持续更新。
1、获取应用安装时间
NSURL *docURL = [[[NSFileManager defaultManager] URLsForDirectory:NSDocumentDirectory inDomains:NSUserDomainMask] lastObject];
NSError *error;
NSDictionary *dict = [[NSFileManager defaultManager] attributesOfItemAtPath:docURL.path error:&error];
NSDate *creationDate = [dict objectForKey:NSFileCreationDate];
NSLog(@"应用安装时间: %@", creationDate);
2、null
打印出是尖括号<null>
,nil
是圆括号(null)
NSLog(@"%@--%@", [NSNull null], nil);
打印出:<null>--(null)
3、子view继承父view的手势,如果不想这样,可以通过手势代理做个判断:
1. 遵守协议<UIGestureRecognizerDelegate>
2. 设置手势的代理:singleTap.delegate = self;
3. 处理手势代理
- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldReceiveTouch:(UITouch *)touch {
//如果是子视图的话,返回NO,表示不要接收touch
// if ([touch.view isDescendantOfView:self.redView]) {
// return NO;
// }
if (touch.view == self.redView) {
return NO;
}
return YES;
}
4、简单的Masonry动画
如果约束还没有生成的时候需要动画,需要先调用[superview layoutIfNeeded],其作用是如果有需要刷新的标记,立即调用layoutSubviews进行布局;如果没有标记,不会调用layoutSubviews。
示例
//如果不能保证做动画前布局已经完成,可以手动调用一下
[self.backgroundView layoutIfNeeded];
[UIView animateWithDuration:0.4 animations:^{
[self.containerView mas_updateConstraints:^(MASConstraintMaker *make) {
make.bottom.equalTo(@0);
}];
//self.containerView的父视图是self.backgroundView
[self.backgroundView layoutIfNeeded];
}];
5、 tableView可以设置部分section高度自适应,部分手动指定高度
1. 国际惯例
_mTableView.estimatedRowHeight = 100;
_mTableView.rowHeight = UITableViewAutomaticDimension;
2. 代理里指定高度
- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath {
if (indexPath.section == 0) {
return UITableViewAutomaticDimension;
} else {
return 45;
}
}
6、 @encode()
返回一个给定的Objective-C 类型编码
NSLog(@"\nchar = %s, short = %s, int = %s, NSInteger = %s,\nchar * = %s, BOOL = %s, SEL = %s, NSObject * = %s,\nCGFloat = %s, double = %s, long long = %s, long = %s,\nid = %s",
@encode(char), @encode(short), @encode(int), @encode(NSInteger),
@encode(char *), @encode(BOOL), @encode(SEL), @encode(NSObject *),
@encode(CGFloat), @encode(double), @encode(long long), @encode(long),
@encode(id));
char = c, short = s, int = i, NSInteger = q,
char * = *, BOOL = B, SEL = :, NSObject * = @,
CGFloat = d, double = d, long long = q, long = q,
id = @
7、NSUserDefaults
- 可变数组
通过mutableArrayValueForKey:
取值。
- 可变数组
-
- 通过
initWithSuiteName:
单独创建一个plist文件
NSUserDefaults *lynn = [[NSUserDefaults alloc] initWithSuiteName:@"LynnZhang"]; [lynn setValue:@{@"name": @"LynnZhang", @"age": @18} forKey:@"userinfo"]; [lynn synchronize];
- 通过
8、内存对其
typedef struct {
char Char;//0-1
short Short;//2-3
double Double;//8-15
int Int;//16-20
} Stu_one;//24
typedef struct {
char Char;//0-1
short Short;//2-3
int Int;//4-7
double Double;//8-15
} Stu_two;//16
其他
- 苹果开放源码:https://opensource.apple.com/tarballs,对于iOS开发者来说,一般要看一下objc。
- GNUstep开源的"Foundation源码"