我正在使用 QuickBlox 框架构建一个聊天应用程序。目前，当聊天 View 打开时，一切看起来都很棒。
但是，当用户开始上下滚动聊天记录时，一些单元格开始发生变化(例如，它们将显示一张应该放在不同行中的图像)。
下面是我的 cellForRowAtIndexPath 代码，如果有人能告诉我我做错了什么
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
QBChatMessage *message = [[ChatService shared] messagsForDialogId:self.dialog.ID][indexPath.row];
if (message.attachments.count > 0) {
ImageTableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:ImageCellIdentifier];
[cell configureCellWithImage:message];
cell.backgroundColor = [UIColor whiteColor];
return cell;
} else {
ChatMessageTableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:ChatMessageCellIdentifier];
[cell configureCellWithMessage:message];
cell.backgroundColor = [UIColor whiteColor];
return cell;
}
}
编辑 请看下面我的 ImageTableViewCell configureCellWithImage 方法:
- (void) configureCellWithImage:(QBChatMessage*)message {
NSString *time = [message.dateSent timeAgoSinceNow];
if ([QBSession currentSession].currentUser.ID == message.senderID) {
// Message was sent by me
NSData *imageData = [FTWCache objectForKey:[NSString stringWithFormat:@"%@", [message.attachments[0] valueForKey:@"ID"]]];
if (imageData) {
// image is already downloaded
dispatch_async(dispatch_get_main_queue(), ^{
UIImage *image = [UIImage imageWithData:imageData];
UIImageView *cellImage = [[UIImageView alloc] init];
[self.backgroundImageView setFrame:CGRectMake(320-155, 10, 140, 140)];
cellImage.frame = CGRectMake(7, 7, 120, 120);
[cellImage setContentMode:UIViewContentModeScaleAspectFill];
cellImage.clipsToBounds = YES;
cellImage.layer.cornerRadius = 5;
cellImage.image = image;
self.backgroundImageView.image = aquaBubble;
[self.backgroundImageView addSubview:cellImage];
[self.contentView addSubview:self.backgroundImageView];
});
} else {
// downloads the image and displays as above
}
} else {
// Message was sent by another user
NSData *imageData = [FTWCache objectForKey:[NSString stringWithFormat:@"%@", [message.attachments[0] valueForKey:@"ID"]]];
if (imageData) {
dispatch_async(dispatch_get_main_queue(), ^{
UIImage *image = [UIImage imageWithData:imageData];
UIImageView *cellImage = [[UIImageView alloc] init];
[self.backgroundImageView setFrame:CGRectMake(padding/2, padding+5, 140, 140)];
cellImage.frame = CGRectMake(13, 7, 120, 120);
[cellImage setContentMode:UIViewContentModeScaleAspectFill];
cellImage.layer.cornerRadius = 5;
cellImage.clipsToBounds = YES;
cellImage.image = image;
self.timeLabel.frame = CGRectMake(20, self.backgroundImageView.frame.size.height + 20, 80, 20);
self.timeLabel.text = [NSString stringWithFormat:@"%@", time];
[self.timeLabel setFont:[UIFont systemFontOfSize:10.0]];
[self.timeLabel setTextColor:[UIColor blackColor]];
[self.contentView addSubview:self.timeLabel];
self.nameAndDateLabel.textAlignment = NSTextAlignmentLeft;
QBUUser *sender = [ChatService shared].usersAsDictionary[@(message.senderID)];
NSInteger loginForColor = [sender.login integerValue];
loginForColor = loginForColor % 255;
self.nameAndDateLabel.text = [NSString stringWithFormat:@"%@", sender.fullName];
self.backgroundImageView.image = orangeBubble;
[self.backgroundImageView addSubview:cellImage];
[self.contentView addSubview:self.backgroundImageView];
});
} else {
// downloads the image and displays as above
}
}
}
最佳答案
细胞得到重用。因此，您每次都必须始终设置/重置单元格的所有属性。
对于每个设置单元格属性的 if 语句，必须有一个 else 语句重置相同的属性 - 即使它只是清除值。
此外，您还必须避免在每次使用单元格时反复添加 subview 。您拥有创建 ImageView 并将其添加到单元格的代码。但是您不断地添加新的 ImageView 。如果需要，只需添加一次。如果它已经存在，请使用新图像更新它而不是添加新图像。
关于ios - 目标 - C : UITableView Content Changing on Scroll，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/32464808/