（轉載）ios開發知識總結 — 上
轉 聽說是iOS開發一年總結的筆記，有空看看
iphone開發筆記
退回輸入鍵盤
- (BOOL) textFieldShouldReturn:(id)textField{
[textField resignFirstResponder];
}
CGRect
CGRect frame = CGRectMake (origin.x, origin.y, size.width, size.height)；矩形
NSStringFromCGRect(someCG) 把CGRect結構轉變爲格式化字符串；
CGRectFromString(aString) 由字符串恢復出矩形；
CGRectInset(aRect) 建立較小或較大的矩形（中心點相同），＋較小 －較大
CGRectIntersectsRect(rect1, rect2) 判斷兩矩形是否交叉，是否重疊
CGRectZero 高度和寬度爲零的／位於（0，0）的矩形常量
CGPoint & CGSize
CGPoint aPoint = CGPointMake(x, y);
CGSize aSize = CGSizeMake(width, height);
設置透明度
[myView setAlpha:value]; (0.0 < value < 1.0)
設置背景色
[myView setBackgroundColor:[UIColor redColor]];
(blackColor;darkGrayColor;lightGrayColor;
whiteColor;grayColor; redColor; greenColor;
blueColor; cyanColor;yellowColor;
magentaColor;orangeColor;purpleColor;
brownColor; clearColor; )
自定義顏色
UIColor *newColor = [[UIColor alloc]
initWithRed:(float) green:(float) blue:(float) alpha:(float)];
0.0~1.0
豎屏
320X480
橫屏
480X320
狀態欄高 (顯示時間和網絡狀態)
20 像素
導航欄、工具欄高(返回)
44像素
隱藏狀態欄
[[UIApplication shareApplication] setStatusBarHidden: YES animated:NO]
橫屏
[[UIApplication shareApplication]
setStatusBarOrientation:UIInterfaceOrientationLandscapeRight].
屏幕變更檢測
orientation == UIInterfaceOrientationLandscapeLeft
全屏
window=[[UIWindow alloc] initWithFrame:[UIScreen mainScreen] bounds];
自動適應父視圖大小：
aView.autoresizingSubviews = YES;
aView.autoresizingMask = (UIViewAutoresizingFlexibleWidth |
UIViewAutoresizingFlexibleHeight);
定義按鈕
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];
設置視圖背景圖片
UIImageView *aView;
[aView setImage:[UIImage imageNamed:@」name.png」]];
view1.backgroundColor = [UIColor colorWithPatternImage:
[UIImage imageNamed:@"image1.png"]];
自定義UISlider的樣式和滑塊
咱們使用的是UISlider的setMinimumTrackImage，和setMaximumTrackImage方法來定義圖片的，這兩個方法能夠設置滑塊左邊和右邊的圖片的，不過若是用的是同一張圖片且寬度和控件寬度基本一致，就不會有變形拉伸的後果，先看代碼，寫在 viewDidLoad中：
//左右軌的圖片
UIImage *stetchLeftTrack= [UIImage imageNamed:@"brightness_bar.png"];
UIImage *stetchRightTrack = [UIImage imageNamed:@"brightness_bar.png"];
//滑塊圖片
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];
//注意這裏要加UIControlStateHightlighted的狀態，不然當拖動滑塊時滑塊將變成原生的控件
[sliderA setThumbImage:thumbImage forState:UIControlStateHighlighted];
[sliderA setThumbImage:thumbImage forState:UIControlStateNormal];
//滑塊拖動時的事件
[sliderA addTarget:self action:@selector(sliderValueChanged:) forControlEvents:UIControlEventValueChanged];
//滑動拖動後的事件
[sliderA addTarget:self action:@selector(sliderDragUp:) forControlEvents:UIControlEventTouchUpInside];
[self.view addSubview:sliderA];
爲了你們實驗方便，我附上背景圖brightness_bar.png和滑塊圖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;
}
活動表單
<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];
}
警告視圖
<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];
}
}
動畫效果
-(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
//指定分區中的行數，默認爲1
- (NSInteger)tableView:(UITableView *)tableView
numberOfRowsInSection:(NSInteger)section
{
return [self.listData count];
}
//設置每一行cell顯示的內容
- (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;
}
圖像、文本標籤和詳細文本標籤
