（转载）ios开发知识总结 — 上

转    据说是iOS开发一年总结的笔记，有空看看

iphone开发笔记



退回输入键盘

  - (BOOL) textFieldShouldReturn:(id)textField{

    [textField  resignFirstResponder];

}



CGRect

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 & CGSize

CGPoint aPoint = CGPointMake(x, y);   

CGSize aSize = CGSizeMake(width, height);



设置透明度

[myView setAlpha:value];   (0.0 < value < 1.0)



设置背景色

[myView setBackgroundColor:[UIColor redColor]]; 

 (blackColor;darkGrayColor;lightGrayColor;

whiteColor;grayColor; redColor; greenColor;

blueColor; cyanColor;yellowColor;

magentaColor;orangeColor;purpleColor;

brownColor; clearColor; )

自定义颜色

UIColor *newColor = [[UIColor alloc]

 initWithRed:(float) green:(float) blue:(float) alpha:(float)]; 

     0.0~1.0

竖屏

320X480



横屏

480X320   



状态栏高 (显示时间和网络状态)

20 像素  



导航栏、工具栏高(返回)

44像素



隐藏状态栏

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



横屏

[[UIApplication shareApplication]

setStatusBarOrientation:UIInterfaceOrientationLandscapeRight].



屏幕变动检测

orientation == UIInterfaceOrientationLandscapeLeft

全屏

window=[[UIWindow alloc] initWithFrame:[UIScreen mainScreen] bounds];



自动适应父视图大小：

aView.autoresizingSubviews = YES;

aView.autoresizingMask = (UIViewAutoresizingFlexibleWidth |

                                      UIViewAutoresizingFlexibleHeight);

 定义按钮

UIButton *scaleUpButton = [UIButton buttonWithType:UIButtonTypeRoundedRect];

[scaleUpButton setTitle:@"放 大" forState:UIControlStateNormal];

scaleUpButton.frame = CGRectMake(40, 420, 100, 40);

[scaleUpButton addTarget:self

 action:@selector(scaleUp)

forControlEvents:UIControlEventTouchUpInside];



设置视图背景图片

UIImageView *aView;

[aView setImage:[UIImage imageNamed:@”name.png”]];

view1.backgroundColor = [UIColor colorWithPatternImage:

[UIImage imageNamed:@"image1.png"]];



自定义UISlider的样式和滑块

我们使用的是UISlider的setMinimumTrackImage，和setMaximumTrackImage方法来定义图片的，这两个方法可以设置滑块左边和右边的图片的，不过如果用的是同一张图片且宽度和控件宽度基本一致，就不会有变形拉伸的后果，先看代码，写在 viewDidLoad中：

    //左右轨的图片

    UIImage *stetchLeftTrack= [UIImage imageNamed:@"brightness_bar.png"];

    UIImage *stetchRightTrack = [UIImage imageNamed:@"brightness_bar.png"];

    //滑块图片

    UIImage *thumbImage = [UIImage imageNamed:@"mark.png"];



    UISlider *sliderA=[[UISlider alloc]initWithFrame:CGRectMake(30, 320, 257, 7)];

    sliderA.backgroundColor = [UIColor clearColor];

    sliderA.value=1.0;

    sliderA.minimumValue=0.7;

    sliderA.maximumValue=1.0;



    [sliderA setMinimumTrackImage:stetchLeftTrack forState:UIControlStateNormal];

    [sliderA setMaximumTrackImage:stetchRightTrack forState:UIControlStateNormal];

    //注意这里要加UIControlStateHightlighted的状态，否则当拖动滑块时滑块将变成原生的控件

    [sliderA setThumbImage:thumbImage forState:UIControlStateHighlighted];

    [sliderA setThumbImage:thumbImage forState:UIControlStateNormal];

    //滑块拖动时的事件

    [sliderA addTarget:self action:@selector(sliderValueChanged:) forControlEvents:UIControlEventValueChanged];

    //滑动拖动后的事件

    [sliderA addTarget:self action:@selector(sliderDragUp:) forControlEvents:UIControlEventTouchUpInside];



    [self.view addSubview:sliderA];



为了大家实验方便，我附上背景图brightness_bar.png和滑块图mark.png

http://pic002.cnblogs.com/images/2011/162291/2011121611431816.png

http://pic002.cnblogs.com/images/2011/162291/2011121611432897.png



 -(IBAction)sliderValueChanged:(id)sender{

UISlider *slider = (UISlider *) sender;

NSString *newText = [[NSString alloc] initWithFormat:@”%d”, (int)(slider.value + 0.5f)];

label.text = newText;

}



活动表单

<UIActionSheetDelegate>



 - (IBActive) someButtonPressed:(id) sender

{

    UIActionSheet *actionSheet = [[UIActionSheet alloc] 

                    initWithTitle:@”Are you sure?”

                    delegate:self

                    cancelButtonTitle:@”No way!”

                    destructiveButtonTitle:@”Yes, I’m Sure!”

