指纹点定位其一

指纹点定位是通过wifi室内定位的一种实现方法。其中重要的一部分是匹配算法。这里粘了部分我写的代码，算是做个记录吧！

程序实现了一个指纹点算法。功能简单，首先需要提供三个定位AP的信号强度，然后根据这三个信号强度，在指纹点数据表中查找。在查找过程中，查找的AP的信号强度是在一个范围内的，即给定的AP的信号强度，加减α。这个α是实验得出的，可以改变。对每一个AP，在数据库指纹点表格中查找，AP_NAME = AP，RSSI_AVG [β-α，β+α]。这样对每一个AP查找的结果可能有多个指纹点，将这些指纹点记录下来，并记录次数。经过三次查找之后，得到的指纹点的记录次数为3的为定位点。

程序实现为GetPosition.apk

 

@Override
     public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_get_position);
        service = new DbService(this);//实例化服务层DbService对象


        insert = (Button)findViewById(R.id.insert);
        position = (Button)findViewById(R.id.position);
        showfinger = (Button)findViewById(R.id.showfinger);
        pos_record = (Button)findViewById(R.id.pos_record);

        insert.setOnClickListener(this);
        insert.setContentDescription("insert button"); //用来判断哪个button按下

        position.setOnClickListener(this);
        position.setContentDescription("position button"); //用来判断哪个button按下

        showfinger.setOnClickListener(this);
        showfinger.setContentDescription("showfinger button"); //用来判断哪个button按下

        pos_record.setOnClickListener(this);
        pos_record.setContentDescription("pos_record button"); //用来判断哪个button按下


        //如果不存在指纹点表格就创建

        String sql = "SELECT name FROM sqlite_master WHERE type='table' AND name= 'fingerprint'" ;
        Cursor cs = service.scanSQL(sql);
        if(!(cs.moveToNext())){
            System.out.println("------there is no that table-------");
            //创建指纹点数据表格

            String sql1 = "CREATE TABLE fingerprint(_id INTEGER PRIMARY KEY,Position TEXT," +
                    "AP_Name TEXT, RSSI_AVG INTEGER)";
            service.execsql(sql1);
        }

        //如果不存在位置记录表格就创建

        sql = "SELECT name FROM sqlite_master WHERE type='table' AND name= 'pos_result'" ;
        cs = service.scanSQL(sql);
        if(!(cs.moveToNext())){
            System.out.println("------there is no that table-------");
            //创建指纹点数据表格

            String sql1 = "CREATE TABLE pos_result(_id INTEGER PRIMARY KEY,Position TEXT," +
                    "Pos_NO TEXT, Time TEXT)";
            service.execsql(sql1);
        }

        //初始化preferences和editor

        preferences = getSharedPreferences("PositionNum", MODE_PRIVATE);
        editor = preferences.edit();

        positions = new HashMap<String,Integer>(); //初始化positions


        handler = new Handler();


    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        getMenuInflater().inflate(R.menu.activity_get_position, menu);
        return true;
    }

    @Override
    public void onClick(View v) {
        // TODO Auto-generated method stub


        CharSequence str = v.getContentDescription();
        System.out.println(str);
        if(str.toString().equals("insert button")){ //如果是插入指纹点button按下

            System.out.println("insert button is down");
            dialogshow();
        }

        if(str.toString().equals("position button")){//如果是定位指纹点按下

            System.out.println("position button is down");
            getposition(); //调用定位方法来实现定位

        }

        if(str.toString().equals("showfinger button")){ //如果是查看指纹点button被按下

            System.out.println("showfinger button is down");
            showFingerPrint();
        }

        if(str.toString().equals("pos_record button")){ //查看路径记录

            System.out.println("pos_record button is down");
            //showFingerPrint();

        }
    }


    private void dialogshow(){ //添加指纹点的对话框

        View view = LayoutInflater.from(this).inflate(R.layout.insert_layout,null);
        ed1 = (EditText)view.findViewById(R.id.posname);
        ed2 = (EditText)view.findViewById(R.id.ap1);
        ed3 = (EditText)view.findViewById(R.id.ap2);
        ed4 = (EditText)view.findViewById(R.id.ap3);



        posnum = preferences.getInt("posNum", 0);    //获取数据

        posnum++;
        if(posnum<10)
            PosName = "Position"+'0'+posnum;
        else
            PosName = "Position"+posnum;
        System.out.println(PosName);
        ed1.setText(PosName);
        ed1.clearFocus();        //失去焦点


        new AlertDialog.Builder(this)
            .setTitle("添加指纹点数据")
            .setIcon(android.R.drawable.ic_menu_manage)
            .setView(view)
            .setPositiveButton("确定", new DialogInterface.OnClickListener() {

                @Override
                public void onClick(DialogInterface dialog, int which) {
                    // TODO Auto-generated method stub

                    editor.putInt("posNum", posnum); //将修改后的posnum存起来

                    editor.commit();        //提交修改


                    // 构建ContentValues对象，并将要插入的数据以键值对的形势进行保存

                    ContentValues contact = new ContentValues();

                    int rssi_avg;
                    contact.put("Position", PosName);
                    contact.put("AP_Name", "AP001");
                    Editable a = ed2.getText();
                    System.out.println(a.toString());
                    rssi_avg = Integer.valueOf(a.toString());
                    contact.put("RSSI_AVG", rssi_avg);
                    long ret = service.InsertInfo(contact,"fingerprint");//调用service的方法完成添加操作

                    if(ret== -1){
                        System.out.println("添加"+"Position_Result"+"表格失败");
                    }

                    contact.put("Position", PosName);
                    contact.put("AP_Name", "AP002");
                    a = ed3.getText();
                    System.out.println(a.toString());
                    rssi_avg = Integer.valueOf(a.toString());
                    contact.put("RSSI_AVG", rssi_avg);
                    ret = service.InsertInfo(contact,"fingerprint");//调用service的方法完成添加操作

                    if(ret== -1){
                        System.out.println("添加"+"Position_Result"+"表格失败");
                    }

                    contact.put("Position", PosName);
                    contact.put("AP_Name", "AP003");
                    a = ed4.getText();
                    System.out.println(a.toString());
                    rssi_avg = Integer.valueOf(a.toString());
                    contact.put("RSSI_AVG", rssi_avg);
                    ret = service.InsertInfo(contact,"fingerprint");//调用service的方法完成添加操作

                    if(ret== -1){
                        System.out.println("添加"+"Position_Result"+"表格失败");
                    }

                }
            })
            .setNegativeButton("取消", new DialogInterface.OnClickListener() {

                @Override
                public void onClick(DialogInterface dialog, int which) {
                    // TODO Auto-generated method stub


                }
            })
            .create().show();
    }

    public void showFingerPrint(){        //显示指纹点

        LinearLayout linearlayout = new LinearLayout(this);
        linearlayout.setOrientation(LinearLayout.VERTICAL);

        ListView lv = new ListView(this);
        View view = LayoutInflater.from(this).inflate(R.layout.fingerprint_title,null);
        lv.addHeaderView(view);

        Cursor c = service.getContacts("fingerprint");//调用服务层的方法获取所有存放的联系人数据


        //使用返回的游标Cursor对象构建ListView的数据适配器

        SimpleCursorAdapter adapter = new SimpleCursorAdapter(this,R.layout.fingerprint_item,c,
                new String[]{"Position","AP_Name","RSSI_AVG"},
                    new int[]{R.id.print_posname,R.id.print_ap,R.id.print_level});

        lv.setAdapter(adapter);                 //设置ListView的数据适配器

        linearlayout.removeAllViews();
        linearlayout.addView(lv);

        new AlertDialog.Builder(this)
            .setTitle("添加指纹点数据")
            .setIcon(android.R.drawable.ic_menu_manage)
            .setView(linearlayout)
            .setPositiveButton("确定", new DialogInterface.OnClickListener() {

                @Override
                public void onClick(DialogInterface dialog, int which) {
                    // TODO Auto-generated method stub


                }
            })
            .create().show();
    }


    public void getposition(){


        /////////////////////////////////////////////////

        View view = LayoutInflater.from(this).inflate(R.layout.getposition,null);
        ed5 = (EditText)view.findViewById(R.id.getap1);
        ed6 = (EditText)view.findViewById(R.id.getap2);
        ed7 = (EditText)view.findViewById(R.id.getap3);

        new AlertDialog.Builder(this)
            .setTitle("输入实测AP数据")
            .setIcon(android.R.drawable.ic_menu_manage)
            .setView(view)
            .setPositiveButton("确定", new DialogInterface.OnClickListener() {

                @Override
                public void onClick(DialogInterface dialog, int which) {
                    // TODO Auto-generated method stub

                    new getpositionThread().start();
                }
            })
            .create().show();
    }

    /**
    *下面的方法用来实现定位算法
    *定位AP的信号强度是通过对话框输入的
    *对每一个AP的查找范围是±2
    *算法是先根据每个AP的信号强度，在设定的±2范围内进行查找，找到的指纹点进行计数。计数最多的，为指纹点
    *方法先对第一个AP进行查找，找到position存放在map中
    *然后对第二个进行查找，将结果存放在map中，如果已经存在就加1，如果不存在就添加
    *然后对第三个，第四个进行相同的操作。
    *最后，map中计数最大的pos就对应定位点
    **/
    public class getpositionThread extends Thread{
        public void run(){
            String str;
            Editable level = ed5.getText();
            System.out.println(level.toString());

