canvasdrawBitmap方法怎么样在Android项目中使用-创新互联

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);

 }
}