先上效果图
ezgif.com-video-to-gif (1).gif
需求1：底部滚动栏最多展示6条数据，若选中数据在6条之后，自动滚动到选中数据项
mRecyclerView.smoothScrollToPosition(i); 需求2：popupwindow弹出动画前整个页面效果变暗
在popupwindow show()方法前调用setBackgroundAlpha(activity,0.6f),在dismiss方法前调用
setBackgroundAlpha(activity,1f)将透明度还原`
public static void setBackgroundAlpha(Activity activity,float bgAlpha) {
WindowManager.LayoutParams lp = activity.getWindow().getAttributes();
lp.alpha = bgAlpha; //0.0-1.0
//解决华为手机设置背景色无效
if (bgAlpha == 1) {
activity.getWindow().clearFlags(WindowManager.LayoutParams.FLAG_DIM_BEHIND);//不移除该Flag的话,在有视频的页面上的视频会出现黑屏的bug
} else {
activity.getWindow().addFlags(WindowManager.LayoutParams.FLAG_DIM_BEHIND);//此行代码主要是解决在华为手机上半透明效果无效的bug
}
activity.getWindow().setAttributes(lp);
}`
需求3：底部滚动栏最多展示6条数据，若小于6条列表自适应高度
重写recyclerView LayoutManager的onMeasure方法，当小于6条是显示list高度
`
//默认显示6条，超过6条滑动显示
mRecyclerView.setLayoutManager(new LinearLayoutManager(mActivity) {
@Override
public void onMeasure(RecyclerView.Recycler recycler, RecyclerView.State state, int widthSpec, int heightSpec) {
int count = getChildCount();
if (count > 0 && count <= 6) {
View firstChildView = recycler.getViewForPosition(0);
measureChild(firstChildView, widthSpec, heightSpec);
setMeasuredDimension(View.MeasureSpec.getSize(widthSpec), firstChildView.getMeasuredHeight() * count);
} else {
super.onMeasure(recycler, state, widthSpec, heightSpec);
}
}
});`