我有一个 UITableView,每个单元格被分成几个部分,每个部分都有不同的标签。该表由 NSDictionaries 的 NSArray 填充,其中包含填充单元格标签的所有数据。 UITableView 的这一部分效果很好。
当我更改其中一个 NSDictionaries 中的某些值,然后使用更新后的 NSArray 重新加载表时,就会出现问题。通常,当我打电话时[myTableView reloadData];
即使(通过调试)我可以看到正在处理更新的数据,也没有更新任何内容。但如果我改变标准:if (cell == nil) {
to if (1) {
, 在里面cellForRowAtIndexPath
方法,那么它的效果就很漂亮。我明白为什么if(1) {
有效,但我不明白为什么我不能重用单元格而只能更改标签文本。
为什么if (cell == nil)
不行?重新初始化每个单元是否会消耗巨大的资源?
CODE:
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
static NSString *cellIdentifier = @"myCell";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier: cellIdentifier];
if (/*cell == nil*/1) {
// Initialize Custom Cell
cell = [[UITableViewCell alloc]initWithStyle:UITableViewCellStyleDefault reuseIdentifier:cellIdentifier];
//// Background View
cellBackgroundView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 622, 43)];
[cellBackgroundView setBackgroundColor:[UIColor colorWithPatternImage:[UIImage imageNamed:@"Images/Library/phase_table_cell.png"]]];
//// Name Label
nameLabel = [[UILabel alloc] initWithFrame:CGRectMake(10, 10, 250, 18)];
[nameLabel setBackgroundColor:[UIColor clearColor]];
[cellBackgroundView addSubview:nameLabel];
//// Percent Complete Label
percentCompleteLabel = [[UILabel alloc] initWithFrame:CGRectMake(300, 10, 30, 18)];
[percentCompleteLabel setBackgroundColor:[UIColor clearColor]];
[percentCompleteLabel setTextAlignment:UITextAlignmentCenter];
[cellBackgroundView addSubview:percentCompleteLabel];
//// Overall Status Label
overallStatusLabel = [[UILabel alloc] initWithFrame:CGRectMake(352, 7, 63, 30)];
[overallStatusLabel setBackgroundColor:[UIColor clearColor]];
[overallStatusLabel setFont:[UIFont boldSystemFontOfSize:12.0]];
[overallStatusLabel setLineBreakMode:UILineBreakModeWordWrap];
[overallStatusLabel setNumberOfLines:2];
[overallStatusLabel setTextAlignment:UITextAlignmentCenter];
[cellBackgroundView addSubview:overallStatusLabel];
//// Finish Date Label
finishDateLabel = [[UILabel alloc] initWithFrame:CGRectMake(425, 10, 55, 18)];
[finishDateLabel setBackgroundColor:[UIColor clearColor]];
[finishDateLabel setTextAlignment:UITextAlignmentCenter];
[finishDateLabel setFont:[UIFont systemFontOfSize:12.0]];
[cellBackgroundView addSubview:finishDateLabel];
//// Overall Weight Label
overallWeightLabel = [[UILabel alloc] initWithFrame:CGRectMake(505, 10, 30, 18)];
[overallWeightLabel setBackgroundColor:[UIColor clearColor]];
[overallWeightLabel setTextAlignment:UITextAlignmentCenter];
[cellBackgroundView addSubview:overallWeightLabel];
//// Green Risk View
greenRiskView = [[UIView alloc] initWithFrame:CGRectMake(557, 4, 61, 10)];
[greenRiskView setBackgroundColor:[UIColor greenColor]];
[greenRiskView setHidden:YES];
[cellBackgroundView addSubview:greenRiskView];
//// Yellow Risk View
yellowRiskView = [[UIView alloc] initWithFrame:CGRectMake(557, 17, 61, 10)];
[yellowRiskView setBackgroundColor:[UIColor yellowColor]];
[yellowRiskView setHidden:YES];
[cellBackgroundView addSubview:yellowRiskView];
//// Red Risk View
redRiskView = [[UIView alloc] initWithFrame:CGRectMake(557, 30, 61, 10)];
[redRiskView setBackgroundColor:[UIColor redColor]];
[redRiskView setHidden:YES];
[cellBackgroundView addSubview:redRiskView];
[cell.contentView addSubview:cellBackgroundView];
}
// Get Current Dictionary
NSDictionary *dictForIndexPath = [self.phaseArray objectAtIndex:[indexPath row]];
// Set Elements
[nameLabel setText:[dictForIndexPath objectForKey:@"name"]];
[percentCompleteLabel setText:[dictForIndexPath objectForKey:@"percentComplete"]];
[overallStatusLabel setText:[dictForIndexPath objectForKey:@"overallStatus"]];
[overallWeightLabel setText:[[NSNumber numberWithInt:[[dictForIndexPath objectForKey:@"overallWeight"] intValue]] stringValue]];
//// Create Finish Date String
NSString *finishDateString = [NSString stringWithFormat:@"%@/%@/%@", [dictForIndexPath objectForKey:@"finishDay"], [dictForIndexPath objectForKey:@"finishMonth"], [dictForIndexPath objectForKey:@"finishYear"]];
[finishDateLabel setText:finishDateString];
//// Pick Risk View
NSString *riskColor = [dictForIndexPath objectForKey:@"riskColor"];
if ([riskColor isEqualToString:@"Green"]) {
[greenRiskView setHidden:NO];
[yellowRiskView setHidden:YES];
[redRiskView setHidden:YES];
} else if ([riskColor isEqualToString:@"Yellow"]) {
[greenRiskView setHidden:YES];
[yellowRiskView setHidden:NO];
[redRiskView setHidden:YES];
} else {
[greenRiskView setHidden:YES];
[yellowRiskView setHidden:YES];
[redRiskView setHidden:NO];
}
return cell;
}