實現多行RadioGroup

Android中的RadioGroup只能橫向或者縱向單行擺放。實現多行RadioGroup實際上是使用了多個RadioGroup，而同時只能有一個RadioGroup起作用。

原文地址：http://www.tutorialforandroid.com/2009/11/select-radiobutton-from-multiple.html

Select a RadioButton from Multiple RadioGroup in Android

I bounds into Radiogroup layout question while trying out something in android. The problem is that you want a RadioButton but you don't want it to just be either horizontally placed or vertically placed which is the default way RadioGroup does. Say you want 2 rows of 4 RadioButton, by default you cant do this with one RadioGroup, so the solution is to make 2 RadioGroup but the problem now is that you need to handle both RadioGroup in turn that when one RadioButton is selected on one RadioGroup the other RadioGroup/s will deselect itself. To do this here is the code on how i did it (it has 3 RadioGroups), it might not be the best solution :)

private Boolean changeGroup = false;
public void onCheckedChanged(RadioGroup group, int checkedId){
  if (group != null && checkedId > -1 && changeGroup == false){
    if(group == frequencyGroup1){
      changeGroup = true;
      frequencyGroup2.clearCheck();
      frequencyGroup3.clearCheck();
      changeGroup = false;
    }else if(group == frequencyGroup2){
      changeGroup = true;
      frequencyGroup1.clearCheck();
      frequencyGroup3.clearCheck();
      changeGroup = false;
    }else if(group == frequencyGroup3){
      changeGroup = true;
      frequencyGroup1.clearCheck();
      frequencyGroup2.clearCheck();
      changeGroup = false;
    }
  }
}

Explanation
Create a flag stating that we mark as whether the function could be execute or not (see below)
private Boolean changeGroup = false;

On the default change function of RadioGroup, create a conditional statement that would execute the change function of all RadioGroup only when our flag state that it can execute the next code block. By default this function will execute when you select a RadioButton on a Group and/or when you call clearCheck() of each RadioGroup, and you may not want to do that especially when we call clearCheck.
if (group != null && checkedId > -1 && changeGroup == false){

The following code will just set the flag to true when users select a RadioButton on any group, thus when other RadioGroup call clearCheck() the code block in the function will not be called.
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