[英]Image loading from background
我正在后台加載圖像。 使用此代碼
-(void)backgroundImageLoading
{
if(isGroupOrFriend)
{
NSAutoreleasePool *pool=[[NSAutoreleasePool alloc] init];
for(NSDictionary *d in m_kwikiArray)
{
NSMutableDictionary *dict=[NSMutableDictionary dictionary];
if([d valueForKey:@"UserImage"]!=nil && ![[d valueForKey:@"UserImage"] isEqualToString:@""])
{
UIImage *img=[UIImage imageWithData:[NSData dataWithContentsOfURL:[NSURL URLWithString:[d valueForKey:@"UserImage"]]]];
if(img!=nil)
[dict setObject:img forKey:@"UserImage"];
}
else
[dict setObject:@"No Image" forKey:@"UserImage"];
//if([d valueForKey:@"imagePath"]!=nil && ![[d valueForKey:@"imagePath"] isEqualToString:@""] )
// [dict setObject:[UIImage imageWithData:[NSData dataWithContentsOfURL:[NSURL URLWithString:[d valueForKey:@"imagePath"]]]] forKey:@"imagePath"];
// else
// [dict setObject:@"NO Image" forKey:@"imagePath"];
if([[d valueForKey:@"Transactions"] count]>0)
{
if([[[d valueForKey:@"Transactions"] objectAtIndex:0] valueForKey:@"UserThumbnail"]!= nil && ![[[[d valueForKey:@"Transactions"] objectAtIndex:0]valueForKey:@"UserThumbnail"] isEqualToString:@""])
{
UIImage *img1=[UIImage imageWithData:[NSData dataWithContentsOfURL:[NSURL URLWithString:[[[d valueForKey:@"Transactions"] objectAtIndex:0] valueForKey:@"UserThumbnail"]]]];
if(img1!=nil)
[dict setObject:img1 forKey:@"UserThumbnail1"];
}
else
[dict setObject:@"NOImage" forKey:@"UserThumbnail1"];
}
else
[dict setObject:@"NOImage" forKey:@"UserThumbnail1"];
if([[d valueForKey:@"Transactions"] count]>1)
{
if([[[d valueForKey:@"Transactions"] objectAtIndex:1] valueForKey:@"UserThumbnail"]!=nil && ![[[[d valueForKey:@"Transactions"] objectAtIndex:1] valueForKey:@"UserThumbnail"] isEqualToString:@""])
{
UIImage *img2=[UIImage imageWithData:[NSData dataWithContentsOfURL:[NSURL URLWithString:[[[d valueForKey:@"Transactions"] objectAtIndex:1] valueForKey:@"UserThumbnail"]]]];
if(img2!=nil)
[dict setObject:img2 forKey:@"UserThumbnail2"];
}
else
[dict setObject:@"NOImage" forKey:@"UserThumbnail2"];
}
else
[dict setObject:@"NOImage" forKey:@"UserThumbnail2"];
[imageForGruopAndFriendArray addObject:dict];
}
//isReloadTable=YES;
[mTable reloadData];
[pool release];
}
else
{
NSAutoreleasePool *pool=[[NSAutoreleasePool alloc] init];
for(NSDictionary *d in m_kwikiArray)
{
NSMutableDictionary *dict=[NSMutableDictionary dictionary];
if([d valueForKey:@"Illustration"]!=nil && ![[d valueForKey:@"Illustration"] isEqualToString:@""])
{
UIImage *img=[UIImage imageWithData:[NSData dataWithContentsOfURL:[NSURL URLWithString:[d valueForKey:@"Illustration"]]]];
if(img!=nil)
[dict setObject:img forKey:@"Illustration"];
}
else
[dict setObject:@"No Image" forKey:@"Illustration"];
if([d valueForKey:@"imagePath"]!=nil && ![[d valueForKey:@"imagePath"] isEqualToString:@""] )
{
UIImage *img1=[UIImage imageWithData:[NSData dataWithContentsOfURL:[NSURL URLWithString:[d valueForKey:@"imagePath"]]]];
if(img1!=nil)
[dict setObject:img1 forKey:@"imagePath"];
}
else
[dict setObject:@"NO Image" forKey:@"imagePath"];
if([[d valueForKey:@"Transactions"] count]>0)
{
if([[[d valueForKey:@"Transactions"] objectAtIndex:0] valueForKey:@"UserThumbnail"]!= nil && ![[[[d valueForKey:@"Transactions"] objectAtIndex:0]valueForKey:@"UserThumbnail"] isEqualToString:@""])
{
UIImage *img2=[UIImage imageWithData:[NSData dataWithContentsOfURL:[NSURL URLWithString:[[[d valueForKey:@"Transactions"] objectAtIndex:0] valueForKey:@"UserThumbnail"]]]];
if(img2!=nil)
[dict setObject:img2 forKey:@"UserThumbnail1"];
}
else
[dict setObject:@"NOImage" forKey:@"UserThumbnail1"];
}
else
[dict setObject:@"NOImage" forKey:@"UserThumbnail1"];
if([[d valueForKey:@"Transactions"] count]>1)
{
if([[[d valueForKey:@"Transactions"] objectAtIndex:1] valueForKey:@"UserThumbnail"]!=nil && ![[[[d valueForKey:@"Transactions"] objectAtIndex:1] valueForKey:@"UserThumbnail"] isEqualToString:@""])
{
UIImage *img3=[UIImage imageWithData:[NSData dataWithContentsOfURL:[NSURL URLWithString:[[[d valueForKey:@"Transactions"] objectAtIndex:1] valueForKey:@"UserThumbnail"]]]];
if(img3!=nil)
[dict setObject:img3 forKey:@"UserThumbnail2"];
}
else
[dict setObject:@"NOImage" forKey:@"UserThumbnail2"];
}
else
[dict setObject:@"NOImage" forKey:@"UserThumbnail2"];
[imageArray addObject:dict];
}
//isReloadTable=YES;
[mTable reloadData];
[pool release];
}
}
在這里,我在每次圖像加載后在方法內使用 reloadData,但在滾動表格后它不加載圖像顯示。
我想在它們加載后立即顯示這些圖像。
請幫我。 提前謝謝。
伊修,
嘗試使用它而不是[mTable reloadData]
:
[mTable beginUpdates];
[mTable endUpdates];
順便說一句,很抱歉,但這段代碼完全不可讀。
Ishu,您的代碼的基本問題是您無法在輔助線程中通過 UIImage imageWithData API 加載圖像。 UIKit APIS 只能在主線程中使用。 您可以做的是下載項目並將它們保存到輔助線程中的文件中,但您仍然需要在主線程中加載該圖像數據。 如果您只想下載然后加載圖像數據,您甚至不需要輔助線程,因為 NSURLConnection class 已經支持異步完成回調,下載會在后台線程中自動完成。
在[m_Table reloadData];
我用這條線
[m_Table performSelectorOnMainThread:@selector(reloadData) withObject:self waitUntilDone:NO];
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