Question

我有一系列5个iVars。（highscore01，highscore02，highScore03，highScore04，highScore05）我想用整数值更新特定的iVar。 iVars定义为整数。 iVars属于一个名为HighScores的类。

要更新的特定iVar是存储在其中的当前值最低的iVar。我想用新值替换最低值。

我有一个方法可以识别具有最低值的ivar，并返回一个字符串“theString”，其中包含要更新的iVar的名称。

我的问题：如何使用“theString”更新正确的iVar。

以下是代码示例。

// If any of the highScore iVars contain 0, then they are still empty.
// Find the first empty iVar and store score there.

 if (scoreVarsFullFlag == NO) // Flag to indicate if any iVars are still zero
 {
 if (theHighScores.highScore01 == 0)
  theHighScores.highScore01 = mainScores.scoreTotal;
 else if (theHighScores.highScore02 == 0)  
  theHighScores.highScore02 = mainScores.scoreTotal;
 else if (theHighScores.highScore03 == 0)
  theHighScores.highScore03 = mainScores.scoreTotal;
 else if (theHighScores.highScore04 == 0)
  theHighScores.highScore04 = mainScores.scoreTotal;
 else if (theHighScores.highScore05 == 0)
  {
   theHighScores.highScore05 = mainScores.scoreTotal;
   scoreVarsFullFlag = YES; // Last scores iVar turns nonzero - set Flag to YES, to indicate no non-zero iVars
  }
 }
 else
 {

  NSLog(@"The Lowest is at %@", [theHighScores findLowestHighScore]);
  NSString * theString;
  theString = [NSString stringWithString:[theHighScores findLowestHighScore]];
  NSLog(@"The String is: %@", theString);
            theHighScores.theString = mainScores.scoreTotal; // This fails
}

最后一行是我尝试将“theString”中标识的iVar设置为新的分数。 “theString”确实包含要更新的iVar的名称，即“HighScore03”等。

如果我手动设置，那将是; theHighScores.highScore03 = mainScores.scoreTotal;

非常感谢任何见解。

Answer 1

如果我是你，我只是使用一个可变数组来允许排序并轻松挑选最低项目。

///store this in your app delegate
NSMutableArray *highscores = [[NSMutableArray alloc] init];



//then when you want to add a high score
[highscores addObject:[NSNumber numberWithDouble:mainScores.scoreTotal]];

NSSortDescriptor *myDescriptor;
myDescriptor = [[NSSortDescriptor alloc] initWithKey:@"doubleValue" ascending:NO];
[highscores sortUsingDescriptors:[NSArray arrayWithObject:myDescriptor]];

///remove the last object if it's over 5
if ([highscores count]>5) {
    [highscores removeLastObject];
}

Answer 2

我认为mjdth的解决方案可能是最好的，但你也可以使用-setValue：forKey :,尽管你必须切换到使用NSNumbers而不是int。

[theHighScores setValue: [NSNumber numberWithInt: mainScores.scoreTotal] forKey: [theHighScores findLowestHighScore]];

Answer 3

听起来你正试图做一些基本的type introspection。具体来说，使用NSSelectorFromString。

int newValue = 1;
SEL methodName = NSSelectorFromString(@"setHighScore03:");
[theHighScores performSelector:methodName withObject:newValue];

String标识要更新的iVar

3 个答案: