IOS开发基础知识--碎片19

UIKeyboardWillShowNotification          // 键盘显示之前UIKeyboardDidShowNotification           // 键盘显示完成后UIKeyboardWillHideNotification          // 键盘隐藏之前UIKeyboardDidHideNotification           // 键盘消息之后UIKeyboardWillChangeFrameNotification   // 键盘大小改变之前UIKeyboardDidChangeFrameNotification    // 键盘大小改变之后

原因就是对象是一个字典，所以不能用点语法,postList.slots错误解决办法：[postList valueForKey:@"slots"]，使用这种语法  valueForKey  就可以了。

UIScreen对象包含了整个屏幕的边界矩形。当构造应用的用户界面接口时，你应该使用该对象的属性来获得推荐的矩形大小，用以构造你的程序窗口。CGRect bound = [[UIScreen mainScreen] bounds];  // 返回的是带有状态栏的Rect  CGRect frame = [[UIScreen mainScreen] applicationFrame];  // 返回的是不带有状态栏的Rect  float scale = [[UIScreen mainScreen] scale]; // 得到设备的自然分辨率  对于scale属性需要做进一步的说明： 以前的iphone 设备屏幕分辨率都是320*480，后来apple 在iPhone 4中采用了名为Retina的显示技术，iPhone 4采用了960x640像素分辨率的显示屏幕。由于屏幕大小没有变，还是3.5英寸，分辨率的提升将iPhone 4的显示分辨率提升至iPhone 3GS的四倍，每英寸的面积里有326个像素。scale属性的值有两个：scale = 1; 的时候是代表当前设备是320*480的分辨率（就是iphone4之前的设备）scale = 2; 的时候是代表分辨率为640*960的分辨率// 判断屏幕类型，普通还是视网膜      float scale = [[UIScreen mainScreen] scale];      if (scale == 1) {          bIsRetina = NO;          NSLog(@"普通屏幕");      }else if (scale == 2) {          bIsRetina = YES;          NSLog(@"视网膜屏幕");      }else{          NSLog(@"unknow screen mode !");      }  

bundle是一个目录,其中包含了程序会使用到的资源. 这些资源包含了如图像,声音,编译好的代码,nib文件(用户也会把bundle称为plug-in). 对应bundle,cocoa提供了类NSBundle.我们的程序是一个bundle. 在Finder中,一个应用程序看上去和其他文件没有什么区别. 但是实际上它是一个包含了nib文件,编译代码,以及其他资源的目录. 我们把这个目录叫做程序的main bundlebundle中的有些资源可以本地化.例如,对于foo.nib,我们可以有两个版本: 一个针对英语用户,一个针对法语用户. 在bundle中就会有两个子目录:English.lPRoj和French.lproj,我们把各自版本的foo.nib文件放到其中. 当程序需要加载foo.nib文件时,bundle会自动根据所设置的语言来加载.通过使用下面的方法得到程序的main bundleNSBundle *myBundle = [NSBundle mainBundle];一般我们通过这种方法来得到bundle.如果你需要其他目录的资源,可以指定路径来取得bundleNSBundle *goodBundle;goodBundle = [NSBundle bundleWithPath:@"~/.myApp/Good.bundle"];一旦我们有了NSBundle 对象,那么就可以访问其中的资源了// Extension is optionalNSString *path = [goodBundle pathForImageResource:@"Mom"];NSImage *momPhoto = [[NSImage alloc] initWithContentsOfFile:path];bundle中可以包含一个库. 如果我们从库得到一个class, bundle会连接库,并查找该类:Class newClass = [goodBundle classNamed:@"Rover"];id newInstance = [[newClass alloc] init];如果不知到class名,也可以通过查找主要类来取得Class aClass = [goodBundle principalClass];id anInstance = [[aClass alloc] init];可以看到, NSBundle有很多的用途.在这章中, NSBundle负责(在后台)加载nib文件. 我们也可以不通过NSWindowController来加载nib文件, 直接使用NSBundle:BOOL successful = [NSBundle loadNibNamed:@"About" owner:someObject];注意噢, 我们指定了一个对象someObject作为nib的File”s Owner获取xml文件NSString *filePath = [[NSBundle mainBundle] pathForResouse:@"re" ofType:@"xml"];NSData *data = [[NSData alloc] initWithContentsOfFile:filePath]; 获取属性列表NSDictionary *dict = [NSDictionary dictionaryWithContentsOfFile:[[NSBundle mainBundle] pathForResource:@"ViewControllers" ofType:@"plist"]]; 

