像转向一样旋转Imageview？

Question

我们可以在Android中使用手指沿着其中心旋转具有源代码（附加图像）的imageview吗？

Answer 1

public class MainActivity extends Activity implements OnTouchListener{ 
private ImageView wheel; 
private double mCurrAngle = 0; 
private double mPrevAngle = 0; 
ImageView bask; 

@Override 
protected void onCreate(Bundle savedInstanceState) { 
super.onCreate(savedInstanceState); 
setContentView(R.layout.activity_main); 

wheel=(ImageView)findViewById(R.id.imageView1); 
wheel.setOnTouchListener(this); 
} 

@Override 
public boolean onTouch(final View v, MotionEvent event) { 
final float xc = wheel.getWidth()/2; 
final float yc = wheel.getHeight()/2; 
final float x = event.getX(); 
final float y = event.getY(); 
switch (event.getAction()) { 
case MotionEvent.ACTION_DOWN: { 
wheel.clearAnimation(); 
mCurrAngle = Math.toDegrees(Math.atan2(x - xc, yc - y)); 
break; 
} 
case MotionEvent.ACTION_MOVE: { 
mPrevAngle = mCurrAngle; 
mCurrAngle = Math.toDegrees(Math.atan2(x - xc, yc - y)); 
animate(mPrevAngle, mCurrAngle, 0); 
System.out.println(mCurrAngle); 
break; 
} 
case MotionEvent.ACTION_UP : { 
mPrevAngle = mCurrAngle = 0; 
break; 
} 
} 
return true; 
} 
private void animate(double fromDegrees, double toDegrees, long durationMillis) { 
final RotateAnimation rotate = new RotateAnimation((float) fromDegrees, (float) toDegrees, 
RotateAnimation.RELATIVE_TO_SELF, 0.5f, 
RotateAnimation.RELATIVE_TO_SELF, 0.5f); 
rotate.setDuration(durationMillis); 
rotate.setFillEnabled(true); 
rotate.setFillAfter(true); 
wheel.startAnimation(rotate); 
System.out.println(mCurrAngle); 
} 
}