Button size and background color change on button press

I'm trying to create a layout with 3 buttons in line, and I'd like to make each one of them width 30% of the screen width. What's the best way to do this?

My second question is, how do I define the on开发者_StackOverflow社区 press color for the button? I would like the buttons to be GREEN and turn RED when pressed.

Thanks! Marco

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The best way to do the color for the buttons is to create custom drawables for you button when pressed/active/disabled/focused (in my example I use button_faded.png, button_down.png & button_up.png) then define an xml to tell the button how to use it:

button.xml:

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

<selector xmlns:android="http://schemas.android.com/apk/res/android">
    <item android:drawable="@drawable/button_faded"
          android:state_enabled="false" />
    <item android:drawable="@drawable/button_down"
          android:state_pressed="true" />
    <item android:drawable="@drawable/button_up"
          android:state_focused="true" />
    <item android:drawable="@drawable/button_up" />
</selector>

Then in your layout set the background to "@drawable/button"

or better yet in your styles.xml create a button style:

<style name="Button">
    <item name="android:layout_width">fill_parent</item>
    <item name="android:layout_height">wrap_content</item>
    <item name="android:textColor">#000000</item>
    <item name="android:textSize">19sp</item>
    <item name="android:background">@drawable/button</item>
    <item name="android:gravity">center</item>
    <item name="android:paddingLeft">0dp</item>
    <item name="android:paddingRight">0dp</item>
    <item name="android:paddingTop">5dp</item>
    <item name="android:paddingBottom">5dp</item>
</style>

and in your layout xml tell the button to use the style:

    <Button style="@style/Button" />

As far as the layout of the buttons... if you are looking for 1/3 of the screen each, create a horizontal LinearyLayout that contains all three buttons. Set the buttons width to fill_parent and give them all the same layout weight of let's say '1'... This should fill the row with the 3 buttons each the same size. You can then adjust the space between them using the layout margins or padding.

---

Display mDisplay= activity.getWindowManager().getDefaultDisplay();
int width= mDisplay.getWidth();
int Height= mDisplay.getHeight();

if(width>height)
{
//Landscape
//set your landscape drawable
}
else
{
//portrait
//set your portrait drawable
}

now take the 30% of width variable, and for color just use drawable with different states see here