Android实战简易教程-第七十七枪（获取附近可用WIFI列表附新书地址）

1.activity_main.xml:

<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">

    <ListView
        android:id="@+id/listView"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"></ListView>

</RelativeLayout>

2.item_wifi_list.xml:

<?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>

3.MainActivity.java:

package demo.androidwar.com.actionbardemo;

import android.app.Activity;
import android.content.Context;
import android.net.wifi.ScanResult;
import android.net.wifi.WifiManager;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.ImageView;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.Toast;

import java.util.List;


public class MainActivity extends Activity {

    private WifiManager wifiManager;
    List<ScanResult> list;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        init();
    }

    private void init() {

        wifiManager = (WifiManager) getSystemService(Context.WIFI_SERVICE);
        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));
        }

    }

    public class MyAdapter extends BaseAdapter {

        LayoutInflater inflater;
        List<ScanResult> list;
        public MyAdapter(Context context, List<ScanResult> list) {
            this.inflater = LayoutInflater.from(context);
            this.list = list;
        }

        @Override
        public int getCount() {
            return list.size();
        }

        @Override
        public Object getItem(int position) {
            return position;
        }

        @Override
        public long getItemId(int position) {
            return position;
        }

        @Override
        public View getView(int position, View convertView, ViewGroup parent) {
            View 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;
        }
    }

}

实例化WifiManager对象，并调用其getScanResults方法返回WIFI扫描到的列表。主要要配置权限：

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="demo.androidwar.com.actionbardemo">

    <uses-permission android:name="android.permission.ACCESS_WIFI_STATE" />
    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">
        <activity android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

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

</manifest>

运行项目实例：