have it
314 resultSize = childDimension + padding;
315 resultMode = MeasureSpecification.ModeType.Exactly;
321 return new MeasureSpecification( resultSize, resultMode );
325 /// Measure the layout and its content to determine the measured width and the measured height.<br />
326 /// If this method is overridden, it is the subclass's responsibility to make
327 /// sure the measured height and width are at least the layout's minimum height
328 /// and width. <br />
330 /// <param name="widthMeasureSpec">horizontal space requirements as imposed by the parent.</param>
331 /// <param name="heightMeasureSpec">vertical space requirements as imposed by the parent.</param>
332 /// <since_tizen> 6 </since_tizen>
333 protected override void OnMeasure(MeasureSpecification widthMeasureSpec, MeasureSpecification heightMeasureSpec)
335 LayoutLength measuredWidth = new LayoutLength(0.0f);
336 LayoutLength measuredHeight = new LayoutLength(0.0f);
338 // Layout takes size of largest child width and largest child height dimensions
339 foreach( LayoutItem childLayout in LayoutChildren )
341 if( childLayout != null )
343 MeasureChild( childLayout, widthMeasureSpec, heightMeasureSpec );
344 LayoutLength childWidth = new LayoutLength(childLayout.MeasuredWidth.Size);
345 LayoutLength childHeight = new LayoutLength( childLayout.MeasuredHeight.Size);
347 Extents childMargin = childLayout.Margin;
348 measuredWidth = new LayoutLength(Math.Max( measuredWidth.AsDecimal(), childWidth.AsDecimal() + childMargin.Start + childMargin.End));
349 measuredHeight = new LayoutLength(Math.Max( measuredHeight.AsDecimal(), childHeight.AsDecimal() + childMargin.Top + childMargin.Bottom));
353 if( 0 == LayoutChildren.Count )
355 // Must be a leaf as has no children
356 measuredWidth = GetDefaultSize( SuggestedMinimumWidth, widthMeasureSpec );
357 measuredHeight = GetDefaultSize( SuggestedMinimumHeight, heightMeasureSpec );
360 SetMeasuredDimensions( new MeasuredSize( measuredWidth, MeasuredSize.StateType.MeasuredSizeOK ),
361 new MeasuredSize( measuredHeight, MeasuredSize.StateType.MeasuredSizeOK ) );
365 /// Called from Layout() when this layout should assign a size and position to each of its children.<br />
366 /// Derived classes with children should override this method and call Layout() on each of their children.<br />
368 /// <param name="changed">This is a new size or position for this layout.</param>
369 /// <param name="left">Left position, relative to parent.</param>
370 /// <param name="top"> Top position, relative to parent.</param>
371 /// <param name="right">Right position, relative to parent.</param>
372 /// <param name="bottom">Bottom position, relative to parent.</param>
373 /// <since_tizen> 6 </since_tizen>
374 protected override void OnLayout(bool changed, LayoutLength left, LayoutLength top, LayoutLength right, LayoutLength bottom)
376 foreach( LayoutItem childLayout in LayoutChildren )
378 if( childLayout !=null )
380 // Use position if explicitly set to child otherwise will be top left.
381 var childLeft = new LayoutLength( childLayout.Owner.Position2D.X );
382 var childTop = new LayoutLength( childLayout.Owner.Position2D.Y );
388 // Margin and Padding only supported when child anchor point is TOP_LEFT.
389 if ( owner.PivotPoint == PivotPoint.TopLeft || ( owner.PositionUsesPivotPoint == false ) )
391 childLeft = childLeft + owner.Padding.Start + childLayout.Margin.Start;
392 childTop = childTop + owner.Padding.Top + childLayout.Margin.Top;
395 childLayout.Layout( childLeft, childTop, childLeft + childLayout.MeasuredWidth.Size, childTop + childLayout.MeasuredHeight.Size );
401 /// Overridden method called when the layout is attached to an owner.<br />
403 /// <since_tizen> 6 </since_tizen>
404 protected override void OnAttachedToOwner()
406 // Layout takes ownership of it's owner's children.
407 foreach (View view in Owner.Children)
409 AddChildToLayoutGroup(view);
412 // Connect to owner ChildAdded signal.
413 Owner.ChildAdded += OnChildAddedToOwner;
415 // Removing Child from the owners View will directly call the LayoutGroup removal API.
418 // Virtual Methods that can be overridden by derived classes.
