向android无边框按钮添加样式（android 4.0+）

Question

I want to add a border to a borderlessbutton. However, if I create my own style with the parent borderlessbutton and I overwrite the background tag I loose the state change animation etc, as this is also defined by the background. I also cannot implement them myself as the native android drawables are not available as public and therefore not accessible. I do not want to have to copy the drawables. Is it only possible to overwrite ondraw progammatically or is there an xml based solution i am missing? (btw this is for a periodic table so this should not involve having an xml file for each button as there are about 100 of them) thanks stephan

Answer 1

The bulk of this comes from this article .

There is a 4 step process to doing something like this:

1. Create an XML file that contains the states.
2. Create an XML file (Or background) for each state
3. Create the style of the button
4. Add the button to your layout, and see what it looks like.

The single most difficult thing is the first step, so I'll show that one here. For the other ones, you can visit the site or do your own thing. Essentially, it will look something like this. Basically needs to capture all of the 4 states. This should be saved in the drawable folder, and the name of this is what your application will use for the name of the drawable.

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

<selector xmlns:android="http://schemas.android.com/apk/res/android">
    <item
        android:state_enabled="false"
        android:drawable="@drawable/loc_for_button_disabled" />
    <item
        android:state_pressed="true"
        android:state_enabled="true"
        android:drawable="@drawable/loc_for_button_pressed" />
    <item
        android:state_focused="true"
        android:state_enabled="true"
        android:drawable="@drawable/loc_for_button_focused" />
    <item
        android:state_enabled="true"
        android:drawable="@drawable/loc_for_button_enabled" />
</selector>

Answer 2

An easy way would be to place your button within a separate layout, eg a LinearLayout and give this layout a background color and a padding of eg 1dp. This would render a "border" around the button. Note, that this is quite costly in regard of layouting, so do not use this method when you have lots of buttons.

The correct solution would be to create your one drawables for all states and build a statelist drawable with your drawables and assign this statelist drawable as your button's background. Actually it's not that much work, just have a look at http://developer.android.com/guide/topics/resources/drawable-resource.html#StateList