                    otherButtonTitles:nil];

    [actionSheet showInView:self.view];

    [actionSheet release];

}

警告视图 

 <UIAlertViewDelegate>



 - (void) actionSheet:(UIActionSheet *)actionSheet didDismissWithButtonIndex:(NSInteger) buttonIndex

{

     if(buttonIndex != [actionSheet cancelButtonIndex])

     {

          NSString *message = [[NSString alloc] initWithFormat:@”You can          

                   breathe easy, everything went OK.”];

          UIAlertView *alert = [[UIAlertView alloc]    

                               initWithTitle:@”Something was done”

                                message:message

                                delegate:self

                                cancelButtonTitle:@”OK”

                                otherButtonTitles:nil];

          [alert show];

          [alert release];

          [message release];

     }

}



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];

}



Table View   <UITableViewDateSource>

#pragma mark -

#pragma mark Table View Data Source Methods

//指定分区中的行数，默认为1

- (NSInteger)tableView:(UITableView *)tableView 

 numberOfRowsInSection:(NSInteger)section

{

return [self.listData count];

}



//设置每一行cell显示的内容

- (UITableViewCell *)tableView:(UITableView *)tableView 

cellForRowAtIndexPath:(NSIndexPath *)indexPath

{

static NSString *SimpleTableIndentifier = @"SimpleTableIndentifier";

UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:SimpleTableIndentifier];

if (cell == nil) {

cell = [[[UITableViewCell alloc] 

initWithStyle:UITableViewCellStyleSubtitle 

reuseIdentifier:SimpleTableIndentifier] 

autorelease];

}

     UIImage *image = [UIImage imageNamed:@"13.gif"];

cell.imageView.image = image;



NSUInteger row = [indexPath row];

cell.textLabel.text = [listData objectAtIndex:row];

     cell.textLabel.font = [UIFont boldSystemFontOfSize:20];



     if(row < 5)

cell.detailTextLabel.text = @"Best friends";

else 

    cell.detailTextLabel.text = @"friends";

return cell;

}

图像、文本标签和详细文本标签



图像：如果设置图像，则它显示在文本的左侧； 文本标签：这是单元的主要文本（UITableViewCellStyleDefault 只显示文本标签）；详细文本标签：这是单元的辅助文本，通常用作解释性说明或标签



UITableViewCellStyleSubtitle

UITableViewCellStyleDefault

UITableViewCellStyleValue1

UITableViewCellStyleValue2



<UITableViewDelegate>

#pragma mark -

#pragma mark Table View Delegate Methods

//把每一行缩进级别设置为其行号

- (NSInteger)tableView:(UITableView *)tableView indentationLevelForRowAtIndexPath:(NSIndexPath *)indexPath

{

NSUInteger row = [indexPath row];

return row;

}

//获取传递过来的indexPath值

- (NSIndexPath *)tableView:(UITableView *)tableView willSelectRowAtIndexPath:(NSIndexPath *)indexPath

{

NSUInteger row = [indexPath row];

if (row == 0) 

return nil;

return indexPath;

}



- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath

{

NSUInteger row = [indexPath row];

NSString *rowValue = [listData objectAtIndex:row];

NSString *message = [[NSString alloc] initWithFormat:@"You selected %@",rowValue];

UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Row Selected"

message:message

    delegate:nil

  cancelButtonTitle:@"Yes, I did!"

  otherButtonTitles:nil];

[alert show];

[alert release];

[message release];

[tableView deselectRowAtIndexPath:indexPath animated:YES];

}



//设置行的高度

- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath

{

return 40;

}



NavigationController 推出push 推出pop

[self.navigationController pushViewController:_detailController animated:YES];

[self.navigationController popViewControllerAnimated:YES];



Debug:

NSLog(@"%s %d", __FUNCTION__, __LINE__);



点击textField外的地方回收键盘



先定义一个UIControl类型的对象，在上面可以添加触发事件，令SEL实践为回收键盘的方法,最后将UIControl的实例加到当前View上。

UIControl *m_control = [[UIControl alloc] initWithFrame:CGRectMake(0, 0, 320, 480)];

[m_control addTarget:self action:@selector(keyboardReturn)

forControlEvents:UIControlEventTouchUpInside];

[self.view addSubview:m_control];



- (void) keyboardReturn

{

[aTextField resignFirstResponder];

}



键盘覆盖输入框

当键盘调出时将输入框覆盖时，可以用下方法：

- (BOOL)textFieldShouldBeginEditing:(UITextField *)textField

{

[self.view setFrame:CGRectMake(0, -100, 320, 480) ];

return YES;

}

- (BOOL)textFieldShouldEndEditing:(UITextField *)textField

{

  [self.view setFrame:CGRectMake(0, 0, 320, 480)];

           return YES;

}

当准备输入时，将视图的位置上调100，这样键盘就不能覆盖到输入框。



当依赖注入方法不好使时，可以在AppDelegate内申明一个全局的控制器实例_anotherViewController，在另一个需要使用_anotherViewController的地方定义以下委托方法，使用共享的UIApplication实例来获取该委托的引用

