如何在android中旋轉按鈕

Question

嗨，在我的應用程序中，我試圖旋轉按鈕關於它的中心，但它不是基於它的中心旋轉，而是從它的位置移動。下面是我的代碼，請幫助我如何解決這個問題。

 public class example extends Activity {
float newAngle,oldAngle=0;


int flag=0;
int n=340;
 RotateAnimation animation,animation1;

    Button arrow;
    Button left,right;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);
     arrow=(Button)findViewById(R.id.img);
     left=(Button)findViewById(R.id.left);
     right=(Button)findViewById(R.id.right);
    final int width = arrow.getWidth();
    final int height = arrow.getHeight();      

     left.setOnClickListener(new OnClickListener() {
        @Override
        public void onClick(View v) {
            // TODO Auto-generated method stub
            if(flag>=0)
            {
                   newAngle = oldAngle+ 30;

                    oldAngle=newAngle;
            }
            flag++;
            Log.i("flag",""+flag);
             animation = new RotateAnimation(oldAngle, newAngle);
             animation.setFillAfter(true);
             animation.setDuration(200);
             arrow.startAnimation(animation);
        }
    });
     }
       }

Answer 1

更輕松...

http://developer.android.com/reference/android/view/animation/RotateAnimation.html#RotateAnimation(float,float,int,flo，int，float ）

new RotateAnimation(_oldAngle, _newAngle, Animation.RELATIVE_TO_SELF, 0.5f, Animation.RELATIVE_TO_SELF, 0.5f);

Answer 2

完整的例子：

 public class MyActivity extends Activity implements View.OnClickListener {

    private ImageView _image;
    private float _newAngle, _oldAngle;


    /**
     * Called when the activity is first created.
     */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        Button button = (Button) findViewById(R.id.button);
        button.setOnClickListener(this);
        _image = (ImageView) findViewById(R.id.image);
    }

    public void onClick(View view) {
        if (view.getId() == R.id.button) {
            _newAngle = _oldAngle + 30;

            LinearLayout.LayoutParams layoutParams = (LinearLayout.LayoutParams) _image.getLayoutParams();
            int centerX = layoutParams.leftMargin + (_image.getWidth()/2);
            int centerY = layoutParams.topMargin + (_image.getHeight()/2);
            RotateAnimation animation = new RotateAnimation(_oldAngle, _newAngle, centerX, centerY);
            animation.setDuration(0);
            animation.setRepeatCount(0);
            animation.setFillAfter(true);
            _image.startAnimation(animation);

            _oldAngle = _newAngle;
        }
    }
}

Answer 3

最簡單的解決方案值得一提：

button.setRotation( angle );

把它放在你的onClick方法中。 例如：

public void onClick( View v ) { v.setRotation( v.getRotation() + 30f ); }

請參閱View API 。

Answer 4

采用

RotateAnimation（float fromDegrees，float toDegrees，float pivotX，float pivotY）

pivotX，pivotY - 按鈕中心的坐標。 看起來你的角度是一樣的