iOS: 学习笔记实例, 用代码控制视图创建与切换

1. 创建iOS, Single View Application.
2. 修改YYViewController.m

//

//  YYViewController.m

//  DynamicViewDemo

//

//  Created by yao_yu on 14-5-28.

//  Copyright (c) 2014年 yao_yu. All rights reserved.

//



#import "YYViewController.h"



@interface YYViewController ()



@property(nonatomic, strong) UIView *body;



@property (nonatomic, strong) UIView *currentPage;



@end



const CGFloat HEIGHTEDGE = 40;



@implementation YYViewController



-(void)createBodyView

{

    CGRect statusBarFrame = [[UIApplication sharedApplication] statusBarFrame];

    CGRect parentFrame = self.view.frame;

    CGRect bodyFrame = CGRectMake(parentFrame.origin.x, parentFrame.origin.y + statusBarFrame.size.height + HEIGHTEDGE, parentFrame.size.width, parentFrame.size.height -  statusBarFrame.size.height - HEIGHTEDGE);

    self.body = [[UIView alloc] initWithFrame:bodyFrame];

    [self.body setBackgroundColor:[UIColor blackColor]];

    [self.view addSubview:self.body];

}



-(void)createCommands

{

    CGRect statusBarFrame = [[UIApplication sharedApplication] statusBarFrame];

    CGRect parentFrame = self.view.frame;

    CGRect bodyFrame = CGRectMake(parentFrame.origin.x, parentFrame.origin.y + statusBarFrame.size.height, parentFrame.size.width, HEIGHTEDGE);

    UIView *view = [[UIView alloc] initWithFrame:bodyFrame];

    [view setBackgroundColor:[UIColor redColor]];

    [self.view addSubview:view];

    

    //添加命令按钮

    const CGFloat COMMANDWIDTH = 50;

    const CGFloat COMMANDHEIGHT = 30;

    CGFloat midx = bodyFrame.size.width/2;

    CGFloat midy = bodyFrame.size.height/2;

    CGRect rect = CGRectMake(midx - COMMANDWIDTH/2, midy - COMMANDHEIGHT/2, COMMANDWIDTH, COMMANDHEIGHT);

    UIButton *btnPage1 = [UIButton buttonWithType:UIButtonTypeRoundedRect];

    [btnPage1 setBackgroundColor:[UIColor clearColor]];

    [btnPage1 setTitle:@"第1页" forState:UIControlStateNormal];

    rect.origin.x -= COMMANDWIDTH + 20;

    btnPage1.frame = rect;

    [btnPage1 addTarget:self action:@selector(onShowPage1:) forControlEvents:UIControlEventTouchUpInside];

    [view addSubview:btnPage1];

    

    btnPage1 = [UIButton buttonWithType:UIButtonTypeRoundedRect];

    [btnPage1 setTitle:@"第2页" forState:UIControlStateNormal];

    rect.origin.x += COMMANDWIDTH + 20;

    btnPage1.frame = rect;

    [btnPage1 addTarget:self action:@selector(onShowPage2:) forControlEvents:UIControlEventTouchUpInside];

    [view addSubview:btnPage1];

    

    btnPage1 = [UIButton buttonWithType:UIButtonTypeRoundedRect];

    [btnPage1 setTitle:@"第3页" forState:UIControlStateNormal];

    rect.origin.x += COMMANDWIDTH + 20;

    btnPage1.frame = rect;

    [btnPage1 addTarget:self action:@selector(onShowPage3:) forControlEvents:UIControlEventTouchUpInside];

    [view addSubview:btnPage1];

    

}



-(void) onShowPage1:(id)sender

{

    [self clearCurrentPage];

    CGRect frame = CGRectMake(0, 0, self.body.frame.size.width, self.body.frame.size.height);

    self.currentPage = [[UIView alloc] initWithFrame: frame];

    [self.currentPage setBackgroundColor:[UIColor blueColor]];

    [self.body addSubview:self.currentPage];

}



-(void) onShowPage2:(id)sender

{

    [self clearCurrentPage];

    CGRect frame = CGRectMake(0, 0, self.body.frame.size.width, self.body.frame.size.height);

    self.currentPage = [[UIView alloc] initWithFrame: frame];

    [self.currentPage setBackgroundColor:[UIColor yellowColor]];

    [self.body addSubview:self.currentPage];

}





-(void) onShowPage3:(id)sender

{

    [self clearCurrentPage];

    CGRect frame = CGRectMake(0, 0, self.body.frame.size.width, self.body.frame.size.height);

    self.currentPage = [[UIView alloc] initWithFrame: frame];

    [self.currentPage setBackgroundColor:[UIColor greenColor]];

    [self.body addSubview:self.currentPage];

}



-(void) clearCurrentPage

{

    if (self.currentPage)

        [self.currentPage removeFromSuperview];

    self.currentPage = nil;

}



- (void)viewDidLoad

{

    [super viewDidLoad];

    self.currentPage = nil;

    [self createBodyView];

    [self createCommands];

	// Do any additional setup after loading the view, typically from a nib.

}



- (void)didReceiveMemoryWarning

{

    [super didReceiveMemoryWarning];

    // Dispose of any resources that can be recreated.

}



@end

 3.运行