用ps设计ios App字体以像素为单位，而ios开发人员写代码的时候是以磅为单位，请问像素与磅之间的换算30px转成磅为单位＝22磅＝二号磅=(像素/96)*72    =(30/96)*72    =22.5磅中文字号VS英文字号(磅)VS像素值的对应关系：八号＝5磅(5pt) ==(5/72)*96=6.67 =6px(像素)七号＝5.5磅 ==(5.5/72)*96=7.3 =7px(像素)小六＝6.5磅 ==(6.5/72)*96=8.67 =8px(像素)六号＝7.5磅 ==(7.5/72)*96=10px(像素)小五＝9磅 ==(9/72)*96=12px(像素)五号＝10.5磅 ==(10.5/72)*96=14px(像素)小四＝12磅 ==(12/72)*96=16px(像素)四号＝14磅 ==(14/72)*96=18.67 =18px(像素)小三＝15磅 ==(15/72)*96=20px(像素)三号＝16磅 ==(16/72)*96=21.3 =21px(像素)小二＝18磅 ==(18/72)*96=24px(像素)二号＝22磅 ==(22/72)*96=29.3 =29px(像素)小一＝24磅 ==(24/72)*96=32px(像素)一号＝26磅 ==(26/72)*96=34.67 =34px(像素)

// 能够定义的button类型有以下6种，// typedef enum {// UIButtonTypeCustom = 0, 自定义风格// UIButtonTypeRoundedRect, 圆角矩形 // UIButtonTypeDetailDisclosure, 蓝色小箭头按钮，主要做详细说明用// UIButtonTypeInfoLight, 亮色感叹号// UIButtonTypeInfoDark, 暗色感叹号// UIButtonTypeContactAdd, 十字加号按钮// } UIButtonType;/* forState: 这个参数的作用是定义按钮的文字或图片在何种状态下才会显现*///以下是几种状态// enum {// UIControlStateNormal = 0, 常规状态显现 // UIControlStateHighlighted = 1 << 0, 高亮状态显现 // UIControlStateDisabled = 1 << 1, 禁用的状态才会显现// UIControlStateSelected = 1 << 2, 选中状态 // UIControlStateApplication = 0x00FF0000, 当应用程序标志时 // UIControlStateReserved = 0xFF000000 为内部框架预留，可以不管他 // };/** 默认情况下，当按钮高亮的情况下，图像的颜色会被画深一点，如果这下面的这个属性设置为no，* 那么可以去掉这个功能*/button1.adjustsImageWhenHighlighted = NO;/*跟上面的情况一样，默认情况下，当按钮禁用的时候，图像会被画得深一点，设置NO可以取消设置*/button1.adjustsImageWhenDisabled = NO;/* 下面的这个属性设置为yes的状态下，按钮按下会发光*/button1.showsTouchWhenHighlighted = YES;长按事件实例：UIButton *aBtn=[UIButton buttonWithType:UIButtonTypeCustom];    [aBtn setFrame:CGRectMake(40, 100, 60, 60)];    [aBtn setBackgroundImage:[UIImage imageNamed:@"111.png"]forState:UIControlStateNormal];    //button点击事件    [aBtn addTarget:self action:@selector(btnShort:)forControlEvents:UIControlEventTouchUpInside];    //button长按事件    UILongPressGestureRecognizer *longPress = [[UILongPressGestureRecognizer alloc] initWithTarget:selfaction:@selector(btnLong:)];     longPress.minimumPressDuration = 0.8; //定义按的时间    [aBtn addGestureRecognizer:longPress];-(void)btnLong:(UILongPressGestureRecognizer*)gestureRecognizer{    if ([gestureRecognizer state] == UIGestureRecognizerStateBegan) {        NSLog(@"长按事件");        UIAlertView *alert=[[UIAlertView alloc]initWithTitle:@"消息" message:@"确定删除该模式吗？" delegate:selfcancelButtonTitle:@"取消" otherButtonTitles:@"删除", nil];        [alert show];    }}

UIApplication对象，这个对象在iOS中是一个单例，我们通过[UIApplication sharedApplication]获得,设置显示消息数，显示在应用程序图标右上角，[UIApplication sharedApplication].applicationIconBadgeNumber=9;可以通过获得NSIntger x=[UIApplication sharedApplication].applicationIconBadgeNumber; 防止屏幕睡眠：[UIApplication sharedApplication].idleTimerDisabled=YES; 设置状态栏样式在app delegate中：[UIApplication sharedApplication].statusBarStyle = UIStatusBarStyleLightContent;

#import "ViewController.h"@interface ViewController (){    NSTimer     *timer;    NSInteger   nowSeconds;}@end@implementation ViewController- (void)viewDidLoad {    [super viewDidLoad];        nowSeconds = 30 * 100;  //(定义的30秒进行倒计)    timer = [NSTimer scheduledTimerWithTimeInterval:0.01 target:self selector:@selector(timerAction) userInfo:nil repeats:YES];        [[NSRunLoop currentRunLoop] addTimer:timer forMode:NSRunLoopCommonModes];}- (void)didReceiveMemoryWarning {    [super didReceiveMemoryWarning];    // Dispose of any resources that can be recreated.}- (void)timerAction{    if(nowSeconds<0)    {        [timer invalidate];        timer = nil;        return;    }    nowSeconds--;    if(nowSeconds<=0)    {        self.mylable.text = @"正在揭晓...";        return;    }    int m = (int)nowSeconds / 6000;    int s = (int)(nowSeconds/100) - m*60;    NSString* f1 = s > 9 ? [NSString stringWithFormat:@"%d",s] : [@"0" stringByAppendingFormat:@"%d",s];    int ms = nowSeconds % 100;    NSString* f2 = ms > 9 ? [NSString stringWithFormat:@"%d",ms] : [@"0" stringByAppendingFormat:@"%d",ms];    self.mylable.text = [NSString stringWithFormat:@"0%d:%@:%@",m,f1,f2];}@end

