/**
* Creates a new {@link GridDropHandler} for
*
* @param gridLayoutRule the corresponding {@link GridLayoutRule}
* @param layout the GridLayout node
* @param view the view instance of the grid layout receiving the drop
*/
public GridDropHandler(GridLayoutRule gridLayoutRule, INode layout, Object view) {
mRule = gridLayoutRule;
mGrid = GridModel.get(mRule.getRulesEngine(), layout, view);
}
/**
* Called when a node is dropped in free-form mode. This will insert the dragged element into the
* grid and returns the newly created node.
*
* @param targetNode the GridLayout node
* @param element the dragged element
* @return the newly created {@link INode}
*/
public INode handleFreeFormDrop(INode targetNode, IDragElement element) {
assert mRowMatch != null;
assert mColumnMatch != null;
String fqcn = element.getFqcn();
INode newChild = null;
Rect bounds = element.getBounds();
int row = mRowMatch.cellIndex;
int column = mColumnMatch.cellIndex;
if (targetNode.getChildren().length == 0) {
//
// Set up the initial structure:
//
//
// Fixed Fixed
// Size Size
// Column Expanding Column Column
// +-----+-------------------------------+-----+
// | | | |
// | 0,0 | 0,1 | 0,2 | Fixed Size Row
// | | | |
// +-----+-------------------------------+-----+
// | | | |
// | | | |
// | | | |
// | 1,0 | 1,1 | 1,2 | Expanding Row
// | | | |
// | | | |
// | | | |
// +-----+-------------------------------+-----+
// | | | |
// | 2,0 | 2,1 | 2,2 | Fixed Size Row
// | | | |
// +-----+-------------------------------+-----+
//
// This is implemented in GridLayout by the following grid, where
// SC1 has columnWeight=1 and SR1 has rowWeight=1.
// (SC=Space for Column, SR=Space for Row)
//
// +------+-------------------------------+------+
// | | | |
// | SCR0 | SC1 | SC2 |
// | | | |
// +------+-------------------------------+------+
// | | | |
// | | | |
// | | | |
// | SR1 | | |
// | | | |
// | | | |
// | | | |
// +------+-------------------------------+------+
// | | | |
// | SR2 | | |
// | | | |
// +------+-------------------------------+------+
//
// Note that when we split columns and rows here, if splitting the expanding
// row or column then the row or column weight should be moved to the right or
// bottom half!
// int columnX = mGrid.getColumnX(column);
// int rowY = mGrid.getRowY(row);
mGrid.setGridAttribute(targetNode, ATTR_COLUMN_COUNT, 2);
// mGrid.setGridAttribute(targetNode, ATTR_COLUMN_COUNT, 3);
// INode scr0 = addSpacer(targetNode, -1, 0, 0, 1, 1);
// INode sc1 = addSpacer(targetNode, -1, 0, 1, 0, 0);
// INode sc2 = addSpacer(targetNode, -1, 0, 2, 1, 0);
// INode sr1 = addSpacer(targetNode, -1, 1, 0, 0, 0);
// INode sr2 = addSpacer(targetNode, -1, 2, 0, 0, 1);
// mGrid.setGridAttribute(sc1, ATTR_LAYOUT_GRAVITY, VALUE_FILL_HORIZONTAL);
// mGrid.setGridAttribute(sr1, ATTR_LAYOUT_GRAVITY, VALUE_FILL_VERTICAL);
//
// mGrid.loadFromXml();
// column = mGrid.getColumn(columnX);
// row = mGrid.getRow(rowY);
}
int startX, endX;
if (mColumnMatch.type == SegmentType.RIGHT) {
endX = mColumnMatch.matchedLine - 1;
startX = endX - bounds.w;
column = mGrid.getColumn(startX);
} else {
startX = mColumnMatch.matchedLine; // TODO: What happens on type=RIGHT?
