android 控件跟随手指移动，类似捕鱼达人效果

 

 

public class TestActivity extends AppCompatActivity {

    private ImageView imageView;
    private ImageView imageView2;
    private Context context;
    //defalut旋转开始角度
    private float dfFromDegrees = -90;
    //旋转结束角度
    private float dfToDegrees = 90;
    private ObjectAnimator animator;
    //动画类型
    private String propertyName = "rotation";
    //持续时间
    private long duration = 3000;
    //重复模式
    int RepeatCount = -1;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_test);
        context = TestActivity.this;
        initView();
        initAnimator();
        animatorStart();
    }

    //初始化动画
    private void initAnimator() {
        animator = ObjectAnimator.ofFloat(imageView, propertyName, dfFromDegrees, dfToDegrees);
        animator.setDuration(duration);
        animator.setRepeatCount(RepeatCount);
        animator.setRepeatMode(ValueAnimator.REVERSE);
    }

    private void initView() {
        imageView = (ImageView) findViewById(R.id.image);
        imageView2 = (ImageView) findViewById(R.id.image2);
        imageView2.setVisibility(View.GONE);
    }

    @Override
    public boolean dispatchTouchEvent(MotionEvent ev) {
        LogUtil.i("countAngle(ev):" + countAngle(ev));
        switch (ev.getAction()) {
            case MotionEvent.ACTION_DOWN:
                LogUtil.i("ACTION_DOWN");
                animatorCancel();
                setImageView2TransLation(ev, true);
                imageView.setRotation(countAngle(ev));
                break;
            case MotionEvent.ACTION_MOVE:
                LogUtil.i("ACTION_MOVE");
                animatorCancel();
                imageView2.setVisibility(View.VISIBLE);
                setImageView2TransLation(ev, true);
                imageView.setRotation(countAngle(ev));
                break;
            case MotionEvent.ACTION_UP:
                LogUtil.i("ACTION_UP");
                imageView2.setVisibility(View.GONE);
                setAnimatorDegrees(dfFromDegrees, dfToDegrees);
                setImageView2TransLation(ev, false);
                animatorStart();
                break;
        }
        return super.dispatchTouchEvent(ev);
    }

    //计算点击角度
    private float countAngle(MotionEvent event) {
        //点击的坐标X
        float clickX = event.getX();
        //点击的坐标Y
        float clickY = event.getY();
        //imageView控件X坐标
        float viewX = imageView.getX() + imageView.getPivotX();
        float viewY = imageView.getY() + imageView.getPivotY();
        return getRotationBetweenLines(viewX, viewY, clickX, clickY);
    }

    //设置控件2位置是否隐藏
    private void setImageView2TransLation(MotionEvent ev, boolean isShow) {
        imageView2.setTranslationX(ev.getX() - imageView2.getWidth() / 2);
        imageView2.setTranslationY(ev.getY() - imageView2.getHeight());
        imageView2.setVisibility(isShow ? View.VISIBLE : View.GONE);
    }

    //设置动画旋转角度
    private void setAnimatorDegrees(float fromDegrees, float toDegrees) {
        animator = ObjectAnimator.ofFloat(imageView, propertyName, fromDegrees, toDegrees);
        animator.setDuration(3000);
        animator.setRepeatCount(-1);
        animator.setRepeatMode(ValueAnimator.REVERSE);
    }

    //开始动画
    private void animatorStart() {
        if (animator != null)
            animator.start();
    }

    //关闭动画
    private void animatorCancel() {
        if (animator != null)
            animator.cancel();
    }

    //centerX、centerY为公共点，xInView、yInView为触摸点的坐标
    public int getRotationBetweenLines(float centerX, float centerY, float xInView, float yInView) {
        double rotation = 0;
        double k1 = (double) (centerY - centerY) / (centerX * 2 - centerX);
        double k2 = (double) (yInView - centerY) / (xInView - centerX);
        double tmpDegree = Math.atan((Math.abs(k1 - k2)) / (1 + k1 * k2)) / Math.PI * 180;

        if (xInView > centerX && yInView < centerY) {  //第一象限
            rotation = 90 - tmpDegree;
        } else if (xInView > centerX && yInView > centerY) //第二象限
        {
            rotation = 90 + tmpDegree;
        } else if (xInView < centerX && yInView > centerY) { //第三象限
            rotation = 270 - tmpDegree;
        } else if (xInView < centerX && yInView < centerY) { //第四象限
            rotation = 270 + tmpDegree;
        } else if (xInView == centerX && yInView < centerY) {
            rotation = 0;
        } else if (xInView == centerX && yInView > centerY) {
            rotation = 180;
        }
        return (int) rotation;
    }

}