public class WaitingDialog extends Dialog {
    private TextView tv_text;

    public WaitingDialog(Context context) {
        super(context);
        getWindow().setBackgroundDrawable(new ColorDrawable(Color.TRANSPARENT));
        setContentView(R.layout.waiting_layout);
        tv_text = (TextView) findViewById(R.id.tv_text);
        setCanceledOnTouchOutside(false);
    }

    public WaitingDialog setMessage(String message) {
        tv_text.setText(message);
        return this;
    }
}

XML:

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_gravity="center">

    <RelativeLayout
        android:layout_width="150dp"
        android:layout_height="150dp"
        android:layout_centerInParent="true"
        android:background="#20000000"
        android:gravity="center">

        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:gravity="center|bottom"
            android:orientation="vertical">

            <ProgressBar
                style="@android:style/Widget.ProgressBar"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content" />

            <TextView
                android:id="@+id/tv_text"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_marginBottom="20dp"
                android:layout_marginTop="20dp"
                android:text="@string/dealing"
                android:textColor="#fff" />
        </LinearLayout>

    </RelativeLayout>

</RelativeLayout>