Android RdioGroup clearCheck 与 setOnCheckedChangeListener 冲突

Question

我正在尝试在单击单选按钮时执行操作：

  dataBinding.radioGroup.setOnCheckedChangeListener { radioGroup: RadioGroup, i: Int ->
       
if( radioGroup.checkedRadioButtonId != -1){
        checkAnswer(i)
       }
    }

在另一个函数中有一个 clearCheck 清除单选按钮。问题是每次调用 clearCheck 时，监听器 setOnCheckedChangeListener 也会调用。

有什么方法可以让运行侦听器在选择单选按钮而不是清除单选按钮时获得运行？

Answer 1

/**
 * <p>Interface definition for a callback to be invoked when the checked
 * radio button changed in this group.</p>
 */
public interface OnCheckedChangeListener {
    /**
     * <p>Called when the checked radio button has changed. When the
     * selection is cleared, checkedId is -1.</p>
     *
     * @param group the group in which the checked radio button has changed
     * @param checkedId the unique identifier of the newly checked radio button
     */
    public void onCheckedChanged(RadioGroup group, @IdRes int checkedId);
}

当你在 RadioGroup 上调用 clearCheck() 方法时，如果有一个 RadioButton 被选中，它会将这个视图的状态设置为未选中，然后通知应用程序一个单选按钮的状态被改变调用您传递给 setOnCheckedChangeListener() 方法的实例的 onCheckedChanged() 方法。

这解释了为什么在您的应用中，如果用户 select 回答错误，它会调用 onCheckedChange() 两次。前者是状态由unchecked变为checked，后者是状态由checked变为unchecked clearCheck()。这是预期的行为。

解决方法：调用clearCheck()方法前清除OnCheckedChangeListener，调用clearCheck()方法后再设置

// Declare this variable
private val onCheckedChangeListener = object : RadioGroup.OnCheckedChangeListener {
    override fun onCheckedChanged(group: RadioGroup?, checkedId: Int) {
        if (checkedId != -1) {
            checkAnswer(checkedId)
        }
    }
}

// Calling this line once, inside onCreate() of Activity 
// or onCreateView() of Fragment for example
dataBinding.radioGroup.setOnCheckedChangeListener(onCheckedChangeListener)

private fun checkAnswer(checkedId: Int) {
    // Your logic to check answer here
    // ...

    // If the answer is wrong, just clear check
    dataBinding.radioGroup.setOnCheckedChangeListener(null)
    dataBinding.radioGroup.clearCheck()
    dataBinding.radioGroup.setOnCheckedChangeListener(onCheckedChangeListener)
}

Android RdioGroup clearCheck 与 setOnCheckedChangeListener 冲突

Android RdioGroup clearCheck conflict with setOnCheckedChangeListener

android

radio-group

kotlin