04-UIKit（UINavigationController、NSAttributeString、UIImageView）

目录：

一、UINavigationController导航视图控制器

二、NSAttributeString属性字符串

三、UIImageView图像处理

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一、UINavigationController导航视图控制器

1 定义：导航视图控制器是控制另外控制器的控制器

2 作用：导航，管理多个视图控制器的跳转，比如我们自己控制视图控制器的跳转更清晰

3 怎么用：创建UINavigationController有一个初始化方法initWithRootViewController：被控制的控制器

* 把navigationcontroller设置成window的根视图

* 从navigationcontroller中跳转到另一个视图控制器：pushViewController

* 从navigationcontroller返回上一个视图控制器：popViewController

在storyboard中设置navigation

editor  ->  embedin ->  navigationController

4 在empty中使用代码添加navigation

在AppDelegate.m中

//UINavigationController

MXFistViewController* fistViewController = [[MXFistViewController alloc] initWithNibName:@"MXFistViewController" bundle:nil];

UINavigationController *navi = [[UINavigationController alloc] initWithRootViewController:fistViewController];

self.window.rootViewController = navi;

5 内部原理

＊ navigation根view不能pop

＊ navigation维护着一个VC栈，先进后出

＊ navi必须有一个根视图，创建navi时一般会直接指定

＊ push一个VC时，上一个VC不会被释放

＊ navi会保存push进去的VC引用计数器

＊ pop出来的VC会立即被释放

＊ 不能pop根视图

6 深入理解navi

＊ .title  .leftBarButtonItem  .leftBarButtonItems  .toolBarItems这些属性设置在具体的某一个被navi包含的VC，不是设置在navi上

＊ 具体的VC 上的toolbar默认是隐藏的，如果显示需要调用一个方法[self.navigationController setToolbarHidden:NO]

＊ UIBarButtonItem 不管是Navigation还是toolbar其中的按键都要用UIBarButton

initWithSystemItem:...设置系统内置按钮

initWithTitle:...文字按钮

initWithImage...图片按钮

- (void)viewDidLoad
{
    [super viewDidLoad];
    //设置navigation标题
    self.title = @"好友圈";
    //设置navigation左右按钮
    self.navigationItem.leftBarButtonItem = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemCompose target:self action:@selector(writeWeibo:)];
    //self.navigationItem.rightBarButtonItem = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemDone target:nil action:nil];
    UIBarButtonItem *button1 = [[UIBarButtonItem alloc] initWithTitle:@"one" style:UIBarButtonItemStyleBordered target:nil action:nil];
    UIBarButtonItem *button2 = [[UIBarButtonItem alloc] initWithTitle:@"two" style:UIBarButtonItemStylePlain target:nil action:nil];
    
    self.navigationItem.rightBarButtonItems = @[button1,button2];
    
    //工具条
    UIBarButtonItem* button3 = [[UIBarButtonItem alloc] initWithTitle:@"首页" style:UIBarButtonItemStyleBordered target:nil action:nil];
    UIBarButtonItem* button4 = [[UIBarButtonItem alloc] initWithTitle:@"消息" style:UIBarButtonItemStyleBordered target:nil action:nil];
    //fixed固定
    UIBarButtonItem* fixed = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemFixedSpace target:nil action:nil];
    fixed.width = 20;//设置固定宽度
    //flexible灵活
    UIBarButtonItem* flexible = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemFlexibleSpace target:nil action:nil];
    //添加工具条中的按钮
    self.toolbarItems = @[fixed,button3,flexible,button4,fixed];
    // Do any additional setup after loading the view from its nib.
}

-(void)viewWillAppear:(BOOL)animated{
    [super viewWillAppear:animated];
    //显示工具条
    [self.navigationController setToolbarHidden:NO animated:YES];
}

-(void)writeWeibo:(UIBarButtonItem*)button{
    MXSecondViewController* second = [[MXSecondViewController alloc] initWithNibName:@"MXSecondViewController" bundle:nil];
    //跳转到另一个view
    //[self.navigationController pushViewController:second animated:YES];

//跳转到被navigation包含的一个view
    UINavigationController *navi = [[UINavigationController alloc] initWithRootViewController:second];
    [self presentViewController:navi animated:YES completion:nil];
    
}

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二、NSAttributeString属性字符串

1 ios6中开始ios7加强

2 在NSString的基础上，加入了属性的功能，字体，颜色，加粗，描边，等

MXAttributeViewController.m
- (void)viewDidLoad
{
    [super viewDidLoad];
    // Do any additional setup after loading the view from its nib.
    [self setup];
    UIBarButtonItem* button = [[UIBarButtonItem alloc] initWithTitle:@"stats" style:UIBarButtonItemStyleBordered target:self action:@selector(statsTap:)];
    //设置导航控制器的右边的button
    self.navigationItem.rightBarButtonItem = button;
}
-(void)statsTap:(UIBarButtonItem*)button{
    MXTextStatsViewController *text = [[MXTextStatsViewController alloc] initWithNibName:@"MXTextStatsViewController" bundle:nil];
    text.textToAnglyze = self.body.textStorage;//传值
    //
    [self.navigationController pushViewController:text animated:YES];
}

-(void)setup{
    NSMutableAttributedString *title = [[NSMutableAttributedString alloc] initWithString:@"outline" attributes:@{NSStrokeWidthAttributeName: @-3,NSStrokeColorAttributeName:self.outlineButton.tintColor}];
    [self.outlineButton setAttributedTitle:title forState:UIControlStateNormal];
}