421 /// Callback when child is added to container.<br />
422 /// Derived classes can use this to set their own child properties on the child layout's owner.<br />
424 /// <param name="child">The Layout child.</param>
425 /// <since_tizen> 6 </since_tizen>
426 protected virtual void OnChildAdd(LayoutItem child)
431 /// Callback when child is removed from container.<br />
433 /// <param name="child">The Layout child.</param>
434 /// <since_tizen> 6 </since_tizen>
435 protected virtual void OnChildRemove(LayoutItem child)
440 /// Ask all of the children of this view to measure themselves, taking into
441 /// account both the MeasureSpec requirements for this view and its padding.<br />
442 /// The heavy lifting is done in GetChildMeasureSpec.<br />
444 /// <param name="widthMeasureSpec">The width requirements for this view.</param>
445 /// <param name="heightMeasureSpec">The height requirements for this view.</param>
446 /// <since_tizen> 6 </since_tizen>
447 protected virtual void MeasureChildren(MeasureSpecification widthMeasureSpec, MeasureSpecification heightMeasureSpec)
449 foreach( LayoutItem childLayout in LayoutChildren )
451 MeasureChild( childLayout, widthMeasureSpec, heightMeasureSpec );
456 /// Ask one of the children of this view to measure itself, taking into
457 /// account both the MeasureSpec requirements for this view and its padding.<br />
458 /// The heavy lifting is done in GetChildMeasureSpecification.<br />
460 /// <param name="child">The child to measure.</param>
461 /// <param name="parentWidthMeasureSpec">The width requirements for this view.</param>
462 /// <param name="parentHeightMeasureSpec">The height requirements for this view.</param>
463 /// <since_tizen> 6 </since_tizen>
464 protected virtual void MeasureChild(LayoutItem child, MeasureSpecification parentWidthMeasureSpec, MeasureSpecification parentHeightMeasureSpec)
466 View childOwner = child.Owner;
468 Extents padding = childOwner.Padding; // Padding of this layout's owner, not of the child being measured.
470 MeasureSpecification childWidthMeasureSpec = GetChildMeasureSpecification( parentWidthMeasureSpec,
471 new LayoutLength(padding.Start + padding.End ),
472 new LayoutLength(childOwner.WidthSpecification) );
474 MeasureSpecification childHeightMeasureSpec = GetChildMeasureSpecification( parentHeightMeasureSpec,
475 new LayoutLength(padding.Top + padding.Bottom),
476 new LayoutLength(childOwner.HeightSpecification) );
478 child.Measure( childWidthMeasureSpec, childHeightMeasureSpec );
482 /// Ask one of the children of this view to measure itself, taking into
483 /// account both the MeasureSpec requirements for this view and its padding.<br />
484 /// and margins. The child must have MarginLayoutParams The heavy lifting is
485 /// done in GetChildMeasureSpecification.<br />
487 /// <param name="child">The child to measure.</param>
488 /// <param name="parentWidthMeasureSpec">The width requirements for this view.</param>
489 /// <param name="widthUsed">Extra space that has been used up by the parent horizontally (possibly by other children of the parent).</param>
490 /// <param name="parentHeightMeasureSpec">The height requirements for this view.</param>
491 /// <param name="heightUsed">Extra space that has been used up by the parent vertically (possibly by other children of the parent).</param>
492 /// <since_tizen> 6 </since_tizen>
493 protected virtual void MeasureChildWithMargins(LayoutItem child, MeasureSpecification parentWidthMeasureSpec, LayoutLength widthUsed, MeasureSpecification parentHeightMeasureSpec, LayoutLength heightUsed)
495 View childOwner = child.Owner;
496 int desiredWidth = childOwner.WidthSpecification;
497 int desiredHeight = childOwner.HeightSpecification;
499 Extents padding = child.Padding; // Padding of this layout's owner, not of the child being measured.
501 MeasureSpecification childWidthMeasureSpec = GetChildMeasureSpecification( parentWidthMeasureSpec,
502 new LayoutLength( padding.Start + padding.End ) +
503 widthUsed, new LayoutLength(desiredWidth) );
506 MeasureSpecification childHeightMeasureSpec = GetChildMeasureSpecification( parentHeightMeasureSpec,
507 new LayoutLength( padding.Top + padding.Bottom )+
508 heightUsed, new LayoutLength(desiredHeight) );
510 child.Measure( childWidthMeasureSpec, childHeightMeasureSpec );