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

Thank you so much, but...is there any easier way to do it? for example, programmatically calculate size of buttons depending on screen density? — user2166726, Dec 06 '13 at 12:43
I tried to do like this: `final float scale = getResources().getDisplayMetrics().density; int dip = (int) (55 * scale); LinearLayout.LayoutParams lp = new LinearLayout.LayoutParams(dip, dip, 0); button.setLayoutParams(lp); ` but button has the same size pn both devices. So it's not work — user2166726, Dec 06 '13 at 14:56
Maybe I can resize button using getWindowManager().getDefaultDisplay().getMetrics(metrics)? — user2166726, Dec 06 '13 at 14:59

score 1 · Answer 1 · edited Dec 06 '13 at 12:42

1

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.

edited Dec 06 '13 at 12:42

Pratik Butani

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answered Dec 06 '13 at 12:10

rahulritesh

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Please tell me, why on Android 1.5 and less versions all works without creating many layout files? – user2166726 Dec 06 '13 at 12:13

score 1 · Answer 2 · answered Dec 06 '13 at 12:26

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.

Pratik Butani · Accepted Answer · 2013-12-06T12:52:43.540

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

values
values-hdpi
values-ldpi
values-mdpi
values-sw600dp
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...

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

3 Answers3