简介

The AlertDialog class allows you to build a variety of dialog designs and is often the only dialog class you’ll need. there are three regions of an alert dialog:

介绍

A StateListDrawable is a drawable object defined in XML that uses a several different images to represent the same graphic, depending on the state of the object. For example, a Button widget can exist in one of several different states (pressed, focused, or niether) and, using a state list drawable, you can provide a different background image for each state. You can describe the state list in an XML file. Each graphic is represented by an “item” element inside a single “selector” element. Each “item” uses various attributes to describe the state in which it should be used as the graphic for the drawable.
During each state change, the state list is traversed top to bottom and the first item that matches the current state is used—the selection is not based on the “best match,” but simply the first item that meets the minimum criteria of the state.

介绍

简单来说，shape就是用来在xml文件中定义形状，代码解析之后就可以当做Drawable一样使用

介绍

Layout which wraps an {@link android.widget.EditText} (or descendant) to show a floating label
when the hint is hidden due to the user inputting text.

问题类型

Layout中添加一个Button

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<Button android:id="@+id/bt_showerror"
    android:layout_width="200dp"
    android:layout_height="wrap_content"
    android:text="ShowError"
/>

简介

Snackbars provide lightweight feedback about an operation. They show a brief message at the
bottom of the screen on mobile and lower left on larger devices. Snackbars appear above all other
elements on screen and only one can be displayed at a time.

简介

Source Code中的介绍如下：

Floating action buttons are used for a special type of promoted action. They are distinguished
by a circled icon floating above the UI and have special motion behaviors related to morphing,
launching, and the transferring anchor point.

Floating action buttons come in two sizes: the default and the mini. The size can be
controlled with the {@code fabSize} attribute.

介绍

The NDK is a toolset that allows you to implement parts of your app using native-code languages such as C and C++. For certain types of apps, this can be helpful so you can reuse existing code libraries written in these languages, but most apps do not need the Android NDK.

介绍

Palette， 英文翻译，调色板，意思比较接近，Google给它的定位应该是颜色萃取器。
看下Source Code
Palette , A helper class to extract prominent colors from an image.
A number of colors with different profiles are extracted from the image

导入AAR、JAR文件