First image: this my custom view TextView using font Cairo, but when I use this class it is not showing the font in preview.
Second image: this is the preview in Android Studio.
And The Exception Details
java.lang.IllegalArgumentException: referent is null
at libcore.util.NativeAllocationRegistry_Delegate.registerNativeAllocation(NativeAllocationRegistry_Delegate.java:71)
at libcore.util.NativeAllocationRegistry.registerNativeAllocation(NativeAllocationRegistry.java:231)
at android.graphics.fonts.Font$Builder.<init>(Font.java:174)
at android.graphics.Typeface$Builder.<init>(Typeface.java:438)
at android.graphics.Typeface$Builder.<init>(Typeface.java:425)
at android.graphics.Typeface.createFromAsset(Typeface.java:960)
at com.optimalpath.contractorguides.utils.spishalViews.STextViewLight.init(STextViewLight.java:29)
at com.optimalpath.contractorguides.utils.spishalViews.STextViewLight.<init>(STextViewLight.java:20)
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
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:404)
at org.jetbrains.android.uipreview.ViewLoader.loadClass(ViewLoader.java:187)
at org.jetbrains.android.uipreview.ViewLoader.loadView(ViewLoader.java:145)
at com.android.tools.idea.rendering.LayoutlibCallbackImpl.loadView(LayoutlibCallbackImpl.java:309)
at android.view.BridgeInflater.loadCustomView(BridgeInflater.java:417)
at android.view.BridgeInflater.loadCustomView(BridgeInflater.java:428)
at android.view.BridgeInflater.createViewFromTag(BridgeInflater.java:332)
at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:961)
at android.view.LayoutInflater.rInflate_Original(LayoutInflater.java:1123)
at android.view.LayoutInflater_Delegate.rInflate(LayoutInflater_Delegate.java:72)
at android.view.LayoutInflater.rInflate(LayoutInflater.java:1097)
at android.view.LayoutInflater.rInflateChildren(LayoutInflater.java:1084)
at android.view.LayoutInflater.rInflate_Original(LayoutInflater.java:1126)
at android.view.LayoutInflater_Delegate.rInflate(LayoutInflater_Delegate.java:72)
at android.view.LayoutInflater.rInflate(LayoutInflater.java:1097)
at android.view.LayoutInflater.rInflateChildren(LayoutInflater.java:1084)
at android.view.LayoutInflater.inflate(LayoutInflater.java:682)
at android.view.LayoutInflater.inflate(LayoutInflater.java:534)
at com.android.layoutlib.bridge.android.support.Adapter.onCreateViewHolder(Unknown Source)
at androidx.recyclerview.widget.RecyclerView$Adapter.createViewHolder(RecyclerView.java:7078)
at androidx.recyclerview.widget.RecyclerView$Recycler.tryGetViewHolderForPositionByDeadline(RecyclerView.java:6235)
at androidx.recyclerview.widget.RecyclerView$Recycler.getViewForPosition(RecyclerView.java:6118)
at androidx.recyclerview.widget.RecyclerView$Recycler.getViewForPosition(RecyclerView.java:6114)
at androidx.recyclerview.widget.LinearLayoutManager$LayoutState.next(LinearLayoutManager.java:2303)
at androidx.recyclerview.widget.LinearLayoutManager.layoutChunk(LinearLayoutManager.java:1627)
at androidx.recyclerview.widget.LinearLayoutManager.fill(LinearLayoutManager.java:1587)
at androidx.recyclerview.widget.LinearLayoutManager.onLayoutChildren(LinearLayoutManager.java:665)
at androidx.recyclerview.widget.RecyclerView.dispatchLayoutStep2(RecyclerView.java:4134)
at androidx.recyclerview.widget.RecyclerView.onMeasure_Original(RecyclerView.java:3540)
at androidx.recyclerview.widget.RecyclerView.onMeasure(RecyclerView.java)
at android.view.View.measure_Original(View.java:24552)
at android.view.View_Delegate.measure(View_Delegate.java:80)
at android.view.View.measure(View.java:24516)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:6828)
at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1552)
at android.widget.LinearLayout.measureVertical(LinearLayout.java:842)
at android.widget.LinearLayout.onMeasure(LinearLayout.java:721)
at android.view.View.measure_Original(View.java:24552)
at android.view.View_Delegate.measure(View_Delegate.java:80)
at android.view.View.measure(View.java:24516)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:6828)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:194)
at android.view.View.measure_Original(View.java:24552)
at android.view.View_Delegate.measure(View_Delegate.java:80)
at android.view.View.measure(View.java:24516)
at androidx.core.widget.NestedScrollView.measureChildWithMargins(NestedScrollView.java:1562)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:194)
at androidx.core.widget.NestedScrollView.onMeasure_Original(NestedScrollView.java:584)
at androidx.core.widget.NestedScrollView.onMeasure(NestedScrollView.java)
at android.view.View.measure_Original(View.java:24552)
at android.view.View_Delegate.measure(View_Delegate.java:80)
at android.view.View.measure(View.java:24516)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:6828)
at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1552)
at android.widget.LinearLayout.measureVertical(LinearLayout.java:842)
at android.widget.LinearLayout.onMeasure(LinearLayout.java:721)
at android.view.View.measure_Original(View.java:24552)
at android.view.View_Delegate.measure(View_Delegate.java:80)
at android.view.View.measure(View.java:24516)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:6828)
at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1552)
at android.widget.LinearLayout.measureVertical(LinearLayout.java:842)
at android.widget.LinearLayout.onMeasure(LinearLayout.java:721)
at android.view.View.measure_Original(View.java:24552)
at android.view.View_Delegate.measure(View_Delegate.java:80)
at android.view.View.measure(View.java:24516)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:6828)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:194)
at android.view.View.measure_Original(View.java:24552)
at android.view.View_Delegate.measure(View_Delegate.java:80)
at android.view.View.measure(View.java:24516)
at android.widget.RelativeLayout.measureChildHorizontal(RelativeLayout.java:735)
at android.widget.RelativeLayout.onMeasure(RelativeLayout.java:481)
at android.view.View.measure_Original(View.java:24552)
at android.view.View_Delegate.measure(View_Delegate.java:80)
at android.view.View.measure(View.java:24516)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:6828)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:194)
at android.view.View.measure_Original(View.java:24552)
at android.view.View_Delegate.measure(View_Delegate.java:80)
at android.view.View.measure(View.java:24516)
at com.android.layoutlib.bridge.impl.RenderSessionImpl.measureView(RenderSessionImpl.java:605)
at com.android.layoutlib.bridge.impl.RenderSessionImpl.inflate(RenderSessionImpl.java:344)
at com.android.layoutlib.bridge.Bridge.createSession(Bridge.java:396)
at com.android.tools.idea.layoutlib.LayoutLibrary.createSession(LayoutLibrary.java:209)
at com.android.tools.idea.rendering.RenderTask.createRenderSession(RenderTask.java:608)
at com.android.tools.idea.rendering.RenderTask.lambda$inflate$6(RenderTask.java:734)
at java.util.concurrent.CompletableFuture$AsyncSupply.run(CompletableFuture.java:1590)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
at java.lang.Thread.run(Thread.java:748)