代码片段

分割字符串：
NSArray *tempArr = [fileName componentsSeparatedByString:@"."];

//颜色
    UIColor  *backgroundColor=[UIColor redColor];
    //字体
    UIFont *font=[UIFont boldSystemFontOfSize:18.0];
    NSDictionary *attrsDic=@{
                             NSForegroundColorAttributeName:backgroundColor,
                             NSFontAttributeName:font
                             };
    self.mySearchBar.attributedPlaceholder = [[NSAttributedString alloc]initWithString:@"请输入展品编号" attributes:attrsDic];

#pragma mark - 更新主页面操作
    dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT,0),^{
        //耗时的操作
       dispatch_async(dispatch_get_main_queue(),^{
            //更新界面
        });
    });
    
#pragma mark - 顺序执行
//    dispatch_queue_t aqueue = dispatch_queue_create("sdfs",DISPATCH_QUEUE_CONCURRENT);
//    dispatch_barrier_async(aqueue, ^{NSLog(@"1111");});
//    dispatch_barrier_async(aqueue, ^{NSLog(@"2222");});
//    dispatch_barrier_async(aqueue, ^{NSLog(@"3333");});
    
    
#pragma mrak - 随机执行
//    dispatch_queue_t aqueue = dispatch_queue_create("sdfs",DISPATCH_QUEUE_CONCURRENT);
//    dispatch_async(aqueue, ^{
//        NSLog(@"111");
//    });
//    dispatch_async(aqueue, ^{
//        NSLog(@"222");
//    });
//    dispatch_async(aqueue, ^{
//        NSLog(@"666");
//    });
//    dispatch_async(aqueue, ^{
//        NSLog(@"999");
//    });
    
    
#pragma mark - 队列执行
//    dispatch_queue_t aqueue = dispatch_queue_create("sdfs",DISPATCH_QUEUE_CONCURRENT);
//    dispatch_group_t group = dispatch_group_create();
//    dispatch_group_async(group,aqueue, ^{
//        NSLog(@"1111");
//        [NSThread sleepForTimeInterval:1.0];
//    });
//    dispatch_group_async(group,aqueue, ^{
//        NSLog(@"2222");
//        [NSThread sleepForTimeInterval:2.0];
//    });
//    dispatch_group_async(group,aqueue, ^{
//        NSLog(@"3333");
//        [NSThread sleepForTimeInterval:3.0];
//    });
//    
//    dispatch_group_notify(group, aqueue, ^{
//        NSLog(@"finish");
//    });

@property(strong,nonatomic)UIRefreshControl *refresh;

[self.refresh beginRefreshing];//viewWillAppear
    [self refreshAction:nil];

self.refresh = [[UIRefreshControl alloc]init];//viewDidLoad
    [self.refresh addTarget:self action:@selector(refreshAction:) forControlEvents:UIControlEventValueChanged];
    self.refresh.attributedTitle = [[NSAttributedString alloc]initWithString:@"下拉刷新"];
    [self.myTableView addSubview:self.refresh];

#pragma mark - refreshMethods
-(void)refreshAction:(NSString*)str
{
    [self.refresh performSelector:@selector(endRefreshing) withObject:nil afterDelay:2.0];
    [self.myTableView reloadData];
}

NSString *resourcePath = [NSString stringWithFormat:@"%@/Resource",[declare applicationLibraryDirectory]];
    if (![[NSFileManager defaultManager]fileExistsAtPath:resourcePath]) {
        [[NSFileManager defaultManager] createDirectoryAtPath:resourcePath withIntermediateDirectories:NO attributes:nil error:nil];
    }

@property (nonatomic, strong) NSArray *dataArray;

#pragma mark - tableView delegate
#define Row_Height 100
- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath
{
    return Row_Height;
}

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
    return self.dataArray.count;
}

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
    static NSString *cellName = @"cell";
    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:cellName];
    
    if (!cell) {
        cell = [[UITableViewCell alloc]init];
        //        cell.selectionStyle = UITableViewCellSelectionStyleNone;
    }
    
    return cell;
}

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
    
}

//筛选信息
    NSArray *arr = [[NSArray alloc]initWithObjects:@"beijing",@"shanghai",@"tianjin",@"shenzhen", nil];
    NSString *string = @"in";
    NSPredicate *pred = [NSPredicate predicateWithFormat:@"SELF CONTAINS %@",string];
    NSLog(@"%@",[arr filteredArrayUsingPredicate:pred]);

