问题，同时存储在数据库到表视图加载数据

Question

HII每一个

我使用下面的代码保存在数据库到表视图加载数据，但其crasing当我重新启动应用程序

InsertRecord是类insertUpdateDelete的

+ (void) getInitialDataToDisplay:(NSString *)dbPath 
{ 


    iICS_testAppDelegate *appDelegate = (iICS_testAppDelegate *)[[UIApplication sharedApplication] delegate]; 

    if (sqlite3_open([dbPath UTF8String], &database) == SQLITE_OK) { 

     const char *sql = "select * from tbl_Users"; 
     sqlite3_stmt *selectstmt; 
     if(sqlite3_prepare_v2(database, sql, -1, &selectstmt, NULL) == SQLITE_OK) { 

      while(sqlite3_step(selectstmt) == SQLITE_ROW) { 

       NSInteger primaryKey = sqlite3_column_int(selectstmt, 0); 
       insertUpdateDelete *InsertRecord = [[insertUpdateDelete alloc] initWithPrimaryKey:primaryKey]; 

       InsertRecord.strFirstName = [NSString stringWithUTF8String:(char *)sqlite3_column_text(selectstmt, 1)]; 
       InsertRecord.strMiddleName = [NSString stringWithUTF8String:(char *)sqlite3_column_text(selectstmt, 2)]; 
       [appDelegate.arrObjects addObject:InsertRecord]; 
       [InsertRecord release]; 
      } 
     } 
    } 
    else 
    { 
     sqlite3_close(database); //Even though the open call failed, close the database connection to release all the memory. 
    } 
    NSLog(@"arrObjects----%@",appDelegate.arrObjects); 
} 

应用在下面的行

InsertRecord.strFirstName = [NSString stringWithUTF8String:(char *)sqlite3_column_text(selectstmt, 1)]; 

崩溃实例3210

崩溃日志is--终止应用程序由于未捕获的异常 'NSInvalidArgumentException'，原因是： '* + [NSString的stringWithUTF8String：]：NULL CSTRING'

Answer 1

您需要检查数据库中的空数据;

// load char in temporary variable 
char *tempChar = sqlite3_column_text(selectstmt, 1); 

if(tempChar == null) // test for null 
    InsertRecord.strFirstName = nil; 
else 
    InsertRecord.strFirstName = [NSString stringWithUTF8String:tempChar]; 

// go to the next field in the database 
tempChar = sqlite3_column_text(selectstmt, 2); 

// do the same type of test 

Answer 2

测试如果sqlite3_column_text(selectstmt, 1)返回一个有效的字符串。

Answer 3

(char *)sqlite3_column_text(selectstmt, 1) should be given nil (null) value. 

所以，当你从数据库中获取的数据添加校验。

一样，

if ((char *)sqlite3_column_text(selectstmt, 1) != nil) 
{ 
    InsertRecord.strFirstName = [NSString stringWithUTF8String:(char *)sqlite3_column_text(selectstmt, 1)]; 

} 
else 
{ 
    InsertRecord.strFirstName = @""; 
}