Question

我想知道如何在UITableView中的选定单元格行中设置图像。

如果我选择第一个单元格，图像应显示在第一个单元格中，稍后当我选择第二个单元格时，图像应仅显示在第二个单元格中（而不是第一个单元格）

基本上，图像应仅显示在所选单元格中。

Answer 1

最干净的方法是继承UITableViewCell。

#import <UIKit/UIKit.h>

@interface SongCell : UITableViewCell
@property (nonatomic, assign) BOOL isPlaying;
@end

@interface SongCell ()
@property (nonatomic, strong) UIImage *speakerImage;
@end

@implementation SongCell

-(void)layoutSubviews
{
    if (!_speakerImage) {
        // http://commons.wikimedia.org/wiki/File:Speaker_Icon.svg
        self.speakerImage = [UIImage imageNamed:@"speaker_icon.png"];
    }

    if(!self.isPlaying){
        self.imageView.image = nil;
    } else {
        self.imageView.image = _speakerImage;
        self.imageView.hidden =NO;
    }
    [super layoutSubviews];
}

- (void)setSelected:(BOOL)selected animated:(BOOL)animated
{
    [super setSelected:selected animated:animated];
    if (!selected) {
        self.isPlaying = NO;
    }
}


-(void)setIsPlaying:(BOOL)isPlaying
{
    _isPlaying = isPlaying;
    [self setNeedsLayout];
}
@end

UITableViews数据源和委托实现

-(NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
{
    return 1;
}

-(NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
    return 20;
}

-(UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
    static NSString *identifier = @"SongCell";
    SongCell *cell = [tableView dequeueReusableCellWithIdentifier:identifier forIndexPath:indexPath];
    return cell;
}

-(void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
    SongCell *cell =(SongCell *)[tableView cellForRowAtIndexPath:indexPath] ;
    cell.isPlaying = !cell.isPlaying;
}

我为你准备了一个演示项目。您可以在GitHub

找到它

Answer 2

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath*)indexPath
{
    [self.tableView deselectRowAtIndexPath:indexPath animated:YES];
    [UIView animateWithDuration:2.0f animations:^{
    [imageView setHidden:NO];
    } completion:^(BOOL finished) {
        ;
    }];
}

Answer 3

您想要imageView的切换类型。

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

    if (cell == nil) {
        cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault
                                      reuseIdentifier:CellIdentifier];
    }

    [cell.imageView setImage: [UIImage imageNamed:@""]];
    return cell;
}

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
    //refresh all cells
    //basically call cellForRowAtIndexPath to reset all cells
    [tableView reloadSections:indexPath.section
             withRowAnimation:UITableViewRowAnimationFade];

    //get cell for the currently selected row
    UITableViewCell *cell = [tableView cellForRowAtIndexPath:indexPath];
    //set image
    [cell.imageView setImage: [UIImage imageNamed:@"loudspeaker.png"]];
}

但这只是一个视觉方面如果您选择第一行并向下滚动并稍后返回第一行，则图片将不再存在，因为-cellForRowAtIndexPath:已被召回，而且由于我们已[cell.imageView setImage: [UIImage imageNamed:@""]];，imageView.image重置。

要处理上述情况，您需要记住选择了哪些行。（您可以通过基本数组实现此目的）

实施例

- (void)viewDidLoad {
    [super viewDidLoad];

    //arrMyDataSource is defined in .h as 'NSArray *arrMyDataSource;'
    //needless to say but this is the tableView's datasource contents
    arrMyDataSource = @[@"Apple",@"Banana",@"Candy",@"Door",@"Elephant"];

    //arrMemoryMap is defined in .h as 'NSMutableArray *arrMemoryMap;'
    //this is one way to remember which row is selected
    arrMemoryMap = [NSMutableArray alloc] init];
    for (int i = 0 ; i < arrMyDataSource.count ; i++) {
        NSNumber *tmpSelectStatus = [NSNumber numberWithBool:NO];
        [arrMemoryMap addObject: tmpSelectStatus];
    }
}

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

    if([[arrMemoryMap objectAtIndex:indexPath.row] boolValue] == YES) {
        [cell.imageView setImage: [UIImage imageNamed:@"loudspeaker.png"]];
    } else {
        [cell.imageView setImage: [UIImage imageNamed:@""]];
    }

    return cell;
}

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
    //first, reset arrMemoryMap for all rows
    for (int i = 0 ; i < arrMemoryMap.count ; i++) {
         if([[arrMemoryMap objectAtIndex:i] boolValue] == YES]) {
             [[arrMemoryMap objectAtIndex:i] setBoolValue: NO];
             break;
         }
    }

    //now, set current row as selected in arrMemoryMap
    [[arrMemoryMap objectAtIndex:indexPath.row] setBoolValue: YES];

    //reload data or particular section
    [tableView reloadSections:indexPath.section
             withRowAnimation:UITableViewRowAnimationFade];
}

如何在UITableView中的选定单元格行中设置图像

3 个答案:

实施例