iOS大量数据读取操作

大量数据读写操作

@interface ViewController ()
@property (nonatomic, strong) NSMutableDictionary *msgCacheDict;

@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view.
    self.msgCacheDict = [[NSMutableDictionary alloc] init];
    [self.msgCacheDict setObject:@[].mutableCopy forKey:@"msgCacheDict"];

}

- (void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event {
dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
        NSArray *array = @[@"1",@"2",@"3"];
        for (NSInteger index = 0; index < 100000; index++) {
            @autoreleasepool {
                [self saveDataArray:array];
            }
        }
    });
}


// 数组多次copy 操作，造成CPU占用很高，会引起卡顿
-(void)saveDataArray:(NSArray *)array {
//    cpu占用率 85%
    NSMutableArray *tempDataArray = [self.msgCacheDict objectForKey:@"msgCacheDict"];
    NSMutableArray *dataArray = [[NSMutableArray alloc] init];
    if (tempDataArray.count > 0) {
        [dataArray addObjectsFromArray:tempDataArray];
    }
    [dataArray insertObject:@"insert" atIndex:0];  // 添加新数据
    [self.msgCacheDict setObject:dataArray forKey:@"msgCacheDict"];
    NSLog(@"========save data1 ===");
}

// 数组不同方式初始化
-(void)saveDataArray2:(NSArray *)array {
//    cpu占用率 90%
    NSMutableArray *tempDataArray = [self.msgCacheDict objectForKey:@"msgCacheDict"];
    NSMutableArray *dataArray = [[NSMutableArray alloc] initWithArray:tempDataArray];
    [dataArray insertObject:@"insert" atIndex:0];  // 添加新数据
    [self.msgCacheDict setObject:dataArray forKey:@"msgCacheDict"];
    NSLog(@"========save data1 ===");
}


// 最佳方式 减少 copy操作
-(void)saveDataArray3:(NSArray *)array  {
 //    cpu占用率 30%  但需要保证存储的是可变数组
    NSMutableArray *dataArray = [self.msgCacheDict objectForKey:@"msgCacheDict"];
    [dataArray insertObject:@"insert" atIndex:0];  // 添加新数据
    NSLog(@"========save data 2 ===");
}
@end

总结

• 减少中间的冗余copy操作，节省CPU占用率
• 异步线程处理、否则卡主线程