如何在IOS中使用可重复使用的单元格

好.我似乎不能很好地了解桌面视图的工作原理.有人可以向我解释细胞在桌面中是否重复使用,特别是滚动时？关于这一点的一个主要痛点是,当我在一个单元格中创建一个动作时,其他单元格会在滚动时受到影响.我尝试使用一个数组作为模型的后端,但是我仍然想到,当不考虑时,它会改变细胞.需要弄清楚的是,当阵列中的模型没有改变时,为什么会改变它们.

一个简单的例子：

表视图单元格与按钮“喜欢”.当我单击其中一个单元格中的按钮时,按钮文本更改为“不同”(到目前为止这么好).但是当我向下滚动时,即使我没有选择它们,其他单元格也显示“不同”.当我向上滚动时,我最初选择的单元格再次更改,较新的单元格也会更改.

我似乎没有想到这一点.如果你能给我一个工作示例的源代码,那将是真棒！谢谢！

- (void)viewDidLoad
{
    [super viewDidLoad];


    likeState = [[NSMutableArray alloc]init];

    int i =0;
    for (i=0; i<20; i++) {
        [likeState addObject:[NSNumber numberWithInt:0]];
    }
} 
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:@"Cell" forIndexPath:indexPath];

    UIButton *myButton = [UIButton buttonWithType:UIButtonTypeRoundedRect];
    [myButton setTitle:@"Like" forState:UIControlStateNormal];
    [myButton addTarget:self action:@selector(tapped:) forControlEvents:UIControlEventTouchUpInside];
    myButton.frame = CGRectMake(14.0,10.0,125.0,25.0);
    myButton.tag =indexPath.row;
    [cell.contentView addSubview:myButton];

    if (cell ==nil) {


    }

    if ([[likeState objectAtIndex:indexPath.row]boolValue]==NO) {
        [myButton setTitle:@"Like" forState:UIControlStateNormal];

    }
    else{
        [myButton setTitle:@"Unlike" forState:UIControlStateNormal];


    }


    return cell;
}
-(void)tapped:(UIButton *)sender{

[likeState replaceObjectAtIndex:sender.tag withObject:[NSNumber numberWithInt:1]];

    [sender setTitle:@"Unlike" forState:UIControlStateNormal];

}

解决方法@H_301_12@

我假设你是通过Storyboard来做的,因为你没有通过Interface Builder创建你的按钮,所以你需要检查一下被重新使用的单元格是否已经有按钮了.
根据您当前的逻辑,您正在创建一个新的按钮实例,一直在单元格重新出现.

我建议如下：

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
    static NSString *CellIdentifier = @"Cell";
    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier forIndexPath:indexPath];

    //following is required when using XIB but not needed when using Storyboard
    /*
     if (cell == nil) {
         cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier];
     }
     */
    //Reason:
    //[1] When using XIB,dequeueReusableCellWithIdentifier does NOT create a cell so (cell == nil) condition occurs
    //[2] When using Storyboard,dequeueReusableCellWithIdentifier DOES create a cell and so (cell == nil) condition never occurs

    //check if cell is being reused by checking if the button already exists in it
    UIButton *myButton = (UIButton *)[cell.contentView viewWithTag:100];

    if (myButton == nil) {
        myButton = [UIButton buttonWithType:UIButtonTypeCustom];
        [myButton setFrame:CGRectMake(14.0,25.0)];
        [myButton setTag:100]; //the tag is what helps in the first step
        [myButton setTitle:@"Like" forState:UIControlStateNormal];
        [myButton setTitleColor:[UIColor blueColor] forState:UIControlStateNormal];
        [myButton addTarget:self action:@selector(tapped:andEvent:) forControlEvents:UIControlEventTouchUpInside];
        [cell.contentView addSubview:myButton];

        NSLog(@"Button created");
    }
    else {
        NSLog(@"Button already created");
    }

    if ([likeState[indexPath.row] boolValue]) {
        [myButton setTitle:@"Unlike" forState:UIControlStateNormal];
    }
    else {
        [myButton setTitle:@"Like" forState:UIControlStateNormal];
    }

    return cell;
}

-(void)tapped:(UIButton *)sender andEvent:(UIEvent *)event
{
    //get index
    NSSet *touches = [event allTouches];
    UITouch *touch = [touches anyObject];
    CGPoint currentTouchPosition = [touch locationInView:self.tableView];
    NSIndexPath *indexPath = [self.tableView indexPathForRowAtPoint:currentTouchPosition];

    //toggle "like" status
    if ([likeState[indexPath.row] boolValue]) {
        [likeState replaceObjectAtIndex:indexPath.row withObject:@(0)];
        [sender setTitle:@"Like" forState:UIControlStateNormal];
    }
    else {
        [likeState replaceObjectAtIndex:indexPath.row withObject:@(1)];
        [sender setTitle:@"Unlike" forState:UIControlStateNormal];
    }
}

如何在IOS中使用可重复使用的单元格

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