/**
* Update the flow on the given FlowView. By default, this causes all of the rows (child views)
* to be rebuilt to match the given constraints for each row. This is called by a
* FlowView.layout to update the child views in the flow.
*
* @param fv the view to reflow
*/
public void layout(FlowView fv) {
int p0 = fv.getStartOffset();
int p1 = fv.getEndOffset();
// we want to preserve all views from the logicalView from being
// removed
View lv = getLogicalView(fv);
int n = lv.getViewCount();
for (int i = 0; i < n; i++) {
View v = lv.getView(i);
v.setParent(lv);
}
fv.removeAll();
for (int rowIndex = 0; p0 < p1; rowIndex++) {
View row = fv.createRow();
fv.append(row);
// layout the row to the current span. If nothing fits,
// force something.
int next = layoutRow(fv, rowIndex, p0);
if (row.getViewCount() == 0) {
row.append(createView(fv, p0, Integer.MAX_VALUE, rowIndex));
next = row.getEndOffset();
}
if (next <= p0) {
throw new StateInvariantError("infinite loop in formatting");
} else {
p0 = next;
}
}
}
/**
* Adjusts the given row if possible to fit within the layout span. By default this will try to
* find the highest break weight possible nearest the end of the row. If a forced break is
* encountered, the break will be positioned there.
*
* @param rowIndex the row to adjust to the current layout span.
* @param desiredSpan the current layout span >= 0
* @param x the location r starts at.
*/
protected void adjustRow(FlowView fv, int rowIndex, int desiredSpan, int x) {
final int flowAxis = fv.getFlowAxis();
View r = fv.getView(rowIndex);
int n = r.getViewCount();
int span = 0;
int bestWeight = BadBreakWeight;
int bestSpan = 0;
int bestIndex = -1;
int bestOffset = 0;
View v;
for (int i = 0; i < n; i++) {
v = r.getView(i);
int spanLeft = desiredSpan - span;
int w = v.getBreakWeight(flowAxis, x + span, spanLeft);
if ((w >= bestWeight) && (w > BadBreakWeight)) {
bestWeight = w;
bestIndex = i;
bestSpan = span;
if (w >= ForcedBreakWeight) {
// it's a forced break, so there is
// no point in searching further.
break;
}
}
span += v.getPreferredSpan(flowAxis);
}
if (bestIndex < 0) {
// there is nothing that can be broken, leave
// it in it's current state.
return;
}
// Break the best candidate view, and patch up the row.
int spanLeft = desiredSpan - bestSpan;
v = r.getView(bestIndex);
v = v.breakView(flowAxis, v.getStartOffset(), x + bestSpan, spanLeft);
View[] va = new View[1];
va[0] = v;
View lv = getLogicalView(fv);
for (int i = bestIndex; i < n; i++) {
View tmpView = r.getView(i);
if (contains(lv, tmpView)) {
tmpView.setParent(lv);
} else if (tmpView.getViewCount() > 0) {
recursiveReparent(tmpView, lv);
}
}
r.replace(bestIndex, n - bestIndex, va);
}
private boolean contains(View logicalView, View v) {
int n = logicalView.getViewCount();
for (int i = 0; i < n; i++) {
if (logicalView.getView(i) == v) {
return true;
}
}
return false;
}
private void recursiveReparent(View v, View logicalView) {
int n = v.getViewCount();
for (int i = 0; i < n; i++) {
View tmpView = v.getView(i);
if (contains(logicalView, tmpView)) {
tmpView.setParent(logicalView);
} else {
recursiveReparent(tmpView, logicalView);
}
}
}
/**
* Creates a row of views that will fit within the layout span of the row. This is called by the
* layout method. This is implemented to fill the row by repeatedly calling the createView
* method until the available span has been exhausted, a forced break was encountered, or the
* createView method returned null. If the remaining span was exhaused, the adjustRow method
* will be called to perform adjustments to the row to try and make it fit into the given span.
*
* @param rowIndex the index of the row to fill in with views. The row is assumed to be empty on
* entry.
* @param pos The current position in the children of this views element from which to start.
* @return the position to start the next row
*/
protected int layoutRow(FlowView fv, int rowIndex, int pos) {
View row = fv.getView(rowIndex);
int x = fv.getFlowStart(rowIndex);
int spanLeft = fv.getFlowSpan(rowIndex);
int end = fv.getEndOffset();
TabExpander te = (fv instanceof TabExpander) ? (TabExpander) fv : null;
// Indentation.
int preX = x;
int availableSpan = spanLeft;
preX = x;
final int flowAxis = fv.getFlowAxis();
boolean forcedBreak = false;
while (pos < end && spanLeft > 0) {
View v = createView(fv, pos, spanLeft, rowIndex);
if (v == null) {
break;
}
int chunkSpan;
if ((flowAxis == X_AXIS) && (v instanceof TabableView)) {
chunkSpan = (int) ((TabableView) v).getTabbedSpan(x, te);
} else {
chunkSpan = (int) v.getPreferredSpan(flowAxis);
}
// If a forced break is necessary, break
if (v.getBreakWeight(flowAxis, pos, spanLeft) >= ForcedBreakWeight) {
int n = row.getViewCount();
if (n > 0) {
/* If this is a forced break and it's not the only view
* the view should be replaced with a call to breakView.
* If it's it only view, it should be used directly. In
* either case no more children should be added beyond this
* view.
*/
v = v.breakView(flowAxis, pos, x, spanLeft);
if (v != null) {
if ((flowAxis == X_AXIS) && (v instanceof TabableView)) {
chunkSpan = (int) ((TabableView) v).getTabbedSpan(x, te);
} else {
chunkSpan = (int) v.getPreferredSpan(flowAxis);
}
} else {
chunkSpan = 0;
}
}
forcedBreak = true;
}
spanLeft -= chunkSpan;
x += chunkSpan;
if (v != null) {
row.append(v);
pos = v.getEndOffset();
}
if (forcedBreak) {
break;
}
}
if (spanLeft < 0) {
// This row is too long and needs to be adjusted.
adjustRow(fv, rowIndex, availableSpan, preX);
} else if (row.getViewCount() == 0) {
// Impossible spec... put in whatever is left.
View v = createView(fv, pos, Integer.MAX_VALUE, rowIndex);
row.append(v);
}
return row.getEndOffset();
}