android wifi讲解 wifi列表显示

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"  
    xmlns:tools="http://schemas.android.com/tools"  
    android:layout_width="match_parent"  
    android:layout_height="match_parent"  
    android:paddingBottom="@dimen/activity_vertical_margin"  
    android:paddingLeft="@dimen/activity_horizontal_margin"  
    android:paddingRight="@dimen/activity_horizontal_margin"  
    android:paddingTop="@dimen/activity_vertical_margin"  
    tools:context=".WifiListActivity" >  
  
    <ListView  
        android:id="@+id/listView"  
        android:layout_width="match_parent"  
        android:layout_height="wrap_content" >  
    </ListView>  
  
</RelativeLayout>  

<?xml version="1.0" encoding="utf-8"?>  
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"  
    android:layout_width="match_parent"  
    android:layout_height="match_parent" >  
  
    <ImageView  
        android:id="@+id/imageView"  
        android:layout_width="wrap_content"  
        android:layout_height="wrap_content"  
        android:layout_alignParentLeft="true"  
        android:layout_alignParentTop="true"  
        android:src="@drawable/ic_launcher" />  
  
    <TextView  
        android:id="@+id/textView"  
        android:layout_width="wrap_content"  
        android:layout_height="wrap_content"  
        android:layout_alignBottom="@+id/imageView"  
        android:layout_marginBottom="14dp"  
        android:layout_toRightOf="@+id/imageView"  
        android:text="TextView" />  
  
    <TextView  
        android:id="@+id/signal_strenth"  
        android:layout_width="wrap_content"  
        android:layout_height="wrap_content"  
        android:layout_alignBaseline="@+id/textView"  
        android:layout_alignBottom="@+id/textView"  
        android:layout_alignParentRight="true"  
        android:text="TextView" />  
  
</RelativeLayout>  

public class WifiListActivity extends Activity {  
  
    private WifiManager wifiManager;  
    List<ScanResult> list;  
    @Override  
    protected void onCreate(Bundle savedInstanceState) {  
        super.onCreate(savedInstanceState);  
        setContentView(R.layout.activity_wifi_list);  
        init();  
    }  
  
    private void init() {  
        wifiManager = (WifiManager) getSystemService(Context.WIFI_SERVICE);  
        openWifi();  
        list = wifiManager.getScanResults();  
        ListView listView = (ListView) findViewById(R.id.listView);  
        if (list == null) {  
            Toast.makeText(this, "wifi未打开！", Toast.LENGTH_LONG).show();  
        }else {  
            listView.setAdapter(new MyAdapter(this,list));  
        }  
          
    }  
      
    /** 
     *  打开WIFI 
     */  
    private void openWifi() {  
       if (!wifiManager.isWifiEnabled()) {  
        wifiManager.setWifiEnabled(true);  
       }  
        
    }  
  
    public class MyAdapter extends BaseAdapter {  
  
        LayoutInflater inflater;  
        List<ScanResult> list;  
        public MyAdapter(Context context, List<ScanResult> list) {  
            // TODO Auto-generated constructor stub  
            this.inflater = LayoutInflater.from(context);  
            this.list = list;  
        }  
  
        @Override  
        public int getCount() {  
            // TODO Auto-generated method stub  
            return list.size();  
        }  
  
        @Override  
        public Object getItem(int position) {  
            // TODO Auto-generated method stub  
            return position;  
        }  
  
        @Override  
        public long getItemId(int position) {  
            // TODO Auto-generated method stub  
            return position;  
        }  
  
        @Override  
        public View getView(int position, View convertView, ViewGroup parent) {  
            // TODO Auto-generated method stub  
            View view = null;  
            view = inflater.inflate(R.layout.item_wifi_list, null);  
            ScanResult scanResult = list.get(position);  
            TextView textView = (TextView) view.findViewById(R.id.textView);  
            textView.setText(scanResult.SSID);  
            TextView signalStrenth = (TextView) view.findViewById(R.id.signal_strenth);  
            signalStrenth.setText(String.valueOf(Math.abs(scanResult.level)));  
            ImageView imageView = (ImageView) view.findViewById(R.id.imageView);  
            //判断信号强度，显示对应的指示图标  
            if (Math.abs(scanResult.level) > 100) {  
                imageView.setImageDrawable(getResources().getDrawable(R.drawable.stat_sys_wifi_signal_0));  
            } else if (Math.abs(scanResult.level) > 80) {  
                imageView.setImageDrawable(getResources().getDrawable(R.drawable.stat_sys_wifi_signal_1));  
            } else if (Math.abs(scanResult.level) > 70) {  
                imageView.setImageDrawable(getResources().getDrawable(R.drawable.stat_sys_wifi_signal_1));  
            } else if (Math.abs(scanResult.level) > 60) {  
                imageView.setImageDrawable(getResources().getDrawable(R.drawable.stat_sys_wifi_signal_2));  
            } else if (Math.abs(scanResult.level) > 50) {  
                imageView.setImageDrawable(getResources().getDrawable(R.drawable.stat_sys_wifi_signal_3));  
            } else {  
                imageView.setImageDrawable(getResources().getDrawable(R.drawable.stat_sys_wifi_signal_4));  
            }  
            return view;  
        }  
  
    }  
  
}