Question

以下是在sqlite db中获取数据的代码：

-(id) init {
    if ((self = [super init])) {
        NSString *sqLiteDb = [[NSBundle mainBundle]pathForResource:@"CourseFindr" ofType:@"sqlite"];
        if (sqlite3_open([sqLiteDb UTF8String], &_db) != SQLITE_OK){
            NSLog(@"Failed to open database!");
        }
    }
    return self;
}

-(void)dealloc {
    sqlite3_close(_db);
}

- (NSArray *)job {
    NSMutableArray *retrieve = [[NSMutableArray alloc] init];
    NSString *query = @"SELECT jID, jName, jDesc, jEarnings, jTags FROM jobs";
    sqlite3_stmt *statement;
    if (sqlite3_prepare_v2(_db, [query UTF8String], -1, &statement, nil) == SQLITE_OK) {
        while (sqlite3_step(statement) == SQLITE_ROW) {
            int _jID = sqlite3_column_int(statement, 0);
            char *jNameChars = (char *) sqlite3_column_text(statement,1);
            char *jDescChars = (char *) sqlite3_column_text(statement, 2);
            char *jEarningsChars = (char *) sqlite3_column_text (statement, 3);
            char *jTagsChars = (char *) sqlite3_column_text(statement, 4);
            NSString *_jName =[[NSString alloc]initWithUTF8String:jNameChars];
            NSString *_jDesc = [[NSString alloc]initWithUTF8String:jDescChars];
            NSString *_jEarnings = [[NSString alloc]initWithUTF8String:jEarningsChars];
            NSString *_jTags = [[NSString alloc]initWithUTF8String:jTagsChars];
            Jobs *jobs = [[Jobs alloc]
                          initWithJID:_jID
                                jName:_jName
                                jDesc:_jDesc
                            jEarnings:_jEarnings
                                jTags:_jTags];
            [retrieve addObject:jobs];
        }
        sqlite3_finalize(statement);
    }
    return retrieve;
}

但它一直在崩溃：

2014-01-09 21:12:39.565 CourseFindr[4595:a0b] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '*** -[NSPlaceholderString initWithUTF8String:]: NULL cString'
*** First throw call stack:
(
    0   CoreFoundation                      0x018255e4 __exceptionPreprocess + 180
    1   libobjc.A.dylib                     0x015a88b6 objc_exception_throw + 44
    2   CoreFoundation                      0x018253bb +[NSException raise:format:] + 139
    3   Foundation                          0x0120fb49 -[NSString initWithUTF8String:] + 89
    4   CourseFindr                         0x000036b5 -[CourseFindrDB jobs] + 645
    5  libdyld.dylib                       0x01e61725 start + 0
    6  ???                                 0x00000001 0x0 + 1
)
libc++abi.dylib: terminating with uncaught exception of type NSException
(lldb)

我不确定这是因为我的libsqlite3.dylib还是与我的数据库不兼容？我的数据库名为'CourseFindr.sqlite'表是

JOBS Table
-jID PK
-jName
-jDesc
-jEarnings
-jTags

它还会在崩溃时保持重定向到main.m.

我以前做过这个，但没有错误。这次我在没有教程的情况下尝试它，但似乎我错过了一些东西。：/

Answer 1

崩溃日志：

2014-01-09 21：12：39.565 CourseFindr [4595：a0b] *由于未捕获的异常'NSInvalidArgumentException'终止应用程序，原因：'* - [NSPlaceholderString initWithUTF8String：]：NULL cString “

告诉您正在向initWithUTF8String传递NULL指针。这是崩溃的原因，并且是根据Apple docs预期的行为：

initWithUTF8String：

...

重要说明：如果bytes为NULL，则引发异常。

因此，检查您传递给initWithUTF8String方法的内容并添加防范以防止传递NULL。类似的东西：

char *jNameChars = (char *) sqlite3_column_text(statement,1);
...
NSString *_jName = jNameChars?[[NSString alloc]initWithUTF8String:jNameChars]:@"";

Answer 2

您可以在异常的第一行找到解决方案。

Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '*** -[NSPlaceholderString initWithUTF8String:]: NULL cString'

这意味着您将空字符串传递给initWithUTF8String方法。

Answer 3

NSLog您传递的所有字符串。因为您将空值传递给initWithUTF8String

SQLite数据库崩溃

3 个答案: