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解决tableView中cell动态加载控件的重用问题

2024-07-14 01:24:08   215人阅读

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

////  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

////  RootViewController.m//  YXTableView////  Copyright (c) 2014年 Y.X. All rights reserved.//#import "RootViewController.h"#import "YXCell.h"#define REUESED_SIZE  100static NSString *reUsedStr[REUESED_SIZE] = {nil}; // 重用标示#define REUESED_FLAG  reUsedStr[0]@interface RootViewController ()<UITableViewDataSource, UITableViewDelegate>@property (nonatomic, strong) UITableView  *mainTableView;@property (nonatomic, strong) NSArray      *dataArray;@end@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:)


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