SomeAppDelegate *appDelegate = (SomeAppDelegate *)[[UIApplication sharedApplication] delegate];

_anotherViewController = appDelegate._anotherViewController;



UIViewController内建Table View



纯代码在UIViewController控制器内建Table View

@interface RootViewController : UIViewController <UITableViewDelegate, UITableViewDataSource> {

NSArray *timeZoneNames;

}

@property (nonatomic,retain) NSArray *timeZoneNames;

@end



(void) loadView

{

UITableView *tableView = [[UITableView alloc] initWithFrame:[[UIScreen mainScreen] applicationFrame]] style: UITableViewStylePlain];

tableView.autoresizingMask = (UIViewAutoresizingFlexibleHeight | UIViewAutoresizingWidth);

tableView.delegate = self;

tableView.dataSource = self;

[tableView reloadData];



self.view = tableView;

[tableView release];

}





将plist文件中的数据赋给数组

NSString *thePath = [[NSBundle mainBundle] pathForResource:@"States" ofType:@"plist"];

NSArray *array = [NSArray arrayWithContentsOfFile:thePath];



UITouch

手指的触摸范围：64X64



#pragma mark -

#pragma mark Touch Events



- (void)touchesBegan:(NSSet *) touches withEvent:(UIEvent *) event {

originFrame = bookCover.frame;

NSLog(@"%s %d", __FUNCTION__,__LINE__);



if ([touches count] == 2)

{

NSArray *twoTouches = [touches allObjects];

UITouch *firstTouch = [twoTouches objectAtIndex:0];

UITouch *secondTouch = [twoTouches objectAtIndex:1];

CGPoint firstPoint = [firstTouch locationInView:bookCover];

CGPoint secondPoint = [secondTouch locationInView:bookCover];



CGFloat deltaX = secondPoint.x - firstPoint.x;

CGFloat deltaY = secondPoint.y - firstPoint.y;

initialDistance = sqrt(deltaX * deltaX + deltaY * deltaY );

frameX = bookCover.frame.origin.x;

frameY = bookCover.frame.origin.y;

frameW = bookCover.frame.size.width;

frameH = bookCover.frame.size.height;

NSLog(@"%s %d", __FUNCTION__,__LINE__);

}

}



- (void)touchesMoved:(NSSet *) touches withEvent:(UIEvent *) event {



if([touches count] == 2)

{

NSLog(@"%s %d", __FUNCTION__,__LINE__);



NSArray *twoTouches = [touches allObjects];

UITouch *firstTouch = [twoTouches objectAtIndex:0];

UITouch *secondTouch = [twoTouches objectAtIndex:1];



CGPoint firstPoint = [firstTouch locationInView:bookCover];

CGPoint secondPoint = [secondTouch locationInView:bookCover];



CGFloat deltaX = secondPoint.x - firstPoint.x;

CGFloat deltaY = secondPoint.y - firstPoint.y;

CGFloat currentDistance = sqrt(deltaX * deltaX + deltaY * deltaY );



if (initialDistance == 0) {

initialDistance = currentDistance;

}

else if (currentDistance != initialDistance)

{

CGFloat changedDistance = currentDistance - initialDistance;

NSLog(@"changedDistance = %f",changedDistance);

[bookCover setFrame:CGRectMake(frameX - changedDistance / 2,

frameY - (changedDistance * frameH) / (2 * frameW),

frameW + changedDistance,

frameH + (changedDistance * frameH) / frameW)];

}

}

}



- (void)touchesEnded:(NSSet *) touches withEvent:(UIEvent *) event {

UITouch *touch = [touches anyObject];



UITouch双击图片变大/还原

if ([touch tapCount] == 2)

{

NSLog(@"%s %d", __FUNCTION__,__LINE__);



if (!flag) {

[bookCover setFrame:CGRectMake(bookCover.frame.origin.x - bookCover.frame.size.width / 2,

bookCover.frame.origin.y - bookCover.frame.size.height / 2,

2 * bookCover.frame.size.width,

2 * bookCover.frame.size.height)];

flag = YES;

}

else {

[bookCover setFrame:CGRectMake(bookCover.frame.origin.x + bookCover.frame.size.width / 4, bookCover.frame.origin.y + bookCover.frame.size.height / 4,

bookCover.frame.size.width / 2, bookCover.frame.size.height / 2)];

flag = NO;

}

}

}



Get the Location of Touches

(CGPoint)locationInView:(UIView *)view

(CGPoint)previousLocationInView:(UIView *)view

view window



Getting Touch Attributes

tapCount(read only) timestamp(read only) phase(read only)



Getting a Touch Object's Gesture Recognizers

gestureRecognizers



Touch Phase

UITouchPhaseBegan

UITouchPhaseMoved

UITouchPhaseStationary

UITouchPhaseEnded

UITouchPhaseCancelled



从Plist里读内容

NSString *plistPath = [[NSBundle mainBundle] pathForResource:@"book" ofType:@"plist"];

