修復內存泄漏的問題iphone

Question

我在我的應用程序中有3個內存泄漏，我找不到如何修復它。我對xcode和目標c很陌生。這裏是我有的代碼：

if(sqlite3_prepare_v2([[DatabaseController sharedDatabaseController] getDb], sqlQueryConverted, -1, &dbStatement, NULL)==SQLITE_OK){ 

     //Run the query 
     while (sqlite3_step(dbStatement) == SQLITE_ROW) 
     {  


      const char *name = (const char *)sqlite3_column_text(dbStatement, 0); 
      int courseId = sqlite3_column_int(dbStatement, 1); 
      const char *location = (const char *)sqlite3_column_text(dbStatement, 2); 
      const char *date = (const char *)sqlite3_column_text(dbStatement, 3); 

      //Convert the returnedElement char to string 
      nameConverted = [[NSString alloc] initWithUTF8String:name]; 
      locationConverted = [[NSString alloc] initWithUTF8String:location]; 
      dateConverted = [[NSString alloc] initWithUTF8String:date]; 

      Course *course = [[[Course alloc]initWithName:nameConverted _id:courseId location:locationConverted courseDate:dateConverted] autorelease]; 

      //Add the course to the to a temporary list to remove duplicated items    
      [tempResults addObject:course]; 

     } 
     [nameConverted release]; 
     [locationConverted release]; 
     [dateConverted release]; 
    } 

我試圖autorelease它也是。此代碼用於過濾搜索並重新加載搜索顯示錶。如果我把release行寫入while聲明中，如果我輸入2個字母，應用程序就會崩潰。我怎麼能解決這個問題？

謝謝。

編輯：我一直在這個問題來回奔跑，沒有運氣。我得出的結論是，儀器出現問題，因爲它仍然顯示內存泄漏。下面的代碼因爲它是今天，當我認爲應該解決這個問題：

NSString *nameConverted = [[NSString alloc] initWithUTF8String:name]; 
      NSString *locationConverted = [[NSString alloc] initWithUTF8String:location]; 
      NSString *dateConverted = [[NSString alloc] initWithUTF8String:date]; 

      Course *course = [[[Course alloc]initWithName:nameConverted _id:courseId location:locationConverted courseDate:dateConverted] autorelease]; 

      //Add the course to the to a temporary list to remove duplicated items    
      [tempResults addObject:course]; 
      course = nil; 
      [course release]; 
      [nameConverted release]; 
      nameConverted = nil; 
      [locationConverted release]; 
      locationConverted = nil; 
      [dateConverted release]; 
      dateConverted = nil; 
      NSLog(@"course retain count %i",[course retainCount]); 
      NSLog(@"name coverted retain count %i",[nameConverted retainCount]); 
      NSLog(@"location coverted retain count %i",[locationConverted retainCount]); 
      NSLog(@"date coverted retain count %i",[dateConverted retainCount]); 

的日誌告訴我，retainCount = 0;，所以我不明白爲什麼有內存泄漏。你們能給我一些建議嗎？

再次感謝。

Answer 1

你在每個循環都有泄漏。你只發布3個最後的NSString。每次你重新分配一個新的NSString給你的3個變量（nameConverted，locationConverted，dateConverted）時，你會忽略它們指向的NSString對象的引用。這意味着內存泄漏。當你離開While循環時，你只能釋放它們中的最後3個。

Answer 2

您是否嘗試過使用：

nameConverted = [[NSString initWithUTF8String:name] autorelease]; 
locationConverted = [[NSString initWithUTF8String:location] autorelease]; 
dateConverted = [[NSString initWithUTF8String:date] autorelease]; 

和拆卸循環之外的版本？ 也不要autoremove課程對象，將其添加到tempResults後釋放它。

Answer 3

您正在每個循環創建一個內存塊，然後只釋放一次。因此，如果while循環運行10次以上，每個字符串的保留計數爲10，但只釋放一次。

要解決，把你的3個版本while循環裏面是這樣的：

if(sqlite3_prepare_v2([[DatabaseController sharedDatabaseController] getDb], sqlQueryConverted, -1, &dbStatement, NULL)==SQLITE_OK){ 

     //Run the query 
     while (sqlite3_step(dbStatement) == SQLITE_ROW) 
     {  


      const char *name = (const char *)sqlite3_column_text(dbStatement, 0); 
      int courseId = sqlite3_column_int(dbStatement, 1); 
      const char *location = (const char *)sqlite3_column_text(dbStatement, 2); 
      const char *date = (const char *)sqlite3_column_text(dbStatement, 3); 

      //Convert the returnedElement char to string 
      nameConverted = [[NSString alloc] initWithUTF8String:name]; 
      locationConverted = [[NSString alloc] initWithUTF8String:location]; 
      dateConverted = [[NSString alloc] initWithUTF8String:date]; 

      Course *course = [[[Course alloc]initWithName:nameConverted _id:courseId location:locationConverted courseDate:dateConverted] autorelease]; 

      //Add the course to the to a temporary list to remove duplicated items    
      [tempResults addObject:course]; 

     [nameConverted release]; 
     [locationConverted release]; 
     [dateConverted release]; 

     } 

    } 

Answer 4

這就是你應該做的。

NSString *nameConverted = [[NSString alloc] initWithUTF8String:name]; 
NSString *locationConverted = [[NSString alloc] initWithUTF8String:location]; 
NSString *dateConverted = [[NSString alloc] initWithUTF8String:date]; 

Course *course = [[Course alloc] initWithName:nameConverted _id:courseId location:locationConverted courseDate:dateConverted]; 
[tempResults addObject:course]; 
[course release]; 

[dateConverted release]; 
[locationConverted release]; 
[nameConverted release];