Android 画图学习总结类的简介

核心提示：首先，如何获取 res 中的资源数据包package：android.content.res主要类：ResourcesAndroid SDK中的简介：Class for accessing an application’s resources.Class for accessing an application’s r

首先，如何获取 res 中的资源

数据包package：android.content.res

主要类：Resources

Android SDK中的简介：Class for accessing an application’s resources.Class for accessing an application’s resources. This sits on top of the asset manager of the application (accessible through getAssets()) and provides a higher-level API for getting typed data from the assets.

其主要接口按照功能，划分为以下三部分：

getXXXX()

例如：

int getColor(int id)

Drawable getDrawable(int id)

String getString(int id)直接获取res中存放的资源

InputStream openRawResource(int id)获取资源的数据流，读取资源数据

void parseBundleExtras(

XmlResourceParser parser, Bundle outBundle)从XML文件中获取数据

Resource为每种资源提供了相应的接口来获取这种资源，除了可以直接获取资源外，还额外提供了以数据流的方式获取资源，这在以后的应用程序开发中会经常使用，那么如何获取Resources了，如下：Resources r = this.getContext().getResources();

其次，如何获取资源中的画图对象

数据包package：android.graphics.drawable

主要类：Drawable

Android SDK中的简介：A Drawable is a general abstraction for “something that can be drawn.” Most often you will deal with Drawable as the type of resource retrieved for drawing things to the screen; the Drawable class provides a generic API for dealing with an underlying visual resource that may take a variety of forms.

看了以上简介，发现Drawable是个virtual class，具体如何画图，需要具体分析Drawable的子类，例如：BitmapDrawable

Android SDK中的简介：A Drawable that wraps a bitmap and can be tiled, stretched, or aligned. You can create a BitmapDrawable from a file path, an input stream, through XML inflation, or from a Bitmap object. It can be defined in an XML file with the element.

其主要接口如下：

BitmapDrawable()