NSDictionary *dictionary = [[NSDictionary alloc] initWithContentsOfFile:plistPath];

NSString *book = [dictionary objectForKey:bookTitle];

[textView setText:book];



(void) initialize {

NSUserDefaults = [NSUserDefaults standardUserDefaults];

NSDictionary *appDefaults = [NSDictionary dictionaryWithObject:@"YES" forKey:@"DeleteBackup"];

[defaults registerDefaults:appDefaults];

}



To get a value of a default, use the valueForKey: method:

[[theDefaultsController values] valueForKey:@"userName"];

To set a value for a default, use setValue:forKey:

[[theDefaultsController values] setValue:newUserName forKey:@"userName"];



[[NSUserDefaults standardUserDefaults] setValue:aVale forKey:aKey];

[[NSUserDefaults standardUserDefaults] valueForKey:aKey];



获取Documents目录

NSArray *paths = NSSearchPathForDictionariesInDomains(NSDocumentDirectory,

NSUserDomainMask, YES);

NSString *documentsDirectory = [paths objectAtIndex:0];

NSString *filename = [documentsDirectory

stringByAppendingPathComponent:@"theFile.txt"];



获取tmp目录

NSString *tempPath = NSTemporaryDirectory();

NSString *tempFile = [tempPath stringByAppendingPathComponent:@"tempFile.txt"];



[[NSUserDefaults standardUserDefaults] setObject:data forKey:@"someKey"];

[[NSUserDefaults standardUserDefaults] objectForKey:aKey];



自定义NavigationBar

navigationBar = [[UINavigationBar alloc] initWithFrame:CGRectMake(0, 0, 320, 44)];

[navigationBar setBarStyle:UIBarStyleBlackOpaque];



myNavigationItem = [[UINavigationItem alloc] initWithTitle:@"Setting"];

[navigationBar setItems:[NSArray arrayWithObject:myNavigationItem]];

[self.view addSubview:navigationBar];



backButton = [[UIBarButtonItem alloc] initWithTitle:@"Back" style:UIBarButtonItemStylePlain target:self action:@selector(back)];

myNavigationItem.leftBarButtonItem = backButton;





利用Safari打开一个链接

NSURL *url = [NSURL URLWithString:@"http://www.cnblogs.com/tracy-e/"];

[[UIApplication sharedApplication] openURL:url];



利用UIWebView显示pdf文件、网页。。。

webView = [[UIWebView alloc] initWithFrame:CGRectMake(0, 0, 320, 480)];

[webView setDelegate:self];

[webView setScalesPageToFit:YES];

[webView setAutoresizingMask:UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight];

[webView setAllowsInlineMediaPlayback:YES];

[self.view addSubview:webView];

NSString *pdfPath = [[NSBundle mainBundle] pathForResource:@"ojc" ofType:@"pdf"];

NSURL *url = [NSURL fileURLWithPath:pdfPath];

NSURLRequest *request = [NSURLRequest requestWithURL:url

cachePolicy:NSURLRequestUseProtocolCachePolicy

timeoutInterval:5];

[webView loadRequest:request];





[myWebView loadRequest:[NSURLRequest requestWithURL:[NSURL

                       URLWithString: @"http://www.cnblogs.com/tracy-e/"]]];



NSString *errorString = [NSString stringWithFormat:@"<html><center><font size=

+5 color ='red'>An Error Occurred:<br>%@</fone></center></html>",error];

[myWebView loadHTMLString:errorString baseURL:nil];



//Stopping a load request when the view is to disappear

- (void)viewWillDisappear:(BOOL)animate{

if ([myWebView loading]){

[myWebView stopLoading];

}

myWebView.delegate = nil;

[UIApplication shareApplication].networkActivityIndicatorVisible = NO;

}

汉字转码

NSString *oriString = @"\u67aa\u738b";

NSString *escapedString = [oriString

stringByReplacingPercentEscapesUsingEncoding: NSUTF8StringEncoding];





Checking for background support on earlier versions of iOS

UIDevice *device = [UIDevice currentDevice];

BOOL backgroundSupported = NO;

if ([device respondsToSelector:@selector(isMultitaskingSupported)]){

backgroundSupported = device.multitaskingSupported;

}



Being a Responsible,Multitasking-Aware Application

# Do not make any OpenGL ES calls from your code.

# Cancel any Bonjour-related services before being suspended.

# Be prepared to handle connection failures in your network-based sockets.

# Save your application state before moving to the background.

# Release any unneeded memory when moving to the background.

# Stop using shared system resources before being suspended.

# Avoid updating your windows and views.

# Respond to connect and disconnect notification for external accessories.

# Clean up resource for active alerts when moving to the background.

# Remove sensitive information from views before moving to the background.

# Do minimal work while running in the background.



Handing the Keyboard notifications

//Call this method somewhere in your view controller setup code

- (void) registerForKeyboardNotifications{



[[NSNotificationCenter defaultCenter] addObserver:self

selector:@selector(keyboardWasShown:)

name:UIKeyboardDidShowNotification

object:nil];

[[NSNotificationCenter defaultCenter] addObserver:self

selector:@selector(keyboardWasHidden:)

name:UIKeyboardDidHideNotification

object:nil];



}



//Called when the UIKeyboardDidShowNotification is sent

- (void)keyboardWasShown:(NSNotification *) aNotification{

if(keyboardShown)

return;

NSDictionary *info = [aNotification userInfo];



//get the size of the keyboard.

NSValue *aValue = [info objectForKey:UIKeyboardFrameBeginUserInfoKey];

CGSize keyboardSize = [aValue CGRectValue].size;



//Resize the scroll view

CGRect viewFrame = [scrollView frame];

viewFrame.size.height -= keyboardSize.height;



//Scroll the active text field into view

CGRect textFieldRect = [activeField frame];

[scrollView scrollRectToVisible:textFieldRect animated:YES];



keyboardShown = YES;

}



//Called when the UIKeyboardDidHideNotification is sent

- (void)keyboardWasHidden:(NSNotification *) aNotification{

NSDictionary *info = [aNotification userInfo];



//Get the size of the keyboard.

NSValue *aValue = [info objectForKey:UIKeyboardFrameEndUserInfoKey];

CGSize keyboardSize = [aValue CGRectValue].size;



//Reset the height of the scroll view to its original value

CGRect viewFrame = [scrollView Frame];

viewFrame.size.height += keyboardSize.height;

scrollView.frame = viewFrame;



keyboardShown = NO;

}



点击键盘的next按钮，在不同的textField之间换行

//首先给不同的textField赋不同的且相邻的tag值

- (BOOL)textFieldShouldReturn:(UITextField *)textField

{

if ([textField returnKeyType] != UIReturnKeyDone)

{

NSInteger nextTag = [textField tag] + 1;

UIView *nextTextField = [[self tableView] viewWithTag:nextTag];

[nextTextField becomeFirstResponder];

}

else {

[textField resignFirstResponder];

}

return YES;

}



Configuring a date formatter

- (void)viewDidLoad {

[super viewDidLoad];

dateFormatter = [[NSDateFormatter alloc] init];

[dateFormatter setGeneratesCalendarDates:YES];

[dateFormatter setLocale:[NSLocale currentLocale]];

[dateFormatter setCalendar:[NSCalendar autoupdatingCurrentCalendar]];

[dateFormatter setTimeZone:[NSTimeZone defaultTimeZone]];

[dateFormatter setDateStyle:NSDateFormatterShortStyle];

DOB.placeholder = [NSString stringWithFormat:@"Example: %@",[dateFormatter stringFromDate:[NSDate date]]];

}



- (void)textFieldDidEndEditing:(UITextField *)textField{

[textField resignFirstResponder];

if ([textField.text isEqualToString:@""])

return;

switch (textField.tag){

case DOBField:

NSDate *theDate = [dateFormatter dateFromString:textField.text];

if (theDate)

[inputDate setObject:theDate forKey:MyAppPersonDOBKey];

break;

default:

break;

}

}



 tableView的cell高度

tableView的cell高度除了在delegate中指定外，还可以在任意位置以[tableView setRowHeight:44]的方式指定



[[self navigationItem] setLeftBarButtonItem:[self editButtonItem]];



- (void)setEditing:(BOOL)editing animated:(BOOL)animated{

[super setEditing:editing animated:animated];

if (editing){

......

}

else{

......

}

}



One added a subview to a view, release the subview to avoid the extra retain count of it, Because when you insert a view as a subview using addSubview:, the subview is retained by its superview. When you remove the subview from its superview using the removeFromSuperview: method, subview is autoreleased.



为UINavigationBar设置背景图片

在iPhone开发中, 有时候我们想给导航条添加背景图片, 实现多样化的导航条效果, 用其他方法往往无法达到理想的效果, 经过网上搜索及多次实验, 确定如下最佳实现方案:

为UINavigatonBar增加如下Category(类别:提供一种为某个类添加方法而又不必编写子类的途径,类别只能添加成员函数，不能添加数据成员):



@implementation UINavigationBar (CustomImage)  

- (void)drawRect:(CGRect)rect {  

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

    [image drawInRect:CGRectMake(0, 0, self.frame.size.width, self.frame.size.height)];  

}  

@end  



例如, 在我的项目中, 添加如下代码:

/////////////////////////////////////////////////////////  

/* input: The image and a tag to later identify the view */  

@implementation UINavigationBar (CustomImage)  

- (void)drawRect:(CGRect)rect {  

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

    [image drawInRect:CGRectMake(0, 0, self.frame.size.width, self.frame.size.height)];  

}  

@end  

/////////////////////////////////////////////////////////  

@implementation FriendsPageViewController  

// Implement viewDidLoad to do additional setup after loading the view, typically from a nib.  

- (void)viewDidLoad {     

    self.navigationBar.tintColor = [UIColor purpleColor];  

    [self initWithRootViewController:[[RegPageViewController alloc] init]];  

    [super viewDidLoad];  

}  

......  

实现的效果如下图:





转载，原文地址 http://blog.csdn.net/wave_1102/archive/2009/11/04/4768212.aspx



为UINavigationBar添加自定义背景



@implementation UINavigationBar (UINavigationBarCategory) 



- (void)drawRect:(CGRect)rect { 

    //颜色填充 

//  UIColor *color = [UIColor redColor]; 

//  CGContextRef context = UIGraphicsGetCurrentContext(); 

//  CGContextSetFillColor(context, CGColorGetComponents( [color CGColor])); 

//  CGContextFillRect(context, rect); 

//  self.tintColor = color; 

    //图片填充 

UIColor *color = [UIColor colorWithRed:46.0f/255.0f

green:87.0f/255.0f blue:29.0f/255.0f alpha:1.0f];



    UIImage *img    = [UIImage imageNamed: @"bg.png"]; 

    [img drawInRect:CGRectMake(0, 0, self.frame.size.width, self.frame.size.height)]; 



    self.tintColor = color; 

} 



@end



加载图片要及时release



你还在使用myImage = [UIImage imageNamed:@"icon.png"]; 吗？



如题，是不是大家为了方便都这样加载图片啊



myImage = [UIImage imageNamed:@"icon.png"];



那么小心了



这种方法在一些图片很少，或者图片很小的程序里是ok的。



但是，在大量加载图片的程序里，请千万不要这样做。



为什么呢 ？？？？？？？



这种方法在application bundle的顶层文件夹寻找由供应的名字的图象。 如果找到图片，装载到iPhone系统缓存图象。那意味图片是(理论上)放在内存里作为cache的。



试想你图片多了，是什么后果？



图片cache极有可能不会响应 memory warnings and release its objects



所以，用图片的时候一定要小心的alloc和release。



推荐使用 NSString *path = [[NSBundle mainBundle] pathForResource:@"icon" ofType:@"png"];



myImage = [UIImage imageWithContentsOfFile:path];



// Todo use of myImage



[myImage release];



From: http://www.cocoachina.com/bbs/simple/?t27420.html



uiwebview打开doc,pdf文件

UIWebView *webView = [[UIWebView alloc]initWithFrame:CGRectMake(0, 55, 320, 300)];

    webView.delegate = self;

    webView.multipleTouchEnabled = YES;

    webView.scalesPageToFit = YES;



    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);

    NSString *documentsDirectory = [paths objectAtIndex:0];

    NSString *docPath = [documentsDirectory stringByAppendingString:@"/doc2003_1.doc"];    NSLog(@"#######%@",docPath);



    NSURL *url = [NSURL fileURLWithPath:docPath];

    NSURLRequest *request = [NSURLRequest requestWithURL:url];

    [webView loadRequest:request];



    [self.view addSubview:webView];

[webView release];



From:http://blog.csdn.net/dadalan/archive/2010/10/22/5959301.aspx



iPhone游戏中既播放背景音乐又播放特效声音的办法



有时候在 iPhone 游戏中，既要播放背景音乐，同时又要播放比如枪的开火音效。此时您可以试试以下方法



    NSString *musicFilePath = [[NSBundle mainBundle] pathForResource:fileName ofType:@"wav"];       //创建音乐文件路径

    NSURL *musicURL = [[NSURL alloc] initFileURLWithPath:musicFilePath]; 

    AVAudioPlayer* musicPlayer = [[AVAudioPlayer alloc] initWithContentsOfURL:musicURL error:nil];

    [musicURL release];

    [musicPlayer prepareToPlay];

    //[musicPlayer setVolume:1];            //设置音量大小

    //musicPlayer .numberOfLoops = -1;//设置音乐播放次数  -1为一直循环



要导入框架 AVFoundation.framework，头文件中 #import <AVFoundation/AVFoundation.h>；做成类的话则更方便。



From: http://blog.csdn.net/dadalan/archive/2010/10/19/5950493.aspx



NSNotificationCenter用于增加回调函数

[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(_willBecomeActive) name:UIApplicationDidBecomeActiveNotification object:nil];



UINavigationBar 背景Hack

LOGO_320×44.png 图片显示在背景上，



@implementation UINavigationBar (UINavigationBarCategory)

- (void)drawRect:(CGRect)rect {

       //加入旋转坐标系代码

    // Drawing code

       UIImage *navBarImage = [UIImage imageNamed:@"LOGO_320×44.png"];

       CGContextRef context = UIGraphicsGetCurrentContext();

       CGContextTranslateCTM(context, 0.0, self.frame.size.height);

       CGContextScaleCTM(context, 1.0, -1.0);      



       CGPoint center=self.center;



