Question

正在为我的tableview单元格做一个自定义单元格，我在customcell类中编写一个条件，如果indexpath.row = 0则为单元格创建2个图像，否则创建3个图像，

我的自定义单元格类

if (appDelegate.rowIndex==0)
        {
            UIButton *lObjImageButton=[UIButton buttonWithType:UIButtonTypeCustom];
            lObjImageButton.frame=CGRectMake(150*0+12.5, 5, 150-10, 290 - 120+10);
            [lObjImageButton setBackgroundColor:[UIColor greenColor]];
            //lObjImageButton.imageView.contentMode  = UIViewContentModeScaleAspectFit;
            [self addSubview:lObjImageButton];

            UIButton *lObjImageButton1=[UIButton buttonWithType:UIButtonTypeCustom];
            lObjImageButton1.frame=CGRectMake(150*1+10+5, 5, 150-10, 170+10);
            [lObjImageButton1 setBackgroundColor:[UIColor redColor]];

            //lObjImageButton1.imageView.contentMode  = UIViewContentModeScaleAspectFit;
            [self addSubview:lObjImageButton1];

            imageButtonArray = [[NSArray alloc] initWithObjects:lObjImageButton, lObjImageButton1, nil];
        }
        else
        {
        UIButton *lObjImageButton=[UIButton buttonWithType:UIButtonTypeCustom];
        lObjImageButton.frame=CGRectMake(150*0+12.5, 5, 150-10, 290 - 120+10);
        [lObjImageButton setBackgroundColor:[UIColor greenColor]];
        //lObjImageButton.imageView.contentMode  = UIViewContentModeScaleAspectFit;
        [self addSubview:lObjImageButton];

        UIButton *lObjImageButton1=[UIButton buttonWithType:UIButtonTypeCustom];
        lObjImageButton1.frame=CGRectMake(150*1+10+5, 5, 150-10, 170+10);
        [lObjImageButton1 setBackgroundColor:[UIColor redColor]];

        //lObjImageButton1.imageView.contentMode  = UIViewContentModeScaleAspectFit;
        [self addSubview:lObjImageButton1];


            UIButton *lObjImageButton2=[UIButton buttonWithType:UIButtonTypeCustom];
            lObjImageButton2.frame=CGRectMake(150*2+10+5, 5, 150-10, 170+10);
            [lObjImageButton2 setBackgroundColor:[UIColor blueColor]];

            //lObjImageButton1.imageView.contentMode  = UIViewContentModeScaleAspectFit;
            [self addSubview:lObjImageButton2];

        imageButtonArray = [[NSArray alloc] initWithObjects:lObjImageButton, lObjImageButton1,lObjImageButton2, nil];
        }

这里的appdelegate.rowindex值在我的viewcontroller里面的cellforrowindex中设置为appdelegate.rowstauts = indexpath.row

我运行应用程序，项目按照我的意愿执行，第一个单元格2图像和剩余单元格3图像，但是当我滚动条件不匹配并使somtime第6个单元格为2个图像并且sumtime 3个单元格为2个图像而我的第1个单元格变为3个图像..

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

    static NSString *CellIdentifier = @"Cell";

    BSImageCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
    appDelegate.rowIndex=indexPath.row;

    NSLog(@"cell.index= %i",cell.index);
    if (cell == nil) {

        cell = [[BSImageCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier];

    }


    return cell;
}

滚动问题就出现了。

Answer 1

问题在于UITableView使这些单元格可以重用，以提高性能。

你必须在cellForRowAtIndexPath中创建这个条件。

-(UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath{
NSString* reusableCellIdentifier = @"";
  if(indexPath.row == 0){
    reusableCellIdentifier = @"firstCell";
  }else{
    reusableCellIdentifier = @"otherCells";
  }
}

Answer 2

使用polymorphism代替检查自定义单元格中的条件。

写两个类：

@interface KSRTwoButtonCell : UITableViewCell { ... }

@interface KSRThreeButtonCell : UITableViewCell { ... }

然后再做

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
    BOOL wantThreeButtonCell = (indexPath.row == 0);

    NSString *cellIdentifier;
    if (wantThreeButtonCell) {
        cellIdentifier = @"ThreeButtonCell";
    }
    else {
        cellIdentifier = @"TwoButtonCell";
    }

    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:cellIdentifier];

    if (cell == nil) {
        if (wantThreeButtonCell) {
            cell = [[KSRThreeButtonCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:cellIdentifier];
        }
        else {
            cell = [[KSRTwoButtonCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:cellIdentifier];
        }
    }

    return cell;
}

Answer 3

定义cell.h文件中的所有按钮和所有属性。用

替换cell.m文件代码

 lObjImageButton=[UIButton buttonWithType:UIButtonTypeCustom];
lObjImageButton.frame=CGRectMake(150*0+12.5, 5, 150-10, 290 - 120+10);
[lObjImageButton setBackgroundColor:[UIColor greenColor]];
[self addSubview:lObjImageButton];
    lObjImageButton1=[UIButton buttonWithType:UIButtonTypeCustom];
    lObjImageButton1.frame=CGRectMake(150*1+10+5, 5, 150-10, 170+10);
    [lObjImageButton1 setBackgroundColor:[UIColor redColor]];

