98d5f04f91
This CL improves the method by which excess space is distributed in GridLayout. Previously, GridLayout would assume weights were arranged in a 'line' and sum the weights in the assumed line to figure out the proportional allocation to each view. The system involved running GridLayout's internal constraint solver twice. Behavior was unspecified (and surprising) when weights appeared in views that were not linked together linearly, typically leaving the last view in each axis with more space than expected (in GridLayout's Bellman-Ford constraint solver, remaining space goes to the last span of the axis). This CL changes the weight distribution mechanism to effectively integrate it with the Bellman-Ford constraint resolution algorithm. It does this by returning a boolean value from the constraint solver saying whether or not the constraints could be solved and then using a binary chop to find a maximum amount of space that can be distributed without violating the constraints. This implementation runs the solver log(<axis size> * <number of Views>) times until finding the maximum amount of space that can be distributed according to the weights without causing a contradiction. We expect the cost of this variation to be around a factor of 10 worse than the previous implementation but to provide a simple and general definition of space distribution via weights that will be open to many future optimizations. As a side effect, this CL also fixes a bug in GridLayout where remaining space was distributed only along the major axis. Bug: 17485996 Change-Id: I120f39e95e90b5b35072ef8a6c348ec541aae42a