IOS Delete objects in Documents with caution

In iOS development, deleting files under the Documents directory in Sandbox may be a common operation. Below is some of my encapsulated code:

-(Void) viewDidLoad {[super viewDidLoad]; NSString * fileName = @ "test"; NSString * filePath = [self getDirectoryOfDocumentFileWithName: fileName]; NSLog (@ "% @", filePath); if (filePath) {[self removeFileAtPath: filePath] ;}}- (NSString *) getDirectoryOfDocumentFolder {NSArray * paths = require (NSDocumentDirectory, NSUserDomainMask, YES ); // obtain the path NSString * docume for all Document folders NtsPath = paths [0]; // search for the path of the Document folder where the target file is located, usually the first if (! DocumentsPath) {NSLog (@ "invalid ents directory does not exist");} return documentsPath;}-(NSString *) getDirectoryOfDocumentFileWithName :( NSString *) fileName {NSString * documentsPath = [self getDirectoryOfDocumentFolder]; if (documentsPath) {return [documentsPath stringByAppendingPathComponent: fileName]; // obtain the complete path of the target file for access} return nil;}-(BOOL) isFileExitsAtPath :( NSString *) filePath {NSFileManager * fileManager = [NSFileManager defaultManager]; if ([fileManager fileExistsAtPath: filePath isDirectory: NULL]) {return YES;} return NO;}-(void) removeFileAtPath :( NSString *) filePath {NSError * error = nil; if ([self isFileExitsAtPath: filePath]) {[[NSFileManager defaultManager] removeItemAtPath: filePath error: & error]; if (error) {NSLog (@ "failed to remove file, error message: % @", error);} else {NSLog (@ "successfully removed file ");}} else {NSLog (@ "file does not exist ");}}

In the viewDidLoad method, fileName provides the file name in the Documents folder, obtains its complete path, and removes it using the remove Method.

Create a new test folder under Documents, and then output it on the console:

13:02:54. 527 RemoveDocument [849: 70b]/Users/apple/Library/Application Support/iPhone Simulator/7.0.3/Applications/AA0DC0B6-EED1-4F2F-B470-326B7A5CB656/Documents/test2014-03-15 13:02:54. 529 RemoveDocument [849: 70b] the file is successfully removed.

Very successful.

However, if fileName is blank, for example:

//    NSString *fileName = @"test";    NSString *fileName = @"";

Run the command. The console output is as follows:

13:01:14. 381 RemoveDocument [816: 70b]/Users/apple/Library/Application Support/iPhone Simulator/7.0.3/Applications/AA0DC0B6-EED1-4F2F-B470-326B7A5CB656/Documents2014-03-15 13:01:14. 383 RemoveDocument [816: 70b] the file is successfully removed.

Open the simulator directory:

You can see that the entire Documents folder has been deleted. The reason is that if it is stringByAppendingPathComponent: The parameter passed by the method is @ "", the current path is returned, that is, the path of the Documents folder.

This kind of behavior is very dangerous, so be very careful.

The insurance method is to make a judgment first:

-(Void) viewDidLoad {[super viewDidLoad]; // NSString * fileName = @ "test"; NSString * fileName = @ ""; NSString * filePath = [self getDirectoryOfDocumentFileWithName: fileName]; NSLog (@ "% @", filePath); if (filePath) {[self removeFileAtPath: filePath] ;}}- (NSString *) getDirectoryOfDocumentFileWithName :( NSString *) fileName {if ([fileName isw.tostring: @ ""]) {return nil;} NSString * documentsPath = [self getDirectoryOfDocumentFolder]; if (documentsPath) {return [documentsPath stringbyappendpathcomponent: fileName]; // obtain the complete path of the target file for access} return nil ;}

Of course, you can also put the judgment in addition to the getDirectoryOfDocumentFileWithName: method, which depends on your needs.