       CGImageRef cgImage= CGImageCreateWithImageInRect(navBarImage.CGImage, CGRectMake(0, 0, 1, 44));

       CGContextDrawImage(context, CGRectMake(center.x-160-80, 0, 80, self.frame.size.height), cgImage);

       CGContextDrawImage(context, CGRectMake(center.x-160, 0, 320, self.frame.size.height), navBarImage.CGImage);

       CGContextDrawImage(context, CGRectMake(center.x+160, 0, 80, self.frame.size.height), cgImage);

}

@end



old code

CGContextDrawImage(context, CGRectMake(0, 0, self.frame.size.width, self.frame.size.height), navBarImage.CGImage);



hack 过logo 不再拉伸


From: http://blog.163.com/fengyi1103@126/blog/static/13835627420106279102671/



清除电话号码中的其他符号（源码）



最近从通讯录读取电话号码，读出得号码如：134－1814－****。

而我需要的为11位纯数字，一直找方法解决此问题，今天终于找到了。。

分享一下……



代码如下：



NSString *originalString = @"(123) 123123 abc";

NSMutableString *strippedString = [NSMutableString

        stringWithCapacity:originalString.length];



NSScanner *scanner = [NSScanner scannerWithString:originalString];

NSCharacterSet *numbers = [NSCharacterSet

        characterSetWithCharactersInString:@"0123456789"];



while ([scanner isAtEnd] == NO) {

  NSString *buffer;

  if ([scanner scanCharactersFromSet:numbers intoString:&buffer]) {

    [strippedString appendString:buffer];

  }

  // --------- Add the following to get out of endless loop

  else {

     [scanner setScanLocation:([scanner scanLocation] + 1)];

  }   

  // --------- End of addition

}



NSLog(@"%@", strippedString); // "123123123"



From： http://stackoverflow.com/questions/1129521/remove-all-but-numbers-from-nsstring





正则判断：字符串只包含字母和数字



NSString *mystring = @"Letter1234";

NSString *regex = @"[a-z][A-Z][0-9]";



NSPredicate *predicate = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", regex];



if ([predicate evaluateWithObject:mystring] == YES) {

    //implement

}





一行代码设置 UITableViewCell 与导航条间距



UITableView 的 cell 默认出现在 uitableview 的第一行，如果你想自定义 UITableViewCell 与导航条间距的话，可以使用下面这行代码



tableview.tableHeaderView = [[[UIView alloc] initWithFrame:CGRectMake(0, 0, 5, 20)]autorelease];



From: http://blog.163.com/fengyi1103@126/blog/static/1383562742010101611107492/





修改 UITableview 滚动条颜色的方法



    UITableview 的滚动条默认颜色是黑色的，如果 UItableview 背景也是深颜色，则滚动条会变的很不明显。您可以用下面这行代码来改变滚动条的颜色



self.tableView.indicatorStyle=UIScrollViewIndicatorStyleWhite;



当然，最后的 “White” 也可以换成其它颜色。





下文件之前获取到文件大小的代码



下面这段代码，能实现在下载文件之前获得文件大小，应用在软件里，能在很大程度上改善用户体验



[m_pASIHTTPRequest setDidReceiveResponseHeadersSelector:@selector(didReceiveResponseHeaders:)];



- (void)didReceiveResponseHeaders:(ASIHTTPRequest *)request

{

    NSLog(@"didReceiveResponseHeaders %@",[m_request.responseHeaders valueForKey:@"Content-Length"]);

｝



网络编程总结 iphone



一：确认网络环境3G/WIFI



    1. 添加源文件和framework



    开发Web等网络应用程序的时候，需要确认网络环境，连接情况等信息。如果没有处理它们，是不会通过Apple的审(我们的)查的。

    Apple 的 例程 Reachability 中介绍了取得/检测网络状态的方法。要在应用程序程序中使用Reachability，首先要完成如下两部：



    1.1. 添加源文件：

    在你的程序中使用 Reachability 只须将该例程中的 Reachability.h 和 Reachability.m 拷贝到你的工程中。如下图：







    1.2.添加framework：

    将SystemConfiguration.framework 添加进工程。如下图：





    2. 网络状态



    Reachability.h中定义了三种网络状态：

    typedef enum {

        NotReachable = 0,            //无连接

        ReachableViaWiFi,            //使用3G/GPRS网络

        ReachableViaWWAN            //使用WiFi网络

    } NetworkStatus;



    因此可以这样检查网络状态：



    Reachability *r = [Reachability reachabilityWithHostName:@“www.apple.com”];

    switch ([r currentReachabilityStatus]) {

            case NotReachable:

                    // 没有网络连接

                    break;

            case ReachableViaWWAN:

                    // 使用3G网络

                    break;

            case ReachableViaWiFi:

                    // 使用WiFi网络

                    break;

    }



    3.检查当前网络环境

    程序启动时，如果想检测可用的网络环境，可以像这样

    // 是否wifi

    + (BOOL) IsEnableWIFI {

        return ([[Reachability reachabilityForLocalWiFi] currentReachabilityStatus] != NotReachable);

