AlertDialog: How To Remove Black Borders Above and Below View

Question

This question has been asked before: AlertDialog custom title has black border

But was not answered satisfactorily - and is missing some information.

---

I'm trying to create a custom dialog in Android without a title and without any buttons along the bottom.

However, the resulting dialog has black "borders"/"spacing"/something along the top and bottom of the view.

From the Documentation:

A dialog made with the base Dialog class must have a title. If you don't call setTitle(), then the space used for the title remains empty, but still visible. If you don't want a title at all, then you should create your custom dialog using the AlertDialog class. However, because an AlertDialog is created easiest with the AlertDialog.Builder class, you do not have access to the setContentView(int) method used above. Instead, you must use setView(View). This method accepts a View object, so you need to inflate the layout's root View object from XML.

So, that's what I did:

Welcome.java

public class Welcome  extends Activity
{
    public void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);

        setContentView(R.layout.welcome);

        LayoutInflater inflater = (LayoutInflater)this.getSystemService(LAYOUT_INFLATER_SERVICE);
        View layout = inflater.inflate(R.layout.welcomedialog, (ViewGroup)findViewById(R.id.layout_root));

        AlertDialog.Builder builder = new AlertDialog.Builder(this);
        builder.setView(layout);
        builder.create().show();
    }
}

welcomedialog.xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
              android:layout_width="fill_parent"
              android:layout_height="fill_parent"
              android:background="@drawable/texturebg"
              android:id="@+id/layout_root"
              android:orientation="vertical"
              android:padding="40px">
    ...
</LinearLayout>

NOTE: I've tried using FrameLayout as the root ViewGroup instead of LinearLayout as per a suggestion I found somewhere - but that didn't help.

Result

---

setBackgroundDrawable Suggestion

public class Welcome  extends Activity
{
    public void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);

        setContentView(R.layout.welcome);

        LayoutInflater inflater = (LayoutInflater)this.getSystemService(LAYOUT_INFLATER_SERVICE);
        View layout = inflater.inflate(R.layout.welcomedialog, (ViewGroup)findViewById(R.id.layout_root));

        AlertDialog.Builder builder = new AlertDialog.Builder(this);
        builder.setView(layout);
        AlertDialog dialog = builder.create();

        dialog.getWindow().setBackgroundDrawable(new ColorDrawable(0));

        dialog.show();
    }
}

Didn't work for me.

Answer 1

If you look at the AlertDialog class source you'll see most of the methods are simply proxy methods (facade) around private AlertController mAlert.

Looking at the AlertController class source you'll see 4 interesting member variables:

private int mViewSpacingLeft;
private int mViewSpacingTop;
private int mViewSpacingRight;
private int mViewSpacingBottom;
private boolean mViewSpacingSpecified = false;

Setting mViewSpacingSpecified to true will remove the borders on the top and bottom of the dialog.

This is done properly by changing this line:

dialog.setView(layout);

to:

dialog.setView(layout, 0, 0, 0, 0);