尝试在项目中用masonry布局tableView的头部。
-(UIView *)tableView:(UITableView *)tableView viewForHeaderInSection:(NSInteger)section
{
if (section == 0) {
UIView *headerView = [[UIView alloc] init];
[headerView mas_makeConstraints:^(MASConstraintMaker *make) {
make.top.equalTo(self.LoginWaytableView.mas_top);
make.left.equalTo(self.LoginWaytableView.mas_left);
make.right.equalTo(self.LoginWaytableView.mas_right);
make.height.equalTo(@200);
}];
UIImageView *imagerView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"景.jpg"]];
[imagerView mas_makeConstraints:^(MASConstraintMaker *make) {
make.top.equalTo(headerView.mas_top).with.offset(10);
make.left.equalTo(headerView.mas_left).with.offset(100);
make.right.equalTo(headerView.mas_right).with.offset(-100);
make.height.equalTo(headerView.mas_height).multipliedBy(0.5);
}];
UILabel *passwordLabel = [[UILabel alloc] init];
passwordLabel.text = @"密码登录";
passwordLabel.textColor = [UIColor blackColor];
[passwordLabel mas_makeConstraints:^(MASConstraintMaker *make) {
make.top.equalTo(imagerView.mas_top).with.offset(10);
make.left.right.equalTo(imagerView);
make.bottom.equalTo(headerView.mas_bottom).with.offset(10);
}];
[headerView addSubview:imagerView];
[headerView addSubview:passwordLabel];
return headerView;
}
return nil;
}
结果报错如下:
***
Terminating app due to uncaught exception 'NSInternalInconsistencyException',
reason: 'couldn't find a common superview for
<UIView: 0x7fecaef1edc0; frame = (0 0; 0 0); layer = <CALayer: 0x6080002301a0>>
and <UITableView: 0x7fecb00d7000;
frame = (0 64; 375 603); clipsToBounds = YES; gestureRecognizers = <NSArray: 0x600000258de0>;
layer = <CALayer: 0x600000234a20>; contentOffset: {0, -64}; contentSize: {375, 842}>'
*** First throw call stack:
崩溃原因大致意思是说，这个UIView和UITableView没有一个共同的父View。
得出使用自动布局autoLayout(Masonry基于约束autoLayout)需要两个View拥有一个共同的父View。很明显，headerView 和 self.LoginWayTableView两个View在目前这个tableView的代理函数中还没有共同的父View。因为headerView还没有加载在self.LoginWayTableView上面。只有当此函数执行结束的时候才被加载上去。到时它们才拥有共同的父Viewself.LoginWaytableView。