    }



    // 是否3G

    + (BOOL) IsEnable3G {

        return ([[Reachability reachabilityForInternetConnection] currentReachabilityStatus] != NotReachable);

    }

    例子：

    - (void)viewWillAppear:(BOOL)animated {   

    if (([Reachability reachabilityForInternetConnection].currentReachabilityStatus == NotReachable) &&

            ([Reachability reachabilityForLocalWiFi].currentReachabilityStatus == NotReachable)) {

            self.navigationItem.hidesBackButton = YES;

            [self.navigationItem setLeftBarButtonItem:nil animated:NO];

        }

    }



    4. 链接状态的实时通知

    网络连接状态的实时检查，通知在网络应用中也是十分必要的。接续状态发生变化时，需要及时地通知用户：



    Reachability 1.5版本

    // My.AppDelegate.h

    #import "Reachability.h"



    @interface MyAppDelegate : NSObject <UIApplicationDelegate> {

        NetworkStatus remoteHostStatus;

    }



    @property NetworkStatus remoteHostStatus;



    @end



    // My.AppDelegate.m

    #import "MyAppDelegate.h"



    @implementation MyAppDelegate

    @synthesize remoteHostStatus;



    // 更新网络状态

    - (void)updateStatus {

        self.remoteHostStatus = [[Reachability sharedReachability] remoteHostStatus];

    }



    // 通知网络状态

    - (void)reachabilityChanged:(NSNotification *)note {

        [self updateStatus];

        if (self.remoteHostStatus == NotReachable) {

            UIAlertView *alert = [[UIAlertView alloc] initWithTitle:NSLocalizedString(@"AppName", nil)

                         message:NSLocalizedString (@"NotReachable", nil)

                        delegate:nil cancelButtonTitle:@"OK" otherButtonTitles: nil];

            [alert show];

            [alert release];

        }

    }



    // 程序启动器，启动网络监视

    - (void)applicationDidFinishLaunching:(UIApplication *)application {



        // 设置网络检测的站点

        [[Reachability sharedReachability] setHostName:@"www.apple.com"];

        [[Reachability sharedReachability] setNetworkStatusNotificationsEnabled:YES];

        // 设置网络状态变化时的通知函数

        [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(reachabilityChanged:)

                                                 name:@"kNetworkReachabilityChangedNotification" object:nil];

        [self updateStatus];

    }



    - (void)dealloc {

        // 删除通知对象

        [[NSNotificationCenter defaultCenter] removeObserver:self];

        [window release];

        [super dealloc];

    }



    Reachability 2.0版本





    // MyAppDelegate.h

    @class Reachability;



        @interface MyAppDelegate : NSObject <UIApplicationDelegate> {

            Reachability  *hostReach;

        }



    @end



    // MyAppDelegate.m

    - (void)reachabilityChanged:(NSNotification *)note {

        Reachability* curReach = [note object];

        NSParameterAssert([curReach isKindOfClass: [Reachability class]]);

        NetworkStatus status = [curReach currentReachabilityStatus];



        if (status == NotReachable) {

            UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"AppName""

                              message:@"NotReachable"

                              delegate:nil

                              cancelButtonTitle:@"YES" otherButtonTitles:nil];

                              [alert show];

                              [alert release];

        }

    }



    - (void)applicationDidFinishLaunching:(UIApplication *)application {

        // ...



        // 监测网络情况

        [[NSNotificationCenter defaultCenter] addObserver:self

                              selector:@selector(reachabilityChanged:)

                              name: kReachabilityChangedNotification

                              object: nil];

        hostReach = [[Reachability reachabilityWithHostName:@"www.google.com"] retain];

        hostReach startNotifer];

        // ...

    }





二：使用NSConnection下载数据



    1.创建NSConnection对象，设置委托对象



    NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:[NSURL URLWithString:[self urlString]]];

    [NSURLConnection connectionWithRequest:request delegate:self];



    2. NSURLConnection delegate委托方法

        - (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response; 

        - (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error; 

        - (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data; 

        - (void)connectionDidFinishLoading:(NSURLConnection *)connection; 



    3. 实现委托方法

    - (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response {

        // store data

        [self.receivedData setLength:0];            //通常在这里先清空接受数据的缓存

    }



    - (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data {

           /* appends the new data to the received data */

        [self.receivedData appendData:data];        //可能多次收到数据，把新的数据添加在现有数据最后

    }



    - (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error {

        // 错误处理

    }



    - (void)connectionDidFinishLoading:(NSURLConnection *)connection {

        // disconnect

        [UIApplication sharedApplication].networkActivityIndicatorVisible = NO;  

        NSString *returnString = [[NSString alloc] initWithData:self.receivedData encoding:NSUTF8StringEncoding];

        NSLog(returnString);

        [self urlLoaded:[self urlString] data:self.receivedData];

        firstTimeDownloaded = YES;

    }