圖像：若是設置圖像，則它顯示在文本的左側； 文本標籤：這是單元的主要文本（UITableViewCellStyleDefault 只顯示文本標籤）；詳細文本標籤：這是單元的輔助文本，一般用做解釋性說明或標籤
UITableViewCellStyleSubtitle
UITableViewCellStyleDefault
UITableViewCellStyleValue1
UITableViewCellStyleValue2
<UITableViewDelegate>
#pragma mark -
#pragma mark Table View Delegate Methods
//把每一行縮進級別設置爲其行號
- (NSInteger)tableView:(UITableView *)tableView indentationLevelForRowAtIndexPath:(NSIndexPath *)indexPath
{
NSUInteger row = [indexPath row];
return row;
}
//獲取傳遞過來的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];
}
//設置行的高度
- (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__);
點擊textField外的地方回收鍵盤
先定義一個UIControl類型的對象，在上面能夠添加觸發事件，令SEL實踐爲回收鍵盤的方法,最後將UIControl的實例加到當前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];
}
鍵盤覆蓋輸入框
當鍵盤調出時將輸入框覆蓋時，能夠用下方法：
- (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;
}
當準備輸入時，將視圖的位置上調100，這樣鍵盤就不能覆蓋到輸入框。
當依賴注入方法很差使時，能夠在AppDelegate內申明一個全局的控制器實例_anotherViewController，在另外一個須要使用_anotherViewController的地方定義如下委託方法，使用共享的UIApplication實例來獲取該委託的引用
SomeAppDelegate *appDelegate = (SomeAppDelegate *)[[UIApplication sharedApplication] delegate];
_anotherViewController = appDelegate._anotherViewController;
UIViewController內建Table View
純代碼在UIViewController控制器內建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];
}
將plist文件中的數據賦給數組
NSString *thePath = [[NSBundle mainBundle] pathForResource:@"States" ofType:@"plist"];
NSArray *array = [NSArray arrayWithContentsOfFile:thePath];
UITouch
手指的觸摸範圍：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雙擊圖片變大/還原
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
從Plist裏讀內容
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];
獲取Documents目錄
NSArray *paths = NSSearchPathForDictionariesInDomains(NSDocumentDirectory,
NSUserDomainMask, YES);
NSString *documentsDirectory = [paths objectAtIndex:0];
NSString *filename = [documentsDirectory
stringByAppendingPathComponent:@"theFile.txt"];
獲取tmp目錄
NSString *tempPath = NSTemporaryDirectory();
NSString *tempFile = [tempPath stringByAppendingPathComponent:@"tempFile.txt"];
[[NSUserDefaults standardUserDefaults] setObject:data forKey:@"someKey"];
[[NSUserDefaults standardUserDefaults] objectForKey:aKey];
自定義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打開一個連接
NSURL *url = [NSURL URLWithString:@"http://www.cnblogs.com/tracy-e/"];
[[UIApplication sharedApplication] openURL:url];
利用UIWebView顯示pdf文件、網頁。。。
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;
}
漢字轉碼
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;
}
點擊鍵盤的next按鈕，在不一樣的textField之間換行
//首先給不一樣的textField賦不一樣的且相鄰的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，還能夠在任意位置以[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.
爲UINavigationBar設置背景圖片
在iPhone開發中, 有時候咱們想給導航條添加背景圖片, 實現多樣化的導航條效果, 用其餘方法每每沒法達到理想的效果, 通過網上搜索及屢次實驗, 肯定以下最佳實現方案:
爲UINavigatonBar增長以下Category(類別:提供一種爲某個類添加方法而又沒必要編寫子類的途徑,類別只能添加成員函數，不能添加數據成員):
@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, 在個人項目中, 添加以下代碼:
/////////////////////////////////////////////////////////
/* 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];
}
......
