Question

我正在阅读编码教程，并且我的代码中出现错误。这是教程https://www.appcoda.com/sqlite-database-ios-app-tutorial/

到目前为止我写的代码如下。我有两个错误。

错误1：

预期＆＃39;;＆＃39;方法原型之后

这显示在第17行：-(void)copyDatabaseIntoDocumentsDirectory{

错误2：

＆copy; copyDatabaseIntoDocumentsDirectory＆＃39;的方法定义找不到

这显示在第35行：@implementation DBManager

我无法弄清楚如何修复它。有人可以帮忙吗？感谢。

//
//  DBManager.m
//  SQLite3DBSample
//
//  Created by Jean Wong on 4/21/18.
//  Copyright © 2018 Jean Wong. All rights reserved.
//

#import "DBManager.h"
#import <sqlite3.h>

@interface DBManager()

@property (nonatomic, strong) NSString *documentsDirectory;
@property (nonatomic, strong) NSString *databaseFilename;

-(void)copyDatabaseIntoDocumentsDirectory{
    // Check if the database file exists in the documents directory.
    NSString *destinationPath = [self.documentsDirectory stringByAppendingPathComponent:self.databaseFilename];
    if (![[NSFileManager defaultManager] fileExistsAtPath:destinationPath]) {
        // The database file does not exist in the documents directory, so copy it from the main bundle now.
        NSString *sourcePath = [[[NSBundle mainBundle] resourcePath] stringByAppendingPathComponent:self.databaseFilename];
        NSError *error;
        [[NSFileManager defaultManager] copyItemAtPath:sourcePath toPath:destinationPath error:&error];

        // Check if any error occurred during copying and display it.
        if (error != nil) {
            NSLog(@"%@", [error localizedDescription]);
        }
    }
}

@end

@implementation DBManager
-(instancetype)initWithDatabaseFilename:(NSString *)dbFilename{
    self = [super init];
    if (self) {
        // Set the documents directory path to the documentsDirectory property.
        NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
        self.documentsDirectory = [paths objectAtIndex:0];

        // Keep the database filename.
        self.databaseFilename = dbFilename;

        // Copy the database file into the documents directory if necessary.
        [self copyDatabaseIntoDocumentsDirectory];
    }
    return self;
}
@end

Answer 1

在@interface中你应该声明原型或属性不是实现，你应该在@implementation部分实现方法。

@interface DBManager()

@property (nonatomic, strong) NSString *documentsDirectory;
@property (nonatomic, strong) NSString *databaseFilename;

@end


@implementation DBManager
-(instancetype)initWithDatabaseFilename:(NSString *)dbFilename{
    self = [super init];
    if (self) {
        // Set the documents directory path to the documentsDirectory property.
        NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
        self.documentsDirectory = [paths objectAtIndex:0];

        // Keep the database filename.
        self.databaseFilename = dbFilename;

        // Copy the database file into the documents directory if necessary.
        [self copyDatabaseIntoDocumentsDirectory];
    }
    return self;
}
-(void)copyDatabaseIntoDocumentsDirectory{
    // Check if the database file exists in the documents directory.
    NSString *destinationPath = [self.documentsDirectory stringByAppendingPathComponent:self.databaseFilename];
    if (![[NSFileManager defaultManager] fileExistsAtPath:destinationPath]) {
        // The database file does not exist in the documents directory, so copy it from the main bundle now.
        NSString *sourcePath = [[[NSBundle mainBundle] resourcePath] stringByAppendingPathComponent:self.databaseFilename];
        NSError *error;
        [[NSFileManager defaultManager] copyItemAtPath:sourcePath toPath:destinationPath error:&error];

    // Check if any error occurred during copying and display it.
        if (error != nil) {
            NSLog(@"%@", [error localizedDescription]);
        }
    }
}
@end

期待＆＃39 ;;＆＃39;方法原型＆amp;未找到方法定义

1 个答案: