plist文件的读写

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在做iOS开发时，经常用到到plist文件，那plist文件是什么呢？它全名是：Property List，属性列表文件，它是一种用来存储串行化后的对象的文件。属性列表文件的扩展名为.plist ，因此通常被称为 plist文件。文件是xml格式的。

Plist文件通常用于储存用户设置，也可以用于存储捆绑的信息

我们创建一个项目来学习plist文件的读写。

1、创建项目Plistdemo

项目创建之后可以找到项目对应的plist文件，打开如下图所示：

在编辑器中显示类似与表格的形式，可以在plist上右键，用源码方式打开，就能看到plist文件的xml格式了。

2、创建plist文件。

按command +N快捷键创建，或者File —> New —> New File，选择Mac OS X下的Property List

创建plist文件名为plistdemo。

打开plistdemo文件，在空白出右键,右键选择Add row 添加数据,添加成功一条数据后，在这条数据上右键看到 value Type选择Dictionary。点加号添加这个Dictionary下的数据

添加完key之后在后面添加Value的值，添加手机号和年龄

创建完成之后用source code查看到plist文件是这样的：

[cpp] view plaincopyprint?

<?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>jack</key>
<dict>
<key>phone_num</key>
<string>13801111111</string>
<key>age</key>
<string>22</string>
</dict>
<key>tom</key>
<dict>
<key>phone_num</key>
<string>13901111111</string>
<key>age</key>
<string>36</string>
</dict>
</dict>
</plist>

<?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>jack</key><dict><key>phone_num</key><string>13801111111</string><key>age</key><string>22</string></dict><key>tom</key><dict><key>phone_num</key><string>13901111111</string><key>age</key><string>36</string></dict></dict></plist>

3、读取plist文件的数据

现在文件创建成功了，如何读取呢，实现代码如下：

[cpp] view plaincopyprint?

- (void)viewDidLoad
{
[super viewDidLoad];
//读取plist
NSString *plistPath = [[NSBundle mainBundle] pathForResource:@"plistdemo" ofType:@"plist"];
NSMutableDictionary *data = [[NSMutableDictionary alloc] initWithContentsOfFile:plistPath];
NSLog(@"%@", data);//直接打印数据。
}

- (void)viewDidLoad{    [super viewDidLoad];    //读取plist    NSString *plistPath = [[NSBundle mainBundle] pathForResource:@"plistdemo" ofType:@"plist"];    NSMutableDictionary *data = [[NSMutableDictionary alloc] initWithContentsOfFile:plistPath];    NSLog(@"%@", data);//直接打印数据。}

打印出来的结果：

[cpp] view plaincopyprint?

PlistDemo[6822:f803] {
jack = {
age = 22;
"phone_num" = 13801111111;
};
tom = {
age = 36;
"phone_num" = 13901111111;
};
}

PlistDemo[6822:f803] {    jack =     {        age = 22;        "phone_num" = 13801111111;    };    tom =     {        age = 36;        "phone_num" = 13901111111;    };}

这样就把数据读取出来了。

4、创建和写入plist文件

在开发过程中，有时候需要把程序的一些配置保存下来，或者游戏数据等等。这时候需要写入Plist数据。

写入的plist文件会生成在对应程序的沙盒目录里。

接着上面读取plist数据的代码，加入了写入数据的代码，

[cpp] view plaincopyprint?

<strong>- (void)viewDidLoad
{
[super viewDidLoad];
//读取plist
NSString *plistPath = [[NSBundle mainBundle] pathForResource:@"plistdemo" ofType:@"plist"];
NSMutableDictionary *data = [[NSMutableDictionary alloc] initWithContentsOfFile:plistPath];
NSLog(@"%@", data);
//添加一项内容
[data setObject:@"add some content" forKey:@"c_key"];
//获取应用程序沙盒的Documents目录
NSArray *paths=NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,NSUserDomainMask,YES);
NSString *plistPath1 = [paths objectAtIndex:0];
//得到完整的文件名
NSString *filename=[plistPath1 stringByAppendingPathComponent:@"test.plist"];
//输入写入
[data writeToFile:filename atomically:YES];
//那怎么证明我的数据写入了呢？读出来看看
NSMutableDictionary *data1 = [[NSMutableDictionary alloc] initWithContentsOfFile:filename];
NSLog(@"%@", data1);
// Do any additional setup after loading the view, typically from a nib.
}
</strong>

<strong>- (void)viewDidLoad{    [super viewDidLoad];    //读取plist    NSString *plistPath = [[NSBundle mainBundle] pathForResource:@"plistdemo" ofType:@"plist"];    NSMutableDictionary *data = [[NSMutableDictionary alloc] initWithContentsOfFile:plistPath];    NSLog(@"%@", data);        //添加一项内容    [data setObject:@"add some content" forKey:@"c_key"];        //获取应用程序沙盒的Documents目录    NSArray *paths=NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,NSUserDomainMask,YES);    NSString *plistPath1 = [paths objectAtIndex:0];        //得到完整的文件名    NSString *filename=[plistPath1 stringByAppendingPathComponent:@"test.plist"];   //输入写入    [data writeToFile:filename atomically:YES];        //那怎么证明我的数据写入了呢？读出来看看    NSMutableDictionary *data1 = [[NSMutableDictionary alloc] initWithContentsOfFile:filename];    NSLog(@"%@", data1);        // Do any additional setup after loading the view, typically from a nib.}</strong>

