如何在 android 工作室中弹出按钮 animation

Question

In a calculator app that I am creating, I want buttons to animate in a pop-up way (scaling-up) when the button is clicked. But that is not the issue. I want the button to stay scaled up (bigger size) as long as the user hold the button. It is supposed to go back to its original size (small size) only when the user releases the button. In the same way button colour has to change from white to blue as long as user hold the button(back to white when released). Is there any way to do that? I am not very good at animations in android studio. So please try to explain it in simple words.

I am also attaching a video that I made for prototyping to illustrate it. Click link below https://drive.google.com/file/d/13B8LAuNW1ymhmliw52BEIkMbJAJQRbfw/view?usp=sharing

Answer 1

You should create an xml file that have a selector as root element. This element selects the shape in base of the corrent state like pressed, focused or enabled.

<?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/button_disabled" />
    <item
        android:state_pressed="true"
        android:state_enabled="true"
        android:drawable="@drawable/button_pressed" />
    <item
        android:state_focused="true"
        android:state_enabled="true"
        android:drawable="@drawable/button_focused" />
    <item
        android:state_enabled="true"
        android:drawable="@drawable/button_enabled" />
</selector>

If you want a different shape with different color and size you must create a new drawable like this:

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

<shape xmlns:android="http://schemas.android.com/apk/res/android" android:shape="rectangle">
    <gradient
        android:startColor="#00CCFF"
        android:centerColor="#0000CC"
        android:endColor="#00CCFF"
        android:angle="90"/>
    <padding android:left="7dp"
        android:top="7dp"
        android:right="7dp"
        android:bottom="7dp" />
    <stroke
        android:width="2dip"
        android:color="#FFFFFF" />
    <corners android:radius= "8dp" />
</shape>

If you want to change the size you can use the attribute size. Then you must implement the on click listener in the mainActivity onCreate file and set the pressed state of the button to true. In a nutshell you must create one selector drawable for the button and two drawable one for the state pressed="true" and one for pressed="false".

Here I put an exaustive example: https://stackoverflow.com/a/29848987/13198061