刪除NSDictionary中的重複代碼用於提交給服務器的參數

Question

下面的代碼顯示了我準備將參數提交給服務器的方式。我有一個if-else子句來檢查並確定要提交的參數，即如果問題ID存在，只提交問題ID，否則提交問題文本和主題ID。

但是，我覺得這是有點重複的，而不是編碼的最佳形式（在我的POV中）。我如何重構代碼，使其更高效（刪除重複）

if(self.question._id || [self.question._id isEqual:[NSNull null]]) 
{ 
    //Set up params for submission 
    NSDictionary *params= [[NSDictionary alloc] initWithObjectsAndKeys: 
          self.answer.text, @"text", 
          //if question id exists, submit question id only 
          self.question._id, @"question_id", 
          shareFb, @"fbShare", 
          shareTwitter, @"twitterShare", 
          self.question.source,@"questionSource", 
          self.answer.videoId,@"youtube_id", 
          nil 
          ]; 
} 
else 
{ 
    //Set up params for submission 
    NSDictionary *params= [[NSDictionary alloc] initWithObjectsAndKeys: 
          self.answer.text, @"text", 
          //else submit question text and topic id 
          self.question.text, @"question_text", 
          self.question.topic._id, @"topic_id", 
          shareFb, @"fbShare", 
          shareTwitter, @"twitterShare", 
          self.question.source,@"questionSource", 
          self.answer.videoId,@"youtube_id", 
          nil 
          ]; 

Answer 1

使用一個可變的字典，那麼您可以在額外的領域響應添加

NSMutableDictionary *params= [[NSMutableDictionary alloc] initWithObjectsAndKeys: 
     self.answer.text, @"text", 
     //if question id exists, submit question id only 
     self.question._id, @"question_id", 
     shareFb, @"fbShare", 
     shareTwitter, @"twitterShare", 
     self.question.source,@"questionSource", 
     self.answer.videoId,@"youtube_id", 
     nil 
     ]; 

if(!(self.question._id == nil || [self.question._id isEqual:[NSNull null]])) 
{ 
    [params setObject:self.question.text forKey:@"question_text"]; 
    [params setObject:self.question.topic._id forKey:@"topic_id"]; 
} 

編輯發表評論1

如果任何PARAMS中的第一條語句被設置上面可能是零，則需要更加小心

NSMutableDictionary *params= [[NSMutableDictionary alloc] init]; 
if (self.answer.text) { 
    [params setObject:self.answer.text forKey:@"text"]; 
} 
• 
• // all the params between self.answer.text and self.answer.videoId 
• 
if (self.answer.videoId) { 
    [params setObject:self.answer.videoId forKey:@"youtube_id"]; 
} 
if(!(self.question._id == nil || [self.question._id isEqual:[NSNull null]])) 
    { 
     if(self.question.text) { 
      [params setObject:self.question.text forKey:@"question_text"]; 
     } 
     if (self.question.topic._id) { 
      [params setObject:self.question.topic._id forKey:@"topic_id"]; 
     } 
    } 
} 

您不能將無對象設置爲鍵（即[params setObject:nil forKey:@"key]會崩潰）