Why buttons has the same size on multiple screens (Android 1.6+)?

Question

Please help me with one problem. When I change min sdk version from 3 (Android 1.5) to 4 (1.6) or higher, all buttons and textviews have the same size on multiple screens although I use dp and sp units. Why might this be?

Simple example (main.xml):

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
              android:orientation="vertical"
              android:layout_width="fill_parent"
              android:layout_height="fill_parent"
>
    <Button 
        android:id="@+id/button"
        android:layout_width="300dp"
        android:layout_height="300dp"
        android:text="OK"
        android:layout_centerInParent="true"
    />
</LinearLayout>

Screenshot from Google Nexus 7: http://s019.radikal.ru/i601/1312/fd/e769f6e3a690.png

Screenshot from Sony Ericsson Xperia Play: http://s019.radikal.ru/i600/1312/9d/6b3f580e7503.png

Answer 1

Create dimen.xml for following folder as per your requirement:

1. values
2. values-hdpi
3. values-ldpi
4. values-mdpi
5. values-sw600dp
6. values-sw720dp-land etc...

and code for that dimen.xml and give xxxdp as you want:

<resources>

    <!-- Default screen margins, per the Android Design guidelines. -->
    <dimen name="button_width">300dp</dimen>
    <dimen name="button_height">300dp</dimen>

</resources>

then after you xml file like:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
              android:orientation="vertical"
              android:layout_width="fill_parent"
              android:layout_height="fill_parent">
    <Button 
        android:id="@+id/button"
        android:layout_width="@dimen/button_width"
        android:layout_height="@dimen/button_height"
        android:text="OK"
        android:layout_centerInParent="true" />
</LinearLayout>

---

FOR PROGRAMMATICALLY:

This also works:

getResources().getDisplayMetrics().density;

This will give you:

• 0.75 - ldpi
• 1.0 - mdpi
• 1.5 - hdpi
• 2.0 - xhdpi
• 3.0 - xxhdpi
• 4.0 - xxxhdpi

May it'll be Helpful...

Thanks...

Answer 2

1.6 Donut added support for different screen sizes and resolutions:

They [apps targeting API level 4] are assumed to support different screen densities and sizes. (Apps targeting earlier versions are assumed to only support medium density normal size screens unless otherwise indicated). They can still explicitly specify screen support either way with the supports-screens manifest tag.

So when your target SDK level is less than 4, you'll get a compatibility mode where dp and sp units don't really have any effect. Only when the target level is 4 or higher, are the pixels scaled accordingly.

Answer 3

What you should do is make different layout files and put it in different folders (like layout-sw300dp, layout-sw400dp, layout-sw600dp). These will be layouts that are to be displayed in screens with different sizes and density.