I have a custom view use kotlin android extension to find sub view, everything work well on real device and virtual device. When use custom view in Android Sutdio Layout preview throw java.lang.NullPointerException
clear and rebuild have done many times
Android studio: 3.2.1
kotlin : 1.2.50-71
But same code work properly on Android studio 3.1.4
This not a simple NPE problem, this may cause by Android Studio Layout Preview
Custom View:
import android.content.Context
import android.util.AttributeSet
import android.view.View
import android.widget.RelativeLayout
import com.youzan.retail.stock.R
import kotlinx.android.synthetic.main.stock_item_setting_icon.view.*
internal class ItemSettingIcon : RelativeLayout {
constructor(context: Context?, attrs: AttributeSet?) : super(context, attrs) {
initLayout(context, attrs)
}
constructor(context: Context?, attrs: AttributeSet?, defStyleAttr: Int) : super(context, attrs, defStyleAttr) {
initLayout(context, attrs)
}
private fun initLayout(context: Context?, attrs: AttributeSet?) {
if (context == null || attrs == null)
return
View.inflate(context, R.layout.stock_item_setting_icon, this)
val typedArray = context.obtainStyledAttributes(attrs, R.styleable.ItemSettingIcon)
item_icon.setImageResource(typedArray.getResourceId(R.styleable.ItemSettingIcon_item_icon, -1)) //NPE here
item_title.setText(typedArray.getResourceId(R.styleable.ItemSettingIcon_item_title, -1))
typedArray.recycle()
}
}
R.layout.stock_item_setting_icon:
<?xml version="1.0" encoding="utf-8"?>
<merge xmlns:android="http://schemas.android.com/apk/res/android">
<ImageView
android:id="@+id/item_icon"
android:layout_width="@dimen/stock_setting_item_icon_size"
android:layout_height="@dimen/stock_setting_item_icon_size"
android:layout_alignParentLeft="true"
android:layout_centerVertical="true"
android:layout_marginLeft="@dimen/stock_content_left_margin" />
<TextView
android:id="@+id/item_title"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerVertical="true"
android:layout_marginLeft="@dimen/stock_10dp"
android:layout_toRightOf="@id/item_icon"
android:text="@string/stock_query"
android:textColor="@color/stock_setting_item_text_color"
android:textSize="@dimen/stock_setting_item_text_size" />
<ImageView
android:id="@+id/item_end_icon"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentRight="true"
android:layout_centerVertical="true"
android:layout_marginRight="@dimen/stock_15dp"
android:src="@drawable/stock_icon_right_arrow" />
</merge>
R.styleable.ItemSettingIcon:
<declare-styleable name="ItemSettingIcon">
<attr name="item_icon" format="reference" />
<attr name="item_title" format="string" />
</declare-styleable>
Error log:
java.lang.NullPointerException
at com.youzan.retail.stock.view.ItemSettingIcon.initLayout(ItemSettingIcon.kt:30)
at com.youzan.retail.stock.view.ItemSettingIcon.<init>(ItemSettingIcon.kt:17)
at sun.reflect.GeneratedConstructorAccessor968.newInstance(Unknown Source)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
at org.jetbrains.android.uipreview.ViewLoader.createNewInstance(ViewLoader.java:401)
at org.jetbrains.android.uipreview.ViewLoader.loadClass(ViewLoader.java:184)
at org.jetbrains.android.uipreview.ViewLoader.loadView(ViewLoader.java:142)
at com.android.tools.idea.rendering.LayoutlibCallbackImpl.loadView(LayoutlibCallbackImpl.java:229)
at android.view.BridgeInflater.loadCustomView(BridgeInflater.java:421)
at android.view.BridgeInflater.loadCustomView(BridgeInflater.java:432)
at android.view.BridgeInflater.createViewFromTag(BridgeInflater.java:336)
at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:730)
at android.view.LayoutInflater.rInflate_Original(LayoutInflater.java:863)
at android.view.LayoutInflater_Delegate.rInflate(LayoutInflater_Delegate.java:72)
at android.view.LayoutInflater.rInflate(LayoutInflater.java:837)
at android.view.LayoutInflater.rInflateChildren(LayoutInflater.java:824)
at android.view.LayoutInflater.rInflate_Original(LayoutInflater.java:866)
at android.view.LayoutInflater_Delegate.rInflate(LayoutInflater_Delegate.java:72)
at android.view.LayoutInflater.rInflate(LayoutInflater.java:837)
at android.view.LayoutInflater.rInflateChildren(LayoutInflater.java:824)
at android.view.LayoutInflater.rInflate_Original(LayoutInflater.java:866)
at android.view.LayoutInflater_Delegate.rInflate(LayoutInflater_Delegate.java:72)
at android.view.LayoutInflater.rInflate(LayoutInflater.java:837)
at android.view.LayoutInflater.rInflateChildren(LayoutInflater.java:824)
at android.view.LayoutInflater.inflate(LayoutInflater.java:515)
at android.view.LayoutInflater.inflate(LayoutInflater.java:394)
at com.android.layoutlib.bridge.impl.RenderSessionImpl.inflate(RenderSessionImpl.java:327)
at com.android.layoutlib.bridge.Bridge.createSession(Bridge.java:386)
at com.android.tools.idea.layoutlib.LayoutLibrary.createSession(LayoutLibrary.java:193)
at com.android.tools.idea.rendering.RenderTask.createRenderSession(RenderTask.java:450)
at com.android.tools.idea.rendering.RenderTask.lambda$inflate$3(RenderTask.java:590)
at java.util.concurrent.FutureTask.run(FutureTask.java:266)
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
at java.util.concurrent.FutureTask.run(FutureTask.java:266)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at java.lang.Thread.run(Thread.java:745)
Is there some mistakes do I make ?
