ios學習:文件簡單讀寫

2013.10.05補充  參考自 http://www.cnblogs.com/chinapcc/archive/2013/04/03/2673092.html

要把自定義類保存到plist文件里，要注意一下三點：

1、自定義類要繼承NSCoding協議，實現 -(void)encodeWithCoder:(NSCoder *)coder 方法和  - (id) initWithCoder: (NSCoder *)coder方法

2、在寫入plist文件時要對數據序列化然后寫入：[NSKeyedArchiver archiveRootObject:array toFile:filename];array是要寫入的數據，filename是plist文件路徑

3、在讀取plist文件數據時要對數據反序列化才能用：NSArray *arr = [NSKeyedUnarchiver unarchiveObjectWithFile: filename];

建議在有條件的情況下還是把數據放到 NSMutableArray / NSArray / NSMutableDictionary / NSDictionary 里，寫入plist文件吧

 

ios項目的文件分工程項目里的文件和程序沙盒里的文件兩種,其中項目工程里的文件是只讀的,為沙盒里的文件可讀可寫.對於讀文件而言,不管是工程里的還是沙盒的,方法都一樣,唯一不同的在於文件路徑的獲取.

1 文件目錄

 

2 txt文件.每一行數據的字段之間是用 \t 來分割

 

3  TWFXCityCode類:

#import <Foundation/Foundation.h>

@interface TWFXCityCode : NSObject
{
   @public
    NSString *cityName;
    NSString *cityCode;
    NSString *pinyin;
    NSString *sortPinyin;
    NSString *provinceName;
    NSString *provinceCode;    
}

@end

 

4 TWFXViewController類的頭文件

#import <UIKit/UIKit.h>
#import "TWFXCityCode.h"

@interface TWFXViewController : UIViewController

@property (retain, nonatomic) NSMutableArray *weatherData;

- (IBAction)btnClick_readFile:(UIButton *)sender;
- (IBAction)btnClick_writePlist:(UIButton *)sender;
- (IBAction)btnClick_readPlist:(UIButton *)sender;
- (IBAction)btnClick_test:(UIButton *)sender;
@end

 

5 項目工程里txt文件的讀取:

NSString *filePath = [[NSBundle mainBundle] pathForResource:@"test123" ofType:@"txt"];

   NSArray *fileData;
    NSError *error;

    //讀取file文件並把內容根據換行符分割后賦值給NSArray
    fileData = [[NSString stringWithContentsOfFile:filePath
                                          encoding:NSUTF8StringEncoding
                                             error:&error]
                componentsSeparatedByString:@"\n"];
    
    
    //獲取NSArray類型對象的迭代器
    NSEnumerator *arrayEnumerator = [fileData objectEnumerator];
    NSString *tempStr;
    
    while (tempStr = [arrayEnumerator nextObject]) {
        
        TWFXCityCode *cityCode = [[TWFXCityCode alloc] init];
        
        //把每行字符串再按 \t 符分割
        NSArray *cityInfo = [tempStr componentsSeparatedByString:@"\t"];
        
        cityCode->cityCode = cityInfo[0];
        cityCode->cityName = cityInfo[1];
        cityCode->pinyin   = cityInfo[2];
        cityCode->sortPinyin = cityInfo[3];
        cityCode->provinceCode = cityInfo[4];
        cityCode->provinceName = cityInfo[5];
        
        [self.weatherData addObject:cityCode];
        [cityCode release];
    }

 

6 把數據保存到沙盒里的plist文件

 //獲取應用程序沙盒的Documents目錄
    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    
    NSString *plistPath1 = [paths objectAtIndex:0];
    
    //得到完整路徑名
    NSString *filename = [plistPath1 stringByAppendingPathComponent:@"weathertest.plist"];
    
    //保存對字符串解析后的數據.dictionary里的value不能是自定類型對象么?還是說自定義類要實現指定的協議?
    //沒辦法,暫時先用一個dictionary來保存value吧
    NSMutableDictionary *myDic = [[NSMutableDictionary alloc] init];
        
    for (TWFXCityCode *city in self.weatherData) {
            
        NSMutableDictionary *tempDic = [[NSMutableDictionary alloc] init];
        [tempDic setValue:city->cityCode forKey:@"cityID"];
        [tempDic setValue:city->cityName forKey:@"cityName"];
        [tempDic setValue:city->pinyin forKey:@"cityPinyin"];
        [tempDic setValue:city->sortPinyin forKey:@"citySortPinyin"];
        [tempDic setValue:city->provinceCode forKey:@"provinceID"];
        [tempDic setValue:city->provinceName forKey:@"provinceName"];
        
        [myDic setValue:tempDic forKey:city->cityCode];
    }
    
    NSLog(@"寫plist文件完成");
    [myDic writeToFile:filename atomically:YES];
    

 

7 沙盒里plist文件的內容