简介
视图动画，主要包括位移，透明度，旋转和缩放，View本身的属性并没有发生变化，只是在这个视图上添加一些渐变的效果，所以总体而言，视图动画只能实现一些简单的动画效果，属性动画功能更强大。
《Android 基础（二十四）》 EditText
简介
A text field allows the user to type text into your app. It can be either single line or multi-line. Touching a text field places the cursor and automatically displays the keyboard. In addition to typing, text fields allow for a variety of other activities, such as text selection (cut, copy, paste) and data look-up via auto-completion.
You can add a text field to you layout with the EditText object. You should usually do so in your XML layout with a < EditText > element.
《Android 基础（二十三）》 Android Studio快捷键
《Android 基础（二十一）》Android 屏幕适配
《Android 基础（二十）》 CoordinatorLayout Behavior
《Android 基础（十九）》 CoordinatorLayout
《Android 基础（十七）》 ViewPager
《Android 基础（十六）》Toast
介绍
A toast provides simple feedback about an operation in a small popup. It only fills the amount of space required for the message and the current activity remains visible and interactive. For example, navigating away from an email before you send it triggers a “Draft saved” toast to let you know that you can continue editing later. Toasts automatically disappear after a timeout.
