android下拉五级菜单联动

一、问题引出

本人是一个不擅长Android的开发的，但是这几天在做联通的一个服务器配件管理系统，做完B/S的又要写C/S的，老板要求没办法。在做的过程中遇到了一个下拉菜单联动的问题，以前没做过，突然做还真有点不知所措了，在网上找了一大堆发现数据都是本地的应该构造好了，没卵用，不过也给了我很多想发，一开始想到用树去解决，可是每个树的节点个数不知道，要是动态创建就会很麻烦。最后在自己的努力下来构造JSON数据格式，其实弄明白感觉很简单，就是并保存你的上一级是谁，你的下一级是谁就可以了，但是数据库做的表没有结构可言很难构造出来有用的数据结构。

二、实例代码

数据库建表如下：

factory 下有多个 type ,这里有一点需要注意，不是 type 下有多个 products_name 而是，factory 和 type 要共同确定有那些 products_name , 好了就这样一次类推，顺序分别是 factory、type 、products_name 、 products_no 、 function .
由此得到的数据库查询语句有：
select factory from bjlt_products_type group by factory ;

select type from bjlt_products_type where factory=#{0} group by type;

select products_name from bjlt_products_type where factory=#{0} and type=#{1} group by products_name;

select products_no from bjlt_products_type where factory=#{0} and type=#{1} and products_name=#{2} group by products_no;

select function from bjlt_products_type where factory=#{0} and type=#{1} and products_name=#{2} and products_no=#{3} group by function;

知道Mybatis的很容易看懂，我这里就不说了;
查询数据结构构造json数据代码

java后端数据代码

@ResponseBody    @RequestMapping("/user_info/requestproductstypeApplication.html")    public String user_infoProductsFactory(HttpServletRequest request, HttpServletResponse response)            throws IOException {        List str_1 = bjlt_products_typeService.factory();        String str1 = "";        String str2 = "";        String str3 = "";        String str4 = "";        String str5 = "";        Json json = new Json();        for (int i = 0; i < str_1.size(); i++) {            str1 = str1 + str_1.get(i) + "$$";List str_2 = bjlt_products_typeService.type(str_1.get(i));str2 = "";for (int j = 0; j < str_2.size(); j++) {str2 = str2 + str_2.get(j) + "$$";                List str_3 = bjlt_products_typeService.products_name(str_1.get(i), str_2.get(j));                str3 = "";                for (int z = 0; z < str_3.size(); z++) {                    str3 = str3 + str_3.get(z) + "$$";List str_4 = bjlt_products_typeService.products_no(str_1.get(i), str_2.get(j),str_3.get(z));str4 = "";for (int q = 0; q < str_4.size(); q++) {str4 = str4 + str_4.get(q) + "$$";List str_5 = bjlt_products_typeService.function(str_1.get(i), str_2.get(j),str_3.get(z), str_4.get(q));str5 = "";for (int k = 0; k < str_5.size(); k++) {str5 = str5 + str_5.get(k) + "$$";}json.add(str_1.get(i) + "$$" + str_2.get(j) + "$$" + str_3.get(z) + "$$" + str_4.get(q), str5);}json.add(str_1.get(i) + "$$" + str_2.get(j) + "$$" + str_3.get(z), str4);}json.add(str_1.get(i) + "$$" + str_2.get(j), str3);            }            json.add(str_1.get(i), str2);        }        json.add("factory", str1);        json.add("result", "ok");        System.out.println(json.toString());        // response.addHeader("Access-Control-Allow-Origin",        // "http://127.0.0.1:8020");        return json.toString();    }

此代码是循环获取每个类别的数据，主要思想为键值保存他的父亲，值保存他下面的儿子，举个例子

{"华为": "BBU$$RRU$$"}//代表华为下有两个类别，到时候value可以直接用split取出字符数组{"华为$$RRU": "RRU3775$$RRU3959$$"}//当有了华为下的儿子，就可以和儿子组合起来和成一个唯一的键，为一个字符串//下面是获取到的整个JSON字符串String str = {  "爱立信$$BBU$$DUS4102": "KDU137624/11$$","华为$$RRU$$RRU3959$$WD5MIRUYC10E": "基带板$$","factory": "华为$$爱立信$$","华为": "BBU$$RRU$$","爱立信$$BBU$$DUS4102$$KDU137624/11": "基带板$$","华为$$BBU": "UMPTb2$$","华为$$RRU": "RRU3775$$RRU3959$$","华为$$RRU$$RRU3959": "WD5MIRUYC10E$$","华为$$BBU$$UMPTb2": "WD22UMPTb2$$","华为$$RRU$$RRU3775$$D5MPRUC19BC": "电源模块$$","result": "ok","华为$$BBU$$UMPTb2$$WD22UMPTb2": "射频单元$$","华为$$RRU$$RRU3775": "D5MPRUC19BC$$","爱立信$$BBU": "DUS4102$$","爱立信$$RRU": "RRUS01B1$$","爱立信$$RRU$$RRUS01B1": "KRC161255/2$$","爱立信$$RRU$$RRUS01B1$$KRC161255/2": "电源模块$$","爱立信": "BBU$$RRU$$"};

和android交互会出现乱码问题，大家可以使用URL编码进行编解码，在最后返回字符串的时候，加入一下代码

UrlUtil.getURLEncoderString(json.toString());//为自己的编码类

Android客户端代码

public class Main2Activity extends AppCompatActivity {    //下拉组件    private Spinner factorySpinner = null;   //厂商    private Spinner typeSpinner = null;  //大类    private Spinner products_nameSpinner = null;     //产品名称    private Spinner products_noSpinner = null;    //产品号    private Spinner functionSpinner = null;    //产品号    //数据适配器    ArrayAdapter factoryAdapter = null;//    ArrayAdapter typeAdapter = null;  //    ArrayAdapter products_nameAdapter = null;    //    ArrayAdapter products_noAdapter = null;    //    ArrayAdapter functionAdapter = null;    //    JSONObject root = null;    static int provincePosition = 3;    HttpClient client;    //    private String[] text = new String[]{"请选择"};    private String[] factory_1 = null;    ProgressDialog waitingDialog=null;    @Override    protected void onCreate(Bundle savedInstanceState)    {        waitingDialog= new ProgressDialog(Main2Activity.this);        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main2);        client = new DefaultHttpClient();        readNet(Contents.HOST+"user_info/requestproductstypeApplication.html");        showWaitingDialog();    }    private void showWaitingDialog() {        waitingDialog.setTitle("我是一个等待Dialog");        waitingDialog.setMessage("等待中...");        waitingDialog.setIndeterminate(true);        waitingDialog.setCancelable(false);        waitingDialog.show();    }    /*     * 设置下拉框，默认的值，内容为请选择     */    private void setSpinner()    {        factorySpinner = (Spinner)findViewById(R.id.spin_factory);        typeSpinner = (Spinner)findViewById(R.id.spin_type);        products_nameSpinner = (Spinner)findViewById(R.id.spin_products_name);        products_noSpinner = (Spinner)findViewById(R.id.spin_products_no);        functionSpinner = (Spinner)findViewById(R.id.spin_function);        //绑定适配器和值        try{            System.out.println(root.getString("factory").split("\\$\\$")[0]);            factoryAdapter = new ArrayAdapter(Main2Activity.this,                    android.R.layout.simple_spinner_item, factory_1);        }catch (Exception e){          e.printStackTrace();        }        factorySpinner.setAdapter(factoryAdapter);        factorySpinner.setSelection(0,true);  //设置默认选中项，此处为默认选中第4个值        typeAdapter = new ArrayAdapter(Main2Activity.this,                android.R.layout.simple_spinner_item, text);        typeSpinner.setAdapter(typeAdapter);        typeSpinner.setSelection(0,true);  //默认选中第0个        products_nameAdapter = new ArrayAdapter(Main2Activity.this,                android.R.layout.simple_spinner_item, text);        products_nameSpinner.setAdapter(products_nameAdapter);        products_nameSpinner.setSelection(0, true);        products_noAdapter = new ArrayAdapter(Main2Activity.this,                android.R.layout.simple_spinner_item, text);        products_noSpinner.setAdapter(products_noAdapter);        products_noSpinner.setSelection(0, true);        functionAdapter = new ArrayAdapter(Main2Activity.this,                android.R.layout.simple_spinner_item, text);        functionSpinner.setAdapter(functionAdapter);        functionSpinner.setSelection(0, true);        //下拉框监听,单开始选中一个值的时候用，就分别设置每个数据适配器的值，因为有先后有顺序，所以要获取上一个的值，才能设置下一个的值        factorySpinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener()        {            // 表示选项被改变的时候触发此方法，            @Override            public void onItemSelected(AdapterView<?> arg0, View arg1, int position, long arg3)            {                try {                    typeAdapter = new ArrayAdapter(Main2Activity.this,                            android.R.layout.simple_spinner_item, root.getString(factorySpinner.getItemAtPosition(position).toString()).split("\\$\\$"));                    typeSpinner.setAdapter(typeAdapter);                }catch (Exception e){                    e.printStackTrace();                }            }            @Override            public void onNothingSelected(AdapterView<?> arg0)            {            }        });        typeSpinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener()        {            @Override            public void onItemSelected(AdapterView<?> arg0, View arg1,                                       int position, long arg3)            {                try {                    products_nameAdapter = new ArrayAdapter(Main2Activity.this,                        android.R.layout.simple_spinner_item, root.getString(factorySpinner.getSelectedItem().toString()+                        "$$"+typeSpinner.getItemAtPosition(position)).split("\\$\\$"));                    products_nameSpinner.setAdapter(products_nameAdapter);                }catch (Exception e){                    e.printStackTrace();                }            }            @Override            public void onNothingSelected(AdapterView<?> arg0)            {            }        });        products_nameSpinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener()        {            @Override            public void onItemSelected(AdapterView<?> arg0, View arg1,                                       int position, long arg3)            {                try {                    products_noAdapter = new ArrayAdapter(Main2Activity.this,                            android.R.layout.simple_spinner_item, root.getString(factorySpinner.getSelectedItem().toString()+                            "$$"+typeSpinner.getSelectedItem().toString()+"$$"+                            products_nameSpinner.getItemAtPosition(position).toString()).split("\\$\\$"));                    products_noSpinner.setAdapter(products_noAdapter);                }catch (Exception e){                    e.printStackTrace();                }            }            @Override            public void onNothingSelected(AdapterView<?> arg0)            {            }        });        products_noSpinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener()        {            @Override            public void onItemSelected(AdapterView<?> arg0, View arg1,                                       int position, long arg3)            {                try {                    functionAdapter = new ArrayAdapter(Main2Activity.this,                            android.R.layout.simple_spinner_item, root.getString(factorySpinner.getSelectedItem().toString()+                            "$$"+typeSpinner.getSelectedItem().toString()+"$$"+                            products_nameSpinner.getSelectedItem().toString()+"$$"+                            products_noSpinner.getItemAtPosition(position).toString()).split("\\$\\$"));                    functionSpinner.setAdapter(functionAdapter);                }catch (Exception e){                    e.printStackTrace();                }            }            @Override            public void onNothingSelected(AdapterView<?> arg0)            {            }        });    }    public void readNet(String url) {        AsyncTask execute = new AsyncTask() {            @Override            protected String doInBackground(String... params) {                String urlString = params[0];                System.out.println(urlString);                HttpGet get = new HttpGet(urlString);                try {                    HttpResponse response = client.execute(get);                    String valueString = EntityUtils.toString(response.getEntity());                    return valueString;                } catch (ClientProtocolException e) {                    // TODO Auto-generated catch block                    e.printStackTrace();                } catch (IOException e) {                    // TODO Auto-generated catch block                    e.printStackTrace();                }                return null;            }            @Override            protected void  onPostExecute (String s) {                try{                    synchronized (this){//最先开始获取顶层的数据，因为他的键值是固定的，在查询的时候不需要条件，我们设置定的为factory；            System.out.println(UrlUtil.getURLDecoderString(s));                        root = new JSONObject(UrlUtil.getURLDecoderString(s));                        String result = root.getString("result");                        String[] string = root.getString("factory").split("\\$\\$");                        factory_1 = new String[string.length+1];                        factory_1[0] = "请选择";                        for (int i = 1;i1;i++){                            factory_1[i] = string[i-1];                        }//不设置其它内容对会获取不到                        super.onPostExecute(result);                    }                }catch (Exception e){                  e.printStackTrace();                }finally {                    waitingDialog.dismiss();                    setSpinner();                }            }        }.execute(url);    }}

android 下拉xml文件

<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"    xmlns:tools="http://schemas.android.com/tools"    android:layout_width="match_parent"    android:layout_height="600dp"    android:orientation="vertical"    android:padding="8dp">    <Spinner        android:id="@+id/spin_factory"        android:layout_width="0dp"        android:layout_height="wrap_content"        android:layout_weight="1" />    <Spinner        android:id="@+id/spin_type"        android:layout_width="0dp"        android:layout_height="wrap_content"        android:layout_weight="1" />    <Spinner        android:id="@+id/spin_products_name"        android:layout_width="0dp"        android:layout_height="wrap_content"        android:layout_weight="1" />    <Spinner        android:id="@+id/spin_products_no"        android:layout_width="0dp"        android:layout_height="wrap_content"        android:layout_weight="1" />    <Spinner        android:id="@+id/spin_function"        android:layout_width="0dp"        android:layout_height="wrap_content"        android:layout_weight="1" />LinearLayout>    LinearLayout>

好了，就这么写内容，由于当时数据库的问题，就先只能这样获取数据了，在查询上效率会面一些，但是一般不会分类太多，多的话那就是大的项目了，可以事先就存在redis中，用Zset，键值还是键，值还是值就获取的更快了。，内容有点多，可以先运行试试，看看效果或许可以在必要的时候帮助你一点。
有好的解答和疑问可以在下方评论，也可以加我的QQ：1402876003.

android下拉五级菜单联动