//改变textView中被选择字体颜色
- (IBAction)changeSelectedColor:(UIButton *)sender {
    //Storage中文是存储 仓库
    [self.body.textStorage addAttribute:NSForegroundColorAttributeName value:sender.backgroundColor range:self.body.selectedRange];
}
//加粗textView中被选择字体
- (IBAction)outlineSelect:(UIButton *)sender {
    //[self.body.textStorage addAttributes:@{NSStrokeColorAttributeName: [UIColor blackColor],NSStrokeWidthAttributeName:[NSNumber numberWithInteger:3]} range:self.body.selectedRange];
    [self.body.textStorage addAttributes:@{NSStrokeColorAttributeName: [UIColor blackColor],NSStrokeWidthAttributeName:@-3} range:self.body.selectedRange];
}
//取消加粗
- (IBAction)unoutlineSelect:(UIButton *)sender {
    [self.body.textStorage removeAttribute:NSStrokeWidthAttributeName range:self.body.selectedRange];
}

MXTextStatsViewController.m

-(void)viewWillAppear:(BOOL)animated{
    [super viewWillAppear:animated];
    [self updateUI];
}
-(void)updateUI{
    self.colorfulLabel.text = [NSString stringWithFormat:@"%d colorful charactrors",[self charactersWithAttribute:NSForegroundColorAttributeName].length];
    self.outlineLabel.text = [NSString stringWithFormat:@"%d outline charactors",[self charactersWithAttribute:NSStrokeWidthAttributeName].length];
}
//
-(NSAttributedString*)charactersWithAttribute:(NSString*)attributeName{
    //创建属性字符串
    NSMutableAttributedString *characters = [[NSMutableAttributedString alloc] init];
    NSUInteger index = 0;
    while ([self.textToAnglyze length] > index) {
        NSRange range;
        //把下标为index有attributeName这个属性的位置和长度 保存在range指向的地址中
        id value = [self.textToAnglyze attribute:attributeName atIndex:index effectiveRange:&range];
        if (value) {

　　　　//添加range范围内的属性字符串到characters
            [characters appendAttributedString:[self.textToAnglyze attributedSubstringFromRange:range]];
            index = range.location + range.length;
        }else{
            index++;
        }
    }
    return characters;
}

知识点

设置label属性使用attributedText

设置textView属性使用textStorage

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三、UIImageView图像处理

contentMode属性，设置图片形状

- (void)viewDidLoad
{
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.
    UIImage *image = [UIImage imageNamed:@"0.png"];
    
    UIImageView *imageView = [[UIImageView alloc]initWithImage:image];
    //设置
    imageView.frame = self.view.frame;
    imageView.contentMode = UIViewContentModeScaleAspectFit;
    [self.view addSubview:imageView];
}

1 代码创建UIImageView，frame默认是图片的大小，.contentMode默认是拉伸，frame如果和图片大小不一致拉伸图片

mode风格

UIViewContentModeScaleToFill,默认拉伸

UIViewContentModeScaleAspectFit, 保持宽高比 ，完全显示，留边

UIViewContentModeScaleAspectFill, 保持宽高比，铺满imageview

Redraw做绘制时使用

UIImageView图片视图控件

＊ 在界面上的有限空间中显示超过界面大小的内容，（图片，文本）UITextView 是UIScrollView的子类

＊ 重要属性

.frame -> scrollView在界面上的实际大小和坐标

.contentSize -> scrollView需要显示的内容大小

一般情况下，内容的大小大于frame的大小，以达到滚动效果

注意：这两个属性一定都要设置，否则看不到

＊ 支持缩放的属性

minimumZoomScale:设置最小的缩放比例

maximumZoomScale:设置最大的缩放比例，一般为1.0

　 //水平方向缩放比例

float horizontalScale = scrollView.frame.size.width / self.imageView.frame.size.width;

//垂直方向缩放比例

float vertical = scrollView.frame.size.height / self.imageView.frame.size.height;

//比较水平和垂直方向哪个最小

float minimumZoomScale = MIN(horizontalScale, vertical);

//缩放最小值

scrollView.minimumZoomScale = minimumZoomScale;

//缩放最大值

scrollView.maximumZoomScale = MAX_SCALE;

scrollView.delegate = self;

//scrollview代理中进行缩放的方法，返回一个view进行缩放 按住alt健进行缩放操作

-(UIView *)viewForZoomingInScrollView:(UIScrollView *)scrollView{

return self.imageView;

}

＊ 其他属性

. showsHorizontalScrollIndicator显示横条

. showsVerticalScrollIndicato 显示竖条

. pagingEnable启动分页控制

. contentInset 内边距

. scrollIndicatorInsets 滚轴的内边距

scrollView.scrollIndicatorInsets = UIEdgeInsetsMake(10, 0, 0, 0);

＊ 委托协议UIScrollViewDelegate

返回哪一个子视图进行缩放：

缩放开始时调用的方法/结束时调用的方法

-(UIView *)viewForZoomingInScrollView:(UIScrollView *)scrollView

作业：视力检查表，

Label.font = [UIFont systemFontSize:100];

界面1：label的字体大小是100 E

按钮 看得见 点击进入

界面2：90 E

按钮 看得见 点击进入

界面3：80 E

。。。

看不见显示结果

- (void)viewDidLoad
{
    [super viewDidLoad];
    self.lableE.font = [UIFont systemFontOfSize:100 - self.size2];
    // Do any additional setup after loading the view from its nib.
}

- (IBAction)lookSee:(UIButton *)sender {
    self.size2 += 10;
    MXViewController *viewController = [[MXViewController alloc] initWithNibName:@"MXViewController" bundle:nil];
    viewController.size2 = self.size2;
    [self.navigationController pushViewController:viewController animated:YES];
}
- (IBAction)noLookSee:(UIButton *)sender {
    NSLog(@"看不见了，您的视力是:%d",100 - self.size2);
}