感觉自己还是很少写实际应用实现的博客。最近在找实习，写博客时间少了，但还是要坚持。今天这篇博客来讲下电商应用中常见的选择类别下拉列表的实现。先看下效果图：  ### 一、下拉列表的实现 其实实现方法有很多，这时实现的也没有什么技术含量，只是总结下自己在项目中的做法，也提供一个思路。 首先是列表的数据，一般数据都是从后台读过来，这里因为没有后台，所以写死在客户端： ~~~ private void initMenuData() { menuData1 = new ArrayList<Map<String, String>>(); String[] menuStr1 = new String[] { "全部", "粮油", "衣服", "图书", "电子产品", "酒水饮料", "水果" }; Map<String, String> map1; for (int i = 0, len = menuStr1.length; i < len; ++i) { map1 = new HashMap<String, String>(); map1.put("name", menuStr1[i]); menuData1.add(map1); } menuData2 = new ArrayList<Map<String, String>>(); String[] menuStr2 = new String[] { "综合排序", "配送费最低" }; Map<String, String> map2; for (int i = 0, len = menuStr2.length; i < len; ++i) { map2 = new HashMap<String, String>(); map2.put("name", menuStr2[i]); menuData2.add(map2); } menuData3 = new ArrayList<Map<String, String>>(); String[] menuStr3 = new String[] { "优惠活动", "特价活动", "免配送费", "可在线支付" }; Map<String, String> map3; for (int i = 0, len = menuStr3.length; i < len; ++i) { map3 = new HashMap<String, String>(); map3.put("name", menuStr3[i]); menuData3.add(map3); } } ~~~ 就是做了简单的封装。弹出列表的实现考虑使用Popwindow。 ~~~ popMenu = new PopupWindow(contentView, LinearLayout.LayoutParams.MATCH_PARENT, LinearLayout.LayoutParams.MATCH_PARENT); popMenu.setOutsideTouchable(true); popMenu.setBackgroundDrawable(new BitmapDrawable()); popMenu.setFocusable(true); popMenu.setAnimationStyle(R.style.popwin_anim_style); popMenu.setOnDismissListener(new OnDismissListener() { public void onDismiss() { productTv.setTextColor(Color.parseColor("#5a5959")); sortTv.setTextColor(Color.parseColor("#5a5959")); activityTv.setTextColor(Color.parseColor("#5a5959")); } }); ~~~ 接着将数据封装到adapter中： ~~~ menuAdapter1 = new SimpleAdapter(this, menuData1, R.layout.item_listview_popwin, new String[] { "name" }, new int[] { R.id.listview_popwind_tv }); menuAdapter2 = new SimpleAdapter(this, menuData2, R.layout.item_listview_popwin, new String[] { "name" }, new int[] { R.id.listview_popwind_tv }); menuAdapter3 = new SimpleAdapter(this, menuData3, R.layout.item_listview_popwin, new String[] { "name" }, new int[] { R.id.listview_popwind_tv }); ~~~ 设置点击标题头弹出列表，并改变标题头的颜色 ~~~ public void onClick(View v) { // TODO Auto-generated method stub switch (v.getId()) { case R.id.supplier_list_product: productTv.setTextColor(Color.parseColor("#39ac69")); popListView.setAdapter(menuAdapter1); popMenu.showAsDropDown(product, 0, 2); menuIndex = 0; break; case R.id.supplier_list_sort: sortTv.setTextColor(Color.parseColor("#39ac69")); popListView.setAdapter(menuAdapter2); popMenu.showAsDropDown(product, 0, 2); menuIndex = 1; break; case R.id.supplier_list_activity: activityTv.setTextColor(Color.parseColor("#39ac69")); popListView.setAdapter(menuAdapter3); popMenu.showAsDropDown(product, 0, 2); menuIndex = 2; break; } } ~~~ showAsDropDown是为了让popwindow定位在Product这个选择标题的正下方。从而实现上面那种方式。 最后完整的贴出代码，还是蛮简单的。最后也会提供代码下载链接。 ~~~ public class MainActivity extends Activity implements OnClickListener { private ListView listView, popListView; private ProgressBar progressBar; private List<Map<String, String>> menuData1, menuData2, menuData3; private PopupWindow popMenu; private SimpleAdapter menuAdapter1, menuAdapter2, menuAdapter3; private LinearLayout product, sort, activity; private ImageView cartIv; private TextView productTv, sortTv, activityTv, titleTv; private int green, grey; private String currentProduct, currentSort, currentActivity; private int menuIndex = 0; private Intent intent; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_supplier_list); findView(); initMenuData(); initPopMenu(); } private void initMenuData() { menuData1 = new ArrayList<Map<String, String>>(); String[] menuStr1 = new String[] { "全部", "粮油", "衣服", "图书", "电子产品", "酒水饮料", "水果" }; Map<String, String> map1; for (int i = 0, len = menuStr1.length; i < len; ++i) { map1 = new HashMap<String, String>(); map1.put("name", menuStr1[i]); menuData1.add(map1); } menuData2 = new ArrayList<Map<String, String>>(); String[] menuStr2 = new String[] { "综合排序", "配送费最低" }; Map<String, String> map2; for (int i = 0, len = menuStr2.length; i < len; ++i) { map2 = new HashMap<String, String>(); map2.put("name", menuStr2[i]); menuData2.add(map2); } menuData3 = new ArrayList<Map<String, String>>(); String[] menuStr3 = new String[] { "优惠活动", "特价活动", "免配送费", "可在线支付" }; Map<String, String> map3; for (int i = 0, len = menuStr3.length; i < len; ++i) { map3 = new HashMap<String, String>(); map3.put("name", menuStr3[i]); menuData3.add(map3); } } @Override public void onClick(View v) { // TODO Auto-generated method stub switch (v.getId()) { case R.id.supplier_list_product: productTv.setTextColor(Color.parseColor("#39ac69")); popListView.setAdapter(menuAdapter1); popMenu.showAsDropDown(product, 0, 2); menuIndex = 0; break; case R.id.supplier_list_sort: sortTv.setTextColor(Color.parseColor("#39ac69")); popListView.setAdapter(menuAdapter2); popMenu.showAsDropDown(product, 0, 2); menuIndex = 1; break; case R.id.supplier_list_activity: activityTv.setTextColor(Color.parseColor("#39ac69")); popListView.setAdapter(menuAdapter3); popMenu.showAsDropDown(product, 0, 2); menuIndex = 2; break; } } protected void findView() { listView = (ListView) findViewById(R.id.supplier_list_lv); product = (LinearLayout) findViewById(R.id.supplier_list_product); sort = (LinearLayout) findViewById(R.id.supplier_list_sort); activity = (LinearLayout) findViewById(R.id.supplier_list_activity); productTv = (TextView) findViewById(R.id.supplier_list_product_tv); sortTv = (TextView) findViewById(R.id.supplier_list_sort_tv); activityTv = (TextView) findViewById(R.id.supplier_list_activity_tv); titleTv = (TextView) findViewById(R.id.supplier_list_title_tv); cartIv = (ImageView) findViewById(R.id.supplier_list_cart_iv); progressBar = (ProgressBar) findViewById(R.id.progress); product.setOnClickListener(this); sort.setOnClickListener(this); activity.setOnClickListener(this); cartIv.setOnClickListener(this); } private void initPopMenu() { initMenuData(); View contentView = View.inflate(this, R.layout.popwin_supplier_list, null); popMenu = new PopupWindow(contentView, LinearLayout.LayoutParams.MATCH_PARENT, LinearLayout.LayoutParams.MATCH_PARENT); popMenu.setOutsideTouchable(true); popMenu.setBackgroundDrawable(new