OC：tableViewCell高度自适应

下面来借助于 UITableView+FDTemplateLayoutCell 演示一下 cell 的高度自适应：孙源老师是用xib实现的，我这里用Masonry代码布局来实现。当然，UITableViewHeaderFooterView也是相似用法。

注意点：

• 1. 在 tableView 里，需要对 cell 进行注册（必须）

// xib
- (void)registerNib:(nullable UINib *)nib forCellReuseIdentifier:(NSString *)identifier; 
// 纯代码
- (void)registerClass:(nullable Class)cellClass forCellReuseIdentifier:(NSString *)identifier; 

• 2. 返回 cell 的高度的三种方法

// 返回由重用标识符指定并由 block 配置的类型的 cell 高度。
- (CGFloat)fd_heightForCellWithIdentifier:(NSString *)identifier configuration:(void (^)(id cell))configuration;

// 该方法和`-fd_heightForCellWithIdentifier:configuration`做一样的事，
// 计算的高度将由其 indexPath 缓存，需要时返回缓存的高度。
// 因此，能节省很多高度计算。
// 无需担心数据源改变导致 cell 高度无效的问题，`-reloadData`或任意触发tableview重载都会重新计算
- (CGFloat)fd_heightForCellWithIdentifier:(NSString *)identifier cacheByIndexPath:(NSIndexPath *)indexPath configuration:(void (^)(id cell))configuration;

// 该方法通过模型实体的标识符缓存高度。
// 如果您的模型已更改，请调用“-invalidateHeightForKey:(id <NSCopying>)key”以使缓存无效并重新计算，
// 它比“cacheByIndexPath”更高效。
- (CGFloat)fd_heightForCellWithIdentifier:(NSString *)identifier cacheByKey:(id<NSCopying>)key configuration:(void (^)(id cell))configuration;

以下为代码：
DetailViewController.h

#import "DetailViewController.h"

#import "FeedEntity.h"
#import "DetailTableViewCell.h"

#import "UITableView+FDTemplateLayoutCell.h"

@interface DetailViewController ()<UITableViewDelegate, UITableViewDataSource>

@property (weak, nonatomic) IBOutlet UITableView *mTableView;

@property (nonatomic, strong) NSMutableArray *dataList;

@end

static NSString *cellIdentifier = @"UITableViewCell";

@implementation DetailViewController


- (void)viewDidLoad {
    [super viewDidLoad];
    
    [self.mTableView registerClass:[DetailTableViewCell class] forCellReuseIdentifier:cellIdentifier];
    
    [self fetchDataFromLocalJSON];
}

#pragma mark - tableViewDataSource && tableViewDelegate

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
    return [self.dataList count];
}

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
    
    DetailTableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:cellIdentifier];

    [self configureCell:cell atIndexPath:indexPath];
    
    return cell;
}

- (void)configureCell:(DetailTableViewCell *)cell atIndexPath:(NSIndexPath *)indexPath {
    
    if (indexPath.row % 2 == 0) {
        cell.accessoryType = UITableViewCellAccessoryDisclosureIndicator;
    } else {
        cell.accessoryType = UITableViewCellAccessoryCheckmark;
    }
    cell.entity = self.dataList[indexPath.row];
}

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

    return [tableView fd_heightForCellWithIdentifier:cellIdentifier cacheByIndexPath:indexPath configuration:^(DetailTableViewCell *cell) {
        [self configureCell:cell atIndexPath:indexPath];
    }];
}

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
    
}

- (void)fetchDataFromLocalJSON {
    NSString *dataFilePath = [[NSBundle mainBundle] pathForResource:@"data" ofType:@"json"];
    NSData *data = [NSData dataWithContentsOfFile:dataFilePath];
    NSDictionary *rootDict = [NSJSONSerialization JSONObjectWithData:data options:NSJSONReadingAllowFragments error:nil];
    NSArray *feedDicts = rootDict[@"feed"];
    
    NSMutableArray *entities = @[].mutableCopy;
    [feedDicts enumerateObjectsUsingBlock:^(id obj, NSUInteger idx, BOOL *stop) {
        [entities addObject:[[FeedEntity alloc] initWithDictionary:obj]];
    }];
    self.dataList = entities;
}

#pragma mark - Getters

- (NSMutableArray *)dataList {
    if (!_dataList) {
        _dataList = [NSMutableArray array];
    }
    return _dataList;
}

@end

DetailTableViewCell.h

#import "DetailTableViewCell.h"

//Libs
#import "UILabel+MZExtension.h"
#import <Masonry/Masonry.h>

//Model
#import "FeedEntity.h"

@interface DetailTableViewCell ()

@property (nonatomic, strong) UILabel *titleLabel;
@property (nonatomic, strong) UILabel *contentLabel;
@property (nonatomic, strong) UIImageView *contentImageView;
@property (nonatomic, strong) UILabel *usernameLabel;
@property (nonatomic, strong) UILabel *timeLabel;