    //lObjImageButton1.imageView.contentMode  = UIViewContentModeScaleAspectFit;
    [self addSubview:lObjImageButton1];


        lObjImageButton2=[UIButton buttonWithType:UIButtonTypeCustom];
        lObjImageButton2.frame=CGRectMake(150*2+10+5, 5, 150-10, 170+10);
        [lObjImageButton2 setBackgroundColor:[UIColor blueColor]];

        //lObjImageButton1.imageView.contentMode  = UIViewContentModeScaleAspectFit;
        [self addSubview:lObjImageButton2];

    imageButtonArray = [[NSArray alloc] initWithObjects:lObjImageButton, lObjImageButton1,lObjImageButton2, nil];

2.在返回单元格之前，在表委托方法中添加以下内容;

if(indexPath.row==0){

            cell.lObjImageButton.frame=CGRectMake(150*0+12.5, 5, 150-10, 290 - 120+10);
            cell.lObjImageButton1.frame=CGRectMake(150*1+10+5, 5, 150-10, 170+10);
cell.lObjImageButton2.hidden =TRUE;

}
else{
cell.lObjImageButton2.hidden =FALSE;
        cell.lObjImageButton.frame=CGRectMake(150*0+12.5, 5, 150-10, 290 - 120+10);

        cell.lObjImageButton1.frame=CGRectMake(150*1+10+5, 5, 150-10, 170+10);

            cell.lObjImageButton2.frame=CGRectMake(150*2+10+5, 5, 150-10, 170+10);

}

希望它会对你有所帮助。

Answer 4

创建- (void)resetCell方法，将单元格重置为初始状态，并创建- (void)configureImageView:(int)rowIndex，在BSImageCell

中配置图像视图

- (void)configureImageView:(int)rowIndex
{
    if (rowIndex==0)
    {
        UIButton *lObjImageButton=[UIButton buttonWithType:UIButtonTypeCustom];
        lObjImageButton.frame=CGRectMake(150*0+12.5, 5, 150-10, 290 - 120+10);
        [lObjImageButton setBackgroundColor:[UIColor greenColor]];
        //lObjImageButton.imageView.contentMode  = UIViewContentModeScaleAspectFit;
        [self addSubview:lObjImageButton];

        UIButton *lObjImageButton1=[UIButton buttonWithType:UIButtonTypeCustom];
        lObjImageButton1.frame=CGRectMake(150*1+10+5, 5, 150-10, 170+10);
        [lObjImageButton1 setBackgroundColor:[UIColor redColor]];

        //lObjImageButton1.imageView.contentMode  = UIViewContentModeScaleAspectFit;
        [self addSubview:lObjImageButton1];

        imageButtonArray = [[NSArray alloc] initWithObjects:lObjImageButton, lObjImageButton1, nil];
    }
    else
    {
        UIButton *lObjImageButton=[UIButton buttonWithType:UIButtonTypeCustom];
        lObjImageButton.frame=CGRectMake(150*0+12.5, 5, 150-10, 290 - 120+10);
        [lObjImageButton setBackgroundColor:[UIColor greenColor]];
        //lObjImageButton.imageView.contentMode  = UIViewContentModeScaleAspectFit;
        [self addSubview:lObjImageButton];

        UIButton *lObjImageButton1=[UIButton buttonWithType:UIButtonTypeCustom];
        lObjImageButton1.frame=CGRectMake(150*1+10+5, 5, 150-10, 170+10);
        [lObjImageButton1 setBackgroundColor:[UIColor redColor]];

        //lObjImageButton1.imageView.contentMode  = UIViewContentModeScaleAspectFit;
        [self addSubview:lObjImageButton1];


        UIButton *lObjImageButton2=[UIButton buttonWithType:UIButtonTypeCustom];
        lObjImageButton2.frame=CGRectMake(150*2+10+5, 5, 150-10, 170+10);
        [lObjImageButton2 setBackgroundColor:[UIColor blueColor]];

        //lObjImageButton1.imageView.contentMode  = UIViewContentModeScaleAspectFit;
        [self addSubview:lObjImageButton2];

        imageButtonArray = [[NSArray alloc] initWithObjects:lObjImageButton, lObjImageButton1,lObjImageButton2, nil];
    }
}

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

        cell = [[BSImageCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier];

    }
    else
    {
        [cell resetCell];
    }
    [cell configureImageView:indexPath];

    return cell;
}

自定义TableView单元格，检查条件

4 个答案: