iphone 开发技巧总结

iphone 开发技巧总结

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：

UIImage*image = [UIImageimageNamed:filename];

CGImageRef imageRef =image.CGImage;

CGRect rect= CGRectMake(origin.x,origin.y ,size.width,size.height);

CGImageRef imageRefRect= CGImageCreateWithImageInRect(imageRef,rect);

UIImage *imageRect = [[UIImagealloc] initWithCGImage:imageRefRect];

 

2、判断设备是iphone还是iphone4的代码：

#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：

- (BOOL)validateEmail: (NSString *)candidate {

NSString*emailRegex= @"[A-Z0-9a-z._%+-]+@[A-Za-z0-9.-]+\\.[A-Za-z]{2,4}";

NSPredicate *emailTest= [NSPredicatepredicateWithFormat:@"SELFMATCHES %@", emailRegex];

 

return [emailTest evaluateWithObject:candidate];

}

 

4、如何把当前的视图作为照片保存到相册中去：

 

#import <QuartzCore/QuartzCore.h>

UIGraphicsBeginImageContext(currentView.bounds.size); //currentView当前的view

[currentView.layer renderInContext:UIGraphicsGetCurrentContext()];

UIImage *viewImage= UIGraphicsGetImageFromCurrentImageContext();

UIGraphicsEndImageContext();

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：

UILocalNotification*notification=[[UILocalNotificationalloc] init];

if (notification!=nil){

NSLog(@">>support local notification");

NSDate *now=[NSDatenew];

notification.fireDate=[now addTimeInterval:10];

notification.timeZone=[NSTimeZonedefaultTimeZone];

notification.alertBody=@"该去吃晚饭了！";

[[UIApplication sharedApplication].scheduleLocalNotification:notification];

}

 

6、捕获iphone通话事件：

CTCallCenter *center =[[CTCallCenter alloc] init];

center.callEventHandler = ^(CTCall*call)

{

NSLog(@"call:%@", call.callState);

}

 

7、iOS4 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 Applicationdoes not run inbackground 一项，勾选即可。

8、使UIimageView的图像旋转：

float rotateAngle= M_PI;

CGAffineTransform transform=CGAffineTransformMakeRotation(rotateAngle);

imageView.transform =transform;

 

9、设置旋转的原点：

 

#import <QuartzCore/QuartzCore.h>

UIImageView *imageView =[[UIImageViewalloc] initWithImage:[UIImageimageNamed:@"bg.png"]];

imageView.layer.anchorPoint= CGPointMake(0.5, 1.0);

 

10、实现自定义的状态栏（遮盖状态栏）：

CGRect frame = {{0, 0},{320, 20}};

UIWindow* wd = [[UIWindowalloc] initWithFrame:frame];

[wd setBackgroundColor:[UIColor clearColor]];

[wdsetWindowLevel:UIWindowLevelStatusBar];

frame= CGRectMake(100, 0, 30, 20);

UIImageView* img = [[UIImageViewalloc] initWithFrame:frame];

[img setContentMode:UIViewContentModeCenter];

[img setImage:[UIImage imageNamed:@"00_0103.png"]];

[wd addSubview:img];

[wd makeKeyAndVisible];

 

[UIView beginAnimations:nil context:nil];

[UIView setAnimationDuration:2];

frame.origin.x+= 150;

[img setFrame:frame];

[UIView commitAnimations];

11、在程序中实现电话的拨打：

//添加电话图标按钮

UIButton *btnPhone =[[UIButton buttonWithType:UIButtonTypeCustom] retain];

btnPhone.frame= CGRectMake(280,10,30,30);

UIImage *image = [UIImageimageNamed:@"phone.png"];     

[btnPhone setBackgroundImage:image forState:UIControlStateNormal];

 

//点击拨号按钮直接拨号

[btnPhone addTarget:self action:@selector(callAction:event:) forControlEvents:UIControlEventTouchUpInside];

 

[cell.contentViewaddSubview:btnPhone];  //cell是一个UITableViewCell

 

//定义点击拨号按钮时的操作

- (void)callAction:(id)senderevent:(id)event{

NSSet *touches= [event allTouches];

UITouch *touch= [touches anyObject];

CGPoint currentTouchPosition= [touch locationInView:self.listTable];

NSIndexPath *indexPath= [self.listTable indexPathForRowAtPoint:currentTouchPosition];

if (indexPath== nil) {

return;

}

NSInteger section= [indexPath section];

NSUInteger row= [indexPath row];

NSDictionary *rowData= [datas objectAtIndex:row];

 

NSString *num= [[NSStringalloc] initWithFormat:@"tel://%@",number]; //number为号码字符串     

[[UIApplication sharedApplication] openURL:[NSURL URLWithString:num]];//拨号

}

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

- (void)textViewDidBeginEditing:(UITextView *)textView{

NSArray*ws= [[UIApplication sharedApplication] windows];

for(UIView *w in ws){

NSArray *vs= [w subviews];

for(UIView *v in vs)

{

if([[NSString stringWithUTF8String:object_getClassName(v)] isEqualToString:@"UIKeyboard"])

{

v.backgroundColor =[UIColor redColor];

}

}

}

 

13、设置时区

 

NSTimeZone *defaultTimeZone= [NSTimeZonedefaultTimeZone];

NSTimeZone *tzGMT =[NSTimeZone timeZoneWithName:@"GMT"];

[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。

 

 

[[NSNotificationCenter defaultCenter] addObserver:self

selector:@selector(keyboardWillHide:)

name:UIKeyboardWillHideNotification

object:nil];

 

- (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

-(int)calculateTextNumber:(NSString *)text

{

float number= 0.0;

int index= 0;

for (index;index < [text length];index++)

{

NSString *protoText= [text substringToIndex:[text length]- index];

NSString *toChangetext= [text substringToIndex:[text length]-1 -index];

NSString *charater;

if ([toChangetext length]==0)

{

charater = protoText;

}

else

{

NSRange range= [text rangeOfString:toChangetext];

charater =[protoText stringByReplacingCharactersInRange:range withString:@""];

 

}

NSLog(charater);

if([charater lengthOfBytesUsingEncoding:NSUTF8StringEncoding]==3)

{

number++;

}

else

{

number = number+0.5;

}

}

returnceil(number);

}

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