在iOS应用中创建日志文件

Question

所以在我的应用程序中,我有一堆数据,我想写入日志文件,然后在UITextView单击按钮时显示它.我知道如何切换UITextView,但我不知道如何创建和更新日志文件(在本地文件系统中).谢谢你的帮助.

Answer 1

基本思想是您创建文件,并在每次登录新行时附加到该文件.你可以很容易地这样做:

写入文件:

NSString *content = @"This is my log";

//Get the file path
NSString *documentsDirectory = [NSSearchPathForDirectoriesInDomains (NSDocumentDirectory, NSUserDomainMask, YES) objectAtIndex:0];
NSString *fileName = [documentsDirectory stringByAppendingPathComponent:@"myFileName.txt"];

//create file if it doesn't exist
if(![[NSFileManager defaultManager] fileExistsAtPath:fileName])
    [[NSFileManager defaultManager] createFileAtPath:fileName contents:nil attributes:nil];

//append text to file (you'll probably want to add a newline every write)
NSFileHandle *file = [NSFileHandle fileHandleForUpdatingAtPath:fileName];
[file seekToEndOfFile];
[file writeData:[content dataUsingEncoding:NSUTF8StringEncoding]];
[file closeFile];

读:

//get file path
NSString *documentsDirectory = [NSSearchPathForDirectoriesInDomains (NSDocumentDirectory, NSUserDomainMask, YES) objectAtIndex:0];
NSString *fileName = [documentsDirectory stringByAppendingPathComponent:@"myFileName.txt"];

//read the whole file as a single string
NSString *content = [NSString stringWithContentsOfFile:fileName encoding:NSUTF8StringEncoding error:nil];