android 获取当前连接WIFI名称的问题

[hackerlyf]

我在程序内通过以下方法获取当前连接的WIFI名称（SSID），这个也是网上找别人的，但在我程序内就获取不到呢？
1、在AndroidManifest.xml文件内增加
<uses-permission android:name="android.permission.ACCESS_WIFI_STATE"></uses-permission>
2、在源代码内通过以下函数获取SSID
private String getSSid(){

WifiManager wm = (WifiManager) getSystemService(WIFI_SERVICE);
if(wm != null){
WifiInfo wi = wm.getConnectionInfo();

if(wi != null){
String s = wi.getSSID();
if(s.length()>2&&s.charAt(0) == '"'&&s.charAt(s.length() -1) == '"'){
return s.substring(0,s.length()-1);
}
}
}
return "";
}
实际跟踪时，发现wm不为null，但wi.getSSID()获取到的是<unknown ssid>，wi的名称是UNINITIALIZED，确认网络是连接上的，是哪里没有初始化还是什么原因？请高手指点；

[danxuezx]

下面是我刚刚实验过的代码：扫描所有可用的wifi，再改下应该就可以获取到当前连接的，供参考，如果你改好了也告诉一下~ MainActivity.java

package com.example.wifistudy;

import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.List;

import android.app.Activity;
import android.app.ActionBar;
import android.app.Fragment;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.net.wifi.ScanResult;
import android.net.wifi.WifiManager;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;
import android.os.Build;

public class MainActivity extends Activity
{
	TextView mainText;
	WifiManager mainWifi;
	WifiReceiver receiverWifi;
	List<ScanResult> wifiList;
	StringBuilder sb = new StringBuilder();

	@Override
	protected void onCreate(Bundle savedInstanceState)
	{
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);

		if (savedInstanceState == null)
		{
			getFragmentManager().beginTransaction()
					.add(R.id.container, new PlaceholderFragment()).commit();
		}
		
		mainText = (TextView) findViewById(R.id.mainText);
	    mainWifi = (WifiManager) getSystemService(Context.WIFI_SERVICE);
	    receiverWifi = new WifiReceiver();
	    registerReceiver(receiverWifi, new IntentFilter(WifiManager.SCAN_RESULTS_AVAILABLE_ACTION));
	    mainWifi.startScan();
	    mainText.setText("\\nStarting Scan...\\n");
	}

	@Override
	public boolean onCreateOptionsMenu(Menu menu)
	{
		menu.add(0, 0, 0, "Refresh");
		// Inflate the menu; this adds items to the action bar if it is present.
		getMenuInflater().inflate(R.menu.main, menu);
		return true;
	}

	@Override
	public boolean onOptionsItemSelected(MenuItem item)
	{
		mainWifi.startScan();
        mainText.setText("Starting Scan");
        
		// Handle action bar item clicks here. The action bar will
		// automatically handle clicks on the Home/Up button, so long
		// as you specify a parent activity in AndroidManifest.xml.
		int id = item.getItemId();
		if (id == R.id.action_settings)
		{
			return true;
		}
		return super.onOptionsItemSelected(item);
	}
	protected void onPause() 
	{
        unregisterReceiver(receiverWifi);
        super.onPause();
    }

    protected void onResume() 
    {
        registerReceiver(receiverWifi, new IntentFilter(WifiManager.SCAN_RESULTS_AVAILABLE_ACTION));
        super.onResume();
    }
	/**
	 * A placeholder fragment containing a simple view.
	 */
	public static class PlaceholderFragment extends Fragment
	{

		public PlaceholderFragment()
		{
		}

		@Override
		public View onCreateView(LayoutInflater inflater, ViewGroup container,
				Bundle savedInstanceState)
		{
			View rootView = inflater.inflate(R.layout.fragment_main, container,
					false);
			return rootView;
		}
	}

	class WifiReceiver extends BroadcastReceiver
	{
		public void onReceive(Context c, Intent intent)
		{
			SimpleDateFormat    formatter    =   new    SimpleDateFormat    ("yyyy年MM月dd日    HH:mm:ss     ");       
			Date    curDate    =   new    Date(System.currentTimeMillis());//获取当前时间       
			String    str    =    formatter.format(curDate); 
						
			sb.append(str);
			sb.append(": \n");
			wifiList = mainWifi.getScanResults();
			for (int i = 0; i < wifiList.size(); i++)
			{
				sb.append(new Integer(i + 1).toString() + ".");
				sb.append((wifiList.get(i)).toString());
				sb.append("\n");
			}
			mainText.setText(sb);
		}
	}

}

activity_main.xml

<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/container"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="com.example.wifistudy.MainActivity"
    tools:ignore="MergeRootFrame" >
    
    <TextView android:id="@+id/mainText"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:ellipsize="none"
        android:maxLines="100"
        android:scrollHorizontally="true">      
    </TextView>
</FrameLayout>

AndroidManifest.xml: 主要是加入下面四行 <!-- 以下是使用wifi访问网络所需的权限 --> <uses-permission android:name="android.permission.CHANGE_NETWORK_STATE"></uses-permission> <uses-permission android:name="android.permission.CHANGE_WIFI_STATE"></uses-permission> <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"></uses-permission> <uses-permission android:name="android.permission.ACCESS_WIFI_STATE"></uses-permission>

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.wifistudy"
    android:versionCode="1"
    android:versionName="1.0" >
<!-- 以下是使用wifi访问网络所需的权限 -->  
    <uses-permission android:name="android.permission.CHANGE_NETWORK_STATE"></uses-permission>  
    <uses-permission android:name="android.permission.CHANGE_WIFI_STATE"></uses-permission>  
    <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"></uses-permission>  
    <uses-permission android:name="android.permission.ACCESS_WIFI_STATE"></uses-permission>  
 
    <uses-sdk
        android:minSdkVersion="14"
        android:targetSdkVersion="19" />

    <application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <activity
            android:name="com.example.wifistudy.MainActivity"
            android:label="@string/app_name" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

</manifest>

[lym_84]

[hackerlyf]

跟我的需求不同，没找到方案，结帖了；