@end

@implementation DetailTableViewCell

- (instancetype)initWithStyle:(UITableViewCellStyle)style reuseIdentifier:(NSString *)reuseIdentifier {
    if (self = [super initWithStyle:style reuseIdentifier:reuseIdentifier]) {
        [self buildViews];
    }
    return self;
}

- (void)setEntity:(FeedEntity *)entity {
    _entity = entity;
    
    self.titleLabel.text = entity.title;
    self.contentLabel.text = entity.content;
    self.contentImageView.image = entity.imageName.length > 0 ? [UIImage imageNamed:entity.imageName] : nil;
    self.usernameLabel.text = entity.username;
    self.timeLabel.text = entity.time;
}

- (void)buildViews {
    
    [self.contentView addSubview:self.titleLabel];
    [self.contentView addSubview:self.contentLabel];
    [self.contentView addSubview:self.contentImageView];
    [self.contentView addSubview:self.usernameLabel];
    [self.contentView addSubview:self.timeLabel];
    
    [self.titleLabel mas_makeConstraints:^(MASConstraintMaker *make) {
        make.left.top.equalTo(@10);
        make.right.equalTo(@-20);
        make.height.equalTo(@17).priorityHigh();
    }];
    
    [self.contentLabel mas_makeConstraints:^(MASConstraintMaker *make) {
        make.left.right.equalTo(self.titleLabel);
        make.height.greaterThanOrEqualTo(@17);
        make.top.equalTo(self.titleLabel.mas_bottom).offset(10);
    }];
    
    [self.contentImageView mas_makeConstraints:^(MASConstraintMaker *make) {
        make.top.equalTo(self.contentLabel.mas_bottom).offset(10).priorityHigh();
        make.left.equalTo(self.titleLabel);
        make.bottom.equalTo(self.usernameLabel.mas_top).offset(-10);
        make.right.lessThanOrEqualTo(@-16);
    }];
    
    [self.usernameLabel mas_makeConstraints:^(MASConstraintMaker *make) {
        make.left.equalTo(self.titleLabel);
        make.size.equalTo(self.usernameLabel);
        make.bottom.equalTo(@-15);
    }];
    
    [self.timeLabel mas_makeConstraints:^(MASConstraintMaker *make) {
        make.right.equalTo(@-20);
        make.centerY.equalTo(self.usernameLabel);
        make.size.equalTo(self.timeLabel);
    }];
}


#pragma mark - Getters

- (UILabel *)titleLabel {
    if (!_titleLabel) {
        _titleLabel = [UILabel labelWithTitle:@"名字" color:@"00006C" fontSize:17];
    }
    return _titleLabel;
}

- (UILabel *)contentLabel {
    if (!_contentLabel) {
        _contentLabel = [UILabel labelWithTitle:@"名字" color:@"555555" fontSize:15];
        _contentLabel.numberOfLines = 0;
    }
    return _contentLabel;
}

- (UILabel *)usernameLabel {
    if (!_usernameLabel) {
        _usernameLabel = [UILabel labelWithTitle:@"名字" color:@"AAAAAA" fontSize:13];
    }
    return _usernameLabel;
}

- (UILabel *)timeLabel {
    if (!_timeLabel) {
        _timeLabel = [UILabel labelWithTitle:@"名字" color:@"8CAAE4" fontSize:13];
    }
    return _timeLabel;
}

- (UIImageView *)contentImageView {
    if (!_contentImageView) {
        _contentImageView = [[UIImageView alloc] init];
    }
    return _contentImageView;
}

@end

FeedEntity.h

#import <Foundation/Foundation.h>

@interface FeedEntity : NSObject

- (instancetype)initWithDictionary:(NSDictionary *)dictionary;

@property (nonatomic, copy, readonly) NSString *identifier;
@property (nonatomic, copy, readonly) NSString *title;
@property (nonatomic, copy, readonly) NSString *content;
@property (nonatomic, copy, readonly) NSString *username;
@property (nonatomic, copy, readonly) NSString *time;
@property (nonatomic, copy, readonly) NSString *imageName;

@end

FeedEntity.m

#import "FeedEntity.h"

@implementation FeedEntity

- (instancetype)initWithDictionary:(NSDictionary *)dictionary {
    self = super.init;
    if (self) {
        _identifier = [self uniqueIdentifier];
        _title = dictionary[@"title"];
        _content = dictionary[@"content"];
        _username = dictionary[@"username"];
        _time = dictionary[@"time"];
        _imageName = dictionary[@"imageName"];
    }
    return self;
}

- (NSString *)uniqueIdentifier {
    static NSInteger counter = 0;
    return [NSString stringWithFormat:@"unique-id-%@", @(counter++)];
}


@end