iOS持久化存储之Plist文件

plist

创建plist文件（xml）

在Xcode里面，我们创建一个Cocoa项目（PlistTest）。之后cmd + n 新建文件，在Resourse里面选择 Property List，并命名为 Data.plist。

之后可以直接在plist文件里面添加项目。

因为plist文件是一个xml文件，我们也可以这样写。

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
    <key>Name</key>
    <string>李金</string>
    <key>Phones</key>
    <array>
        <string>123456</string>
        <string>234567</string>
    </array>
</dict>
</plist>

因为我们把plist文件放在了沙盒的资源目录下，当应用启动的时候，这个文件会被写到 main bundle 里面。

---

代码部分

1. plist文件读取

NSString *errorDesc = nil;
NSPropertyListFormat format;
NSString *plistPath ;
NSString *rootPath = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES)objectAtIndex:0];

plistPath = [rootPath stringByAppendingPathComponent:@"Data.plist"];
    if (![[NSFileManager defaultManager] fileExistsAtPath:plistPath]) {
        plistPath = [[NSBundle mainBundle] pathForResource:@"Data" ofType:@"plist"];
   }
    NSData *plistXML = [[NSFileManager defaultManager] contentsAtPath:plistPath];
    NSDictionary *temp = (NSDictionary *)[NSPropertyListSerialization
                                          propertyListFromData:plistXML
                                          mutabilityOption:NSPropertyListMutableContainersAndLeaves
                                          format:&format
                                          errorDescription:&errorDesc];
    if (!temp) {
        NSLog(@"Error reading plist: %@, format: %lu", errorDesc, (unsigned long)format);
    }
    self.personName = [temp objectForKey:@"Name"];
    self.phoneNumbers = [NSMutableArray arrayWithArray:[temp objectForKey:@"Phones"]];

2. plist文件写入

NSArray *name = @[@"李1",@"李2",@"李3",@"李4",@"李5",@"李6"];
    personName = [name objectAtIndex:rand()%5];
    
    NSString *error;
    NSString *rootPath = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) objectAtIndex:0];
    NSString *plistPath = [rootPath stringByAppendingPathComponent:@"Data.plist"];
    NSDictionary *plistDict = [NSDictionary dictionaryWithObjects:
                               [NSArray arrayWithObjects: personName, phoneNumbers, nil]
                                                          forKeys:[NSArray arrayWithObjects: @"Name", @"Phones", nil]];
    NSData *plistData = [NSPropertyListSerialization dataFromPropertyList:plistDict
                                                                   format:NSPropertyListXMLFormat_v1_0
                                                         errorDescription:&error];
    if(plistData) {
        [plistData writeToFile:plistPath atomically:YES];
    }
    else {
        NSLog(@"error");
    }

具体代码可以在github里面看到。

---

用代码创建plist文件

plise文件中的数据属性必须是下面这些：

• NSDictionary
• NSArrat
• NSString
• NSDate
• NSData
• NSNumber

** 代码1: **创建一个plist文件，一个NSDictionary对象（根对象），并加入一个数字；

    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    NSString *documentsDirectory = [paths objectAtIndex:0];
    NSString *path = [documentsDirectory stringByAppendingPathComponent:@"plist.plist"];
    NSFileManager *fileManager = [NSFileManager defaultManager];
    
    NSMutableDictionary *data;
    
    if ([fileManager fileExistsAtPath: path]) {
        data = [[NSMutableDictionary alloc] initWithContentsOfFile:path];
    }
    else {
        // 没有不存在这个文件，那么创建一个空的字典
        data = [[NSMutableDictionary alloc] init];
    }
    
    //插入数据
    data[@"value"] = @(5);
    [data writeToFile: path atomically:YES];
    
    //读取数据
    NSMutableDictionary *savedStock = [[NSMutableDictionary alloc] initWithContentsOfFile:path];
    int value1;
    value1 = [savedStock[@"value"] intValue];
    NSLog(@"%i",value1);

参考资料：

[1] Apple Dev Library

[2] Stackoverflow Q&A