Question

我在我的plist文件中编写新词典时遇到问题，我希望每次用户填写表单时都保存数据。我现在使用的代码只覆盖数据而不保存原来的字典。

这里是代码：

//////////// Save data into plist /////////////////
// get paths from root direcory
NSArray *paths = NSSearchPathForDirectoriesInDomains (NSDocumentDirectory, NSUserDomainMask, YES);
// get documents path
NSString *documentsPath = [paths objectAtIndex:0];
// get the path to our Data/plist file
NSString *plistPath = [documentsPath stringByAppendingPathComponent:@"Data.plist"];

// set the variables to the values in the text fields
self.titlestring = titleexperiencia.text;
self.descriptionstring = descriptionexperiencia.text;
self.coordinadastring = [self deviceLocation];

// create dictionary with values in UITextFields
NSDictionary *plistDict = [NSDictionary dictionaryWithObjects: [NSArray arrayWithObjects: titlestring, descriptionstring,coordinadastring, nil] forKeys:[NSArray arrayWithObjects: @"Title", @"Description", @"Coordinate", nil]];

NSString *error = nil;
// create NSData from dictionary
NSData *plistData = [NSPropertyListSerialization dataFromPropertyList:plistDict format:NSPropertyListXMLFormat_v1_0 errorDescription:&error];

// check is plistData exists
if(plistData) 
{
    // write plistData to our Data.plist file
    [plistData writeToFile:plistPath atomically:YES];
    NSLog(@"Saved in Data Plist");

}
else 
{
    NSLog(@"Error in saveData: %@", error);
    [error release];
}

我还尝试使用AddObject：而不是writeToFile：但这会导致应用程序崩溃。

Answer 1

好吧，崩溃可能是由于你过度释放错误变量而造成的。

Answer 2

阅读plistPath的内容：
NSMutableData * myData = [NSMutableData dataWithContentsOfFile：plistPath];
并改变这一点：

// create NSData from dictionary
NSData *plistData = [NSPropertyListSerialization dataFromPropertyList:plistDict format:NSPropertyListXMLFormat_v1_0 errorDescription:&error];

到：

// create NSData from dictionary
NSData *plistData = [NSPropertyListSerialization dataFromPropertyList:plistDict format:NSPropertyListXMLFormat_v1_0 errorDescription:&error];  
[myData appdendData:plistData];

最后将myData写入文件。

希望有所帮助！

IOS在plist中创建字典列表

2 个答案: