iphone开发中的一些小技巧
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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;
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:
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. }
16.使得device长期电量,不锁屏
UIApplication sharedApplication].idleTimerDisabled = YES;
17.ios6转屏问题解决方法
原来的方法:
- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation
2. {
3. return (interfaceOrientation == UIInterfaceOrientationPortrait);
4. }
5.
代替的方法:
6. -(BOOL)shouldAutorotate
7. {
8. return NO;
9. }
10.
11. -(NSUInteger)supportedInterfaceOrientations
12. {
13. return UIInterfaceOrientationMaskPortrait;
14. }
18 ,判断是否有网络链接
引入systemConfing framework 然后下载Reachability. h 和Reachability.m 类,
实现
Reachability *networkReachability = [Reachability reachabilityForInternetConnection]; NetworkStatus networkStatus = [networkReachability currentReachabilityStatus]; if (networkStatus == NotReachable) { NSLog(@"There IS NO internet connection"); } else { NSLog(@"There IS internet connection"); } }
19.隐藏状态栏
[UIApplication sharedApplication].statusBarHidden = YES;
或者
// iOS3.2+支持
[application setStatusBarHidden:NO withAnimation:UIStatusBarAnimationFade];
上述方法只能实现在程序跳过loading(即启动画面)的时候才能隐藏状态栏。如果想要在启动画面开始即隐藏状态栏,则要修改app的info.plist文件,新增UIStatusBarHidden键(Statusbar is initially hidden),其值是YES。
同理:对于状态栏的颜色改变,也要分别从两处着手,代码[[UIApplicationsharedAppli
[self.navigationController setNavigationBarHidden:YES];21.隐藏选项卡tabbar
方法一:
[self.tabBarController.tabBar setHidden:YES];
此方法的问题:虽然tabBar栏被隐藏了,但该区域成一片空白区,无法被其他视图使用。
方法二:
对于navigationController+tabBarController的结构,可以在push下一级的childController之前将childController的hidesBottomBarWhenPushed
1 - (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
2 {
3 self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
4 if (self) {
5 // Custom initialization.
6 self.hidesBottomBarWhenPushed= YES;
7 }
8 return self;
9 }
- - (void)makeTabBarHidden:(BOOL)hide
- {
- if ( [self.tabBarController.view.subviews count] < 2 )
- {
- return;
- }
- UIView *contentView;
- if ( [[self.tabBarController.view.subviews objectAtIndex:0] isKindOfClass:[UITabBar class]] )
- {
- contentView = [self.tabBarController.view.subviews objectAtIndex:1];
- }
- else
- {
- contentView = [self.tabBarController.view.subviews objectAtIndex:0];
- }
- // [UIView beginAnimations:@"TabbarHide" context:nil];
- if ( hide )
- {
- contentView.frame = self.tabBarController.view.bounds;
- }
- else
- {
- contentView.frame = CGRectMake(self.tabBarController.view.bounds.origin.x,
- self.tabBarController.view.bounds.origin.y,
- self.tabBarController.view.bounds.size.width,
- self.tabBarController.view.bounds.size.height - self.tabBarController.tabBar.frame.size.height);
- }
- self.tabBarController.tabBar.hidden = hide;
- // [UIView commitAnimations];
- }
- - (void)viewWillAppear:(BOOL)animated
- {
- [self setFullScreen:YES];
- }
- - (void)viewWillDisappear:(BOOL)animated
- {
- [self setFullScreen:NO];
- }
- - (void)setFullScreen:(BOOL)fullScreen
- {
- // 状态条
- [UIApplication sharedApplication].statusBarHidden = fullScreen;
- // 导航条
- [self.navigationController setNavigationBarHidden:fullScreen];
- // tabBar的隐藏通过在初始化方法中设置hidesBottomBarWhenPushed属性来实现
- }
22.UITextView 清空时键盘的改变
- -(BOOL)textField:(UITextField*)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string
- {
- NSMutableString *newValue = [textField.text mutableCopy];
- [newValue replaceCharactersInRange:range withString:string];
- if ([newValue length]== 0) {
- textField.returnKeyType=UIReturnKeyDone;
- [textField reloadInputViews];
- }
- else {
- textField.returnKeyType=UIReturnKeySearch;
- [textField reloadInputViews];
- }
- return YES;
- }
- iphone开发中的一些小技巧
- 转:iphone开发中的一些小技巧
- iphone开发中的一些小技巧
- iphone开发中的一些小技巧
- iphone开发中的一些小技巧
- iphone开发中的一些小技巧
- iphone开发中的一些小技巧
- iphone开发中的一些小技巧
- iphone开发中的一些小技巧
- iphone开发中的一些小技巧
- iphone开发中的一些小技巧
- iphone开发中的一些小技巧
- iphone开发中的一些小技巧
- iphone开发中的一些小技巧
- iphone开发中的一些小技巧
- iphone开发中的一些小技巧
- iphone开发中的一些小技巧
- iphone开发中的一些小技巧
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