Question

When using fill_parent, maxWidth has no effect.

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
              android:layout_width="fill_parent"
              android:layout_height="match_parent"
              android:orientation="vertical">
    <LinearLayout android:layout_width="fill_parent"
                  android:layout_height="match_parent"
                  android:orientation="vertical">
        <EditText android:layout_width="match_parent"
                  android:layout_height="wrap_content"
                  android:maxWidth="50dip"/>
    </LinearLayout>    
</LinearLayout>

Answer 1

The attribute maxWidth has no effect on a width of match_parent (or the deprecated fill_parent), they are mutually exclusive. You need to use wrap_content.

Also any layout that only has one child can probably be removed, for instance you can simplify you current layout to:

<?xml version="1.0" encoding="utf-8"?>
<EditText xmlns:android="http://schemas.android.com/apk/res/android"
          android:layout_width="wrap_content"
          android:layout_height="wrap_content"
          android:maxWidth="50dip"/>