            String sql = "SELECT Position FROM fingerprint WHERE RSSI_AVG BETWEEN "+level
            +"-2 AND "+level+"+2 AND AP_Name = 'AP001'";
            System.out.println(sql);
            Cursor cs = service.scanSQL(sql);
            System.out.println("the number is :"+ cs.getCount());
            while(cs.moveToNext()){
                 str = cs.getString(0);
                System.out.println(str);
                positions.put(str, 1); //对第一个定位AP进行添加操作


            }

            //对第二个定位AP进行处理

            level = ed6.getText();

            sql = "SELECT Position FROM fingerprint WHERE RSSI_AVG BETWEEN "+level
            +"-2 AND "+level+"+2 AND AP_Name = 'AP002'";
            System.out.println(sql);
            cs = service.scanSQL(sql);
            System.out.println("the number is :"+ cs.getCount());
            while(cs.moveToNext()){
                str = cs.getString(0);
                System.out.println(str);
                //positions.put(str, positions.get(str)+1);

                if(positions.get(str) == null){
                    positions.put(str, 1);
                }else
                    positions.put(str, positions.get(str)+1);

            }

            //对第三个定位AP进行处理

            level = ed7.getText();

            sql = "SELECT Position FROM fingerprint WHERE RSSI_AVG BETWEEN "+level
            +"-2 AND "+level+"+2 AND AP_Name = 'AP003'";
            System.out.println(sql);
            cs = service.scanSQL(sql);
            System.out.println("the number is :"+ cs.getCount());
            while(cs.moveToNext()){
                str = cs.getString(0);
                System.out.println(str);
                if(positions.get(str) == null){
                    positions.put(str, 1);
                }else
                    positions.put(str, positions.get(str)+1);

            }

            handler.post(new Runnable01());

        }
    }

    //handler.post方法调用之后执行

    public class Runnable01 implements Runnable{

        @Override
        public void run() {
            // TODO Auto-generated method stub

            position_result = new Bundle();

            String result =new String();
            System.out.println("the number of positions is :"+positions.size());
            Object[] array = positions.keySet().toArray();
            for(int i = 0;i< positions.size();i++){
                System.out.println("指纹点的权值记录结果为："+array[i]+" : "+positions.get(array[i]));
                result += "指纹点的权值记录结果为："+array[i]+" : "+positions.get(array[i])+"\n";

            }
            result += "--------------------------------------------\n";
            result += "the result is ： \n";

            String str;
            if(positions.containsValue(3)){
                for(int i = 0;i< positions.size();i++){
                    str = (String)array[i];
                    if(positions.get(str)==3){
                        System.out.println("指纹点的权值记录结果为："+str+" : 3");
                        result +="指纹点"+str+"的权值为： 3\n";
                        position_num++;
                        position_result.putInt("number", position_num);
                        position_result.putString(" "+position_num, str);
                    }
                }
            }else{
                if(positions.containsValue(2) ){
                    for(int i = 0;i< positions.size();i++){
                        str = (String)array[i];
                        if(positions.get(array[i])==2){
                            System.out.println("指纹点的权值记录结果为："+str+" : 2");
                            result +="指纹点"+array[i]+"的权值为： 2\n";
                            position_num++;
                            position_result.putInt("number", position_num);
                            position_result.putString(" "+position_num, str);
                        }
                    }
                }else
                    result += "未找到指纹点";
            }

            result += "the sum is :" +position_result.getInt("number");


            TextView tv = new TextView(GetPosition.this);
            tv.setText(result);
            ScrollView scrollview = new ScrollView(GetPosition.this);
            scrollview.addView(tv);
            new AlertDialog.Builder(GetPosition.this)
            .setTitle("添加指纹点数据")
            .setIcon(android.R.drawable.ic_menu_manage)
            .setMessage("AP001 :" +ed5.getText() +" ; AP002 :"+ed6.getText()+" ; AP003 :"+ed7.getText()+"\n")
            .setView(scrollview)
            .setPositiveButton("确定", new DialogInterface.OnClickListener() {

                @Override
                public void onClick(DialogInterface dialog, int which) {
                    // TODO Auto-generated method stub

                    position_result.clear();
                    position_num =0;
                    positions.clear();
                }
            })
            .create().show();

        }
    }

程序里面用到了数据库方面的知识。在事件监听方面我用了Activity本身作为事件监听器，在响应方法里面判断是那个Button产生的事件，这种实现方式，感觉不怎么好。呵呵，代码就贴这些吧