精通IOS開發第六版學習第五章---旋轉和佈局

這一章主要介紹了兩種方法設置屏幕的旋轉和自動佈局

1. 使用constraints

在story board 中完成

2. 使用代碼的方式

主要介紹這種方式

需要去除view的auto layout.

效果如下：

代碼如下：

//
//  ViewController.m
//  L05-Restructure
//
//  Created by zhengna on 15/6/24.
//  Copyright (c) 2015年 zhengna. All rights reserved.
//

#import "ViewController.h"

@interface ViewController ()
@property (weak, nonatomic) IBOutlet UIButton *actionButton1;
@property (weak, nonatomic) IBOutlet UIButton *actionButton2;
@property (weak, nonatomic) IBOutlet UIButton *actionButton3;
@property (weak, nonatomic) IBOutlet UIButton *actionButton4;

@property (weak, nonatomic) IBOutlet UIView *contentView;

@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.
    UIApplication *app = [UIApplication sharedApplication];
    UIInterfaceOrientation currentOrientation = app.statusBarOrientation;
    [self doLayoutForOrientation:currentOrientation];
}

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

- (void)willAnimateRotationToInterfaceOrientation:(UIInterfaceOrientation)toInterfaceOrientation duration:(NSTimeInterval)duration{
    [self doLayoutForOrientation:toInterfaceOrientation];
}

- (void)doLayoutForOrientation:(UIInterfaceOrientation)orientation{

    if (UIInterfaceOrientationIsPortrait(orientation)) {
        [self layoutPortrait];
    }else{
        [self layoutLandscape];
    }
}

static const CGFloat buttonHeight = 40;
static const CGFloat buttonWidth = 120;
static const CGFloat spacing =20;

- (void)layoutPortrait{

    CGRect b = self.view.bounds;
    
    CGFloat contentWidth = CGRectGetWidth(b) - (2 * spacing);
    CGFloat contentHeight = CGRectGetHeight(b) - (4 * spacing) - (2 * buttonHeight);
    
    self.contentView.frame = CGRectMake(spacing, spacing, contentWidth, contentHeight);
    
    CGFloat buttonRow1y = contentHeight + (2 * spacing);
    CGFloat buttonRow2y = buttonRow1y + buttonHeight + spacing;
    
    CGFloat buttonCol1x = spacing;
    CGFloat buttonCol2x = CGRectGetWidth(b) - buttonWidth - spacing;
    
    self.actionButton1.frame = CGRectMake(buttonCol1x, buttonRow1y, buttonWidth, buttonHeight);
    self.actionButton2.frame = CGRectMake(buttonCol2x, buttonRow1y, buttonWidth, buttonHeight);
    self.actionButton3.frame = CGRectMake(buttonCol1x, buttonRow2y, buttonWidth, buttonHeight);
    self.actionButton4.frame = CGRectMake(buttonCol2x, buttonRow2y, buttonWidth, buttonHeight);
    
}

- (void)layoutLandscape{

    CGRect b = self.view.bounds;
    
    CGFloat contentWidth = CGRectGetWidth(b) - buttonWidth - (3 * spacing);
    CGFloat contentHeight = CGRectGetHeight(b) - (2 * spacing);
    
    self.contentView.frame = CGRectMake(spacing, spacing, contentWidth, contentHeight);
    
    CGFloat buttonX = CGRectGetWidth(b) - buttonWidth - spacing;
    CGFloat buttonRow1y = spacing;
    CGFloat buttonRow4y = CGRectGetHeight(b) - buttonHeight - spacing;
    CGFloat buttonRow2y = buttonRow1y + floor((buttonRow4y - buttonRow1y) * 0.333);
    CGFloat buttonRow3y = buttonRow1y + floor((buttonRow4y - buttonRow1y) * 0.667);
    
    self.actionButton1.frame = CGRectMake(buttonX, buttonRow1y, buttonWidth, buttonHeight);
    self.actionButton2.frame = CGRectMake(buttonX, buttonRow2y, buttonWidth, buttonHeight);
    self.actionButton3.frame = CGRectMake(buttonX, buttonRow3y, buttonWidth, buttonHeight);
    self.actionButton4.frame = CGRectMake(buttonX, buttonRow4y, buttonWidth, buttonHeight);
    
}

@end

這裏主要涉及幾個新事物：

1. CGRect 方形

2. bounds and frame 它們都是一種CGRect

3. CGRectMake(): let you easily create a CGRect 快速生成一個Rect並把它放入父容器
4. CGRectGetHeight() 求它的高
5. CGRectGetWidth() 求它的寬

程序根據不同的屏幕方向，運用不同的計算方法計算出view中幾個element的位置和大小。