自定义cell的高度

//
//  RootTableViewController.m
//  Share
//
//  Created by lanouhn on 15/1/20.
//  Copyright (c) 2015年 niutiantian. All rights reserved.
//

#import "RootTableViewController.h"
#import "CustomTableViewCell.h"
#import "DetailViewController.h"

static NSString *cellIndentifer = @"cell";

@interface RootTableViewController ()

@end

@implementation RootTableViewController

- (void)dealloc
{
    self.charString = nil;
    self.secondString = nil;
    self.custom = nil;
    [super dealloc];
}

- (void)viewDidLoad {
    [super viewDidLoad];
    self.charString = @"只要有吃的，鱼就不停地吃？因为不知饥饱，鱼缸里的鱼因为喂食太多，给撑死了？只要有吃的，鱼就不停地吃？因为不知饥饱，鱼缸里的鱼因为喂食太多，给撑死了？只要有吃的，鱼就不停地吃？因为不知饥饱，鱼缸里的鱼因为喂食太多，给撑死了？";
    self.secondString = @"只要有吃的，鱼就不停地吃？因为不知饥饱，鱼缸里的鱼因为喂食太多，给撑死了？只要有吃的，鱼就不停地吃？因为不知饥饱，鱼缸";
    
        //注册cell
    [self.tableView registerClass:[CustomTableViewCell class] forCellReuseIdentifier:cellIndentifer];
    self.custom = [self.tableView dequeueReusableCellWithIdentifier:cellIndentifer];
}

- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

#pragma mark - Table view data source

- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView {

return 1;
}

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {

return 10;
}

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
    CustomTableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:cellIndentifer forIndexPath:indexPath];
    if (indexPath.row % 2 == 0) {
        cell.label.text = _charString;
        [cell resetLabelFram:_charString];
        
    } else {
        cell.label.text = _secondString;
        [cell resetLabelFram:_secondString];
    }
        //错误案例
//    if (indexPath.row % 2 == 0) {
//        self.tableView.rowHeight = [CustomTableViewCell heigehtCharString:_charString];
//    } else {
//        self.tableView.rowHeight = [CustomTableViewCell heigehtCharString:_secondString];
//    }
    return cell;
}

- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath {
        //方法一
//    if (indexPath.row % 2 == 0) {
//       return [CustomTableViewCell heigehtCharString:_charString];
//    } else {
//        return [CustomTableViewCell heigehtCharString:_secondString];
//    }
        //方法二
    if (indexPath.row % 2 == 0) {
        self.custom.label.text = _charString;
       
    } else {
        self.custom.label.text = _secondString;
    
    }
    CGRect rect = [self.custom.label.text boundingRectWithSize:CGSizeMake([UIScreen mainScreen].bounds.size.width, 0) options:NSStringDrawingUsesLineFragmentOrigin | NSStringDrawingUsesFontLeading attributes:@{NSFontAttributeName: [UIFont systemFontOfSize:17]} context:nil];
    return rect.size.height;

}

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
    DetailViewController *detail = [[DetailViewController alloc] init];
    [self.navigationController pushViewController:detail animated:YES];
    [detail release];
}

@end

//
//  CustomTableViewCell.m
//  Share
//
//  Created by lanouhn on 15/1/20.
//  Copyright (c) 2015年 niutiantian. All rights reserved.
//

#import "CustomTableViewCell.h"

@implementation CustomTableViewCell

-(instancetype)initWithStyle:(UITableViewCellStyle)style reuseIdentifier:(NSString *)reuseIdentifier {
    if (self = [super initWithStyle:style reuseIdentifier:reuseIdentifier]) {
        self.label = [[UILabel alloc] initWithFrame:CGRectMake(0, 0, self.bounds.size.width, self.bounds.size.height)];
        _label.numberOfLines = 0;
        [self addSubview:_label];
        [_label release];
    }
    return self;
}

+ (CGFloat)heigehtCharString: (NSString *)aString
{
    CGRect rect = [aString boundingRectWithSize:CGSizeMake([UIScreen mainScreen].bounds.size.width, 0) options:NSStringDrawingUsesLineFragmentOrigin | NSStringDrawingUsesFontLeading attributes:@{NSFontAttributeName: [UIFont systemFontOfSize:17]} context:nil];
    return  rect.size.height;
    
}
    //重设label的高度
- (void)resetLabelFram: (NSString *)aString
{
       CGRect rect = [aString boundingRectWithSize:CGSizeMake([UIScreen mainScreen].bounds.size.width, 0) options:NSStringDrawingUsesLineFragmentOrigin | NSStringDrawingUsesFontLeading attributes:@{NSFontAttributeName: [UIFont systemFontOfSize:17]} context:nil];
    
    _label.frame = CGRectMake(0, 0, self.bounds.size.width, rect.size.height);
}

@end