Android使用动态调整控件参数的方法写自定义动画

公司的项目里要用到一个自定义的控件，一个窗帘随着手指滑动按钮进行上拉或者下滑，本质上是个很简单的东西，用属性动画分分钟就能搞定

Paste_Image.png

但难就难在因为帘子向上滑的太多就会很密集，很难看，所以需要滑到帘子长度三分之二的时候停止滑动向上平移

纠...纠结了...

一开始的解决方案是做了三个动画，一个压缩帘子一个平移帘子一个平移按钮

实现是实现了但是出现了个不同步的问题，这也难怪，就算用动画流控制同时开始但毕竟运动速度都不一样，难免出现本来帘子开始运动时在按钮下半部分到顶了成上半部分了

遂改之

换了个思路，既然直接用动画平移不行，那何不动态赋给控件值改变帘子的控件高度和帘子距离顶部距离，然后把按钮和帘子的底部关联起来？

 private void doanmi() {
        if (anim2==null){
            anim = ValueAnimator.ofFloat(flag.getHeight(),flag.getHeight()/4);
            anim.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
                @Override
                public void onAnimationUpdate(ValueAnimator animation) {
                    currentValue1 = (float) animation.getAnimatedValue();
                    final ViewGroup.LayoutParams[] para1 = new ViewGroup.LayoutParams[1];
                    para1[0] = flag.getLayoutParams();
                    para1[0].height = (int) currentValue1;
                    flag.setLayoutParams(para1[0]);
                }
            });
            anim.setDuration(3000);
            anim2 = ValueAnimator.ofFloat( 0,-glass.getHeight()/4);
            anim2.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
                @Override
                public void onAnimationUpdate(ValueAnimator animation) {
                    currentValue2 = (float) animation.getAnimatedValue();
                    RelativeLayout.LayoutParams layout=(RelativeLayout.LayoutParams)flag.getLayoutParams();
                    layout.topMargin= (int) currentValue2+device.getHeight();
                    flag.setLayoutParams(layout);
                }
            });
            anim2.setDuration(5000);
        }else{
            if (path==PathEnum.DOWN){
                anim.setFloatValues(currentValue1,glass.getHeight()+15f);
                anim.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
                    @Override
                    public void onAnimationUpdate(ValueAnimator animation) {
                        float currentValue1 = (float) animation.getAnimatedValue();
                        final ViewGroup.LayoutParams[] para1 = new ViewGroup.LayoutParams[1];
                        para1[0] = flag.getLayoutParams();
                        para1[0].height = (int) currentValue1;
                        flag.setLayoutParams(para1[0]);
                    }
                });
                anim2.setFloatValues(currentValue2,0);
                anim2.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
                    @Override
                    public void onAnimationUpdate(ValueAnimator animation) {
                        float currentValue2 = (float) animation.getAnimatedValue();
                        RelativeLayout.LayoutParams layout=(RelativeLayout.LayoutParams)flag.getLayoutParams();
                        layout.topMargin= (int)currentValue2+device.getHeight();
                        flag.setLayoutParams(layout);
                    }
                });
                anim.setDuration(3000);
                anim2.setDuration(5000);
            }else{
                anim.setFloatValues(currentValue1,glass.getHeight()/4);
                anim.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
                    @Override
                    public void onAnimationUpdate(ValueAnimator animation) {
                        float currentValue1 = (float) animation.getAnimatedValue();
                        final ViewGroup.LayoutParams[] para1 = new ViewGroup.LayoutParams[1];
                        para1[0] = flag.getLayoutParams();
                        para1[0].height = (int) currentValue1;
                        flag.setLayoutParams(para1[0]);
                    }
                });
                anim2.setFloatValues(0,-glass.getHeight()/4);
                anim2.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
                    @Override
                    public void onAnimationUpdate(ValueAnimator animation) {
                        float currentValue2 = (float) animation.getAnimatedValue();
                        RelativeLayout.LayoutParams layout=(RelativeLayout.LayoutParams)flag.getLayoutParams();
                        layout.topMargin= (int) currentValue2+device.getHeight();
                        flag.setLayoutParams(layout);
                    }
                });
                anim.setDuration(3000);
                anim2.setDuration(5000);
            }
        }
        anim.start();
        anim2.start();
    }

    private void endMove() {
        if(anim2 != null) {
            anim.cancel();
            anim2.cancel();
        }else{
            Log.a("no device");
        }
    }