一個UITableView頭部添加一個UIView檩赢，都用snpkit(Swift代碼)布局燃异，一般代碼寫法
override func viewDidLoad() {
super.viewDidLoad()
self.view.addSubview(listView)
listView.snp.makeConstraints { make in
make.edges.equalToSuperview()
}
listView.tableHeaderView = headBackView
headBackView.snp.makeConstraints { make in
make.width.equalTo(listView.snp.width)
make.height.equalTo(100)
}
}
1
很明顯墓猎，view遮住了cell工猜，原因是：
- 在viewDidLoad中乃秀，
listView添加headerView時顽频，headBackView的frame并沒有生成藤肢，listView.tableHeaderView高度為0 - 后面刷新布局時，
headBackView高度改變已經(jīng)不能影響listView.tableHeaderView的布局了 - 因此糯景，需要線確定
headBackView的frame嘁圈，再給listView.tableHeaderView賦值
override func viewDidLoad() {
super.viewDidLoad()
self.view.addSubview(headBackView)
headBackView.snp.makeConstraints { make in
make.top.left.right.equalToSuperview()
make.height.equalTo(100)
}
self.view.addSubview(listView)
listView.snp.makeConstraints { make in
make.edges.equalToSuperview()
}
}
// 在布局完成后的方法中，再操作
override func viewDidAppear(_ animated: Bool) {
super.viewDidAppear(animated)
if listView.tableHeaderView == nil {
headBackView.removeFromSuperview()
listView.tableHeaderView = headBackView
headBackView.snp.remakeConstraints { make in
make.width.equalTo(listView.snp.width)
make.height.equalTo(100)
}
}
}
2
在某個時間點蟀淮，頭部view高度變化
override func viewDidAppear(_ animated: Bool) {
super.viewDidAppear(animated)
if listView.tableHeaderView == nil {
headBackView.removeFromSuperview()
listView.tableHeaderView = headBackView
headBackView.snp.remakeConstraints { make in
make.width.equalTo(listView.snp.width)
make.height.equalTo(100)
}
DispatchQueue.main.asyncAfter(deadline: .now() + 3) {
self.headBackView.snp.updateConstraints { make in
make.height.equalTo(200)
}
}
}
}
3
view還是遮擋了
listView最住，但現(xiàn)在istView.tableHeaderView的高度有100，也就是說：listView.tableHeaderView被賦值后灭贷，snpkit不能在改變它的布局當
headView發(fā)生高度變化時温学，只能先取消istView.tableHeaderView賦值，添加到self.view中甚疟，更改布局仗岖，再賦值給istView.tableHeaderView
override func viewDidAppear(_ animated: Bool) {
super.viewDidAppear(animated)
if listView.tableHeaderView == nil {
headBackView.removeFromSuperview()
listView.tableHeaderView = headBackView
headBackView.snp.remakeConstraints { make in
make.width.equalTo(listView.snp.width)
make.height.equalTo(100)
}
DispatchQueue.main.asyncAfter(deadline: .now() + 3) {
self.listView.tableHeaderView = nil
self.view.addSubview(self.headBackView)
self.headBackView.snp.remakeConstraints { make in
make.width.equalTo(0)
make.height.equalTo(300)
}
// 添加一個延時，再去刷新
DispatchQueue.main.asyncAfter(deadline: .now() + 0.001) {
self.headBackView.removeFromSuperview()
self.listView.tableHeaderView = self.headBackView
self.headBackView.snp.remakeConstraints { make in
make.width.equalTo(self.listView.snp.width)
make.height.equalTo(300)
}
}
}
}
}
4
