adaptesGridCrossAxisCount function
根据宽度约束布局最大宽度
Implementation
int adaptesGridCrossAxisCount(BoxConstraints constraints) {
int maxWidth = 2;
if (constraints.maxWidth > kExtraLargeWidthBreakpoint) {
maxWidth = 6;
} else if (constraints.maxWidth > kLargeWidthBreakpoint) {
maxWidth = 4;
} else if (constraints.maxWidth > kMediumWidthBreakpoint) {
maxWidth = 3;
} else if (constraints.maxWidth > kSmallWidthBreakpoint) {
maxWidth = 2;
}
return maxWidth;
}