当我为每个单元格设置图像时，我的应用程序正在滚动并且搜索非常慢。图片提升得更快，但搜索时仍然很慢。这是我在行中的单元格中的代码。有什么想法吗？
@interface UIImage (TPAdditions)
- (UIImage*)imageScaledToSize:(CGSize)size;
@end
@implementation UIImage (TPAdditions)
- (UIImage*)imageScaledToSize:(CGSize)size {
UIGraphicsBeginImageContext(size);
[self drawInRect:CGRectMake(0, 0, size.width, size.height)];
UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return image;
}
@end
的cellForRowAtIndexPath
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *CellIdentifier = @"Cell";
static NSInteger buton1_tag = 100;
static NSInteger buton2_tag = 101;
if (indexPath.section == 0) {
CellIdentifier = @"CellMuzikEkle";
}else{
if(indexPath.row == 0 && !self.editing)
CellIdentifier = @"CellPlayereEkle";
else
CellIdentifier = @"CellDizi";
}
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (cell == nil) {
cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:CellIdentifier];
if (indexPath.section == 1 && indexPath.row == 0 && !self.editing) // Grubu ekle
cell = [[[NSBundle mainBundle] loadNibNamed:@"Cell4" owner:self options:nil] objectAtIndex:0];
else{
if (indexPath.section == 0) {
cell = [[[NSBundle mainBundle] loadNibNamed:@"Cell" owner:self options:nil] objectAtIndex:5];
UIButton *ipodbuton = (UIButton *) [cell.contentView viewWithTag:buton1_tag];
[ipodbuton addTarget:self action:@selector(iPoddan_Ekle:) forControlEvents:UIControlEventTouchUpInside];
UIButton *yuklenenler = (UIButton *) [cell.contentView viewWithTag:buton2_tag];
[yuklenenler addTarget:self action:@selector(Yuklenenlerden_Ekle:) forControlEvents:UIControlEventTouchUpInside];
}else{
cell.textLabel.font = [UIFont boldSystemFontOfSize:15.0];
cell.textLabel.numberOfLines=2;
cell.detailTextLabel.font = [UIFont systemFontOfSize:13];
[cell.imageView.layer setBorderWidth: 1.5];
}
}
}
if (indexPath.section == 1 && !self.editing && indexPath.row != 0)
cell.accessoryType =UITableViewCellAccessoryDetailDisclosureButton;
else
cell.accessoryType =UITableViewCellAccessoryNone;
if(indexPath.section == 0){
cell.textLabel.text = @"";
cell.detailTextLabel.text = @"";
cell.imageView.image = nil;
}else{
if (indexPath.row > 0 || self.editing) {
if (!self.editing)
indexPath = [NSIndexPath indexPathForRow:indexPath.row - 1 inSection:indexPath.section];
NSArray *aradizi = tableView == self.searchDisplayController.searchResultsTableView ? [[NSArray alloc] initWithArray:self.filteredListContent] : [[NSArray alloc] initWithArray:self.dizi];
if ([[NSUserDefaults standardUserDefaults] boolForKey:cellresimyuk_s])
cell.imageView.image = [[self Resim_Artwork:[aradizi objectAtIndex:indexPath.row]] imageScaledToSize:CGSizeMake(65, 50)];
else
cell.imageView.image = nil;
cell.textLabel.text = [[aradizi objectAtIndex:indexPath.row] objectForKey:isim_s];
NSTimeInterval theTimeInterval = [[[aradizi objectAtIndex:indexPath.row] objectForKey:sure_s] intValue] - 1;
NSDateFormatter* dateFormatter = [[NSDateFormatter alloc] init];
NSDate *date1;
if (theTimeInterval >= 3600) {
[dateFormatter setDateFormat:@"HH:mm:ss"];
date1 = [dateFormatter dateFromString:@"00:00:00"];
}else{
[dateFormatter setDateFormat:@"mm:ss"];
date1 = [dateFormatter dateFromString:@"00:00"];
}
NSDate *date2 = [[NSDate alloc] initWithTimeInterval:theTimeInterval sinceDate:date1];
cell.detailTextLabel.text = [dateFormatter stringFromDate:date2];
}else{
if (tableView == self.searchDisplayController.searchResultsTableView)
cell.textLabel.text = AramaSonuclrPlayerEkle_lclz;
else
cell.textLabel.text = GrubuPlayereEkle_lclz;
}
}
return cell;
}
Resim_Artwork
- (UIImage *)Resim_Artwork:(NSDictionary *)dictr{
