2023年6月27日发(作者：)

Android⾃定义RadioGroupX实现多⾏多列布局前⾔今天在做新需求的时候，活动有多个类型可以选择，UI给的设计图为多⾏多列排版，且单项选择，细细想来，⾕歌并没有为我们提供类似的控件，初步设想使⽤RecyclerView实现多⾏多列布局，然后再⽤代码控制逻辑部分，总感觉不太稳妥，⼜想到让UI⼩姐姐重新设计⼀番？感觉也不太稳妥，这样UI⼩姐姐就会认为我菜，为了不让別⼈觉得我菜，⼲脆⾃定义RadioGroupX实现多⾏多列布局。思考在⼯作中，⾯对⼀个功能，⾸先想到的是应该怎样实现完成它，然后再考虑究竟怎样实现才更优雅。正如前⾯提到，实现这种需求是可以⽤多种姿势完成，⽐如使⽤RecyclerView，或者使⽤ConstraintLayout装有多个TextView的布局，⽤代码控制选项逻辑，在思考⼀番后，总感觉太⽣硬，不太优雅，代码量多也许容易出bug。于是通过阅读⾕歌为我们提供的RadioGroup源码得出⼀些灵感，阅读源码往往能使⾃⼰⼤彻⼤悟。⽐如在RadioGroup中为什么只⽀持单⾏多列或者多⾏单列布局，主要原因是因为RadioGroup extends LineLayout,所以導致了很多局限性。看到这⾥突然联想到GridView⽀持多⾏多列布局，于是乎，模仿RadioGroup源码⾃定义⼀个容器继承GridView。初识OnHierarchyChangeListener接⼝OnHierarchyChangeListener接⼝位于ViewGroup java⽂件中，在⽇常⼯作中，⼏乎不会⽤到，在developer官⽹⽂档中给出了这样的解释：⼯作中，我们对addView()和RemoveView()这两个⽅法⼀定不陌⽣，其实我们在操作这两个⽅法的时候就会触发OnHierarchyChangeListener接⼝中的java void onChildViewAdded(View parent, View child)和java voidonChildViewRemoved(View parent, View child);两个⽅法回调，源码中也给了详细解释。我们可以直接在源码中阅读注释加以理解。参照RadioGroup源码定义内部类PassThroughHierarchyChangeListenerprivate inner class PassThroughHierarchyChangeListener : OnHierarchyChangeListener { private val mOnHierarchyChangeListener: OnHierarchyChangeListener? = null @RequiresApi(N__BEAN_MR1) override fun onChildViewAdded( parent: View, child: View ) { if (parent == this@MultiLineRadioGroup && child is RadioButton) { var id = () // generates an id if it's missing if (id == _ID) { id = teViewId() (id) } heckedChangeListener( mChildOnCheckedChangeListener ) } mOnHierarchyChangeListener?.onChildViewAdded(parent, child) } /** * {@inheritDoc} */ override fun onChildViewRemoved(parent: View, child: View) { if (parent == this@MultiLineRadioGroup && child is RadioButton) { heckedChangeListener(null) } mOnHierarchyChangeListener?.onChildViewRemoved(parent, child) } }在上⾯重写kotlin onChildViewAdded( parent: View, child: View )和kotlinonChildViewRemoved(parent: View, child: View)两个⽅法，我们着重关注onChildViewAdded⽅法，当我们在容器中添加⼦控件时，有多少个⼦孩⼦该⽅法就会触发多少次，我们在此动态设置⼦View的选中事件监听。定义CheckedStateTracker实现kedChangeListener接⼝

