超简单自定义滚动选择器

效果图：

自定义滚动选择器WheelView

public class WheelView extends ScrollView {
    public static final String TAG = WheelView.class.getSimpleName();

    public static class OnWheelViewListener {
        public void onSelected(int selectedIndex, String item) {
        }
    }


    private Context context;
//    private ScrollView scrollView;

    private LinearLayout views;

    public WheelView(Context context) {
        super(context);
        init(context);
    }

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

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

    //    String[] items;
    List<String> items;

    private List<String> getItems() {
        return items;
    }

    public void setItems(List<String> list) {
        if (null == items) {
            items = new ArrayList<String>();
        }
        items.clear();
        items.addAll(list);

        // 前面和后面补全
        for (int i = 0; i < offset; i++) {
            items.add(0, "");
            items.add("");
        }

        initData();

    }


    public static final int OFF_SET_DEFAULT = 1;
    int offset = OFF_SET_DEFAULT; // 偏移量（需要在最前面和最后面补全）

    public int getOffset() {
        return offset;
    }

    public void setOffset(int offset) {
        this.offset = offset;
    }

    int displayItemCount; // 每页显示的数量

    int selectedIndex = 1;


    private void init(Context context) {
        this.context = context;

//        scrollView = ((ScrollView)this.getParent());
//        Log.d(TAG, "scrollview: " + scrollView);
        Log.d(TAG, "parent: " + this.getParent());
//        this.setOrientation(VERTICAL);
        this.setVerticalScrollBarEnabled(false);

        views = new LinearLayout(context);
        views.setOrientation(LinearLayout.VERTICAL);
        this.addView(views);

        scrollerTask = new Runnable() {

            public void run() {

                int newY = getScrollY();
                if (initialY - newY == 0) { // stopped
                    final int remainder = initialY % itemHeight;
                    final int divided = initialY / itemHeight;
//                    Log.d(TAG, "initialY: " + initialY);
//                    Log.d(TAG, "remainder: " + remainder + ", divided: " + divided);
                    if (remainder == 0) {
                        selectedIndex = divided + offset;

                        onSeletedCallBack();
                    } else {
                        if (remainder > itemHeight / 2) {
                            WheelView.this.post(new Runnable() {
                                @Override
                                public void run() {
                                    WheelView.this.smoothScrollTo(0, initialY - remainder + itemHeight);
                                    selectedIndex = divided + offset + 1;
                                    onSeletedCallBack();
                                }
                            });
                        } else {
                            WheelView.this.post(new Runnable() {
                                @Override
                                public void run() {
                                    WheelView.this.smoothScrollTo(0, initialY - remainder);
                                    selectedIndex = divided + offset;
                                    onSeletedCallBack();
                                }
                            });
                        }


                    }


                } else {
                    initialY = getScrollY();
                    WheelView.this.postDelayed(scrollerTask, newCheck);
                }
            }
        };


    }

    int initialY;

    Runnable scrollerTask;
    int newCheck = 50;

    public void startScrollerTask() {

        initialY = getScrollY();
        this.postDelayed(scrollerTask, newCheck);
    }

    private void initData() {
        displayItemCount = offset * 2 + 1;

        for (String item : items) {
            views.addView(createView(item));
        }

        refreshItemView(0);
    }

    int itemHeight = 0;

    private TextView createView(String item) {
        TextView tv = new TextView(context);
        tv.setLayoutParams(new LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.WRAP_CONTENT));
        tv.setSingleLine(true);
        tv.setTextSize(TypedValue.COMPLEX_UNIT_SP, 18);
        tv.setText(item);
        tv.setGravity(Gravity.CENTER);
        int padding = dip2px(12);
        tv.setPadding(padding, padding, padding, padding);
        if (0 == itemHeight) {
            itemHeight = getViewMeasuredHeight(tv);
            Log.d(TAG, "itemHeight: " + itemHeight);
            views.setLayoutParams(new LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, itemHeight * displayItemCount));
            LinearLayout.LayoutParams lp = (LinearLayout.LayoutParams) this.getLayoutParams();
            this.setLayoutParams(new LinearLayout.LayoutParams(lp.width, itemHeight * displayItemCount));
        }
        return tv;
    }


    @Override
    protected void onScrollChanged(int l, int t, int oldl, int oldt) {
        super.onScrollChanged(l, t, oldl, oldt);

//        Log.d(TAG, "l: " + l + ", t: " + t + ", oldl: " + oldl + ", oldt: " + oldt);

//        try {
//            Field field = ScrollView.class.getDeclaredField("mScroller");
//            field.setAccessible(true);
//            OverScroller mScroller = (OverScroller) field.get(this);
//
//
//            if(mScroller.isFinished()){
//                Log.d(TAG, "isFinished...");
//            }
//
//        } catch (Exception e) {
//            e.printStackTrace();
//        }


        refreshItemView(t);

        if (t > oldt) {
//            Log.d(TAG, "向下滚动");
            scrollDirection = SCROLL_DIRECTION_DOWN;
        } else {
//            Log.d(TAG, "向上滚动");
            scrollDirection = SCROLL_DIRECTION_UP;

        }


    }

    private void refreshItemView(int y) {
        int position = y / itemHeight + offset;
        int remainder = y % itemHeight;
        int divided = y / itemHeight;

        if (remainder == 0) {
            position = divided + offset;
        } else {
            if (remainder > itemHeight / 2) {
                position = divided + offset + 1;
            }

//            if(remainder > itemHeight / 2){
//                if(scrollDirection == SCROLL_DIRECTION_DOWN){
//                    position = divided + offset;
//                    Log.d(TAG, ">down...position: " + position);
//                }else if(scrollDirection == SCROLL_DIRECTION_UP){
//                    position = divided + offset + 1;
//                    Log.d(TAG, ">up...position: " + position);
//                }
//            }else{
                position = y / itemHeight + offset;
//                if(scrollDirection == SCROLL_DIRECTION_DOWN){
//                    position = divided + offset;
//                    Log.d(TAG, "<down...position: " + position);
//                }else if(scrollDirection == SCROLL_DIRECTION_UP){
//                    position = divided + offset + 1;
//                    Log.d(TAG, "<up...position: " + position);
//                }
//            }
//        }

//        if(scrollDirection == SCROLL_DIRECTION_DOWN){
//            position = divided + offset;
//        }else if(scrollDirection == SCROLL_DIRECTION_UP){
//            position = divided + offset + 1;
        }

        int childSize = views.getChildCount();
        for (int i = 0; i < childSize; i++) {
            TextView itemView = (TextView) views.getChildAt(i);
            if (null == itemView) {
                return;
            }
            if (position == i) {
                //这个是选中的字体颜色
                itemView.setTextColor(Color.parseColor("#000000"));
            } else if (position==i-1||position==i+1){
                //这个是选中的下一行的字体颜色
                itemView.setTextColor(Color.parseColor("#ffbbbbbb"));
            } else if (position==i-2||position==i+2){
                //这个是选中的下两行的字体颜色
                itemView.setTextColor(Color.parseColor("#FFE8E6E6"));
            }
        }
    }

    /**
     * 获取选中区域的边界
     */
    int[] selectedAreaBorder;

    private int[] obtainSelectedAreaBorder() {
        if (null == selectedAreaBorder) {
            selectedAreaBorder = new int[2];
            selectedAreaBorder[0] = itemHeight * offset;
            selectedAreaBorder[1] = itemHeight * (offset + 1);
        }
        return selectedAreaBorder;
    }


    private int scrollDirection = -1;
    private static final int SCROLL_DIRECTION_UP = 0;
    private static final int SCROLL_DIRECTION_DOWN = 1;

    Paint paint;
    int viewWidth;

    @Override
    public void setBackgroundDrawable(Drawable background) {

        if (viewWidth == 0) {
            viewWidth = ((Activity) context).getWindowManager().getDefaultDisplay().getWidth();
            Log.d(TAG, "viewWidth: " + viewWidth);
        }

        if (null == paint) {
            paint = new Paint();
            //这个是线的颜色
            paint.setColor(Color.parseColor("#FFE8E6E6"));
            paint.setStrokeWidth(dip2px(1f));
        }

        background = new Drawable() {
            @Override
            public void draw(Canvas canvas) {
                canvas.drawLine(viewWidth * 1 / 6, obtainSelectedAreaBorder()[0], viewWidth * 5 / 6, obtainSelectedAreaBorder()[0], paint);
                canvas.drawLine(viewWidth * 1 / 6, obtainSelectedAreaBorder()[1], viewWidth * 5 / 6, obtainSelectedAreaBorder()[1], paint);
            }

            @Override
            public void setAlpha(int alpha) {

            }

            @Override
            public void setColorFilter(ColorFilter cf) {

            }

            @SuppressLint("WrongConstant")
            @Override
            public int getOpacity() {
                return 0;
            }
        };


        super.setBackgroundDrawable(background);

    }

    @Override
    protected void onSizeChanged(int w, int h, int oldw, int oldh) {
        super.onSizeChanged(w, h, oldw, oldh);
        Log.d(TAG, "w: " + w + ", h: " + h + ", oldw: " + oldw + ", oldh: " + oldh);
        viewWidth = w;
        setBackgroundDrawable(null);
    }

    /**
     * 选中回调
     */
    private void onSeletedCallBack() {
        if (null != onWheelViewListener) {
            onWheelViewListener.onSelected(selectedIndex, items.get(selectedIndex));
        }

    }

    public void setSeletion(int position) {
        final int p = position;
        selectedIndex = p + offset;
        this.post(new Runnable() {
            @Override
            public void run() {
                WheelView.this.smoothScrollTo(0, p * itemHeight);
            }
        });

    }

    public String getSeletedItem() {
        return items.get(selectedIndex);
    }

    public int getSeletedIndex() {
        return selectedIndex - offset;
    }


    @Override
    public void fling(int velocityY) {
        super.fling(velocityY / 3);
    }