if ([dictr objectForKey:videoid_s]) {
if ([self Dosya_Varmi:[[rsm_favori stringByAppendingPathComponent:[dictr objectForKey:videoid_s]] stringByAppendingPathExtension:@"png"]])
return [UIImage imageWithContentsOfFile:[[rsm_favori stringByAppendingPathComponent:[dictr objectForKey:videoid_s]] stringByAppendingPathExtension:@"png"]];
}else{
if ([[[dictr objectForKey:urlsi_s] pathExtension] isEqualToString:@"mp4"]) {
AVURLAsset *assetresim = [[AVURLAsset alloc] initWithURL:[NSURL fileURLWithPath:[kDocdir stringByAppendingPathComponent:[dictr objectForKey:urlsi_s]]] options:nil];
AVAssetImageGenerator *gen = [[AVAssetImageGenerator alloc] initWithAsset:assetresim];
gen.appliesPreferredTrackTransform = YES;
int suresi = CMTimeGetSeconds(assetresim.duration);
if (suresi > 0) {
CMTime time;
if (suresi>6)
time = CMTimeMakeWithSeconds(6.0, 600);
else
time = CMTimeMakeWithSeconds(0.0, 600);
NSError *error = nil;
CMTime actualTime;
CGImageRef image = [gen copyCGImageAtTime:time actualTime:&actualTime error:&error];
UIImage *thumb = [[UIImage alloc] initWithCGImage:image];
CGImageRelease(image);
return thumb;
}
}else {
if ([dictr objectForKey:kaynak_s]) {
AVAsset *asset = [AVURLAsset URLAssetWithURL:[NSURL URLWithString:[dictr objectForKey:urlsi_s]] options:nil];
for ( AVMetadataItem* item in [asset commonMetadata] ) {
if ([[item commonKey] isEqualToString:@"artwork"] )
if (item.dataValue != nil)
if ([UIImage imageWithData:item.dataValue])
return [UIImage imageWithData:item.dataValue];
}
}else{
if ([self Dosya_Varmi:[kDocdir stringByAppendingPathComponent:[dictr objectForKey:urlsi_s]]]){
AVAsset *asset = [AVURLAsset URLAssetWithURL:[NSURL fileURLWithPath:[kDocdir stringByAppendingPathComponent:[dictr objectForKey:urlsi_s]]] options:nil];
for ( AVMetadataItem* item in [asset commonMetadata] ) {
if ([[item commonKey] isEqualToString:@"artwork"] )
if (item.dataValue != nil)
if ([UIImage imageWithData:item.dataValue])
return [UIImage imageWithData:item.dataValue];
}
}
}
}
}
return [self Resimm:@".varsayilan" Koordinat:CGRectMake(120,1320, 80, 60) retinami:0 grubu:6];
}
tableView willDisplayCell
- (void)tableView:(UITableView *)tableView willDisplayCell:(UITableViewCell *)cell forRowAtIndexPath:(NSIndexPath *)indexPath {
NSArray *viewControllers = [self.tabBarController viewControllers];
NSArray *viewControllers2 = [[viewControllers objectAtIndex:0] viewControllers];
Player *detailViewController = (Player *)[viewControllers2 objectAtIndex:0];
[detailViewController.temalar Cell_Tema:cell];
cell.textLabel.backgroundColor = [UIColor clearColor];
cell.detailTextLabel.backgroundColor = [UIColor clearColor];
cell.textLabel.textColor = [detailViewController.temalar Baslik_Renk];
cell.detailTextLabel.textColor = [detailViewController.temalar Bilgi_Renk];
[cell.imageView.layer setBorderColor: [tableView.separatorColor CGColor]];
[((UIButton *) [cell.contentView viewWithTag:100]) setBackgroundImage:[self Resimm:@".buton" Koordinat:CGRectMake(0,1350, 94, 35) retinami:0 grubu:7] forState:UIControlStateNormal];
[((UIButton *) [cell.contentView viewWithTag:100]) setTitleColor:[detailViewController.temalar Baslik_Renk] forState:UIControlStateNormal];
[((UIButton *) [cell.contentView viewWithTag:101]) setBackgroundImage:[self Resimm:@".buton" Koordinat:CGRectMake(0,1350, 94, 35) retinami:0 grubu:7] forState:UIControlStateNormal];
[((UIButton *) [cell.contentView viewWithTag:101]) setTitleColor:[detailViewController.temalar Baslik_Renk] forState:UIControlStateNormal];
}
答案 0 :(得分：1)
这里：
NSArray *aradizi = tableView == self.searchDisplayController.searchResultsTableView ?
