setVisibility(View.INVISIBLE) 导致异常，为什么？

Question

why my setVisibility(View.INVISIBLE) causes exception while setVisibility for TextView works. I also tried set it for ImageView and it also does not work - I am getting exception too

public void alertdiag() {
    AlertDialog.Builder dialogBuilder = new AlertDialog.Builder(this);
    LayoutInflater inflater = this.getLayoutInflater();
    View dialogView = inflater.inflate(R.layout.alertdiag_layout, null);
    dialogBuilder.setView(dialogView).show();

    View Divider1 = (View) dialogView.findViewById(R.style.Divider1);
    Divider1.setVisibility(View.INVISIBLE); //causes java.lang.IllegalStateException: Could not execute method of the activity"

    TextView HELP0 = (TextView) dialogView.findViewById(R.id.HELP0); 
    HELP0.setVisibility(View.INVISIBLE); // this works
}

alertdiag_layout.xml:

<View style="@style/Divider1"
    android:layout_below="@+id/HELP3"
    android:background="#000000"            
    android:layout_alignRight="@+id/HELP_FIX_LINE"
    android:layout_alignLeft="@+id/HELP3"
/>  

<TextView
    android:id="@+id/HELP0"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_centerHorizontal="true"
    android:layout_below="@+id/HELP_FIX_LINE"     
    android:textStyle="bold"
    android:typeface="normal"
/>          

styles.xml:

<style name="Divider1">
    <item name="android:layout_width">match_parent</item>
    <item name="android:layout_height">1dp</item>
</style>

Answer 1

You are trying to set the Visibility to a Style (R.style.Divider1)

Add an Id to your View and change the R.style.Divider1 to R.id.yourNewId

  <View style="@style/Divider1" android:id="@+id/yourNewId"
    android:layout_below="@id/HELP3" android:background="#000000"
    android:layout_alignRight="@id/HELP_FIX_LINE"         
    android:layout_alignLeft="@id/HELP3" />

Answer 2

Add id attribute to your view

  <View style="@style/Divider1"
   android:id="@+id/my_view"
   android:layout_below="@id/HELP3"
   android:background="#000000"         
   android:layout_alignRight="@id/HELP_FIX_LINE"
   android:layout_alignLeft="@id/HELP3"
    /> 

NOTE: I switched @+id/HELP3 and @+id/HELP_FIX_LINE with @id/HELP3 and @id/HELP_FIX_LINE respectively because @+id/ is only used when you are giving a view an id. It is not used to refer other views.

Now, Change this line of code

 View Divider1 = (View) dialogView.findViewById(R.style.Divider1);

with

View Divider1 = (View) dialogView.findViewById(R.id.my_view);

It will find the view with the given id, instead of style.

To make the view invisible you need to set

Divider1.setVisibility(View.INVISIBLE);

setVisibility must be used on the view, not on the style.