如何解决数据绑定,MaterialCardView应该像Radiogroup
我正在尝试实现两个MaterialCardViews,它们应该像Radiogroup一样工作。因此,如果我单击其中一个,则应取消选中另一个。我正在使用viewModel,liveData和自定义双向数据绑定来保存这些值以备后用(每封电子邮件发送)。
我成功编写了.xml并实现了检查逻辑,但是我却难以实现取消检查逻辑。
XML,简短版本可提供更好的可见性
<layout
xmlns:app="http://schemas.android.com/apk/res-auto">
<data>
<variable
name="vm"
type="com.example.app.data.viewmodel.EmailViewModel" />
</data>
<com.google.android.material.card.MaterialCardView
android:id="@+id/cardViewOne"
android:checkable="true"
android:clickable="true"
android:focusable="true"
<!-- Custom Two way databinding -->
app:state_checked="@={vm.cardOptionOneChecked}"
</com.google.android.material.card.MaterialCardView>
<com.google.android.material.card.MaterialCardView
android:id="@+id/cardViewTwo"
android:checkable="true"
android:clickable="true"
android:focusable="true"
<!-- Custom Two way databinding -->
app:state_checked="@={vm.cardOptionTwoChecked}">
</com.google.android.material.card.MaterialCardView>
</layout>
ViewModel
class EmailViewModel @ViewModelInject constructor(
@Assisted private val savedStateHandle: SavedStateHandle
) : ViewModel() {
// Variable for Id = cardViewOne
val cardOptionOneChecked = MutableLiveData<Boolean>()
// Variable for Id = cardViewTwo
val cardOptionTwoChecked = MutableLiveData<Boolean>()
}
CardViewAdapter.kt
@BindingAdapter("state_checked")
fun setStateChecked(view: MaterialCardView,liveData: MutableLiveData<Boolean>) {
if (view.isChecked != liveData.value) {
liveData.value = view.isChecked
}
}
@InverseBindingAdapter(attribute = "state_checked")
fun getStateChecked(view: MaterialCardView,): Boolean {
return view.isChecked
}
// I don't know what logic belongs here to make it work!
// Current approach just checks the current view and does nothing more. How can I save the last
// checked value?
@BindingAdapter("state_checkedAttrChanged")
fun setCheckedAttrListener(
view: MaterialCardView,attrChange: InverseBindingListener,) {
view.apply {
setOnClickListener { view.isChecked = true }
setOnCheckedChangeListener { card,isChecked ->
if (card.isChecked && card != view) {
card.isChecked = false
}
}
attrChange.onChange()
}
}
感谢您的帮助,非常感谢!
P.S:如果有更好,更轻松的方式来实现这一目标,例如从视图中告诉viewModel保存isChecked,请通知我。 MaterialCardView默认情况下实现了“ isChecked”,但没有逻辑。
解决方法
好的,我已经解决了问题:
首先,更改绑定适配器
我实际上看不到使用双向数据绑定来实现上述书面案例的任何方法。这是新的绑定适配器
// View = Clicked MaterialCard,liveData = value in viewModel
@BindingAdapter("state_checked")
fun setStateChecked(view: MaterialCardView,liveData: MutableLiveData<Boolean>) {
if (view.isChecked != liveData.value) {
if (liveData.value != null) {
view.isChecked = liveData.value!!
}
}
}
第二,更改XML布局,因为我们不再使用双向数据绑定
<layout
xmlns:app="http://schemas.android.com/apk/res-auto">
<data>
<variable
name="vm"
type="com.example.app.data.viewmodel.EmailViewModel" />
</data>
<com.google.android.material.card.MaterialCardView
android:id="@+id/cardViewOne"
android:checkable="true"
android:clickable="true"
android:focusable="true"
<!-- Deleted "=" -->
app:state_checked="@{vm.cardOptionOneChecked}"
</com.google.android.material.card.MaterialCardView>
<com.google.android.material.card.MaterialCardView
android:id="@+id/cardViewTwo"
android:checkable="true"
android:clickable="true"
android:focusable="true"
<!-- Deleted "=" -->
app:state_checked="@{vm.cardOptionTwoChecked}">
</com.google.android.material.card.MaterialCardView>
</layout>
第三,更改视图模型
class EmailViewModel @ViewModelInject constructor(
@ApplicationContext context: Context,@Assisted private val savedStateHandle: SavedStateHandle
) : ViewModel() {
val cardOptionOneChecked = MutableLiveData<Boolean>()
val cardOptionTwoChecked = MutableLiveData<Boolean>()
// Added
fun firstCardClicked() {
cardOneChecked.value = true
cardTwoChecked.value = false
}
fun secondCardClicked() {
cardOneChecked.value = false
cardTwoChecked.value = true
}
}
第四,将clickListener添加到XML或Fragment(此处为Fragment)
cardViewOne.setOnClickListener {
viewModel.firstCardClicked()
}
cardViewTwo.setOnClickListener {
viewModel.secondCardClicked()
}
如果有人有任何疑问,请将其写在评论中,我会帮忙的。
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