iOS开发中小技巧

Time: 22 September 2014
Categories:
iOS 30
Tags:
Objective-c 30

偶尔在搜索问题答案时，会有额外的收获。让你忍不住想，原来还可以这么干，太方便了，于是逐步记录着

###退回输入键盘： - (BOOL) textFieldShouldReturn:(id)textField{ [textField resignFirstResponder]; }

###绘制CGRect ,以及CGPoint & CGSize CGRect frame = CGRectMake (origin.x, origin.y, size.width, size.height)；矩形 NSStringFromCGRect(someCG) 把CGRect结构转变为格式化字符串； CGRectFromString(aString) 由字符串恢复出矩形； CGRectInset(aRect) 创建较小或较大的矩形（中心点相同），＋较小－较大 CGRectIntersectsRect(rect1, rect2) 判断两矩形是否交叉，是否重叠 CGRectZero 高度和宽度为零的／位于（0，0）的矩形常量 CGPoint aPoint = CGPointMake(x, y); CGSize aSize = CGSizeMake(width, height);

###隐藏状态栏：

 [[UIApplication shareApplication] setStatusBarHidden: YES animated:NO]

###横屏：

[[UIApplication shareApplication] setStatusBarOrientation:UIInterfaceOrientationLandscapeRight]. 
orientation == UIInterfaceOrientationLandscapeLeft 
window=[[UIWindow alloc] initWithFrame:[UIScreen mainScreen] bounds];全屏 

###自动适应父视图大小：

aView.autoresizingSubviews = YES; 
aView.autoresizingMask = (UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight); 

###设置视图背景图片

UIImageView *aView; 
[aView setImage:[UIImage imageNamed:@”name.png”]]; 
view1.backgroundColor = [UIColor colorWithPatternImage:[UIImage imageNamed:@"image1.png"]]; 
UISlider *slider = (UISlider *) sender; 
NSString *newText = [[NSString alloc] initWithFormat:@”%d”, (int)(slider.value + 0.5f)]; 
label.text = newText; 

###动画效果

-(void)doChange:(id)sender 
{ 
    if(view2 == nil) 
{ 
    [self loadSec]; 
} 
[UIView beginAnimations:nil context:NULL]; 
[UIView setAnimationDuration:1]; 
[UIView setAnimationTransition:([view1 superview] ? UIViewAnimationTransitionFlipFromLeft : UIViewAnimationTransitionFlipFromRight)forView : self.view cache:YES]; 
if([view1 superview]!= nil) 
{ 
    [view1 removeFromSuperview]; 
    [self.view addSubview:view2]; 
}else{ 
    [view2 removeFromSuperview]; 
    [self.view addSubview:view1]; 
} 
[UIView commitAnimations]; 

###随机数的使用

#import <time.h> 
#import <mach/mach_time.h> 
srandom()的使用 
srandom((unsigned)(mach_absolute_time() & 0xFFFFFFFF)); 
//直接使用 random() 来调用随机数 

###在UIImageView 中旋转图像

float rotateAngle = M_PI; 
CGAffineTransform transform =CGAffineTransformMakeRotation(rotateAngle); 
imageView.transform = transform; 

###读取一般性文档文件

NSString *tmp; 
NSArray *lines;/*将文件转化为一行一行的*/ 
lines = [[NSString  stringWithContentsOfFile:@"testFileReadLines.txt"] componentsSeparatedByString:@”\n”]; 
NSEnumerator *nse = [lines objectEnumerator]; 
// 读取<>里的内容 
while(tmp = [nse nextObject]) { 
    NSString *stringBetweenBrackets = nil; 
    NSScanner *scanner = [NSScanner scannerWithString:tmp]; 
    [scanner scanUpToString:@"<"intoString:nil]; 
    [scanner scanString:@"<"intoString:nil]; 
    [scanner scanUpToString:@">"intoString:&stringBetweenBrackets]; 
    NSLog([stringBetweenBrackets description]); 
} 