實現的效果以下圖:
轉載，原文地址 http://blog.csdn.net/wave_1102/archive/2009/11/04/4768212.aspx
爲UINavigationBar添加自定義背景
@implementation UINavigationBar (UINavigationBarCategory)
- (void)drawRect:(CGRect)rect {
//顏色填充
// UIColor *color = [UIColor redColor];
// CGContextRef context = UIGraphicsGetCurrentContext();
// CGContextSetFillColor(context, CGColorGetComponents( [color CGColor]));
// CGContextFillRect(context, rect);
// self.tintColor = color;
//圖片填充
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
加載圖片要及時release
你還在使用myImage = [UIImage imageNamed:@"icon.png"]; 嗎？
如題，是否是你們爲了方便都這樣加載圖片啊
myImage = [UIImage imageNamed:@"icon.png"];
那麼當心了
這種方法在一些圖片不多，或者圖片很小的程序裏是ok的。
可是，在大量加載圖片的程序裏，請千萬不要這樣作。
爲何呢 ？？？？？？？
這種方法在application bundle的頂層文件夾尋找由供應的名字的圖象。 若是找到圖片，裝載到iPhone系統緩存圖象。那意味圖片是(理論上)放在內存裏做爲cache的。
試想你圖片多了，是什麼後果？
圖片cache極有可能不會響應 memory warnings and release its objects
因此，用圖片的時候必定要當心的alloc和release。
推薦使用 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打開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遊戲中既播放背景音樂又播放特效聲音的辦法
有時候在 iPhone 遊戲中，既要播放背景音樂，同時又要播放好比槍的開火音效。此時您能夠試試如下方法
NSString *musicFilePath = [[NSBundle mainBundle] pathForResource:fileName ofType:@"wav"]; //建立音樂文件路徑
NSURL *musicURL = [[NSURL alloc] initFileURLWithPath:musicFilePath];
AVAudioPlayer* musicPlayer = [[AVAudioPlayer alloc] initWithContentsOfURL:musicURL error:nil];
[musicURL release];
[musicPlayer prepareToPlay];
//[musicPlayer setVolume:1]; //設置音量大小
//musicPlayer .numberOfLoops = -1;//設置音樂播放次數 -1爲一直循環
要導入框架 AVFoundation.framework，頭文件中 #import <AVFoundation/AVFoundation.h>；作成類的話則更方便。
From: http://blog.csdn.net/dadalan/archive/2010/10/19/5950493.aspx
NSNotificationCenter用於增長回調函數
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(_willBecomeActive) name:UIApplicationDidBecomeActiveNotification object:nil];
UINavigationBar 背景Hack
LOGO_320×44.png 圖片顯示在背景上，
@implementation UINavigationBar (UINavigationBarCategory)
- (void)drawRect:(CGRect)rect {
//加入旋轉座標系代碼
// 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 過logo 再也不拉伸
From: http://blog.163.com/fengyi1103@126/blog/static/13835627420106279102671/
清除電話號碼中的其餘符號（源碼）
最近從通信錄讀取電話號碼，讀出得號碼如：134－1814－****。
而我須要的爲11位純數字，一直找方法解決此問題，今天終於找到了。。
分享一下……
代碼以下：
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
正則判斷：字符串只包含字母和數字
NSString *mystring = @"Letter1234";
NSString *regex = @"[a-z][A-Z][0-9]";
NSPredicate *predicate = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", regex];
if ([predicate evaluateWithObject:mystring] == YES) {
//implement
}
一行代碼設置 UITableViewCell 與導航條間距
UITableView 的 cell 默認出如今 uitableview 的第一行，若是你想自定義 UITableViewCell 與導航條間距的話，可使用下面這行代碼
tableview.tableHeaderView = [[[UIView alloc] initWithFrame:CGRectMake(0, 0, 5, 20)]autorelease];
From: http://blog.163.com/fengyi1103@126/blog/static/1383562742010101611107492/
修改 UITableview 滾動條顏色的方法
UITableview 的滾動條默認顏色是黑色的，若是 UItableview 背景也是深顏色，則滾動條會變的很不明顯。您能夠用下面這行代碼來改變滾動條的顏色
self.tableView.indicatorStyle=UIScrollViewIndicatorStyleWhite;
固然，最後的 「White」 也能夠換成其它顏色。
下文件以前獲取到文件大小的代碼
