[iOS基础控件 - 4.3] APP列表 xib的使用

A.storyboard和xib

1.storyboard: 相对xib较重量级，控制整个应用的所有界面

2.xib: 轻量级，一般用来描述局部界面

B.使用

1.新建xib文件

New File ==> User Interface ==> Empty

2.打开新建的xib文件，出现可视化窗口

（1）拖入一个UIView （不是UIViewController）

（2）设置大小：开启可自定义尺寸 ==> 定义尺寸

（3）拖入图标图片、名字、下载按钮，调整设置

3.在代码中获取xib中的view，并设置数据

（1）从xib获取view

a.方法1:

         // 1.获取xib中的view, xib中可以同时定义多个view，注意名字不带扩展名
         NSArray *viewArray = [[NSBundle mainBundle] loadNibNamed:@"app" owner:nil options:nil];
         UIView *appView = [viewArray lastObject];

b.方法2:

         UINib *nib = [UINib nibWithNibName:@"app" bundle:[NSBundle mainBundle]];
         NSArray *viewArray = [nib instantiateWithOwner:nil options:nil];
         UIView *appView = [viewArray lastObject];

（2）取出View中的元素，设置图片

a.方法1，使用SubView数组：

         // 3.设置图片
         UIImageView *iconView = appView.subviews[];
         iconView.image = [UIImage imageNamed:appData.icon];

注意：按照教程是按照下图的顺序排列数组元素（imageView应该是subviews[0]，但是实际编程发现却不是，所以此方法并不稳定）

b.方法2，使用tag：

         // 3.设置图片
         UIImageView *iconView = [appView viewWithTag:];
         iconView.image = [UIImage imageNamed:appData.icon];

（3）设置名字

         // 4.设置名字
         UILabel *nameLabel = [appView viewWithTag:];
         nameLabel.text = appData.name;

（4）下载按钮已经在xib中定义好，不必使用代码

C.实现代码

 #import "ViewController.h"
 #import "App.h"

 #define ICON_KEY @"icon"
 #define NAME_KEY @"name"
 #define APP_WIDTH 85
 #define APP_HEIGHT 90
 #define MARGIN_HEAD 20
 #define ICON_WIDTH 50
 #define ICON_HEIGHT 50
 #define NAME_WIDTH APP_WIDTH
 #define NAME_HEIGHT 20
 #define DOWNLOAD_WIDTH (APP_WIDTH - 20)
 #define DOWNLOAD_HEIGHT 20

 @interface ViewController ()

 /** 存放应用信息 */
 @property(nonatomic, strong) NSArray *apps; // 应用列表

 @end

 @implementation ViewController

 - (void)viewDidLoad {
     [super viewDidLoad];
     // Do any additional setup after loading the view, typically from a nib.

     [self loadApps];
 }

 - (void)didReceiveMemoryWarning {
     [super didReceiveMemoryWarning];
     // Dispose of any resources that can be recreated.
 }

 #pragma mark 取得应用列表
 - (NSArray *) apps {
     if (nil == _apps) {
         // 1.获得plist的全路径
         NSString *path = [[NSBundle mainBundle] pathForResource:@"app.plist" ofType:nil];

         // 2.加载数据
         NSArray *dictArray  = [NSArray arrayWithContentsOfFile:path];

         // 3.将dictArray里面的所有字典转成模型，放到新数组中
         NSMutableArray *appArray = [NSMutableArray array];
         for (NSDictionary *dict in dictArray) {
             // 3.1创建模型对象
             App *app = [App appWithDictionary:dict];

             // 3.2 添加到app数组中
             [appArray addObject:app];
         }

         _apps = appArray;
     }

     return _apps;
 }

 #pragma mark 加载全部应用列表
 - (void) loadApps {
     int appColumnCount = [self appColumnCount];
     int appRowCount = [self appRowCount];

     CGFloat marginX = (self.view.frame.size.width - APP_WIDTH * appColumnCount) / (appColumnCount + );
     CGFloat marginY = (self.view.frame.size.height - APP_HEIGHT * appRowCount) / (appRowCount + ) + MARGIN_HEAD;

     int column = ;
     int row = ;
     for (int index=; index<self.apps.count; index++) {
         App *appData = self.apps[index];

         // 1.获取xib中的view, xib中可以同时定义多个view，注意名字不带扩展名
 //        NSArray *viewArray = [[NSBundle mainBundle] loadNibNamed:@"app" owner:nil options:nil];
 //        UIView *appView = [viewArray lastObject];

         UINib *nib = [UINib nibWithNibName:@"app" bundle:[NSBundle mainBundle]];
         NSArray *viewArray = [nib instantiateWithOwner:nil options:nil];
         UIView *appView = [viewArray lastObject];

         // 2.定义每个app的位置、尺寸
         CGFloat appX = marginX + column * (marginX + APP_WIDTH);
         CGFloat appY = marginY + row * (marginY + APP_HEIGHT);
         appView.frame = CGRectMake(appX, appY, APP_WIDTH, APP_HEIGHT);

         // 3.设置图片
         UIImageView *iconView = [appView viewWithTag:];
         iconView.image = [UIImage imageNamed:appData.icon];

         // 4.设置名字
         UILabel *nameLabel = [appView viewWithTag:];
         nameLabel.text = appData.name;

         // 5.加入此app信息到总view
         [self.view addSubview:appView];

         column++;
         if (column == appColumnCount) {
             column = ;
             row++;
         }
     }
 }

 #pragma mark 计算列数
 - (int) appColumnCount {
     int count = ;
     count = self.view.frame.size.width / APP_WIDTH;

     if ((int)self.view.frame.size.width % (int)APP_WIDTH == ) {
         count--;
     }

     return count;
 }

 #pragma mark 计算行数
 - (int) appRowCount {
     int count = ;
     count = (self.view.frame.size.height - MARGIN_HEAD) / APP_HEIGHT;

     if ((int)(self.view.frame.size.height - MARGIN_HEAD) % (int)APP_HEIGHT == ) {
         count--;
     }

     return count;
 }

 @end