An issue with the Setaplha () report null pointer when the Android control transparency is set

You must set the Android:background= "" Property in the Android control to otherwise report a null pointer

XML code

<textview
Android:id= "@+id/dialog_back"
Android:layout_width= "Match_parent"
android:layout_height= "Match_parent"
android:background= "#000000"
/>

Java code

Textback = (TextView) Findviewbyid (r.id.dialog_back);
Textback.getbackground (). Setalpha (130); the Android:background property is not set in//xml, and the null pointer error is reported here .

An issue with the Setaplha () report null pointer when the Android control transparency is set