private inner class CheckedStateTracker : kedChangeListener { override fun onCheckedChanged( buttonView: CompoundButton, isChecked: Boolean ) { // prevents from infinite recursion if (mProtectFromCheckedChange) { return } mProtectFromCheckedChange = true if (mCheckedId != -1) { setCheckedStateForView(mCheckedId, false) } mProtectFromCheckedChange = false val id = setCheckedId(id) } }在onCheckedChanged⽅法中处理⼦View也就是RadioButton的选中与取消事件，通过以上两个步骤，基本完成了，View选中事件监听和事件处理逻辑RadioGroupX完整代码class RadioGroupX: GridLayout { private var mProtectFromCheckedChange = false var mCheckedId = -1 private val mChildOnCheckedChangeListener: kedChangeListener = CheckedStateTracker() private val mPassThroughListener: PassThroughHierarchyChangeListener = PassThroughHierarchyChangeListener() private var mOnCheckedChangeListener: OnCheckedChangeListener? = null constructor(context: Context?): this(context, null) constructor(context: Context?, attrs: AttributeSet?): this(context, attrs, 0) constructor(context: Context?, attrs: AttributeSet?, defStyleAttr: Int): super(context, attrs, defStyleAttr) init { ierarchyChangeListener(mPassThroughListener) } override fun addView(child: View?, index: Int, params: Params?) { if (child is RadioButton) { if (ked) { mProtectFromCheckedChange = true if (mCheckedId != -1) { setCheckedStateForView(mCheckedId, false) } mProtectFromCheckedChange = false setCheckedId() } } w(child, index, params) } fun check(@IdRes id: Int) { // don't even bother if (id != -1 && id == mCheckedId) { return } if (mCheckedId != -1) { setCheckedStateForView(mCheckedId, false) } if (id != -1) { setCheckedStateForView(id, true) } setCheckedId(id) } private fun setCheckedId(@IdRes id: Int) { val changed = id != mCheckedId mCheckedId = id mOnCheckedChangeListener?.onCheckedChanged(this, mCheckedId)// if (changed) {// val afm: AutofillManager = temService(// AutofillManager::// )// afm?.notifyValueChanged(this)// } } private fun setCheckedStateForView(viewId: Int, checked: Boolean) { val checkedView = findViewById(viewId) if (checkedView != null && checkedView is RadioButton) { ked = checked } } private inner class CheckedStateTracker : kedChangeListener { override fun onCheckedChanged( buttonView: CompoundButton, isChecked: Boolean ) { // prevents from infinite recursion if (mProtectFromCheckedChange) { return } mProtectFromCheckedChange = true if (mCheckedId != -1) { setCheckedStateForView(mCheckedId, false) } mProtectFromCheckedChange = false val id = setCheckedId(id) } } fun setOnCheckedChangeListener(listener: OnCheckedChangeListener) { mOnCheckedChangeListener = listener } interface OnCheckedChangeListener { fun onCheckedChanged(group: RadioGroupX?, @IdRes checkedId: Int) } private inner class PassThroughHierarchyChangeListener : OnHierarchyChangeListener { private val mOnHierarchyChangeListener: OnHierarchyChangeListener? = null @RequiresApi(N__BEAN_MR1) override fun onChildViewAdded( parent: View, child: View ) { if (parent == this@RadioGroupX && child is RadioButton) { var id = () // generates an id if it's missing if (id == _ID) { id = teViewId() (id) } heckedChangeListener( mChildOnCheckedChangeListener ) } mOnHierarchyChangeListener?.onChildViewAdded(parent, child) } /** * {@inheritDoc} */ override fun onChildViewRemoved(parent: View, child: View) { if (parent == this@RadioGroupX && child is RadioButton) { heckedChangeListener(null) } mOnHierarchyChangeListener?.onChildViewRemoved(parent, child) } }}xml中使⽤

activity事件处理部分和使⽤RadioGroup原理⼀样，照搬即可。总结通过上⾯短短⼏步，我们基本完成了需求中的排版问题，如果不阅读借鉴源码中的思路，我想我是很难写出来，⾄少不会在很短时间就完成需求设计，所以⼯作我应该做到更多的阅读源码，了解源码中的设计思路和思想，这样⾃⼰才能有所提⾼。以上就是本⽂的全部内容，希望对⼤家的学习有所帮助，也希望⼤家多多⽀持。