//提取字符串中的字母或数字
    NSString *originalString = @"daxf1bw2cq3d45f6ge7h8i9j0";
    
    // Intermediate
    NSMutableString *numberString = [[NSMutableString alloc] init];
    NSString *tempStr;
    NSScanner *scanner = [NSScanner scannerWithString:originalString];
    NSCharacterSet *numbers = [NSCharacterSet characterSetWithCharactersInString:@"qwe"];
    
    while (![scanner isAtEnd]) {
        // Throw away characters before the first number.
        [scanner scanUpToCharactersFromSet:numbers intoString:NULL];
        
        // Collect numbers.
        BOOL isSccess = [scanner scanCharactersFromSet:numbers intoString:&tempStr];;
        [numberString appendString:tempStr];
        tempStr = @"";
        
        NSLog(@"tempStr:%@   numberString:%@   bool:%d",tempStr,numberString,isSccess);
    }

//导航条按钮
UIButton *rightBtn = [UIButton buttonWithType:UIButtonTypeCustom];
    rightBtn.backgroundColor = [UIColor clearColor];
    rightBtn.frame = CGRectMake(0, 0, 40, 40);
    [rightBtn setImage:[UIImage imageNamed:@"button5"] forState:UIControlStateNormal];
    [rightBtn setImage:[UIImage imageNamed:@"button5_pressed"] forState:UIControlStateHighlighted];
    [rightBtn addTarget:self action:@selector(rightBtnClick:) forControlEvents:UIControlEventTouchUpInside];
    UIBarButtonItem *barBtn = [[UIBarButtonItem alloc]initWithCustomView:rightBtn];
    self.navigationItem.rightBarButtonItem = barBtn;
    
    UIBarButtonItem *nItem = [[UIBarButtonItem alloc] initWithTitle:@"" style:UIBarButtonItemStylePlain target:self action:nil];
    self.navigationItem.leftBarButtonItem = nItem;

//宏定义 变量字符串化
#define WARN_IF(EXP) 
do { if (EXP) 
        fprintf( stderr,"Warning " #EXP "
" ); 
} while(0)
    int x = 0;
    WARN_IF(x == 0);

//cookies
NSHTTPCookieStorage *pool = [NSHTTPCookieStorage sharedHTTPCookieStorage];
NSArray *cookies = [pool cookies];
for (NSHTTPCookie *cookie in cookies ) {
    [pool deleteCookie:cookie];
}

isFinite( number ) 函数用于检查其参数是否是无穷大。
如果 number 是有限数字（或可转换为有限数字），那么返回 true。否则，如果 number 是 NaN（非数字），或者是正、负无穷大的数，则返回 false

学习了FMDB三方库的使用，对sqlite进行操作时 表名、参数名不用带单引号 值必须带单引号 如：@"UPDATE %@ SET %@ = '%@' WHERE %@ = '%@'", TABLENAME,  AGE, @"15", AGE, @"12”//修改数据

segue跳转：

[self performSegueWithIdentifier:@"goToRootView" sender:nil];

添加tableViewcell编辑操作。

//-(UITableViewCellEditingStyle)tableView:(UITableView *)tableView editingStyleForRowAtIndexPath:(NSIndexPath *)indexPath
//{   
//    return UITableViewCellEditingStyleDelete;
//}
//
//- (void)tableView:(UITableView*)tableView commitEditingStyle:(UITableViewCellEditingStyle)editingStyle forRowAtIndexPath:(NSIndexPath*)indexPath {
//    if (editingStyle == UITableViewCellEditingStyleDelete) {
//        
//        //[self.da removeObjectAtIndex:indexPath.row];
//        [self.myTableView deleteRowsAtIndexPaths:@[indexPath]
//                                withRowAnimation:UITableViewRowAnimationAutomatic];
//        [self.myTableView reloadData];
//    }
//}
//
//-(BOOL)tableView:(UITableView *)tableView canEditRowAtIndexPath:(NSIndexPath *)indexPath
//{
//    return YES;
//}

//    [self.myTableView beginUpdates];

//    NSArray *indexPaths = @[indexPath];

//    [self.myTableView deleteRowsAtIndexPaths:indexPaths withRowAnimation:UITableViewRowAnimationLeft];

//    [self.myTableView endUpdates];