endX = startX + bounds.w;
}
int startY, endY;
if (mRowMatch.type == SegmentType.BOTTOM) {
endY = mRowMatch.matchedLine - 1;
startY = endY - bounds.h;
row = mGrid.getRow(startY);
} else if (mRowMatch.type == SegmentType.BASELINE) {
// TODO: The rowSpan should always be 1 for baseline alignments, since
// otherwise the alignment won't work!
startY = endY = mRowMatch.matchedLine;
} else {
startY = mRowMatch.matchedLine;
endY = startY + bounds.h;
}
int endColumn = mGrid.getColumn(endX);
int endRow = mGrid.getRow(endY);
int columnSpan = endColumn - column + 1;
int rowSpan = endRow - row + 1;
// Make sure my math was right:
assert mRowMatch.type != SegmentType.BASELINE || rowSpan == 1 : rowSpan;
// If the item almost fits into the row (at most N % bigger) then just enlarge
// the row; don't add a rowspan since that will defeat baseline alignment etc
if (!mRowMatch.createCell
&& bounds.h
<= MAX_CELL_DIFFERENCE
* mGrid.getRowHeight(mRowMatch.type == SegmentType.BOTTOM ? endRow : row, 1)) {
if (mRowMatch.type == SegmentType.BOTTOM) {
row += rowSpan - 1;
}
rowSpan = 1;
}
if (!mColumnMatch.createCell
&& bounds.w
<= MAX_CELL_DIFFERENCE
* mGrid.getColumnWidth(
mColumnMatch.type == SegmentType.RIGHT ? endColumn : column, 1)) {
if (mColumnMatch.type == SegmentType.RIGHT) {
column += columnSpan - 1;
}
columnSpan = 1;
}
if (mColumnMatch.type == SegmentType.CENTER_HORIZONTAL) {
column = 0;
columnSpan = mGrid.actualColumnCount;
}
// Temporary: Ensure we don't get in trouble with implicit positions
mGrid.applyPositionAttributes();
// Split cells to make a new column
if (mColumnMatch.createCell) {
int columnWidthPx = mGrid.getColumnDistance(column, mColumnMatch.matchedLine);
// assert columnWidthPx == columnMatch.distance; // TBD? IF so simplify
int columnWidthDp = mRule.getRulesEngine().pxToDp(columnWidthPx);
int maxX = mGrid.getColumnMaxX(column);
boolean insertMarginColumn = false;
if (mColumnMatch.margin == 0) {
columnWidthDp = 0;
} else if (mColumnMatch.margin != UNDEFINED) {
int distance = abs(mColumnMatch.matchedLine - (maxX + mColumnMatch.margin));
insertMarginColumn = column > 0 && distance < 2;
if (insertMarginColumn) {
int margin = mColumnMatch.margin;
if (ViewMetadataRepository.INSETS_SUPPORTED) {
IViewMetadata metadata = mRule.getRulesEngine().getMetadata(fqcn);
if (metadata != null) {
Margins insets = metadata.getInsets();
if (insets != null) {
// TODO:
// Consider left or right side attachment
// TODO: Also consider inset of element on cell to the left
margin -= insets.left;
}
}
}
columnWidthDp = mRule.getRulesEngine().pxToDp(margin);
}
}
column++;
mGrid.splitColumn(column, insertMarginColumn, columnWidthDp, mColumnMatch.matchedLine);
if (insertMarginColumn) {
column++;
}
}
// Split cells to make a new row
if (mRowMatch.createCell) {
int rowHeightPx = mGrid.getRowDistance(row, mRowMatch.matchedLine);
// assert rowHeightPx == rowMatch.distance; // TBD? If so simplify
int rowHeightDp = mRule.getRulesEngine().pxToDp(rowHeightPx);
int maxY = mGrid.getRowMaxY(row);
boolean insertMarginRow = false;
if (mRowMatch.margin == 0) {
rowHeightDp = 0;
} else if (mRowMatch.margin != UNDEFINED) {
int distance = abs(mRowMatch.matchedLine - (maxY + mRowMatch.margin));
insertMarginRow = row > 0 && distance < 2;
if (insertMarginRow) {
int margin = mRowMatch.margin;
IViewMetadata metadata = mRule.getRulesEngine().getMetadata(element.getFqcn());
if (metadata != null) {
Margins insets = metadata.getInsets();
if (insets != null) {
// TODO:
// Consider left or right side attachment
// TODO: Also consider inset of element on cell to the left
margin -= insets.top;
}
}
rowHeightDp = mRule.getRulesEngine().pxToDp(margin);
}
}
row++;
mGrid.splitRow(row, insertMarginRow, rowHeightDp, mRowMatch.matchedLine);
if (insertMarginRow) {
row++;
}
}
// Figure out where to insert the new child
int index = mGrid.getInsertIndex(row, column);
if (index == -1) {
// Couldn't find a later place to insert
newChild = targetNode.appendChild(fqcn);
} else {
GridModel.ViewData next = mGrid.getView(index);
newChild = targetNode.insertChildAt(fqcn, index);
// Must also apply positions to the following child to ensure
// that the new child doesn't affect the implicit numbering!
