在一个典型的MVC结构 中，Model部分负责保存目标数据，View部分主要负责实现数据的界面以及将数据显示出来，二者在Controller的操作下协同工作。在iOS应用中，View的实现主要由UIView及其派生类实现，主要由UILabel、UIImageView等等类来显示不同的信息。
这里展示一个demo来说明个人对UIView同数据交互的一种观点，个人意见仅供参考，欢迎讨论。
1、首先建立一个UIView的子类用于定制我们的视图对象
头文件：
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#import <uikit uikit.h="">@interface UserInfoView : UIView//@property (nonatomic,copy) NSString *imgString;//@property (nonatomic,copy) NSString *nameString;//@property (nonatomic,copy) NSString *addrString;//@property (nonatomic,copy) NSString *infoString;//@property (nonatomic,copy) NSString *countString;//@property (nonatomic,copy) NSString *attString;//@property (nonatomic,copy) NSString *fansString;@property (nonatomic,retain) NSDictionary *param;- (void)loadData;@end</uikit> |
m文件：
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#import "UserInfoView.h"#import "RectButton.h"@interface UserInfoView()//UI控件@property (nonatomic,retain) UIImageView *userImage;@property (nonatomic,retain) UILabel *nameLabel;@property (nonatomic,retain) UILabel *addressLabel;@property (nonatomic,retain) UILabel *infoLabel;@property (nonatomic,retain) UILabel *countLabel;@property (nonatomic,retain) RectButton *attButton;@property (nonatomic,retain) RectButton *fansButton;@property (nonatomic,retain) UIButton *profileButton;@property (nonatomic,retain) UIButton *moreButton;//数据成员//@property (nonatomic,copy) NSString *imgString;@property (nonatomic,copy) NSString *nameString;@property (nonatomic,copy) NSString *addrString;@property (nonatomic,copy) NSString *infoString;@property (nonatomic,copy) NSString *countString;//@property (nonatomic,copy) NSString *attString;//@property (nonatomic,copy) NSString *fansString;@end@implementation UserInfoView- (id)init{ CGRect frameRect = CGRectMake(0, 0, 320, 200);
self = [self initWithFrame:frameRect];
if (self)
{
NSLog(@"Init called");
}
return self;
}- (id)initWithFrame:(CGRect)frame{ self = [super initWithFrame:frame];
if (self)
{
self.backgroundColor = [UIColor lightGrayColor];
_userImage = [[UIImageView alloc] initWithFrame:CGRectZero];
[self addSubview:_userImage];
_nameLabel = [[UILabel alloc] initWithFrame:CGRectZero];
[self addSubview:_nameLabel];
_addressLabel = [[UILabel alloc] initWithFrame:CGRectZero];
[self addSubview:_addressLabel];
_infoLabel = [[UILabel alloc] initWithFrame:CGRectZero];
[self addSubview:_infoLabel];
_attButton = [[RectButton alloc] initWithFrame:CGRectZero];
[self addSubview:_attButton];
_fansButton = [[RectButton alloc] initWithFrame:CGRectZero];
[self addSubview:_fansButton];
_profileButton = [[UIButton alloc] initWithFrame:CGRectZero];
[self addSubview:_profileButton];
_moreButton = [[UIButton alloc] initWithFrame:CGRectZero];
[self addSubview:_moreButton];
_countLabel = [[UILabel alloc] initWithFrame:CGRectZero];
[self addSubview:_countLabel];
}
return self;
}- (void)setParam:(NSDictionary *)param{ _param = param;
_nameString = [_param objectForKey:@"Name"];
_addrString = [_param objectForKey:@"Address"];
_infoString = [_param objectForKey:@"Infomation"];
_countString = [_param objectForKey:@"Count"];
[self loadData];
}- (void)layoutSubviews{ _userImage.frame = CGRectMake(20, 20, 80, 80);
_userImage.backgroundColor = [UIColor yellowColor];
_nameLabel.frame = CGRectMake(120, 20, 180, 20);
_nameLabel.backgroundColor = [UIColor yellowColor];
_addressLabel.frame = CGRectMake(120, 50, 180, 20);
_addressLabel.backgroundColor = [UIColor yellowColor];
_infoLabel.frame = CGRectMake(120, 80, 180, 20);
_infoLabel.backgroundColor = [UIColor yellowColor];
_attButton.frame = CGRectMake(20, 110, 60, 60);
_attButton.backgroundColor = [UIColor greenColor];
_fansButton.frame = CGRectMake(93, 110, 60, 60);
_fansButton.backgroundColor = [UIColor greenColor];
_profileButton.frame = CGRectMake(167, 110, 60, 60);
_profileButton.backgroundColor = [UIColor greenColor];
_moreButton.frame = CGRectMake(240, 110, 60, 60);
_moreButton.backgroundColor = [UIColor greenColor];
_countLabel.frame = CGRectMake(20, 180, 280, 15);
_countLabel.backgroundColor = [UIColor whiteColor];
[self loadData];
}- (void)loadData{ if (self.nameString.length != 0)
{
_nameLabel.text = self.nameString;
}
if (self.addrString.length != 0)
{
_addressLabel.text = self.addrString;
}
if (self.infoString.length != 0)
{
_infoLabel.text = self.infoString;
}
if (self.countString.length != 0)
{
_countLabel.text = self.countString;
}
}@end |
在这个UserInfoView新建的时候，在initWithFrame中建立各个子视图，但是只是单纯新建一个对象而已，其frame设置为0。另 外，还重写了init函数，在函数中设置了指定的View大小，这样在Controller新建视图的时候不需要指定参数直接按照指定值进行操作。
UserInfoView中各个子视图的设置，在layoutSubView中完成，包括设置子视图的frame和背景颜色。layoutSubView函数可能经常被调用到，主要由以下几种情况：
· 当addSubView被调用时，被添加视图以及其子视图的layoutSubView会被调用；
· 当视图的frame发生改变时，会调用该视图的layoutSubView；
· 当滚动UIScrollView的时候会调用该视图及其父视图的layoutSubView；
· 旋转设备的时候；
· 向该视图发送setNeedLayout消息的时候。
2. 由Controller向View中发送数据
ViewController类的实现如下：
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#import "ViewController.h"#import "UserInfoView.h"@interface ViewController ()@property (nonatomic,retain) UIButton *People1;@property (nonatomic,retain) UIButton *People2;@property (nonatomic,retain) UserInfoView *userView;@end@implementation ViewController- (void)viewDidLoad{ [super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
_userView = [[UserInfoView alloc] init];
[self.view addSubview:_userView];
_People1 = [UIButton buttonWithType:UIButtonTypeSystem];
_People1.frame = CGRectMake(20, 240, 120, 40);
[_People1 setTitle:@"张三" forState:UIControlStateNormal];
_People1.backgroundColor = [UIColor lightGrayColor];
[_People1 addTarget:self action:@selector(setPeople1Data) forControlEvents:UIControlEventTouchUpInside];
[self.view addSubview:_People1];
_People2 = [UIButton buttonWithType:UIButtonTypeSystem];
_People2.frame = CGRectMake(180, 240, 120, 40);
[_People2 setTitle:@"李四" forState:UIControlStateNormal];
_People2.backgroundColor = [UIColor lightGrayColor];
[_People2 addTarget:self action:@selector(setPeople2Data) forControlEvents:UIControlEventTouchUpInside];
[self.view addSubview:_People2];
/* view.nameString = @"张三"; view.addrString = @"北京";
view.infoString = @"学生";
view.countString = @"12345";
view.nameString = @"李四";
view.addrString = @"上海";
view.infoString = @"工程师";
view.countString = @"54321";*/
}- (void)setPeople1Data{ NSLog(@"setPeople1Data called.");
NSDictionary *param = @{@"Name": @"张三", @"Address" : @"北京", @"Infomation" : @"学生", @"Count" : @"12345"};
_userView.param = param;
}- (void)setPeople2Data{ NSLog(@"setPeople2Data called.");
NSDictionary *param = @{@"Name": @"李四", @"Address" : @"上海", @"Infomation" : @"工程师", @"Count" : @"54321"};
_userView.param = param;
}- (void)didReceiveMemoryWarning{ [super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}@end |
ViewController的默认视图上，分别实现了两个按钮并分别设置了响应函数。我们的目的是通过选择不同的按钮来改变UserInfoView中 显示的数据。从两个响应函数setPeople1Data和setPeople2Data的实现可知，UserInfoView所需要的信息都被封装在了一个字典型变量param中，对view的修改仅仅做了一个操作，即将该字典变量赋给了UserInfoView实例的一个property，通过这种改变一下目标view属性的方式即可完成对显示信息的更改。这样，Controller并不关心UserInfoView实例是如何解析字典参数的，也不需要对该实例进行其他操作，当需要更新数据的时候只需要一次赋值就可以了。如此可以最大程度地解除Controller和View的耦合性，提高代码的逻辑简洁度和可复用性。
再回到 UserInfoView类中的实现方法。如何实现在字典类property改变的同时对自己的子视图进行重写数据操作呢？方法很简单。首先将重写子视图数据的代码分离到loadData函数中，然后重写NSDictionary *param这个property的set方法（即setParam），然后在该set方法和layoutSubView方法中调用loadData方法就可以了。