[[NSArray alloc] initWithArray:self.filteredListContent] :
[[NSArray alloc] initWithArray:self.dizi];
尽可能避免在cellForRowAtIndexPath中创建对象 无论如何，你不需要：
NSArray *aradizi = tableView == self.searchDisplayController.searchResultsTableView ?
self.filteredListContent :
self.dizi;
在这里，您似乎正在动态创建和调整缩略图大小。 ：
if ([[NSUserDefaults standardUserDefaults] boolForKey:cellresimyuk_s])
cell.imageView.image = [[self Resim_Artwork:[aradizi objectAtIndex:indexPath.row]]
imageScaledToSize:CGSizeMake(65, 50)];
这势必会阻塞顺畅的tableView scolling。所有这些都应该进行预处理和缓存，或至少在此处理一次并缓存以供重用。
这样耗时的nonUI处理可以进入另一个线程，这样即使图像还没有准备好显示，你的scolling也会保持平稳。有点像...
if ([[NSUserDefaults standardUserDefaults] boolForKey:cellresimyuk_s])
dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
UIImage* image =
[[self Resim_Artwork:[aradizi objectAtIndex:indexPath.row]]
imageScaledToSize:CGSizeMake(65, 50)];
dispatch_async(dispatch_get_main_queue(), ^{
//check our cell is still valid
if ([[self.tableView cellForRowAtIndexPath:indexPath] isEqual:cell]){
cell.imageView.image = image;
}
});
});
else
cell.imageView.image = nil;
关于日期格式化程序：这些是重量级对象，您需要确保只创建一次，保留一个属性以供重用。我建议你做以下事情：
为零日期声明两个日期格式化程序属性和另一个属性。在viewDidLoad中初始化它们：
- (void)viewDidLoad {
[super viewDidLoad];
self.hoursFormat = [[NSDateFormatter alloc] init];
[self.hoursFormat setDateFormat:@"HH:mm:ss"];
self.minsFormat = [[NSDateFormatter alloc]init];
[self.minsFormat setDateFormat:@"mm:ss"];
self.zeroDate = [self.hoursFormat dateFromString:@"00:00:00"];
}
然后在cellForRowAtIndexPath：
NSDate* date = [self.zeroDate dateByAddingTimeInterval:theTimeInterval];
if (theTimeInterval >= 3600) {
self.label.text = [self.hoursFormat stringFromDate:date];
} else {
self.label.text = [self.minsFormat stringFromDate:date];
}
答案 1 :(得分：0)
他是，谢谢你的回答。表现非常好。但是自从我做了这个改变之后，程序就关闭了。 新代码：
NSMutableArray *aradizi;
if (tableView == self.searchDisplayController.searchResultsTableView)
aradizi = self.filteredListContent;
if (indexPath.section == 2 && tableView != self.searchDisplayController.searchResultsTableView)
aradizi = self.dizi_klasorler;
if (indexPath.section == 3)
aradizi = self.dizi_veriler;
if ([[NSUserDefaults standardUserDefaults] boolForKey:cellresimyuk_s]){
if (cell.imageView.image == nil)
cell.imageView.image = [[self Resimm:@".varsayilan" Koordinat:CGRectMake(120,1320, 80, 60) retinami:0 grubu:6] Resim_Skala:CGSizeMake(60, 45)];
dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
UIImage* image = [[self Resim_Artwork:[[aradizi objectAtIndex:indexPath.row] objectForKey:urlsi_s]] Resim_Skala:CGSizeMake(60, 45)];
dispatch_async(dispatch_get_main_queue(), ^{
//check our cell is still valid
if (tableView == self.searchDisplayController.searchResultsTableView){
if ([[self.searchDisplayController.searchResultsTableView cellForRowAtIndexPath:indexPath] isEqual:cell])
cell.imageView.image = image;
}else{
if ([[self.tableView cellForRowAtIndexPath:indexPath] isEqual:cell])
cell.imageView.image = image;
}
});
});
}else
cell.imageView.image = nil;
http://img29.imageshack.us/img29/1083/ekranresmi2013020301553.png
http://img502.imageshack.us/img502/5591/ekranresmi2013012919525.png
