objective-c - 调用 Objective-C 方法时访问错误

Question

我是 Objective-c 的新手。我已经上过 python 和 c++ 类(class)，但我对 Objective-C 非常感兴趣，所以最近几天我一直在自学。该程序应该比较两个位置的文件并添加丢失的文件。一个简单的同步，尽管目前尚未实现所有功能。

该错误是由 recursivelyGetContentsOfDirectory 函数引起的。它返回错误 EXEC_BAD_ACCESS。由于它实际上不在函数中，我假设它与它的定义方式有关。

   #import <AppKit/AppKit.h>

@interface Sync : NSControl{
    NSURL *baseToDirectory;
    NSURL *baseFromDirectory;

    NSArray *filesInBaseFromDirectory;

    IBOutlet NSTextField *baseToDirectoryLabel;
    IBOutlet NSTextField *baseFromDirectoryLabel;
}
- (IBAction)chooseBaseSyncFromDirectory:(id)sender;
- (IBAction)chooseBaseSyncToDirectory:(id)sender;
- (IBAction)performSync:(id)sender;

void recursivelyGetContentsOfDirectory (NSURL *path);

@end

实现文件

#import "Sync.h"

@implementation Sync


- (IBAction)chooseBaseSyncFromDirectory:(id)sender {

    NSOpenPanel* openDlg = [NSOpenPanel openPanel];
    [openDlg setCanChooseDirectories:YES];
    [openDlg setCanChooseFiles:NO];
    //Open the directory
    if ([openDlg runModal] == NSFileHandlingPanelOKButton) {
        NSArray *files = [openDlg URLs];
        NSString *fileAsString = [[files objectAtIndex:0] path];
        [baseFromDirectoryLabel setStringValue:fileAsString];
        baseFromDirectory = [files objectAtIndex:0];
        recursivelyGetContentsOfDirectory(baseFromDirectory);
    }
}

- (IBAction)chooseBaseSyncToDirectory:(id)sender {
    NSOpenPanel* openDlg = [NSOpenPanel openPanel];
    [openDlg setCanChooseDirectories:YES];
    [openDlg setCanChooseFiles:NO];

    if ([openDlg runModal] == NSFileHandlingPanelOKButton) {
        NSArray *files = [openDlg URLs];
        NSString *fileAsString = [[files objectAtIndex:0] path];
        [baseToDirectoryLabel setStringValue:fileAsString];
        baseToDirectory = [files objectAtIndex:0];
    }
}

void recursivelyGetContentsOfDirectory (NSURL *path){
    NSFileManager *tempManager;
    NSArray *contentsOfDirectory = [tempManager contentsOfDirectoryAtPath:[path path] error:nil];
    for (int i = 0; i < (int)[contentsOfDirectory count] ; i = i+1) {
        if ([[contentsOfDirectory objectAtIndex:i] isDirectory]) {
            NSString *next = [NSString stringWithString:[path path]];
            [next stringByAppendingString:[contentsOfDirectory objectAtIndex:i]];
            NSURL *nextPath = [NSURL URLWithString:next];
            recursivelyGetContentsOfDirectory(nextPath);
        } else {
            NSLog(@"Non-Directory Found");
        }
    }
}

- (IBAction)performSync:(id)sender {

}

@end

Answer 1

NSFileManager *tempManager;

您没有创建 tempManager

应该是这样的

NSFileManager *tempManager=[[NSFileManager alloc] init];

如果您不使用 ARC，您有责任(自动)释放 tempManager。

或使用NSFileManager *tempManager = [NSFileManager defaultManager]