<?xml version="1.0" encoding="utf-8"?>

<manifest xmlns:android="http://schemas.android.com/apk/res/android" >

    <supports-screens
        android:smallScreens="false"
        android:normalScreens="false"
        android:largeScreens="true"
        android:xlargeScreens="true"
        android:requiresSmallestWidthDp="600"
        />

    <application>

        <!-- Declare our main activity, which will be different than the
             main activity for phones.
             -->
        <activity
            android:name="com.dummies.tasks.tablet.activity.TaskListAndEditorActivity" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>

    </application>

</manifest>
<?xml version="1.0" encoding="utf-8"?>

<manifest xmlns:android="http://schemas.android.com/apk/res/android" >

    <compatible-screens>
        <!-- all large size screens -->
        <screen android:screenSize="large" android:screenDensity="ldpi" />
        <screen android:screenSize="large" android:screenDensity="mdpi" />
        <screen android:screenSize="large" android:screenDensity="hdpi" />
        <screen android:screenSize="large" android:screenDensity="xhdpi"/>
        <!-- all xlarge size screens -->
        <screen android:screenSize="xlarge" android:screenDensity="ldpi"/>
        <screen android:screenSize="xlarge" android:screenDensity="mdpi"/>
        <screen android:screenSize="xlarge" android:screenDensity="hdpi"/>
        <screen android:screenSize="xlarge" android:screenDensity="xhdpi"/>
    </compatible-screens>

    <application>

        <!-- Declare our main activity, which will be different than the
             main activity for phones.
             -->
        <activity
            android:name="com.dummies.tasks.tablet.activity.TaskListAndEditorActivity" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>

    </application>

</manifest>
Switch to compatible-screens instead of supports-screens
Switch to compatible-screens instead of supports-screens

http://developer.android.com/guide/practices/screens-distribution.html

"If you want to prevent your application from being downloaded on larger screens, use <compatible-screens>, as discussed in the previous section about Declaring an App is Only for Handsets."
