iOS 6.0 Masonry自动布局表头/表尾时崩溃解决方案

iOS 6.0 Masonry自动布局表头/表尾时崩溃解决方案

Masonry

iOS6.0

UITableView

tableHeaderView

tableFooterView

iOS6.0

提示：若您的App不需要支持到iOS6.0，那么您没必要继续阅读这篇文章

支持原创，请阅读原文

解决方案

- (void)configTableView {
if (self.tableView != nil) {
return;
}
self.tableView = [[UITableView alloc] init];
[self.view addSubview:self.tableView];
[self.tableView mas_makeConstraints:^(MASConstraintMaker *make) {
make.edges.mas_equalTo(self.view);
}];

NSArray *array = [self headerViewWithHeight:self.view.frame.size.height addToView:self.view];
UIView *headerView = [array firstObject];
[headerView layoutIfNeeded];
UIButton *button = [array lastObject];
CGFloat h = button.frame.size.height + button.frame.origin.y + 40;
h = h < self.view.frame.size.height ? self.view.frame.size.height : h;

[headerView removeFromSuperview];
[self headerViewWithHeight:h addToView:nil];
}

- (NSArray *)headerViewWithHeight:(CGFloat)height addToView:(UIView *)toView {
// 注意，绝对不能给tableheaderview直接添加约束，必闪退
UIView *headerView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, self.view.frame.size.width, height)];

if (toView) {
[toView addSubview:headerView];
} else {
self.tableView.tableHeaderView = headerView;
}

UIImageView *imgView = [[UIImageView alloc] init];
[headerView addSubview:imgView];
imgView.backgroundColor = [UIColor greenColor];
imgView.layer.cornerRadius = 50;
imgView.layer.masksToBounds = YES;
imgView.layer.borderWidth = 0.5;
imgView.layer.borderColor = [UIColor redColor].CGColor;

CGFloat screenWidth = [UIScreen mainScreen].bounds.size.width;

UILabel *tipLabel = [[UILabel alloc] init];
tipLabel.text = @"这里是提示信息，通常会比较长，可能会超过两行。为了适配6.0，我们需要指定preferredMaxLayoutWidth，但是要注意，此属性一旦设置，不是只在6.0上生效，任意版本的系统的都有作用，因此此值设置得一定要准备，否则计算结果会不正确。我们一定要注意，不能给tableview的tableHeaderView和tableFooterView添加约束，在6.0及其以下版本上会crash，其它版本没有";
tipLabel.textAlignment = NSTextAlignmentCenter;
tipLabel.textColor = [UIColor blackColor];
tipLabel.backgroundColor = [UIColor clearColor];
tipLabel.numberOfLines = 0;
tipLabel.preferredMaxLayoutWidth = screenWidth - 30;
[headerView addSubview:tipLabel];

UIButton *button = [UIButton buttonWithType:UIButtonTypeCustom];
[button setTitle:@"Show detail" forState:UIControlStateNormal];
[button setTitleColor:[UIColor whiteColor] forState:UIControlStateNormal];
[button setBackgroundColor:[UIColor blueColor]];
button.layer.cornerRadius = 6;
button.clipsToBounds = YES;
button.layer.masksToBounds = YES;

[headerView addSubview:button];

[imgView mas_makeConstraints:^(MASConstraintMaker *make) {
make.top.mas_equalTo(80);
make.centerX.mas_equalTo(headerView);
make.width.height.mas_equalTo(100);
}];

[tipLabel mas_makeConstraints:^(MASConstraintMaker *make) {
make.left.mas_equalTo(self.view).offset(15);
make.right.mas_equalTo(self.view).offset(-15);
make.top.mas_equalTo(imgView.mas_bottom).offset(40);
}];

[button mas_makeConstraints:^(MASConstraintMaker *make) {
make.top.mas_greaterThanOrEqualTo(tipLabel.mas_bottom).offset(80);
make.left.mas_equalTo(tipLabel);
make.right.mas_equalTo(tipLabel);
make.height.mas_equalTo(45);
}];

return @[headerView, button];
}

NSArray *array = [self headerViewWithHeight:self.view.frame.size.height addToView:self.view];
UIView *headerView = [array firstObject];
[headerView layoutIfNeeded];
UIButton *button = [array lastObject];
CGFloat h = button.frame.size.height + button.frame.origin.y + 40;
h = h < self.view.frame.size.height ? self.view.frame.size.height : h;

[headerView removeFromSuperview];
[self headerViewWithHeight:h addToView:nil];

headerView

headerView

self.view

self.tableView.tableHeaderView = headerView

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