// TODO: We can later check whether the implied number is equal to
// what it already is such that we don't need this
next.applyPositionAttributes();
}
// Set the cell position (gravity) of the new widget
int gravity = 0;
if (mColumnMatch.type == SegmentType.RIGHT) {
gravity |= GravityHelper.GRAVITY_RIGHT;
} else if (mColumnMatch.type == SegmentType.CENTER_HORIZONTAL) {
gravity |= GravityHelper.GRAVITY_CENTER_HORIZ;
}
mGrid.setGridAttribute(newChild, ATTR_LAYOUT_COLUMN, column);
if (mRowMatch.type == SegmentType.BASELINE) {
// There *is* no baseline gravity constant, instead, leave the
// vertical gravity unspecified and GridLayout will treat it as
// baseline alignment
// gravity |= GravityHelper.GRAVITY_BASELINE;
} else if (mRowMatch.type == SegmentType.BOTTOM) {
gravity |= GravityHelper.GRAVITY_BOTTOM;
} else if (mRowMatch.type == SegmentType.CENTER_VERTICAL) {
gravity |= GravityHelper.GRAVITY_CENTER_VERT;
}
// Ensure that we have at least one horizontal and vertical constraint, otherwise
// the new item will be fixed. As an example, if we have a single button in the
// table which we inserted *without* a gravity, and we then insert a button
// above it with a vertical gravity, then only the top column would be considered
// stretchable, and it will fill all available vertical space and the previous
// button will jump to the bottom.
if (!GravityHelper.isConstrainedHorizontally(gravity)) {
gravity |= GravityHelper.GRAVITY_LEFT;
}
/* This causes problems: Try placing two buttons vertically from the top of the layout.
We need to solve the free column/free row problem first.
if (!GravityHelper.isConstrainedVertically(gravity)
// There is no baseline constant, so we have to leave it unconstrained instead
&& mRowMatch.type != SegmentType.BASELINE
// You also can't baseline align one element with another that has vertical
// alignment top or bottom, so when we first "freely" place views (e.g.
// at a particular y location), also place it freely (no constraint).
&& !mRowMatch.createCell) {
gravity |= GravityHelper.GRAVITY_TOP;
}
*/
mGrid.setGridAttribute(newChild, ATTR_LAYOUT_GRAVITY, getGravity(gravity));
mGrid.setGridAttribute(newChild, ATTR_LAYOUT_ROW, row);
// Apply spans to ensure that the widget can fit without pushing columns
if (columnSpan > 1) {
mGrid.setGridAttribute(newChild, ATTR_LAYOUT_COLUMN_SPAN, columnSpan);
}
if (rowSpan > 1) {
mGrid.setGridAttribute(newChild, ATTR_LAYOUT_ROW_SPAN, rowSpan);
}
// Ensure that we don't store columnCount=0
if (mGrid.actualColumnCount == 0) {
mGrid.setGridAttribute(mGrid.layout, ATTR_COLUMN_COUNT, Math.max(1, column + 1));
}
return newChild;
}