Android零碎知识（一）

public abstract Resources getResources ()

Return a Resources instance for your application‘s package.

BitmapFactory
extends Object

java.lang.Object
   ? android.graphics.BitmapFactory 

Class Overview

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Creates Bitmap objects from various sources, including files, streams, and byte-arrays. 

public void translate (float dx, float dy)
Added in API level 1
Preconcat the current matrix with the specified translation

When working with matrices, the word concatenation refers to multiplication.

Since matrix multiplication is not commutative, there is a separate word for backwards multiplication.
Pre-concatenating a to b means setting a = b × a. (As opposed to a = a × b, which will give a different matrix)

The canvas maintains a matrix and the canvas is manipulated by methods which are well defined in OpenGL