引入#import <BlocksKit/BlocksKit.h>#import <BlocksKit/BlocksKit+UIKit.h>常见的一些blocks:    //视图    UIView *bcView=[[UIView alloc]init];    bcView.backgroundColor=[UIColor redColor];    bcView.frame=CGRectMake(30, 40, 50, 20);    [bcView bk_whenTapped:^{        NSLog(@"单击响应");    }];    [bcView bk_whenDoubleTapped:^{        NSLog(@"双击响应");    }];    [bcView bk_whenTouches:1 tapped:3 handler:^{        NSLog(@"三击响应");    }];    [self.view addSubview:bcView];            //Control    btn=[[UIButton alloc]initWithFrame:CGRectMake(70, 70, 50, 50)];    [btn setTitle:@"Save" forState:UIControlStateNormal];    btn.backgroundColor=[UIColor grayColor];    [btn bk_addEventHandler:^(id sender) {        NSLog(@"UIControlEventTouchUpInside响应");        //判断跟移除响应        [self getUIButtonEventHandler];    } forControlEvents:UIControlEventTouchUpInside];    [self.view addSubview:btn];            //UIAlertView    UIAlertView *alertView=[UIAlertView bk_showAlertViewWithTitle:@"弹出窗效果" message:@"你好，请选择" cancelButtonTitle:@"取消" otherButtonTitles:@[@"确定",@"不想选"] handler:^(UIAlertView *alertView, NSInteger buttonIndex) {        if (buttonIndex==0) {            NSLog(@"你选择第一个");        }        else if(buttonIndex==1)        {            NSLog(@"你选择第二个");        }        else        {            NSLog(@"选择其它个");        }    }];    [alertView show];            __block NSInteger total=0;    UIAlertView *otherAlertView=[[UIAlertView alloc]bk_initWithTitle:@"动态增加" message:@"是否是要增加"];    NSInteger index1 = [otherAlertView bk_addButtonWithTitle:@"确定" handler:^{ total++;        NSLog(@"%ld",total);    }];    [otherAlertView.bk_dynamicDelegate alertView:otherAlertView clickedButtonAtIndex:index1];    [otherAlertView show];            UIAlertView *showAlert=[[UIAlertView alloc] initWithTitle:@"系统自带的alertview" message:@"显示信息" delegate:self cancelButtonTitle:@"取消" otherButtonTitles: nil];    showAlert.bk_cancelBlock=^()    {        NSLog(@"取消响应");    };    showAlert.bk_willShowBlock = ^(UIAlertView *view) { NSLog(@"显示之前响应");};    showAlert.bk_didShowBlock = ^(UIAlertView *view) { NSLog(@"显示出弹出窗响应"); };    [showAlert show];        //UIActionSheet    UIActionSheet *myactionSheet=[[UIActionSheet alloc]initWithTitle:@"显示信息" delegate:self cancelButtonTitle:@"取消" destructiveButtonTitle:@"相关内容的显示" otherButtonTitles:nil];    myactionSheet.bk_cancelBlock=^()    {        NSLog(@"选择取消actionSheet");    };    [myactionSheet showInView:self.view];            //UITextField    UITextField *myTextField = [[UITextField alloc] init];    myTextField.backgroundColor=[UIColor yellowColor];    myTextField.frame=CGRectMake(10, 130, 80, 20);    myTextField.bk_shouldBeginEditingBlock=^(UITextField *textField) {        NSLog(@"shouldBeginEditingBlock");        return YES;    };    myTextField.bk_shouldBeginEditingBlock = ^(UITextField *textField) { NSLog(@"shouldBeginEditingBlock");        return YES;    };    myTextField.bk_didBeginEditingBlock = ^(UITextField *textField) { NSLog(@"didBeginEditingBlock");    };    myTextField.bk_shouldEndEditingBlock = ^(UITextField *textField) { NSLog(@"shouldEndEditingBlock");        return YES;    };    myTextField.bk_didEndEditingBlock = ^(UITextField *textField) { NSLog(@"didEndEditingBlock ");    };    myTextField.bk_shouldChangeCharactersInRangeWithReplacementStringBlock = ^(UITextField *textField, NSRange range, NSString *replacement) { NSLog(@"shouldChangeCharactersInRangeWithReplacementStringBlock"); return YES;    };    myTextField.bk_shouldClearBlock = ^(UITextField *textField) { NSLog(@"shouldClearBlock");        return YES;    };    myTextField.bk_shouldReturnBlock = ^(UITextField *textField) { NSLog(@"shouldReturnBlock");        return YES;    };    [self.view addSubview:myTextField];