无法呈现具有Custom StateListDrawable的视图

Question

我想根据视图的选定状态动态选择一个Drawable。。我使用了布尔状态而不是字符串，因为这篇文章不支持字符串。以下是代码详细信息：

attrs.xml

<declare-styleable name="StateView">
<attr name="state_not_available" format="boolean" />
<attr name="state_idle" format="boolean" />
<attr name="state_busy" format="boolean" />
</declare-styleable>

selector_driver_state.xml

<selector
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:custom="http://schemas.android.com/apk/res-auto">
<item custom:state_not_available="true"
android:drawable="@drawable/drawable_icon_not_available"/>
<item custom:state_idle="true"
android:drawable="@drawable/drawable_icon_idle"/>
<item custom:state_busy="true"
android:drawable="@drawable/drawable_icon_busy"/>
<item android:drawable="@drawable/drawable_icon_busy" />
</selector>

StateView.kt

class StateView @JvmOverloads constructor(
context: Context, attrs: AttributeSet? = null, defStyleAttr: Int = 0
) : View(context, attrs, defStyleAttr) {
private var STATE_NOT_AVAILABLE = intArrayOf(R.attr.state_not_available)
private var STATE_IDLE = intArrayOf(R.attr.state_idle)
private var STATE_BUSY = intArrayOf(R.attr.state_busy)
private var mStateNotAvail : Boolean = false
private var mStateIdle : Boolean = false
private var mStateBusy : Boolean = false
init {
initAttrs(context, attrs)
}
private fun initAttrs(context: Context, attrs: AttributeSet?) {
attrs?.let {
val attrArr = context.obtainStyledAttributes(attrs, R.styleable.StateView)
try {
mStateNotAvail = attrArr.getBoolean(R.styleable.StateView_state_not_available, false)
mStateIdle = attrArr.getBoolean(R.styleable.StateView_state_idle, false)
mStateBusy = attrArr.getBoolean(R.styleable.StateView_state_busy, false)
}
finally {
attrArr.recycle()
}
}
}
fun setStateBusy(state: Boolean) {
mStateNotAvail = false
mStateIdle = false
mStateBusy = state
invalidate()
requestLayout()
}
override fun onCreateDrawableState(extraSpace: Int): IntArray {
val drawableStates = super.onCreateDrawableState(extraSpace + 1)
if(mStateNotAvail)
mergeDrawableStates(drawableStates, STATE_NOT_AVAILABLE)
else if(mStateIdle)
mergeDrawableStates(drawableStates, STATE_IDLE)
else
mergeDrawableStates(drawableStates, STATE_BUSY)
return drawableStates
}

用法：

<com.abc.package.components.StateView
android:layout_width="20dp"
android:layout_height="20dp"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintTop_toTopOf="parent"
android:id="@+id/viewState"
app:state_idle="true"                    ----> not working!
android:layout_marginLeft="10dp"/>

问题是StateView未进行渲染。我尝试以编程方式设置状态，但使用setStateBusy无法正常工作。有线索吗？非常感谢。

Answer 1

1. 不能将String属性与选择器Drawable一起使用。您需要为StateView定义一个自定义字符串属性app:state="Idle">，并根据所选状态以编程方式更改可绘制内容。

   //attrs.xml 中的更改

   <declare-styleable name="StateView"> <attr name="state" format="reference|string" /> </declare-styleable>

   //布局文件中的更改

   <com.abc.package.components.StateView app:state="Idle" ...

2. 在StateView类中添加以下方法setState

   fun setState(state: String) { if(state?.equals("idle")){ imageView.setDrawable(R.drawable. drawable_icon_idle); } if(state?.equals("busy")){ imageView.setDrawable(R.drawable. drawable_icon_busy); } ...
}

希望这能解决您的问题。现在，您还可以从StateView.kt类中删除大部分行