下面這段代碼，能實如今下載文件以前得到文件大小，應用在軟件裏，能在很大程度上改善用戶體驗
[m_pASIHTTPRequest setDidReceiveResponseHeadersSelector:@selector(didReceiveResponseHeaders:)];
- (void)didReceiveResponseHeaders:(ASIHTTPRequest *)request
{
NSLog(@"didReceiveResponseHeaders %@",[m_request.responseHeaders valueForKey:@"Content-Length"]);
｝
網絡編程總結 iphone
一：確認網絡環境3G/WIFI
1. 添加源文件和framework
開發Web等網絡應用程序的時候，須要確認網絡環境，鏈接狀況等信息。若是沒有處理它們，是不會經過Apple的審(咱們的)查的。
Apple 的 例程 Reachability 中介紹了取得/檢測網絡狀態的方法。要在應用程序程序中使用Reachability，首先要完成以下兩部：
1.1. 添加源文件：
在你的程序中使用 Reachability 只須將該例程中的 Reachability.h 和 Reachability.m 拷貝到你的工程中。以下圖：
1.2.添加framework：
將SystemConfiguration.framework 添加進工程。以下圖：
2. 網絡狀態
Reachability.h中定義了三種網絡狀態：
typedef enum {
NotReachable = 0, //無鏈接
ReachableViaWiFi, //使用3G/GPRS網絡
ReachableViaWWAN //使用WiFi網絡
} NetworkStatus;
所以能夠這樣檢查網絡狀態：
Reachability *r = [Reachability reachabilityWithHostName:@「www.apple.com」];
switch ([r currentReachabilityStatus]) {
case NotReachable:
// 沒有網絡鏈接
break;
case ReachableViaWWAN:
// 使用3G網絡
break;
case ReachableViaWiFi:
// 使用WiFi網絡
break;
}
3.檢查當前網絡環境
程序啓動時，若是想檢測可用的網絡環境，能夠像這樣
// 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. 連接狀態的實時通知
網絡鏈接狀態的實時檢查，通知在網絡應用中也是十分必要的。接續狀態發生變化時，須要及時地通知用戶：
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;
// 更新網絡狀態
- (void)updateStatus {
self.remoteHostStatus = [[Reachability sharedReachability] remoteHostStatus];
}
// 通知網絡狀態
- (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];
}
}
// 程序啓動器，啓動網絡監視
- (void)applicationDidFinishLaunching:(UIApplication *)application {
// 設置網絡檢測的站點
[[Reachability sharedReachability] setHostName:@"www.apple.com"];
[[Reachability sharedReachability] setNetworkStatusNotificationsEnabled:YES];
// 設置網絡狀態變化時的通知函數
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(reachabilityChanged:)
name:@"kNetworkReachabilityChangedNotification" object:nil];
[self updateStatus];
}
- (void)dealloc {
// 刪除通知對象
[[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 {
// ...
// 監測網絡狀況
[[NSNotificationCenter defaultCenter] addObserver:self
selector:@selector(reachabilityChanged:)
name: kReachabilityChangedNotification
object: nil];
hostReach = [[Reachability reachabilityWithHostName:@"www.google.com"] retain];
hostReach startNotifer];
// ...
}
二：使用NSConnection下載數據
1.建立NSConnection對象，設置委託對象
NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:[NSURL URLWithString:[self urlString]]];
[NSURLConnection connectionWithRequest:request delegate:self];
2. NSURLConnection delegate委託方法
- (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. 實現委託方法
- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response {
// store data
[self.receivedData setLength:0]; //一般在這裏先清空接受數據的緩存
}
- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data {
/* appends the new data to the received data */
[self.receivedData appendData:data]; //可能屢次收到數據，把新的數據添加在現有數據最後
}
- (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error {
// 錯誤處理
}
- (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;
}
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