IOS開發中多線程的使用,ios開發多線程
1.開啟線程的方法一
NSThread * thread=[[NSThread alloc] initWithTarget:self selector:@selector(_update) object:nil];
2.開啟線程的方法二
[NSThread detachNewThreadSelector:@selector(_update) toTarget:self withObject:nil];
3.開啟線程的方法三
[self performSelectorInBackground:@selector(_update) withObject:nil];
4.開啟線程的方法四
NSOperationQueue *queue=[[NSOperationQueue alloc] init]; [queue addOperationWithBlock:^{ for(int i=0;i<50;i++){ printf("子線程\n"); } }];
5.開啟線程的方法五
//第一步開啟線程池 NSOperationQueue * queue=[[NSOperationQueue alloc] init]; //設定並發數目 [queue setMaxConcurrentOperationCount:2]; //第二部建立多線程添加到線程池 NSInvocationOperation * thread1=[[NSInvocationOperation alloc] initWithTarget:self selector:@selector(_update1) object:nil]; NSInvocationOperation *thread2=[[NSInvocationOperation alloc] initWithTarget:self selector:@selector(_update2) object:nil]; [thread1 setQueuePriority:NSOperationQueuePriorityVeryLow]; [thread2 setQueuePriority:NSOperationQueuePriorityVeryHigh]; [queue addOperation:thread1]; [queue addOperation:thread2];
1.核心思想
考慮到如果載入網狀圖片會延遲,在一個主線程載入會影響控制項的渲染,此時可以採取多線程,非同步載入完成後重新整理UI。
2.實現思路
通過為UIImageView 增加類目來實現多線程下載。
主要代碼:
#import "UIImageView+thread.h"@implementation UIImageView(load)- (void) setImageWithUrl:(NSString *)url{ [self performSelectorInBackground:@selector(_loadImage:) withObject:url];}- (void) _loadImage:(NSString *)u{ @autoreleasepool { NSURL *url=[NSURL URLWithString:u]; NSData *data=[NSData dataWithContentsOfURL:url]; UIImage *image=[UIImage imageWithData:data]; [self performSelectorOnMainThread:@selector(setImage:) withObject:image waitUntilDone:NO]; }}