iOS8 Masonry UITableViewCell 自适

iOS8中实现了UITableViewCell 高度自适应方式 简化了自适应高度代码。

1:初始化tableView

- (void)viewDidLoad {

[super viewDidLoad];

_tableView = [[UITableView alloc] initWithFrame:CGRectZero style:UITableViewStyleGrouped];

_tableView.dataSource = self;

_tableView.delegate = self;

_tableView.backgroundColor = [UIColor grayColor];

_tableView.estimatedRowHeight = 120;

_tableView.rowHeight = UITableViewAutomaticDimension;

[self.view addSubview:_tableView];

}

这里 _tableView.estimatedRowHeight = 120;和_tableView.rowHeight = UITableViewAutomaticDimension;是实现自适应高度的关键。第一个意思是预设高度。这个高度和实现的高度尽量差距小可以保证速度更快

2: 实现UITableViewDataSource 与 UITableViewDelegate 协议

这里是常见的实现方式 需要注意的是

- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath; 

这个方法不能实现。

3: 自定义Cell 实现自适应高度的关键在  cell的contentView的上下左右约束必须定义。意思就是说自适应的约束条件是依赖cell的contentView的上下左右约束。这也是其关键 以下为一自定义cell使用示例

#import "TBSessionTableViewCell.h"

#import "Masonry.h"

#import "TBEntity.h"

#define TagImgHead 1000

#define TagTitle 1001

#define TagDetail 1002

@implementation TBSessionTableViewCell

- (void)bindData:(TBEntity*)entity indexPath:(NSIndexPath*)indexPath {

__weak TBSessionTableViewCell *weakSelf = self;

UIImageView *imageViewHead = [self.contentView viewWithTag:TagImgHead];

if(nil == imageViewHead) {

imageViewHead = [[UIImageView alloc] init];

imageViewHead.tag = TagImgHead;

imageViewHead.backgroundColor = [UIColor clearColor];

[self.contentView addSubview:imageViewHead];

}

imageViewHead.image = [UIImage imageNamed:@"boy_head_img"];

UILabel *labelTitel = [self.contentView viewWithTag:TagTitle];

if (nil == labelTitel) {

labelTitel  = [[UILabel alloc] init];

labelTitel.tag = TagTitle;

labelTitel.backgroundColor = [UIColor greenColor];

labelTitel.font = [UIFont systemFontOfSize:28];

[self.contentView addSubview:labelTitel];

}

labelTitel.text = entity.title;

UITextView *textView = [self.contentView viewWithTag:TagDetail];

if (nil == textView) {

textView = [[UITextView alloc] init];

textView.tag = TagDetail;

textView.font = [UIFont systemFontOfSize:22];

textView.backgroundColor = [UIColor blueColor];

textView.userInteractionEnabled = NO;

textView.scrollEnabled = NO;

[textView setShowsVerticalScrollIndicator:NO];

[textView setShowsHorizontalScrollIndicator:NO];

[self.contentView addSubview:textView];

}

textView.text = entity.detail;

[imageViewHead mas_remakeConstraints:^(MASConstraintMaker *make) {

make.left.equalTo(weakSelf.contentView.mas_left).mas_equalTo(10);

make.top.equalTo(weakSelf.contentView.mas_top).mas_equalTo(10);

make.width.equalTo(@60);

make.height.equalTo(@60);

make.bottom.mas_lessThanOrEqualTo(@-10);//保证底部至少与图片有10的距离

}];

[labelTitel mas_remakeConstraints:^(MASConstraintMaker *make) {

make.top.equalTo(weakSelf.contentView.mas_top).mas_offset(10);

make.left.equalTo(weakSelf.contentView.mas_left).mas_offset(80);

make.width.mas_equalTo(weakSelf.contentView.frame.size.width-80-10);

make.height.equalTo(@28);

}];

CGFloat fW = weakSelf.contentView.frame.size.width-80-10;

//计数字高度

CGSize contentSize = [textView.text boundingRectWithSize:CGSizeMake(fW, MAXFLOAT)

options:NSStringDrawingUsesLineFragmentOrigin |

NSStringDrawingTruncatesLastVisibleLine |

NSStringDrawingUsesFontLeading

attributes:@{NSFontAttributeName : [UIFont systemFontOfSize:22.0]}

context:nil].size;

[textView mas_remakeConstraints:^(MASConstraintMaker *make) {

make.left.equalTo(weakSelf.contentView.mas_left).mas_offset(80);

make.top.equalTo(@58);

make.width.mas_equalTo(fW);

make.height.mas_equalTo(contentSize.height);

make.bottom.mas_lessThanOrEqualTo(@-10).priorityLow();//处理约束冲突警告保证底部10距离

}];

}