ios - 如何在设置动态值后将数据保存到 ios 中的 plist 中？

Question

<plist version="1.0">
    <dict>
            <key>InfoValue</key>
            <string>false</string>
            <key>AudioValue</key>
            <string>true</string>
            <key>VideoValue</key>
            <string>true</string>
            <key>DescValue</key>
            <string>true</string>
            <key>LinkValue</key>
            <string>true</string>
   </dict>
</plist>

这是 plist 文件，我想动态更改 InfoValue。在我的代码中，我使用 like

settingsPath=[[NSBundle mainBundle] pathForResource:@"SettingsValue" ofType:@"plist"];
settingsItem = [[NSMutableDictionary alloc] initWithContentsOfFile:settingsPath];

[settingsItem setObject:@"false" forKey:@"InfoValue"];

之后

[settingsItem writeToFile:settingsPath atomically:YES];

但它没有将数据保存到 plist 文件中。相反，我收到以下错误:

-[NSConcreteValue getFileSystemRepresentation:maxLength:]: unrecognized selector sent to instance 0x8fad490
2013-02-27 10:26:44.479 vCamView[1577:c07] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', 
 reason: '-[NSConcreteValue getFileSystemRepresentation:maxLength:]: unrecognized selector sent to instance 0x8fad490'
*** First throw call stack:
(0x33dc012 0x2944e7e 0x34674bd 0x33cbbbc 0x33cb94e 0x2354915 0x23548b9 0x2354872 
   0x235468f 0x1e207 0x2958705 0x188f920 0x188f8b8 0x1950671 0x1950bcf 0x1a90747 
   0x2342e83 0x339b376 0x339ae06 0x3382a82 0x3381f44 0x3381e1b 0x376f7e3 0x376f668 
   0x188c65c 0x27e2 0x2715)

Answer 1

您不能修改包内的文件。它是只读的。尝试将 plist 保存在 DocumentDirectory

    NSString *directoryPath = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,  NSUserDomainMask, YES)objectAtIndex:0];
    NSString *filePath = [directoryPath stringByAppendingPathComponent:@"SettingsValue.plist"];

   // Read from document directory
    settingsItem = [[NSMutableDictionary alloc] initWithContentsOfFile:filePath]; 

    // update the dictionary
    [settingsItem setObject:@"false" forKey:@"InfoValue"];

   // write back to file  
    [settingsItem writeToFile:filePath atomically:YES];