解决tableView中cell动态加载控件的重用问题

解决tableView中cell动态加载控件的重用问题

tableView的cell,有时候需要在运行时取得对应的数据后才能够动态的创建该cell中的控件并加载到该cell中,此时,你一定会遇到重用问题,即使你能做到该cell只根据数值加载了一回控件,你也没法保证不出现重用问题:)

效果(请注意查看,移动下面的格子时,上面出现了重用的问题)

源码:

YXCell.h

//

// YXCell.h

// YXTableView

// Copyright (c) 2014年 Y.X. All rights reserved.

#import UIKit/UIKit.h 

@interface YXCell : UITableViewCell

@property (nonatomic, strong) NSString *count; // 控件个数

@property (nonatomic, assign) BOOL flag; // 控制标签

@end

//

// YXCell.m

// YXTableView

// Copyright (c) 2014年 Y.X. All rights reserved.

#import "YXCell.h"

@implementation YXCell

- (id)initWithStyle:(UITableViewCellStyle)style reuseIdentifier:(NSString *)reuseIdentifier

 self = [super initWithStyle:style reuseIdentifier:reuseIdentifier];

 if (self)

 return self;

@synthesize count = _count;

- (void)setCount:(NSString *)count

 if ([count intValue] 0 _flag == NO)

 _flag = YES;

 UIScrollView *scrollView = [[UIScrollView alloc] initWithFrame:CGRectMake(0, 0, 320, 100)];

 scrollView.contentSize = CGSizeMake([count intValue]*100, 100);

 for (int i = 0; i [count intValue]; i++)

 UILabel *tmpLabel = [[UILabel alloc] initWithFrame:CGRectMake(i*100, 0, 100, 100)];

 tmpLabel.text = [NSString stringWithFormat:@"%d", i];

 tmpLabel.textAlignment = NSTextAlignmentCenter;

 tmpLabel.font = [UIFont fontWithName:@"HelveticaNeue-UltraLight"

 size:40.f];

 [scrollView addSubview:tmpLabel];

 [self addSubview:scrollView];

 _count = count;

@end

//

// RootViewController.m

// YXTableView

// Copyright (c) 2014年 Y.X. All rights reserved.

#import "RootViewController.h"

#import "YXCell.h"


static NSString *reUsedStr[REUESED_SIZE] = {nil}; // 重用标示

#define REUESED_FLAG reUsedStr[0]


@property (nonatomic, strong) UITableView *mainTableView;

@property (nonatomic, strong) NSArray *dataArray;

@implementation RootViewController

+ (void)initialize

 if (self == [RootViewController class])

 for (int i = 0; i REUESED_SIZE; i++)

 reUsedStr[i] = [NSString stringWithFormat:@"YouXianMing_%d", i];

- (void)viewDidLoad

 [super viewDidLoad];

 // 数据源

 _dataArray = @[[NSString stringWithFormat:@"%d", arc4random()%20 + 5],

 [NSString stringWithFormat:@"%d", arc4random()%20 + 5],

 [NSString stringWithFormat:@"%d", arc4random()%20 + 5],

 [NSString stringWithFormat:@"%d", arc4random()%20 + 5],

 [NSString stringWithFormat:@"%d", arc4random()%20 + 5],

 [NSString stringWithFormat:@"%d", arc4random()%20 + 5],

 [NSString stringWithFormat:@"%d", arc4random()%20 + 5],

 [NSString stringWithFormat:@"%d", arc4random()%20 + 5],

 [NSString stringWithFormat:@"%d", arc4random()%20 + 5],

 [NSString stringWithFormat:@"%d", arc4random()%20 + 5],

 [NSString stringWithFormat:@"%d", arc4random()%20 + 5],

 [NSString stringWithFormat:@"%d", arc4random()%20 + 5],

 [NSString stringWithFormat:@"%d", arc4random()%20 + 5],

 [NSString stringWithFormat:@"%d", arc4random()%20 + 5],

 [NSString stringWithFormat:@"%d", arc4random()%20 + 5],

 [NSString stringWithFormat:@"%d", arc4random()%20 + 5],

 [NSString stringWithFormat:@"%d", arc4random()%20 + 5],

 [NSString stringWithFormat:@"%d", arc4random()%20 + 5],

 [NSString stringWithFormat:@"%d", arc4random()%20 + 5],

 [NSString stringWithFormat:@"%d", arc4random()%20 + 5],

 [NSString stringWithFormat:@"%d", arc4random()%20 + 5],

 [NSString stringWithFormat:@"%d", arc4random()%20 + 5],

 [NSString stringWithFormat:@"%d", arc4random()%20 + 5],

 [NSString stringWithFormat:@"%d", arc4random()%20 + 5]];

 // UITableView

 _mainTableView = [[UITableView alloc] initWithFrame:self.view.bounds

 style:UITableViewStylePlain];

 _mainTableView.delegate = self;

 _mainTableView.dataSource = self;

 [self.view addSubview:_mainTableView];


#pragma mark - UITableView delegate dataSource

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

 return [_dataArray count];

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath

 YXCell *cell = [tableView dequeueReusableCellWithIdentifier:REUESED_FLAG];

 if (cell == nil)

 cell = [[YXCell alloc] initWithStyle:UITableViewCellStyleDefault

 reuseIdentifier:REUESED_FLAG];

 cell.count = _dataArray[indexPath.row];

 return cell;

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

 return 100;

@end

几个比较关键的地方:

本例中出现的重用问题由下面部分引发:

如果要解决这个重用问题,我们只能够让这个cell不重用,那就得定义足够多的重用标示才行,改成如下即可:

效果:

总结:

为何要处心积虑弄这种不重用的cell呢?当然,这是为了满足特定的需求而出现的适合于少量的cell的情形,对于这种动态加载的cell,你亲自动手试一下或许就能明白作者本人为何如此设计的用心良苦:)