Objective-C常用代码

CGRect的新写法：

CGRect frame = (CGRect){0,0,image.size};
CGRect sframe = (CGRect){0,0,10,10};

CGFloat x = CGRectGetMinX(frame);
CGFloat y = CGRectGetMinY(frame);
CGFloat width = CGRectGetWidth(frame);
CGFloat height = CGRectGetHeight(frame);

获取导航栏和状态栏的高度
CGRect rect = [[UIApplication sharedApplication] statusBarFrame];
状态栏的高度：
float status height =  rect.size.height;

导航栏的高度：
float navigationheight = self.navigationController.navigationBar.frame.size.height;

创建实例对象的新写法：

self.sendBtn = ({
        UIButton *btn = [UIButton buttonWithType:UIButtonTypeCustom];
        btn.layer.backgroundColor = [UIColor colorWithRed:0 green:123/255.0 blue:250.0/255 alpha:1.0].CGColor;
        btn.layer.cornerRadius = 2.0;
       
        [btn setTitle:@"发送" forState:UIControlStateNormal];
        btn.titleLabel.font = [UIFont systemFontOfSize:14.0f];
        btn.autoresizingMask = UIViewAutoresizingFlexibleLeftMargin;
        [btn addTarget:self action:@selector(sendBtnPressed:) forControlEvents:UIControlEventTouchUpInside];
        btn;
    });

弱引用

__weak typeof(self) weakSelf = self;

主线程

dispatch_async(dispatch_get_main_queue(), ^{

});

block使用

1）声明：
typedef void (^SubjectInputCallBack)(NSString * input);
2）定义：
@property(nonatomic,copy)SubjectInputCallBack inputCallback;
3）使用：
cell.inputCallback =^(NSString*input){
                eventModel.subject = input;
};
再如：
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
    GPOperationTableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:cellIdentify];
    cell.infoLabel.text = self.dataSource[indexPath.row];
    cell.cellActionCallBackBlock = ^(GPOperationTableViewCell *cell){
        //NSIndexPath *index = [tableView indexPathForCell:cell];
        //indexPath直接使用，它会对应相应cell的indexPath，不用重新根据cell来获取
       //若是对cell有删除操作的话，记得tableView reloadData一下，不然的话这些数据是没有进行相应的更新的，,或者是根据cell获取[tableView indexPathForCell:cell]也可以
        NSLog(@"indexPath:row = %ld, section = %ld",(long)indexPath.row,(long)indexPath.section);
    };
    return cell;
}

方法中添加block
- (void)textFieldDidChange:(NSString *)text complishBlock:(void(^)(NSInteger index))complishBlock;

谓词刷选数组：predicate

dataSource是array，存放model对象，model对象有select属性，
NSPredicate * predicate = [NSPredicate predicateWithFormat:[NSString stringWithFormat:@"select == 1"]];
NSArray * select = [dataSource filteredArrayUsingPredicate:predicate];
if (select && select.count > 0) {
      return select;
}

创建indexpath:

NSIndexPath *indexPath = [NSIndexPath indexPathForRow:self.dataSoure.count - 1 inSection:0];

textField限制输入长度

- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string {
    if (range.location +range.length > textField.text.length) {
        return NO;
    }
    NSInteger lenght = textField.text.length + string.length - range.length;
    return lenght <= 24;
}

计算字符串size：

+ (CGSize)boundingALLRectWithSize:(NSString*)str Font:(UIFont*)font Size:(CGSize)size {
    NSMutableAttributedString *attributedString = [[NSMutableAttributedString alloc] initWithString:str];
    NSMutableParagraphStyle *style = [NSMutableParagraphStyle new];
    [style setLineSpacing:2.0f];
    [attributedString addAttribute:NSParagraphStyleAttributeName value:style range:NSMakeRange(0,str.length)];
    CGRect textRect = [str boundingRectWithSize:size options:NSStringDrawingUsesLineFragmentOrigin attributes:@{NSFontAttributeName:font,NSParagraphStyleAttributeName:style} context:nil];
    CGSize realSize = CGSizeZero;
    realSize = textRect.size;
    realSize.width = ceilf(realSize.width);
    realSize.height = ceilf(realSize.height);
    return realSize;
}