Android自定义View图片按Path运动和旋转

/** 
 * author : stone 
 * email : aa86799@163.com 
 * time : 16/5/29 15 29 
 */ 
public class EarthPathView extends View { 
 
 private Path mPath; 
 private Paint mPaint; 
 private Bitmap mBitmap; 
 private PathMeasure mPathMeasure; 
 private float[] mPoint; 
 private float[] mTan; 
 private float mDdegrees; 
 
 public EarthPathView(Context context) { 
  this(context, null); 
 } 
 
 public EarthPathView(Context context, AttributeSet attrs) { 
  this(context, attrs, 0); 
 } 
 
 public EarthPathView(Context context, AttributeSet attrs, int defStyleAttr) { 
  super(context, attrs, defStyleAttr); 
 
  mPaint = new Paint(); 
  mPaint.setColor(Color.RED); 
  mPaint.setStyle(Paint.Style.STROKE); 
  mPaint.setStrokeWidth(10); 
 
  InputStream is = getResources().openRawResource(R.drawable.earth); 
  mBitmap = BitmapFactory.decodeStream(is); 
 
 } 
 
 public void setPath(Path path) { 
  mPath = path; 
  mPathMeasure = new PathMeasure(path, false); 
  mPoint = new float[2]; 
  mTan = new float[2]; 
 
 } 
 
 @Override 
 protected void onDraw(Canvas canvas) { 
  super.onDraw(canvas); 
  if (mPath == null) { 
   return; 
  } 
 
 
  canvas.rotate(mDdegrees+=2, getWidth()/2, getHeight()/2); 
  canvas.drawPath(mPath, mPaint); 
 
  float degress = (float) Math.toDegrees(Math.atan2(mTan[1], mTan[0])); 
  Matrix matrix = new Matrix(); 
  matrix.postRotate(degress, mBitmap.getWidth() / 2, mBitmap.getHeight() / 2); 
  matrix.postTranslate(mPoint[0] - mBitmap.getWidth() / 2, mPoint[1] - mBitmap.getHeight() / 2); 
  canvas.drawBitmap(mBitmap, matrix, null); 
 
 
 } 
 
 @TargetApi(Build.VERSION_CODES.HONEYCOMB) 
 public void startAnim() { 
  ValueAnimator animator = ValueAnimator.ofFloat(0, mPathMeasure.getLength()); 
  animator.setDuration(2000); 
  animator.setInterpolator(new LinearInterpolator()); //插值器 
  animator.setRepeatCount(ValueAnimator.INFINITE); 
  animator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() { 
   @Override 
   public void onAnimationUpdate(ValueAnimator animation) { 
    float distance = (float) animation.getAnimatedValue(); 
    mPathMeasure.getPosTan(distance, mPoint, mTan); 
    invalidate(); 
   } 
  }); 
  animator.start(); 
 } 
} 

package com.stone.canvaspath; 
 
import android.app.Activity; 
import android.graphics.Path; 
import android.os.Bundle; 
 
import com.stone.canvaspath.earth.EarthPathView; 
 
/** 
 * author : stone 
 * email : aa86799@163.com 
 * time : 16/5/29 15 27 
 */ 
public class EarthActivity extends Activity { 
 
 private EarthPathView mPathView; 
 private Path mPath; 
 
 @Override 
 protected void onCreate(Bundle savedInstanceState) { 
  super.onCreate(savedInstanceState); 
 
  int w = getResources().getDisplayMetrics().widthPixels; 
  int h = getResources().getDisplayMetrics().heightPixels; 
 
  mPathView = new EarthPathView(this); 
 
  setContentView(mPathView); 
 
  int min = Math.min(w, h); 
  buildPath(w / 2 + 100, h / 2 + 100, min / 4); 
 
  mPathView.setPath(mPath); 
 
  mPathView.startAnim(); 
 } 
 
 private void buildPath(float x, float y, float radius) { 
  mPath = new Path(); 
  mPath.addCircle(x, y, radius, Path.Direction.CW); 
 } 
 
}