Merge "Improve GridLayout's weight calculations" into lmp-mr1-dev
diff --git a/core/java/android/widget/GridLayout.java b/core/java/android/widget/GridLayout.java
index defc26c..161ae7e 100644
--- a/core/java/android/widget/GridLayout.java
+++ b/core/java/android/widget/GridLayout.java
@@ -1613,7 +1613,11 @@
equivalent to the single-source shortest paths problem on a digraph, for
which the O(n^2) Bellman-Ford algorithm the most commonly used general solution.
*/
- private void solve(Arc[] arcs, int[] locations) {
+ private boolean solve(Arc[] arcs, int[] locations) {
+ return solve(arcs, locations, true);
+ }
+
+ private boolean solve(Arc[] arcs, int[] locations, boolean modifyOnError) {
String axisName = horizontal ? "horizontal" : "vertical";
int N = getCount() + 1; // The number of vertices is the number of columns/rows + 1.
boolean[] originalCulprits = null;
@@ -1631,10 +1635,14 @@
if (originalCulprits != null) {
logError(axisName, arcs, originalCulprits);
}
- return;
+ return true;
}
}
+ if (!modifyOnError) {
+ return false; // cannot solve with these constraints
+ }
+
boolean[] culprits = new boolean[arcs.length];
for (int i = 0; i < N; i++) {
for (int j = 0, length = arcs.length; j < length; j++) {
@@ -1658,6 +1666,7 @@
}
}
}
+ return true;
}
private void computeMargins(boolean leading) {
@@ -1697,8 +1706,8 @@
return trailingMargins;
}
- private void solve(int[] a) {
- solve(getArcs(), a);
+ private boolean solve(int[] a) {
+ return solve(getArcs(), a);
}
private boolean computeHasWeights() {
@@ -1740,28 +1749,18 @@
return deltas;
}
- private void shareOutDelta() {
- int totalDelta = 0;
- float totalWeight = 0;
+ private void shareOutDelta(int totalDelta, float totalWeight) {
+ Arrays.fill(deltas, 0);
for (int i = 0, N = getChildCount(); i < N; i++) {
View c = getChildAt(i);
LayoutParams lp = getLayoutParams(c);
Spec spec = horizontal ? lp.columnSpec : lp.rowSpec;
float weight = spec.weight;
if (weight != 0) {
- int delta = getMeasurement(c, horizontal) - getOriginalMeasurements()[i];
- totalDelta += delta;
- totalWeight += weight;
- }
- }
- for (int i = 0, N = getChildCount(); i < N; i++) {
- LayoutParams lp = getLayoutParams(getChildAt(i));
- Spec spec = horizontal ? lp.columnSpec : lp.rowSpec;
- float weight = spec.weight;
- if (weight != 0) {
int delta = Math.round((weight * totalDelta / totalWeight));
deltas[i] = delta;
- // the two adjustments below are to counter the above rounding and avoid off-by-ones at the end
+ // the two adjustments below are to counter the above rounding and avoid
+ // off-by-ones at the end
totalDelta -= delta;
totalWeight -= weight;
}
@@ -1771,12 +1770,46 @@
private void solveAndDistributeSpace(int[] a) {
Arrays.fill(getDeltas(), 0);
solve(a);
- shareOutDelta();
- arcsValid = false;
- forwardLinksValid = false;
- backwardLinksValid = false;
- groupBoundsValid = false;
- solve(a);
+ int deltaMax = parentMin.value * getChildCount() + 1; //exclusive
+ if (deltaMax < 2) {
+ return; //don't have any delta to distribute
+ }
+ int deltaMin = 0; //inclusive
+
+ float totalWeight = calculateTotalWeight();
+
+ int validDelta = -1; //delta for which a solution exists
+ boolean validSolution = true;
+ // do a binary search to find the max delta that won't conflict with constraints
+ while(deltaMin < deltaMax) {
+ final int delta = (deltaMin + deltaMax) / 2;
+ invalidateValues();
+ shareOutDelta(delta, totalWeight);
+ validSolution = solve(getArcs(), a, false);
+ if (validSolution) {
+ validDelta = delta;
+ deltaMin = delta + 1;
+ } else {
+ deltaMax = delta;
+ }
+ }
+ if (validDelta > 0 && !validSolution) {
+ // last solution was not successful but we have a successful one. Use it.
+ invalidateValues();
+ shareOutDelta(validDelta, totalWeight);
+ solve(a);
+ }
+ }
+
+ private float calculateTotalWeight() {
+ float totalWeight = 0f;
+ for (int i = 0, N = getChildCount(); i < N; i++) {
+ View c = getChildAt(i);
+ LayoutParams lp = getLayoutParams(c);
+ Spec spec = horizontal ? lp.columnSpec : lp.rowSpec;
+ totalWeight += spec.weight;
+ }
+ return totalWeight;
}
private void computeLocations(int[] a) {