    @Override
    public boolean onTouchEvent(MotionEvent ev) {
        if (ev.getAction() == MotionEvent.ACTION_UP) {

            startScrollerTask();
        }
        return super.onTouchEvent(ev);
    }

    private OnWheelViewListener onWheelViewListener;

    public OnWheelViewListener getOnWheelViewListener() {
        return onWheelViewListener;
    }

    public void setOnWheelViewListener(OnWheelViewListener onWheelViewListener) {
        this.onWheelViewListener = onWheelViewListener;
    }

    private int dip2px(float dpValue) {
        final float scale = context.getResources().getDisplayMetrics().density;
        return (int) (dpValue * scale + 0.5f);
    }

    private int getViewMeasuredHeight(View view) {
        int width = MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED);
        int expandSpec = MeasureSpec.makeMeasureSpec(Integer.MAX_VALUE >> 2, MeasureSpec.AT_MOST);
        view.measure(width, expandSpec);
        return view.getMeasuredHeight();
    }
}

使用：

private void checkYears() {
        //加载布局
        View contentView = View.inflate(PdQueryActivity.this, R.layout.pop_window_data, null);
        //创建pop窗口
        //1.contentView 内部布局
        //2.pop窗口的宽度与高度一般设置成 WRAP_CONTENT
        //3.最后一个参数 代表是否聚集
        PopupWindow pop = new PopupWindow(contentView,
                ViewGroup.LayoutParams.MATCH_PARENT,
                ViewGroup.LayoutParams.WRAP_CONTENT, true);

        //在此pop的区域 外点击关闭此窗口
        pop.setAnimationStyle(R.style.picture_WeChat_style);
        pop.setBackgroundDrawable(new ColorDrawable(alpha));
        pop.setOutsideTouchable(true);
        //设置一个背景
        //pop.setBackgroundDrawable(getResources().getDrawable(R.drawable.ic_launcher));
        //设置一个空背景
        Bitmap bitmap = BitmapFactory.decodeResource(getResources(), 100);
        pop.setBackgroundDrawable(new BitmapDrawable(getResources(), bitmap));

        /**
         * 点击popupWindow让背景变暗
         */
        final WindowManager.LayoutParams lp = getWindow().getAttributes();
        lp.alpha = 0.7f;//代表透明程度，范围为0 - 1.0f
        getWindow().addFlags(WindowManager.LayoutParams.FLAG_DIM_BEHIND);
        getWindow().setAttributes(lp);
        /**
         * 退出popupWindow时取消暗背景
         */
        pop.setOnDismissListener(new PopupWindow.OnDismissListener() {
            @Override
            public void onDismiss() {
                lp.alpha = 1.0f;
                getWindow().addFlags(WindowManager.LayoutParams.FLAG_DIM_BEHIND);
                getWindow().setAttributes(lp);
            }
        });

        //在布局内查找组件
        WheelView loopView = (WheelView) contentView.findViewById(R.id.loopView);
        TextView queding = (TextView) contentView.findViewById(R.id.queding);
        TextView quxiao = (TextView) contentView.findViewById(R.id.quxiao);

        String mYears = years.getText().toString();

        List<String> mList = Arrays.asList(YEARS);
        for (int i = 0; i < mList.size(); i++) {
            if (mYears.equals(mList.get(i))) {
                loopView.setSeletion(i);
            }
        }
        loopView.setOffset(2);
        loopView.setItems(mList);
        queding.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                String seletedItem = loopView.getSeletedItem();
                if (seletedItem.equals("")) {
                    years.setText(Arrays.asList(YEARS).get(0));
                } else {
                    years.setText(loopView.getSeletedItem());
                }
                pop.dismiss();
//                        Toast.makeText(MainActivity.this,loopView.getSeletedItem(),Toast.LENGTH_LONG).show();
            }
        });
        quxiao.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                pop.dismiss();
//                        Toast.makeText(MainActivity.this,"您点击了取消！！！",Toast.LENGTH_LONG).show();
            }
        });
        pop.showAtLocation(years, Gravity.BOTTOM, 0, 0);
    }

布局pop_window_data：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@drawable/pop_bg"
    android:orientation="vertical">

    <com.zbzl.ui.dynamic.query.precedence.custom.WheelView
        android:id="@+id/loopView"
        android:layout_width="match_parent"
        android:layout_height="150dp"
        android:layout_marginTop="50dp" />

    <LinearLayout
        android:gravity="center_horizontal"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginTop="40dp"
        android:paddingBottom="25dp">

        <TextView
            android:id="@+id/quxiao"
            android:layout_width="120dp"
            android:layout_height="40dp"
            android:background="@drawable/gray_text_bg"
            android:gravity="center"
            android:text="取消"
            android:textColor="@color/green"
            android:textSize="17sp" />


        <TextView
            android:layout_marginLeft="20dp"
            android:id="@+id/queding"
            android:layout_width="120dp"
            android:layout_height="40dp"
            android:background="@drawable/green_text_bg"
            android:gravity="center"
            android:text="确定"
            android:textColor="@color/white"
            android:textSize="17sp" />

    </LinearLayout>

</LinearLayout>

本文地址：https://blog.csdn.net/ZHUHUOHUO/article/details/110225236