iPhone开发中一些使用小技巧

来源：互联网发布：js获取ip和端口编辑：程序博客网时间：2024/05/21 10:27

经过iphone开发，我发现在开发过程中最难的就是一些嘈杂的细节，而了解一些小技巧就会达到事半功倍的效果，下面我就总结一下在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 imageimageRef = image.CGImage;

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

6. CGImageRef imageRefRect = CGImageCreateWithImageInRect(imageRef, rect);

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:

2. @selector(currentMode)] ? CGSizeEqualToSize(CGSizeMake(640, 960),

3. [[UIScreen mainScreen] currentMode].size) : NO)

3、判断邮箱输入的是否正确：

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

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

3. NSPredicate *emailTest = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", emailRegex];

4. return [emailTest evaluateWithObject:candidate];

5. }

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

3. [currentView.layer renderInContext:UIGraphicsGetCurrentContext()];

4. UIImage *viewImage = UIGraphicsGetImageFromCurrentImageContext();

5. UIGraphicsEndImageContext();

6. 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. if (notification!=nil) {

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

4. NSDate *now=[NSDate new];

5. notification.fireDate=[now addTimeInterval:10];

6. notification.timeZone=[NSTimeZone defaultTimeZone];

7. notification.alertBody=@"该去吃晚饭了！";

8. [[UIApplication sharedApplication].scheduleLocalNotification:notification];

9. }

6、捕获iphone通话事件：

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

2. center.callEventHandler = ^(CTCall *call)

3. {

4. NSLog(@"call:%@", call.callState);

5. }

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. CGAffineTransform transform =CGAffineTransformMakeRotation(rotateAngle);

3. imageView.transform = transform;

9、设置旋转的原点：

1. #import <QuartzCore/QuartzCore.h>

2. UIImageView *imageView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"bg.png"]];

3. 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. UIWindow* wd = [[UIWindow alloc] initWithFrame:frame];

3. [wd setBackgroundColor:[UIColor clearColor]];

4. [wd setWindowLevel:UIWindowLevelStatusBar];

5. frame = CGRectMake(100, 0, 30, 20);

6. UIImageView* img = [[UIImageView alloc] initWithFrame:frame];

7. [img setContentMode:UIViewContentModeCenter];

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

9. [wd addSubview:img];

10.[wd makeKeyAndVisible];

11.[UIView beginAnimations:nil context:nil];

12.[UIView setAnimationDuration:2];

13.frame.origin.x += 150;

14.[img setFrame:frame];

15.[UIView commitAnimations];

11、在程序中实现电话的拨打：

1. //添加电话图标按钮

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

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

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

5. [btnPhone setBackgroundImage:image forState:UIControlStateNormal];

6. //点击拨号按钮直接拨号

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

8. [cell.contentView addSubview:btnPhone]; //cell是一个UITableViewCell

9. //定义点击拨号按钮时的操作

10.- (void)callAction:(id)sender event:(id)event{

11.NSSet *touches = [event allTouches];

12.UITouch *touch = [touches anyObject];

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

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

15.if (indexPath == nil) {

16.return;

17.}

18.NSInteger section = [indexPath section];

19.NSUInteger row = [indexPath row];

20.NSDictionary *rowData = [datas objectAtIndex:row];

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

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

23.}

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

3. for(UIView *w in ws){

4. NSArray *vs = [w subviews];

5. for(UIView *v in vs)

6. {

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

8. {

9. v.backgroundColor = [UIColor redColor];

10.}

11.}

12.}

13、设置时区

1. NSTimeZone *defaultTimeZone = [NSTimeZone defaultTimeZone];

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

3. [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. selector:@selector(keyboardWillHide:)

3. name:UIKeyboardWillHideNotification

4. object:nil];

5. - (IBAction)keyboardWillHide:(NSNotification *)note

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

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

9. NSString *charater;

10.if ([toChangetext length]==0)

11.{

12.charater = protoText;

13.}

14.else

15.{

16.NSRange range = [text rangeOfString:toChangetext];

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

18.}

19.NSLog(charater);

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

21.{

22.number++;

23.}

24.else

25.{

26.numbernumber = number+0.5;

27.}

28.}

29.return ceil(number);

30.}