从左到右的动画滑动面板？答案

【问题标题】：Left to right animated sliding panel?从左到右的动画滑动面板？
【发布时间】：2011-10-02 02:04:54
【问题描述】：

我正在尝试在我的布局中添加一个类似于滑动抽屉的滑动面板，不同之处在于它将放置在我的主布局的左侧而不是覆盖它。我的布局左上角有一个小按钮，当我单击它时，它会展开/折叠面板。当它展开/折叠时，我希望动画平滑，以便与其相邻的视图也会移动。这是我尝试过的代码。面板在第一次展开/折叠后停止工作：

public Animation expandHiddenPanel(final View v, final boolean expand) {
    panelExpanded = expand;
    v.measure(MeasureSpec.makeMeasureSpec(200, MeasureSpec.AT_MOST), 
              MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED));

    final int initialWidth = v.getMeasuredWidth();
    Log.i("test", "initialWidth = " + initialWidth);

    v.getLayoutParams().width = 0;
    v.setVisibility(View.VISIBLE);

    Animation a = new Animation() {
        @Override
        protected void applyTransformation(float interpolatedTime, Transformation t) {
            int newWidth;

            if (expand) {
                newWidth = (int)(initialWidth * interpolatedTime);
                Log.i("test", "new Width = " + newWidth);
            }
            else {
                newWidth = (int)(initialWidth * (1 - interpolatedTime));
                Log.i("test", "new Width = " + newWidth);
            }

            v.getLayoutParams().width = newWidth;
            v.requestLayout();              
        }

        @Override
        public boolean willChangeBounds() {
            return true;
        }
    };

    a.setInterpolator(new AccelerateInterpolator());
    a.setDuration(2500);
    v.startAnimation(a);

    return a;
}

【问题讨论】：

标签： android animation expand collapse

【解决方案1】：

确保如果你想以增长的宽度显示动画，然后在 xml 文件中提及布局特定的宽度，并使用下面的代码根据宽度展开和折叠动画。

//expand animation      
public static void expand(final View v) {
        v.measure(LayoutParams.WRAP_CONTENT, LayoutParams.MATCH_PARENT);
        final int targtetWidth = v.getMeasuredWidth();
        Log.v("view width", "view expand width==>"+targtetWidth);
        v.getLayoutParams().width = 0;
        v.setVisibility(View.VISIBLE);

        Animation a = new Animation() {
            @Override
            protected void applyTransformation(float interpolatedTime,Transformation t) {
                v.getLayoutParams().width = interpolatedTime == 1 ? LayoutParams.WRAP_CONTENT: (int)(targtetWidth * interpolatedTime);
                v.requestLayout();
            }

            @Override
            public boolean willChangeBounds() {
                return true;
            }
        };

        a.setDuration(100);
        v.startAnimation(a);
    }

//collapse animation
    public static void collapse(final View v) {
        final int initialWidth = v.getMeasuredWidth();
        Log.v("initial width", "initial width==>"+initialWidth); 
        Animation a = new Animation() {
            @Override
            protected void applyTransformation(float interpolatedTime,
                    Transformation t) {
                if (interpolatedTime == 1) {
                    Log.v("interpolated", "interpolated time is 1");
                    v.setVisibility(View.GONE);
                } else {

                    v.getLayoutParams().width = initialWidth - (int) (initialWidth * interpolatedTime);
                    Log.v("interpolated", "interpolated time is===>"+v.getLayoutParams().width);
                    v.requestLayout();
                }
            }

            @Override
            public boolean willChangeBounds() {
                return true;
            }
        };

        // 1dp/ms
        Log.v("duration", "duration for collapse==>"+((int)(initialWidth /v.getContext().getResources().getDisplayMetrics().density)));
        a.setDuration((int) (initialWidth / v.getContext().getResources().getDisplayMetrics().density));
        v.startAnimation(a);
    }

【讨论】：