Button with selector for background color - when clicked the background color is extending out of the button

问题

To begin with.. the button is added dynamically through code and hence cannot apply the styles in xml.

I have few buttons in my activity and i am using a selector to change the background color. The button also has a "shape" attached to it, for border.

image_border.xml

<?xml version="1.0" encoding="UTF-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android" >

    <solid android:color="@color/dark_grey" />

    <stroke
        android:width="4dp"
        android:color="@color/light_grey" />

    <padding
        android:bottom="4dp"
        android:left="4dp"
        android:right="4dp"
        android:top="4dp" />

</shape>

button_background_blue.xml

<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">

    <item android:drawable="@color/blue" android:state_pressed="true"/>
    <item android:drawable="@color/dark_grey" android:state_focused="true"/>
    <item android:drawable="@drawable/image_border"/>

</selector>

Now when i click on the button, the background color, changes just fine. But, the background color is extending beyond the button's size. I am not sure where it is happening.

Please refer to the images below...

Before clicking the button :

After clicking the button :

I think the color is extending into the padding or something, but i am really not pretty sure, why this is occuring.

回答1:

This should be your selector:

<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
    <item android:drawable="@drawable/image_border_blue" android:state_pressed="true"/>
    <item android:drawable="@drawable/image_border_dark_grey" android:state_focused="true"/>
    <item android:drawable="@drawable/image_border"/>
</selector>

And just add these drawables:

image_border_blue

<?xml version="1.0" encoding="UTF-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android" >
    <solid android:color="@color/blue" />
    <stroke
        android:width="4dp"
        android:color="@color/light_grey" />
    <padding
        android:bottom="4dp"
        android:left="4dp"
        android:right="4dp"
        android:top="4dp" />
</shape>

image_border_dark_grey

<?xml version="1.0" encoding="UTF-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android" >
    <solid android:color="@color/dark_grey" />
    <stroke
        android:width="4dp"
        android:color="@color/light_grey" />
    <padding
        android:bottom="4dp"
        android:left="4dp"
        android:right="4dp"
        android:top="4dp" />
</shape>

回答2:

Create another shape using those color you used in selector...suppose for Blue color...create shape named btn_pressed.xml...

<?xml version="1.0" encoding="UTF-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android" >

    <solid android:color="@color/blue" />

    <stroke
        android:width="4dp"
        android:color="@color/blue" />

    <padding
        android:bottom="4dp"
        android:left="4dp"
        android:right="4dp"
        android:top="4dp" />

</shape>

Then place this shape in place of @color/blue in the selector as follows...

<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">

    <item android:drawable="@drawable/btn_pressed" android:state_pressed="true"/>
    <item android:drawable="@color/dark_grey" android:state_focused="true"/>
    <item android:drawable="@drawable/image_border"/>

</selector>

Follow same process for @color/dark_grey.

来源：https://stackoverflow.com/questions/22095326/button-with-selector-for-background-color-when-clicked-the-background-color-is