iOS常用代码块demo1
1.GCD定时器
dispatch_queue_t queue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0);
dispatch_source_t timer = dispatch_source_create(DISPATCH_SOURCE_TYPE_TIMER, 0, 0,queue);
dispatch_source_set_timer(timer,dispatch_walltime(NULL, 0),1.0*NSEC_PER_SEC, 0); //每秒执行
dispatch_source_set_event_handler(timer, ^{
//倒计时结束，关闭
dispatch_source_cancel(timer);
dispatch_async(dispatch_get_main_queue(), ^{
});
});
dispatch_resume(timer);
2.图片上绘制文字
- (UIImage *)imageWithTitle:(NSString *)title fontSize:(CGFloat)fontSize
{
//画布大小
CGSize size=CGSizeMake(self.size.width,self.size.height);
//创建一个基于位图的上下文
UIGraphicsBeginImageContextWithOptions(size,NO,0.0);//opaque:NO scale:0.0
[self drawAtPoint:CGPointMake(0.0,0.0)];
//文字居中显示在画布上
NSMutableParagraphStyle* paragraphStyle = [[NSParagraphStyle defaultParagraphStyle] mutableCopy];
paragraphStyle.lineBreakMode = NSLineBreakByCharWrapping;
paragraphStyle.alignment=NSTextAlignmentCenter;//文字居中
//计算文字所占的size,文字居中显示在画布上
CGSize sizeText=[title boundingRectWithSize:self.size options:NSStringDrawingUsesLineFragmentOrigin
attributes:@{NSFontAttributeName:[UIFont systemFontOfSize:fontSize]}context:nil].size;
CGFloat width = self.size.width;
CGFloat height = self.size.height;
CGRect rect = CGRectMake((width-sizeText.width)/2, (height-sizeText.height)/2, sizeText.width, sizeText.height);
//绘制文字
[title drawInRect:rect withAttributes:@{ NSFontAttributeName:[UIFont systemFontOfSize:fontSize],NSForegroundColorAttributeName:[ UIColor whiteColor],NSParagraphStyleAttributeName:paragraphStyle}];
//返回绘制的新图形
UIImage *newImage= UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return newImage;
}
3.查找一个视图的所有子视图
- (NSMutableArray *)allSubViewsForView:(UIView *)view
{
NSMutableArray *array = [NSMutableArray arrayWithCapacity:0];
for (UIView *subView in view.subviews)
{
[array addObject:subView];
if (subView.subviews.count > 0)
{
[array addObjectsFromArray:[self allSubViewsForView:subView]];
}
}
return array;
}
4.计算文件大小
//文件大小
- (long long)fileSizeAtPath:(NSString *)path
{
NSFileManager *fileManager = [NSFileManager defaultManager];
if ([fileManager fileExistsAtPath:path])
{
long long size = [fileManager attributesOfItemAtPath:path error:nil].fileSize;
return size;
}
return 0;
}
//文件夹大小
- (long long)folderSizeAtPath:(NSString *)path
{
NSFileManager *fileManager = [NSFileManager defaultManager];
long long folderSize = 0;
if ([fileManager fileExistsAtPath:path])
{
NSArray *childerFiles = [fileManager subpathsAtPath:path];
for (NSString *fileName in childerFiles)
{
NSString *fileAbsolutePath = [path stringByAppendingPathComponent:fileName];
if ([fileManager fileExistsAtPath:fileAbsolutePath])
{
long long size = [fileManager attributesOfItemAtPath:fileAbsolutePath error:nil].fileSize;
folderSize += size;
}
}
}
return folderSize;
}
5.UIView的设置部分圆角
CGRect rect = view.bounds;
CGSize radio = CGSizeMake(30, 30);//圆角尺寸
UIRectCorner corner = UIRectCornerTopLeft|UIRectCornerTopRight;//这只圆角位置
UIBezierPath *path = [UIBezierPath bezierPathWithRoundedRect:rect byRoundingCorners:corner cornerRadii:radio];
CAShapeLayer *masklayer = [[CAShapeLayer alloc]init];//创建shapelayer
masklayer.frame = view.bounds;
masklayer.path = path.CGPath;//设置路径
view.layer.mask = mask layer;
6.计算字符串字符长度，一个汉字算两个字符
//方法一：
- (int)convertToInt:(NSString*)strtemp
{
int strlength = 0;
char* p = (char*)[strtemp cStringUsingEncoding:NSUnicodeStringEncoding];
for (int i=0 ; i<[strtemp lengthOfBytesUsingEncoding:NSUnicodeStringEncoding] ;i++)
{
if (*p)
{
p++;
strlength++;
}
else
{
p++;
}
}
return strlength;
}
//方法二：
-(NSUInteger) unicodeLengthOfString: (NSString *) text
{
NSUInteger asciiLength = 0;
for (NSUInteger i = 0; i < text.length; i++)
{
unichar uc = [text characterAtIndex: i];
asciiLength += isascii(uc) ? 1 : 2;
}
return asciiLength;
}
防止滚动视图手势覆盖侧滑手势
[scrollView.panGestureRecognizer requireGestureRecognizerToFail:self.navigationController.interactivePopGestureRecognizer];
去掉导航栏返回的标题
[[UIBarButtonItem appearance]setBackButtonTitlePositionAdjustment:UIOffsetMake(0, -60)forBarMetrics:UIBarMetricsDefault];
