背景圖設定的基本方法

在實作App時，常需要設定背景圖。在此提供六種設定的方法
Xcode版本4.5.1


1. 開啓一個專案

2. 在storyBoard上加上一個button

3. 加入一個背景所需要的圖檔

4. 在mainViewController.h 註冊button
#import <UIKit/UIKit.h>

@interface mainViewController : UIViewController

@property (weak, nonatomic) IBOutlet UIButton *changeButton;
@end

5. 在mainViewController.m加入六種背景圖的設定程式碼。此六種會由按鍵控制，而輪流出現。
#import "mainViewController.h"

@interface mainViewController ()

@end

@implementation mainViewController

@synthesize changeButton;

int caseNum=0;

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

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

- (IBAction)changeBackground:(id)sender {
   
   caseNum++;
   
    switch (caseNum) {
        case 1:
           
            [self setBackgroundImage1];
           
            [changeButton setTitle:@"改變背景:第一種設定" forState:UIControlStateNormal];
         
            break;
       
        case 2:
           
            [self clearBackgroundImage1];
         
            [changeButton setTitle:@"改變背景:第一種清除" forState:UIControlStateNormal];
           
            break;
           
        case 3:
           
            [self setBackgroundImage2];
           
            [changeButton setTitle:@"改變背景:第二種設定" forState:UIControlStateNormal];
           
            break;
           
        case 4:
           
            [self clearBackgroundImage2];
           
            [changeButton setTitle:@"改變背景:第二種清除" forState:UIControlStateNormal];
           
            break;
           
        case 5:
           
            [self setBackgroundImage3];
           
            [changeButton setTitle:@"改變背景:第三種設定" forState:UIControlStateNormal];
           
            break;
           
        case 6:
           
            [self clearBackgroundImage3];
           
            [changeButton setTitle:@"改變背景:第三種清除" forState:UIControlStateNormal];
           
            break;
           
        case 7:
           
            [self setBackgroundImage4];
           
            [changeButton setTitle:@"改變背景:第四種設定" forState:UIControlStateNormal];
           
            break;
           
        case 8:
           
            [self clearBackgroundImage4];
           
            [changeButton setTitle:@"改變背景:第四種清除" forState:UIControlStateNormal];
           
            break;
           
        case 9:
           
            [self setBackgroundImage5];
           
            [changeButton setTitle:@"改變背景:第五種設定" forState:UIControlStateNormal];
           
            break;
           
        case 10:
           
            [self clearBackgroundImage5];
           
            [changeButton setTitle:@"改變背景:第五種清除" forState:UIControlStateNormal];
           
            break;
           
        case 11:
           
            [self setBackgroundImage6];
           
            [changeButton setTitle:@"改變背景:第六種設定" forState:UIControlStateNormal];
           
            break;
           
        case 12:
           
            [self clearBackgroundImage6];
           
            [changeButton setTitle:@"改變背景:第六種清除" forState:UIControlStateNormal];
           
            caseNum = 0;
           
            break;
           
        default:
           
            break;
    }

   
}

- (void) setBackgroundImage1
{
    // 水平、垂直並排（repeat）
    UIColor *bgColor = [[UIColor alloc] initWithPatternImage:[UIImage imageNamed:@"TaiwanMap.jpg"]];
    self.view.backgroundColor = bgColor;
   
}

- (void) clearBackgroundImage1
{
    self.view.backgroundColor = [UIColor clearColor];
}

- (void) setBackgroundImage2
{
     // 水平、垂直並排（repeat）
     self.view.backgroundColor = [UIColor colorWithPatternImage:[UIImage imageNamed:@"TaiwanMap.jpg"]];
    
}

- (void) clearBackgroundImage2
{
    self.view.backgroundColor = [UIColor clearColor];
}


- (void) setBackgroundImage3
{
     UIImage *img = [[UIImage alloc]initWithContentsOfFile:
     [[NSBundle mainBundle]pathForResource:@"TaiwanMap" ofType:@"jpg"]];
     [self.view setBackgroundColor:[UIColor colorWithPatternImage:img]];
    
}

- (void) clearBackgroundImage3
{
    self.view.backgroundColor = [UIColor clearColor];
}


- (void) setBackgroundImage4
{
     // 滿版的背景圖（圖片會被撐大)
     UIGraphicsBeginImageContext(self.view.frame.size);
     [[UIImage imageNamed:@"TaiwanMap.jpg"] drawInRect:self.view.bounds];
     UIImage *backgroundImage = UIGraphicsGetImageFromCurrentImageContext();
     UIGraphicsEndImageContext();
     self.view.backgroundColor = [UIColor colorWithPatternImage:backgroundImage];
    
}

- (void) clearBackgroundImage4
{
    self.view.backgroundColor = [UIColor clearColor];
}


- (void) setBackgroundImage5
{
     //滿版的背景圖（圖片會被撐大)
     UIImageView *contentView = [[UIImageView alloc] initWithFrame:[[UIScreen mainScreen] applicationFrame]];
     [contentView setImage:[UIImage imageNamed:@"TaiwanMap.jpg"]];
    contentView.frame  = CGRectMake(0, 0, 1024, 768);   //設定填滿螢幕大小

    [self.view addSubview:contentView];
    [self.view sendSubviewToBack:contentView];

   
    //self.view = contentView;

}

- (void) clearBackgroundImage5
{
   
    for(UIView *subview in [self.view subviews]) {
        if([subview isKindOfClass:[UIImageView class]]) {
            [subview removeFromSuperview];
        } else {
            // Do nothing - not a UIButton or subclass instance
        }
    }

}


- (void) setBackgroundImage6 {

     //貼入一張圖到UIImageView，再轉到 self.view ，最後再設定到最後面當背景圖，此法只會顯示一張不被放大的圖。
     UIImageView *customBackground = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"TaiwanMap.jpg"]];
     [self.view addSubview:customBackground];
     [self.view sendSubviewToBack:customBackground];

}

- (void) clearBackgroundImage6
{
    for(UIView *subview in [self.view subviews]) {
        if([subview isKindOfClass:[UIImageView class]]) {
            [subview removeFromSuperview];
        } else {
            // Do nothing - not a UIButton or subclass instance
        }
    }
}
@end

6, 執行結果