记录跟随recyclerview滑动的指示器

老早之前做的一个功能，横向recyclerview滑动时，底部做跟随滑动指示器。今天代码不用了，记录下代码。

XML 复制代码

<LinearLayout
                    android:layout_width="match_parent"
                    android:layout_height="wrap_content"
                    android:layout_marginTop="@dimen/fourteen"
                    android:orientation="vertical"
                    android:paddingLeft="@dimen/sixteen"
                    android:paddingRight="@dimen/sixteen">

                    <androidx.recyclerview.widget.RecyclerView
                        android:id="@+id/rv_teacher"
                        android:layout_width="match_parent"
                        android:layout_height="wrap_content">

                    </androidx.recyclerview.widget.RecyclerView>

                    <RelativeLayout
                        android:id="@+id/scroll_bar_bg"
                        android:layout_width="30dp"
                        android:layout_height="4dp"
                        android:layout_gravity="center"
                        android:layout_marginTop="@dimen/six"
                        android:background="@drawable/bg_fast_view">

                        <View
                            android:id="@+id/scroll_bar"
                            android:layout_width="20dp"
                            android:layout_height="4dp"
                            android:layout_centerVertical="true"
                            android:background="@drawable/bg_scroll_bar" />
                    </RelativeLayout>

                </LinearLayout>

bg_fast_view

XML 复制代码

<shape xmlns:android="http://schemas.android.com/apk/res/android">

    <solid
        android:color="@color/Gray"/>

    <corners
        android:radius="@dimen/ten"/>

</shape>

bg_scroll_bar

XML 复制代码

<shape xmlns:android="http://schemas.android.com/apk/res/android">

    <solid
        android:color="@color/title_bg"/>

    <corners
        android:radius="@dimen/ten"/>

</shape>

java 复制代码

RelativeLayout scrollBarBg = view.findViewById(R.id.parent_layout);
View scrollBar = view.findViewById(R.id.main_line);

 GridLayoutManager layoutManager = new GridLayoutManager(mContext, 2);
            layoutManager.setOrientation(LinearLayoutManager.HORIZONTAL);
            rvTeacher.setLayoutManager(layoutManager);
            teacherAdapter = new RecommendTeacherRVAdapter(mContext);
            rvTeacher.setAdapter(teacherAdapter);
            rvTeacher.addOnScrollListener(new RecyclerView.OnScrollListener() {
                public int range = 0;

                @Override
                public void onScrollStateChanged(RecyclerView recyclerView, int newState) {
                    super.onScrollStateChanged(recyclerView, newState);

                }

                @Override
                public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
                    super.onScrolled(recyclerView, dx, dy);

                    //整体的总宽度，注意是整体，包括在显示区域之外的。
                    int temp = recyclerView.computeHorizontalScrollRange();
                    if (temp > range) {
                        range = temp;
                    }
                    int offset = recyclerView.computeHorizontalScrollOffset();
                    int extent = recyclerView.computeHorizontalScrollExtent();

                    float proportion = (float) (offset * 1.0 / (range - extent));
                    //计算滚动条宽度
                    float transMaxRange = scrollBarBg.getWidth() - scrollBar.getWidth();
                    //设置滚动条移动
                    scrollBar.setTranslationX(transMaxRange * proportion);
                }

            });