<转>iphone开发中的一些小技巧

1、如果在程序中想对某张图片进行处理的话（得到某张图片的一部分）可一用以下代码：
 
1 UIImage *image = [UIImage imageNamed:filename];
2 CGImageRef imageRef = image.CGImage;
3 
4 CGRect rect = CGRectMake(origin.x, origin.y ,size.width, size.height);
5 
6 CGImageRef imageRefRect = CGImageCreateWithImageInRect(imageRef, rect);
7 
8 UIImage *imageRect = [[UIImage alloc] initWithCGImage:imageRefRect];

 

2、判断设备是iphone还是iphone4的代码：

 

1 #define isRetina ([UIScreen instancesRespondToSelector:@selector(currentMode)] ? CGSizeEqualToSize(CGSizeMake(640, 960), [[UIScreen mainScreen] currentMode].size) : NO)

 

3、判断邮箱输入的是否正确：

 

 1 - (BOOL) validateEmail: (NSString *) candidate {
 2 
 3 NSString *emailRegex = @"[A-Z0-9a-z._%+-]+@[A-Za-z0-9.-]+\.[A-Za-z]{2,4}"; 
 4 
 5 NSPredicate *emailTest = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", emailRegex]; 
 6 
 7  
 8 
 9 return [emailTest evaluateWithObject:candidate];
10 
11 }

 

 

4、如何把当前的视图作为照片保存到相册中去：

 

 1 #import <QuartzCore/QuartzCore.h>
 2 
 3 UIGraphicsBeginImageContext(currentView.bounds.size);     //currentView 当前的view
 4 
 5 [currentView.layer renderInContext:UIGraphicsGetCurrentContext()];
 6 
 7 UIImage *viewImage = UIGraphicsGetImageFromCurrentImageContext();
 8 
 9 UIGraphicsEndImageContext();
10 
11 UIImageWriteToSavedPhotosAlbum(viewImage, nil, nil, nil);

 

 

5、本地通知（类似于push通知）按home键到后台 十秒后触发：

 1 UILocalNotification *notification=[[UILocalNotification alloc] init]; 
 2 
 3 if (notification!=nil) { 
 4 
 5 NSLog(@">> support local notification"); 
 6 
 7 NSDate *now=[NSDate new]; 
 8 
 9 notification.fireDate=[now addTimeInterval:10]; 
10 
11 notification.timeZone=[NSTimeZone defaultTimeZone]; 
12 
13 notification.alertBody=@"该去吃晚饭了！"; 
14 
15 [[UIApplication sharedApplication].scheduleLocalNotification:notification];
16 
17 }

 

 

6、捕获iphone通话事件：

1 CTCallCenter *center = [[CTCallCenter alloc] init];
2 
3 center.callEventHandler = ^(CTCall *call) 
4 
5 {
6 
7 NSLog(@"call:%@", call.callState);
8 
9 }
View Code

 

 

7、iOS 4 引入了多任务支持，所以用户按下 “Home” 键以后程序可能并没有退出而是转入了后台运行。如果您想让应用直接退出，最简单的方法是：在 info－plist 里面找到 Application does not run in background 一项，勾选即可。

 

8、使UIimageView的图像旋转：

 

1 float rotateAngle = M_PI;
2 
3 CGAffineTransform transform =CGAffineTransformMakeRotation(rotateAngle);
4 
5 imageView.transform = transform;

 

 

9、设置旋转的原点：

 

1 #import <QuartzCore/QuartzCore.h>
2 
3 UIImageView *imageView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"bg.png"]];
4 
5 imageView.layer.anchorPoint = CGPointMake(0.5, 1.0);

 

 

10、实现自定义的状态栏（遮盖状态栏）：

 1 CGRect frame = {{0, 0}, {320, 20}};
 2 
 3 UIWindow* wd = [[UIWindow alloc] initWithFrame:frame];
 4 
 5 [wd setBackgroundColor:[UIColor clearColor]];
 6 
 7 [wd setWindowLevel:UIWindowLevelStatusBar];
 8 
 9 frame = CGRectMake(100, 0, 30, 20);
10 
11 UIImageView* img = [[UIImageView alloc] initWithFrame:frame];
12 
13 [img setContentMode:UIViewContentModeCenter];
14 
15 [img setImage:[UIImage imageNamed:@"00_0103.png"]];
16 
17 [wd addSubview:img];
18 
19 [wd makeKeyAndVisible];
20 
21  
22 
23 [UIView beginAnimations:nil context:nil];
24 
25 [UIView setAnimationDuration:2];
26 
27 frame.origin.x += 150;
28 
29 [img setFrame:frame];
30 
31 [UIView commitAnimations];

 

 

11、在程序中实现电话的拨打：

 

//添加电话图标按钮 

1 UIButton *btnPhone = [[UIButton buttonWithType:UIButtonTypeCustom] retain]; 
2 
3 btnPhone.frame = CGRectMake(280,10,30,30); 
4 
5 UIImage *image = [UIImage imageNamed:@"phone.png"];     
6 
7 [btnPhone setBackgroundImage:image forState:UIControlStateNormal];

 

 

//点击拨号按钮直接拨号 

1 [btnPhone addTarget:self action:@selector(callAction:event:)forControlEvents:UIControlEventTouchUpInside]; 
2 
3  
4 
5 [cell.contentView addSubview:btnPhone];  //cell是一个UITableViewCell

 

 

//定义点击拨号按钮时的操作 

 1 - (void)callAction:(id)sender event:(id)event{ 
 2 
 3 NSSet *touches = [event allTouches]; 
 4 
 5 UITouch *touch = [touches anyObject]; 
 6 
 7 CGPoint currentTouchPosition = [touch locationInView:self.listTable]; 
 8 
 9 NSIndexPath *indexPath = [self.listTable indexPathForRowAtPoint: currentTouchPosition]; 
10 
11 if (indexPath == nil) { 
12 
13 return; 
14 
15 } 
16 
17 NSInteger section = [indexPath section]; 
18 
19 NSUInteger row = [indexPath row]; 
20 
21 NSDictionary *rowData = [datas objectAtIndex:row]; 
22 
23  
24 
25 NSString *num = [[NSString alloc] initWithFormat:@"tel://%@",number]; //number为号码字符串     
26 
27 [[UIApplication sharedApplication] openURL:[NSURL URLWithString:num]]; //拨号 
28 
29 }

 

 

12、更改iphone的键盘颜色：

 

1.只有这2种数字键盘才有效果。UIKeyboardTypeNumberPad，UIKeyboardTypePhonePad

2. keyboardAppearance ＝ UIKeyboardAppearanceAlert 

 1 - (void)textViewDidBeginEditing:(UITextView *)textView{
 2 
 3 NSArray *ws = [[UIApplication sharedApplication] windows];
 4 
 5 for(UIView *w in ws){
 6 
 7 NSArray *vs = [w subviews];
 8 
 9 for(UIView *v in vs)
10 
11 {
12 
13 if([[NSString stringWithUTF8String:object_getClassName(v)] isEqualToString:@"UIKeyboard"])
14 
15 {
16 
17 v.backgroundColor = [UIColor redColor];
18 
19 }
20 
21 }
22 
23 }

 

 

13、设置时区

 

1 NSTimeZone *defaultTimeZone = [NSTimeZone defaultTimeZone];
2 
3 NSTimeZone *tzGMT = [NSTimeZone timeZoneWithName:@"GMT"];
4 
5 [NSTimeZone setDefaultTimeZone:tzGMT];

 

上面两个时区任意用一个。

 

14、Ipad隐藏键盘的同时触发方法。

 

 1 [[NSNotificationCenter defaultCenter] addObserver:self
 2 
 3 selector:@selector(keyboardWillHide:)
 4 
 5 name:UIKeyboardWillHideNotification
 6 
 7   object:nil];
 8 
 9  
10 
11 - (IBAction)keyboardWillHide:(NSNotification *)note

 

14、在一个程序中打开另一个程序的方法。

 

http://www.cocoachina.com/iphonedev/sdk/2010/0322/768.html

15、计算字符串的字数

 

 1 -(int)calculateTextNumber:(NSString *)text
 2 {
 3     float number = 0.0;
 4     int index = 0;
 5     for (index; index < [text length]; index++)
 6 {
 7 
 8 NSString *protoText = [text substringToIndex:[text length] - index];
 9 
10 NSString *toChangetext = [text substringToIndex:[text length] -1 -index];
11 
12 NSString *charater;
13 
14 if ([toChangetext length]==0)
15 {
16     charater = protoText;
17 }
18 else 
19 {
20     NSRange range = [text rangeOfString:toChangetext];
21     charater = [protoText         stringByReplacingCharactersInRange:range withString:@""];
22 }
23 
24 NSLog(charater);
25 
26 if ([charater lengthOfBytesUsingEncoding:NSUTF8StringEncoding] == 3)
27 {
28     number++;
29 }
30 else 
31 {
32     number = number+0.5;
33 }
34 
35 }
36 
37 return ceil(number);
38 
39 }

ref:http://blog.csdn.net/kevinpake/article/details/12879055

posted @ 2013-10-29 17:21  Cyber9527  阅读(103)  评论(0)    收藏  举报