canvas drawBitmap方法怎么样在Android项目中使用

这篇文章给大家介绍 canvas drawBitmap方法怎么样在Android项目中使用，内容非常详细，感兴趣的小伙伴们可以参考借鉴，希望对大家能有所帮助。

 Android canvas drawBitmap方法详解及实例

之前自己在自定义view，用到canvas.drawBitmap(Bitmap, SrcRect, DesRect, Paint)的时候，对其中的第2和3个参数的含义含糊不清。看源码函数也没理解，然后看了一些其他的博客加上自己的理解，整理如下。首先，我们看一张图片，今天就要绘制这张图片。

然后将图片用红色的线条分成4个部分，如下：

我们自定义一个View,代码如下：

public class PoterDuffLoadingView extends View { private Resources mResources; private Paint mBitPaint; private Bitmap mBitmap; private int mTotalWidth, mTotalHeight; private Bitmap girlBitmap; private int girlBitWidth , girlBitHeight; private Rect girlSrcRect , girlDesRect; public PoterDuffLoadingView(Context context) {  super(context);  mResources = getResources();  initBitmap(); } private void initBitmap() {  //美女图片的宽和高  girlBitmap = ((BitmapDrawable)mResources.getDrawable(R.drawable.a1)).getBitmap();  girlBitWidth = girlBitmap.getWidth();  girlBitHeight = girlBitmap.getHeight(); } @Override protected void onDraw(Canvas canvas) {  super.onDraw(canvas);  canvas.drawBitmap(girlBitmap, girlSrcRect, girlDesRect, null); } @Override protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {  super.onMeasure(widthMeasureSpec, heightMeasureSpec); } @Override protected void onSizeChanged(int w, int h, int oldw, int oldh) {  Log.d("xxxxxx", "onSizeChanged , w = "+w+" , h = "+h+" , mBitWidth = "+mBitWidth+" , mBitHeight = "+mBitHeight);  super.onSizeChanged(w, h, oldw, oldh);  mTotalWidth = w;  mTotalHeight = h;  girlSrcRect = new Rect(0, 0, girlBitWidth, girlBitHeight);  girlDesRect = new Rect(0, 0, girlBitWidth, girlBitHeight); }}