iOS-runloop在大量数据刷新列表的应用

前言

• 在大量加载列表数据的时候，每次都要做列表刷新，那么就会有卡顿的现象。

直接应用

• ViewController.h

#import "ViewController.h"

@interface ViewController : UIViewController

@end

• ViewController.m

#import "EOCNewsTableViewControllerNew.h"

@interface EOCNewsTableViewControllerNew ()

@property (nonatomic, assign) CFRunLoopObserverRef observer;
@property (nonatomic, strong) NSMutableArray *indexs;

@end

@implementation EOCNewsTableViewControllerNew

- (void)viewDidLoad {
    [super viewDidLoad];
    self.indexs = [NSMutableArray arrayWithCapacity:3];
    
    __weak typeof(self) weakSelf = self;
    self.observer = CFRunLoopObserverCreateWithHandler(CFAllocatorGetDefault(), kCFRunLoopBeforeWaiting, YES, 0, ^(CFRunLoopObserverRef observer, CFRunLoopActivity activity) {
        
        CFStringRef model = CFRunLoopCopyCurrentMode(CFRunLoopGetCurrent());
        NSLog(@"%@",(__bridge NSString *) model);
        CFRelease(model);
        
        [weakSelf.indexs removeAllObjects];
        NSArray *visibleCells = [weakSelf.tableView visibleCells];
        for (UITableViewCell *cell in visibleCells) {
            if (fabs([cell rowHeight] - cell.frame.size.height) > 0.1) { //图片加载不知道cell的高度 cell默认为 比如10,而加载后为比如10.1,所以要加一个判断
                [weakSelf.indexs addObject:[weakSelf.tableView indexPathForCell:cell]];
            }
        }
        
        if (weakSelf.indexs.count > 0) {
            dispatch_async(dispatch_get_main_queue(), ^{
                NSLog(@"update Row");
                [weakSelf.tableView reloadRowsAtIndexPaths:weakSelf.indexs withRowAnimation:UITableViewRowAnimationFade];
            });
        }
    });
    CFRunLoopAddObserver(CFRunLoopGetMain(), self.observer, kCFRunLoopCommonModes);
}

- (void)viewWillDisappear:(BOOL)animated {
    [super viewWillDisappear:animated];
    CFRunLoopRemoveObserver(CFRunLoopGetMain(), self.observer, kCFRunLoopCommonModes);
}

@end