电子书阅读器开发 （一）

从今天开始陪大家一起开发一款电子书阅读器，主要是想帮助初学者快速入门ios。

 首先解决两个问题：1.对txt文件分页 2.实现翻页的效果

-(NSString *)readStrFromTxt:(NSString *)fileName
{
    NSError *error;
    
    NSString *textFileContents = [NSString
                                  
                                  stringWithContentsOfFile:[[NSBundle mainBundle]
                                                            
                                                            pathForResource:fileName
                                                            
                                                            ofType:@"txt"]
                                  
                                  encoding:NSUTF8StringEncoding
                                  
                                  error: & error];
    
    // If there are no results, something went wrong
    
    if (textFileContents == nil) {
        
        // an error occurred
        
        NSLog(@"Error reading text file. %@", [error localizedFailureReason]);
        
    }
    
    return textFileContents;
}

读取txt文本文件，并且转化为字符串

bRect=CGRectMake(BOOK_LEFT, BOOK_TOP, BOOK_WIDTH, BOOK_HEIGHT);
allStr=[self readStrFromTxt:@"aizaixianjingderizi"];
NSArray *arrContent=[allStr componentsSeparatedByString:@"　　"];
NSString *curCotentLine=@"";
for (int i=0; i<10; i++) {
   NSString *tempStr=[arrContent objectAtIndex:i];
   NSLog(@"tempStr.length:%d",tempStr.length);
   curCotentLine=[NSString stringWithFormat:@"%@%@",curCotentLine,tempStr];
}

分行显示txt文件的内容

分页显示我们使用pageconroller这个控件

// 设置UIPageViewController的配置项
    NSDictionary *options =[NSDictionary dictionaryWithObject:[NSNumber numberWithInteger:UIPageViewControllerSpineLocationMin]
                                                       forKey: UIPageViewControllerOptionSpineLocationKey];
    // 实例化UIPageViewController对象，根据给定的属性
    _pageController = [[UIPageViewController alloc] initWithTransitionStyle:UIPageViewControllerTransitionStylePageCurl
                                                          navigationOrientation:UIPageViewControllerNavigationOrientationHorizontal
                                                                        options: options];
    // 设置UIPageViewController对象的代理
    _pageController.dataSource = self;
    
    
    // 定义“这本书”的尺寸
    [[_pageController view] setFrame:[[self view] bounds]];

    
    // 让UIPageViewController对象，显示相应的页数据。
    // UIPageViewController对象要显示的页数据封装成为一个NSArray。
    // 因为我们定义UIPageViewController对象显示样式为显示一页（options参数指定）。
    // 如果要显示2页，NSArray中，应该有2个相应页数据。
    initialViewController =[[UIViewController alloc]init];// 得到第一页
    UITextView *txtView=[[UITextView alloc]initWithFrame:bRect];
    txtView.text=curCotentLine;
    [initialViewController.view addSubview:txtView];
    
    NSArray *viewControllers =[NSArray arrayWithObject:initialViewController];
    [_pageController setViewControllers:viewControllers
                              direction:UIPageViewControllerNavigationDirectionForward
                               animated:NO
                             completion:nil];
    
    // 在页面上，显示UIPageViewController对象的View
    [self addChildViewController:_pageController];
    [[self view] addSubview:[_pageController view]];

下面是pageconroller里面的委托函数

#pragma mark- UIPageViewControllerDataSource

// 返回上一个ViewController对象
- (UIViewController *)pageViewController:(UIPageViewController *)pageViewController viewControllerBeforeViewController:(UIViewController *)viewController{
    
    UIViewController *beforeControl=[[UIViewController alloc]init];
    
    if(curIndex>WORD_COUNT)
    {
        curPage--;
        
        curIndex-=WORD_COUNT;

        UITextView *beforeTxt=[[UITextView alloc]initWithFrame:bRect];
        NSString *beforeStr=[allStr substringWithRange:NSMakeRange(curIndex, WORD_COUNT)];
        beforeTxt.text=beforeStr;
        
        NSArray *arrContent=[allStr componentsSeparatedByString:@"　　"];
        NSString *curCotentLine=@"";
        for (int i=0; i<10; i++) {
            NSString *tempStr=[arrContent objectAtIndex:i+curPage*10];
            curCotentLine=[NSString stringWithFormat:@"%@%@",curCotentLine,tempStr];
        }
        beforeTxt.text=curCotentLine;
        
        NSLog(@"beforeStr:%@",beforeStr);
        
        [beforeControl.view addSubview:beforeTxt];
    }
    
    NSLog(@"curindex:%d",curIndex);
    
    return beforeControl;
}

// 返回下一个ViewController对象
- (UIViewController *)pageViewController:(UIPageViewController *)pageViewController viewControllerAfterViewController:(UIViewController *)viewController{
    
    UIViewController *afterConrol=[[UIViewController alloc]init];
    
    if(curIndex+WORD_COUNT<allStr.length)
    {
        curPage++;
        
        UITextView *afterTxt=[[UITextView alloc]initWithFrame:bRect];
        NSString *afterStr=[allStr substringWithRange:NSMakeRange(curIndex,WORD_COUNT)];
        afterTxt.text=afterStr;
        
        NSLog(@"afterStr:%d",afterStr.length);
        
        NSArray *arrContent=[allStr componentsSeparatedByString:@"　　"];
        NSString *curCotentLine=@"";
        for (int i=0; i<10; i++) {
            NSString *tempStr=[arrContent objectAtIndex:i+curPage*10];
            curCotentLine=[NSString stringWithFormat:@"%@%@",curCotentLine,tempStr];
        }
        afterTxt.text=curCotentLine;
        
        [afterConrol.view addSubview:afterTxt];
        
        curIndex+=WORD_COUNT;
    }
    
    NSLog(@"curindex:%d",curIndex);
    
    return afterConrol;
}

分别是翻页时候的显示效果。。。。今天就写到这了。。。。。未完待续。。。。。。下面附上效果截图。。。。。。