在获取到自己手工创建的plistdemo.plist数据后，在这些数据后面加了一项内容，证明输入写入了。

怎么证明添加的内容写入了呢？下面是打印结果：

plist文件读写实例

在cocos2d-x中，对于plist文件，既可以读取，也可以进行写入的操作；下面先来看一个plist文件：

 1 <?xml version="1.0" encoding="UTF-8"?> 2 <!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd"/> 3  4 <plist version="1.0"> 5     <dict> 6         <key>string element key</key> 7         <string>string element value</string> 8         <key>array</key> 9         <array>10             <dict>11                 <key>string in dictInArray key 0</key>12                 <string>string in dictInArray value 0</string>13                 <key>string in dictInArray key 1</key>14                 <string>string in dictInArray value 1</string>15             </dict>16             <string>string in array</string>17             <array>18                 <string>string 0 in arrayInArray</string>19                 <string>string 1 in arrayInArray</string>20             </array>21         </array>22         <key>dictInDict, Hello World</key>23         <dict>24             <key>string in dictInDict key</key>25             <string>string in dictInDict value</string>26             <key>bool</key>27             <true/>28             <key>integer</key>29             <integer>1024</integer>30             <key>float</key>31             <real>1024.1024170</real>32             <key>double</key>33             <real>1024.1230000000000000</real>34         </dict>35     </dict>36 </plist>

View Code

先不看上面的plist文件到底有些什么内容；实际上它是由下一段代码生成的。

 1 auto root = Dictionary::create(); 2     auto string = String::create("string element value"); 3     root->setObject(string, "string element key"); // 添加一个键值对 4      5     auto array = Array::create();  // 创建一个array 6      7     auto dictInArray = Dictionary::create(); 8     dictInArray->setObject(String::create("string in dictInArray value 0"), "string in dictInArray key 0"); 9     dictInArray->setObject(String::create("string in dictInArray value 1"), "string in dictInArray key 1");10     array->addObject(dictInArray); // 往数组中添加一个键值对11     12     array->addObject(String::create("string in array")); // 往数组中添加一个字符串13     14     auto arrayInArray = Array::create();15     arrayInArray->addObject(String::create("string 0 in arrayInArray"));16     arrayInArray->addObject(String::create("string 1 in arrayInArray"));17     array->addObject(arrayInArray); // 往数组中添加一个数组18     19     root->setObject(array, "array");20     21     auto dictInDict = Dictionary::create();22     dictInDict->setObject(String::create("string in dictInDict value"), "string in dictInDict key");23    24     //add boolean to the plist25     auto booleanObject = Bool::create(true);26     dictInDict->setObject(booleanObject, "bool");27     28     //add interger to the plist29     auto intObject = Integer::create(1024);30     dictInDict->setObject(intObject, "integer");31     32     //add float to the plist33     auto floatObject = Float::create(1024.1024f);34     dictInDict->setObject(floatObject, "float");35     36     //add double to the plist37     auto doubleObject = Double::create(1024.123);38     dictInDict->setObject(doubleObject, "double");39     40     root->setObject(dictInDict, "dictInDict, Hello World");41 // end with /42     std::string writablePath = FileUtils::getInstance()->getWritablePath();43     std::string fullPath = writablePath + "text.plist";44     if(root->writeToFile(fullPath.c_str()))45         log("see the plist file at %s", fullPath.c_str());46     else47         log("write plist file failed");48     49     // 读取上面创建的内容50     auto loadDict = __Dictionary::createWithContentsOfFile(fullPath.c_str());51     auto loadDictInDict = (__Dictionary*)loadDict->objectForKey("dictInDict, Hello World");52     auto boolValue = (__String*)loadDictInDict->objectForKey("bool");53     CCLOG("%s",boolValue->getCString());54     auto floatValue = (__String*)loadDictInDict->objectForKey("float");55     CCLOG("%s",floatValue->getCString());56     auto intValue = (__String*)loadDictInDict->objectForKey("integer");57     CCLOG("%s",intValue->getCString());58     auto doubleValue = (__String*)loadDictInDict->objectForKey("double");59     CCLOG("%s",doubleValue->getCString());

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因此可以看出，对符合一定格式的plist文件，可以通过Dictionary进行操作。cocos2dx 3.0 的Dictionary，可以实现对Array，Dictionary，Integer，String，Bool等基础数据类型进行读写。

下面再来看另一种读取方式: 假定plist文件如下;

1 <plist version="1.0">2 <dict>3     <key>name</key>4     <string>Ls</string>5     <key>isgirl</key>6     <false/>7 </dict>8 </plist>

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读取方式二，这种方法是借助VectorMap来进行读的:

1  FileUtils * fu = FileUtils::getInstance();2     ValueMap vm = fu->getValueMapFromFile("Info.plist");3     log("%s", vm["name"].asString().c_str()); // 读取string -->Ls4     bool bl = vm["isgirl"].asBool(); // 读取bool -->05     log("%d", bl);

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如果文件节点也是一个ValueMap，则可以通过xm["xx"].asValueMap()将节点转换为ValueMap；如果根节点为数组也可能直接通过ValueVector.getValueVectorFromFile("xx")读取数据；

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