BitmapDrawable()); popMenu.setFocusable(true); popMenu.setAnimationStyle(R.style.popwin_anim_style); popMenu.setOnDismissListener(new OnDismissListener() { public void onDismiss() { productTv.setTextColor(Color.parseColor("#5a5959")); sortTv.setTextColor(Color.parseColor("#5a5959")); activityTv.setTextColor(Color.parseColor("#5a5959")); } }); popListView = (ListView) contentView .findViewById(R.id.popwin_supplier_list_lv); contentView.findViewById(R.id.popwin_supplier_list_bottom) .setOnClickListener(new OnClickListener() { public void onClick(View arg0) { popMenu.dismiss(); } }); menuAdapter1 = new SimpleAdapter(this, menuData1, R.layout.item_listview_popwin, new String[] { "name" }, new int[] { R.id.listview_popwind_tv }); menuAdapter2 = new SimpleAdapter(this, menuData2, R.layout.item_listview_popwin, new String[] { "name" }, new int[] { R.id.listview_popwind_tv }); menuAdapter3 = new SimpleAdapter(this, menuData3, R.layout.item_listview_popwin, new String[] { "name" }, new int[] { R.id.listview_popwind_tv }); popListView.setOnItemClickListener(new OnItemClickListener() { public void onItemClick(AdapterView<?> arg0, View arg1, int pos, long arg3) { popMenu.dismiss(); if (menuIndex == 0) { currentProduct = menuData1.get(pos).get("name"); titleTv.setText(currentProduct); productTv.setText(currentProduct); Toast.makeText(MainActivity.this, currentProduct, Toast.LENGTH_SHORT).show(); } else if (menuIndex == 1) { currentSort = menuData2.get(pos).get("name"); titleTv.setText(currentSort); sortTv.setText(currentSort); Toast.makeText(MainActivity.this, currentSort, Toast.LENGTH_SHORT).show(); } else { currentActivity = menuData3.get(pos).get("name"); titleTv.setText(currentActivity); activityTv.setText(currentActivity); Toast.makeText(MainActivity.this, currentActivity, Toast.LENGTH_SHORT).show(); } } }); } } ~~~ ### 二、加载圆形ProgressBar的显示 就是效果图中的那种加载ProgressBar，圆形ProgresBar可以用原生的Bar来实现，但样式单一，之前我做这种效果第一时间总是考虑到帧动画，但用这种方式需要有很多图片来链接起来，这样一来实现麻烦，二来图片多了占内存。下面用改变原生ProgressBar的动画来实现这种效果，非常简单： ~~~ <ProgressBar android:id="@+id/progress" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_centerInParent="true" android:indeterminateDrawable="@drawable/shape_progress" android:indeterminateDuration="1000" /> ~~~ indeterminateDrawable是加载背景图片，indeterminateDuration是旋转的速度。这里的思路是用xml来画一张图，它是环形的，且环形圈中有渐变颜色。如下： ~~~ <rotate xmlns:android="http://schemas.android.com/apk/res/android" android:fromDegrees="0" android:pivotX="50%" android:pivotY="50%" android:toDegrees="360" > <shape android:innerRadiusRatio="3" android:shape="ring" android:thicknessRatio="10" android:useLevel="false" > <gradient android:centerColor="#8cd4aa" android:centerY="0.50" android:endColor="#ffffff" android:startColor="#39ac69" android:type="sweep" android:useLevel="false" /> </shape> </rotate> ~~~ rotate设置旋转动画，360度旋转。shape="ring"设置背景为圆。android:innerRadiusRatio="3"设置内环半径，android:thicknessRatio="10"设置外环半径。最后为了让环中颜色有渐变效果，使用gradient来设置。gradient可以有三种渐变方式，线性，辐射，扫描。这里type要设置成扫描。然后设置中心点，开始颜色和结束颜色，就能实现上面的那种效果了。 好了，到这里整个效果就讲完了。贴上源码下载地址： [https://github.com/reallin/PopWin_MeiTuan](https://github.com/reallin/PopWin_MeiTuan)