Android RecyclerView 打造带悬浮效果的联系人

项目要求，联系人页面，怎样才能好看一点呢？ 又不要用ListView，又要带悬浮的标。来吧，说一下联系人的点

首先有个SideBarView 就是侧边字母栏，这个东西呢 关于自定义view ,我了两个SideBarView 

两种不同风格的SideBarView Tisp;

先贴代码吧

第一种

public class SildeBar extends View {

    public static final String TAG = "SlideBar";
    // 触摸事件
    private OnTouchingLetterChangedListener onTouchingLetterChangedListener;
    // 26个字母
    public static String[] b = { "A", "B", "C", "D", "E", "F", "G", "H", "I", "J", "K", "L", "M", "N", "O", "P", "Q",
            "R", "S", "T", "U", "V", "W", "X", "Y", "Z", "#" };
    private int choose = -1;// 选中
    private Paint paint = new Paint();

    private TextView mTextDialog;
    private float singleHeight;

    public static int dialogColor[] = { R.drawable.dialog_color_blue, R.drawable.dialog_color_green,
            R.drawable.dialog_color_orange, R.drawable.dialog_color_purple, R.drawable.dialog_color_red };;

    public void setTextView(TextView mTextDialog) {
        this.mTextDialog = mTextDialog;
    }

    public SildeBar(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
    }

    public SildeBar(Context context, AttributeSet attrs) {
        super(context, attrs);
    }

    public SildeBar(Context context) {
        super(context);
    }

    /**
     * 重写这个方法
     */
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        // 获取焦点改变背景颜色.
        int height = getHeight();// 获取对应高度
        int width = getWidth(); // 获取对应宽度

        // 获取每一个字母的高度
        singleHeight = (height * 1f) / b.length;
        singleHeight = (height * 1f - singleHeight/2) / b.length;
        for (int i = 0; i < b.length; i++) {
           // paint.setColor(Color.rgb(23, 122, 216));

            paint.setColor(Color.GRAY);
            paint.setTypeface(Typeface.DEFAULT_BOLD);
            paint.setAntiAlias(true);
            paint.setTextSize(35);
            // 选中的状态
            if (i == choose) {
                paint.setColor(Color.parseColor("#c60000"));
                paint.setFakeBoldText(true);
            }
            // x坐标等于中间-字符串宽度的一半.
            float xPos = width / 2 - paint.measureText(b[i]) / 2;
            float yPos = singleHeight * i + singleHeight;
            canvas.drawText(b[i], xPos, yPos, paint);
            paint.reset();// 重置画笔
        }

    }

    @RequiresApi(api = Build.VERSION_CODES.JELLY_BEAN)
    @Override
    public boolean dispatchTouchEvent(MotionEvent event) {
        final int action = event.getAction();
        final float y = event.getY();// 点击y坐标
        final int oldChoose = choose;
        final OnTouchingLetterChangedListener listener = onTouchingLetterChangedListener;
        final int c = (int) (y / getHeight() * b.length);// 点击y坐标所占总高度的比例*b数组的长度就等于点击b中的个数.

        switch (action) {
            case MotionEvent.ACTION_UP:
                setBackgroundDrawable(new ColorDrawable(0x00808080));
                choose = -1;//
                invalidate();
                if (mTextDialog != null) {
                    mTextDialog.setVisibility(View.INVISIBLE);
                }
                break;
            // 除开松开事件的任何触摸事件
            default:
                setBackgroundResource(R.drawable.bg_slide_bar);

                if (oldChoose != c) {
                    if (c >= 0 && c < b.length) {
                        if (listener != null) {
                            listener.onTouchingLetterChanged(b[c]);
                        }
                        if (mTextDialog != null) {
                            mTextDialog.setText(b[c]);
                            mTextDialog.setVisibility(View.VISIBLE);


                            // 动态改变文字dialog的位置
//                            int right = mTextDialog.getLeft();
//                            mTextDialog.setX(right / 2 * 3);
//                            if(c>24){
//                                mTextDialog.setY(singleHeight * 24);
//                            }else{
//                                mTextDialog.setY(singleHeight * c);
//                            }
                            mTextDialog.setBackground(getContext().getResources().getDrawable(dialogColor[c / 6]));
                        }

                        choose = c;
                        invalidate();
                    }
                }

                break;
        }
        return true;
    }

    /**
     * 向外公开的方法
     *
     * @param onTouchingLetterChangedListener
     */
    public void setOnTouchingLetterChangedListener(OnTouchingLetterChangedListener onTouchingLetterChangedListener) {
        this.onTouchingLetterChangedListener = onTouchingLetterChangedListener;
    }

    /**
     * 接口
     *
     * @author coder
     *
     */
    public interface OnTouchingLetterChangedListener {
        public void onTouchingLetterChanged(String s);
    }

}

这里面放置了几张图。

第二种 就是开源项目

 QuickSideBarView 这个 去百度搜一下  挺好用的

public  abstract  class RcvAdapter<VH extends RecyclerView.ViewHolder> extends  RecyclerView.Adapter<VH>{

    private ArrayList<ContactListInfo> item = new ArrayList<ContactListInfo>();

    public RcvAdapter(){
        setHasStableIds(true);
    }

    public void add(ContactListInfo object){
        item.add(object);
        notifyDataSetChanged();
    }
//添加 索引 列表
    public void add(int index ,ContactListInfo object){
        item.add(index,object);
    }
//添加成哥列表的数据进去
    public void addAll(Collection<? extends ContactListInfo> collection){
        if(collection!=null){
            item.addAll(collection);
            notifyDataSetChanged();
        }
    }
    public void addAll(ContactListInfo... items){
        addAll(Arrays.asList(items));
    }

    public void clear() {
        item.clear();
        notifyDataSetChanged();
    }
    public void remove(String object) {
        item.remove(object);
        notifyDataSetChanged();
    }
    public ContactListInfo getItem(int position){
        return item.get(position);
    }

    @Override
    public long getItemId(int position) {
        return  getItem(position).hashCode();
    }

    @Override
    public int getItemCount() {
        return item.size();
    }

    public abstract long getHeaderId(int position);

    public abstract RecyclerView.ViewHolder onCreateHeaderViewHolder(ViewGroup parent);

    public abstract void onBindHeaderViewHolder(RecyclerView.ViewHolder holder, int position);


}

他的adapter 写成了一个 抽象类，方便我们继承