ListView与GridView自适应高度,与Bug解决gridView.getNumColumns() = -1

ListView自适应：

public static void setListViewHeightBasedOnChildren(ListView listView) {
ListAdapter listAdapter = listView.getAdapter();
if (listAdapter == null) {
return;
}
int totalHeight = 0;
for (int i = 0; i < listAdapter.getCount(); i++) {
View listItem = listAdapter.getView(i, null, listView);
listItem.measure(0, 0);
totalHeight += listItem.getMeasuredHeight();
}

ViewGroup.LayoutParams params = listView.getLayoutParams();

params.height = totalHeight
+ (listView.getDividerHeight() * (listAdapter.getCount() - 1));
listView.setLayoutParams(params);
}

GridView自适应，存在Bug待解决

// listView.getNumColumns() = -1?; 始终返回 -1；

public static void setListViewHeightBasedOnChildren(GridView listView) {
// 获取listview的adapter
ListAdapter listAdapter = listView.getAdapter();
if (listAdapter == null) {
return;
}
// 固定列宽，有多少列
int col = 3;
// listView.getNumColumns() = -1?;
// i每次加4，相当于listAdapter.getCount()小于等于4时 循环一次，计算一次item的高度，
// listAdapter.getCount()小于等于8时计算两次高度相加
/*for (int i = 0; i < listAdapter.getCount(); i += col) {
// 获取listview的每一个item
View listItem = listAdapter.getView(i, null, listView);
listItem.measure(0, 0);
// 获取item的高度和
totalHeight += listItem.getMeasuredHeight();
}*/
View listItem = listAdapter.getView(0, null, listView);
listItem.measure(0, 0);
// 获取item的高度和
int totalHeight = listItem.getMeasuredHeight();
// 获取listview的布局参数
ViewGroup.LayoutParams params = listView.getLayoutParams();
if (listAdapter.getCount() % col != 0) {
totalHeight = totalHeight * (listAdapter.getCount() / col + 1);
} else {
totalHeight = totalHeight * (listAdapter.getCount() / col);
}

// 设置高度
params.height = totalHeight;
// 设置margin
((MarginLayoutParams) params).setMargins(10, 10, 10, 10);
// 设置参数
listView.setLayoutParams(params);
}

Field field = GridView.class.getDeclaredField("mRequestedNumColumns"); // 获得申明的字段field.setAccessible(true); // 设置访问权限column = Integer.valueOf(field.get(gridView).toString()); // 获取字段的值