Question

我试图制作一个可以显示所有wifi接入点列表的wifi扫描器。我的代码如下：

MainActivity.java：

package com.example.wifiscanner;

import java.util.List;

import android.annotation.SuppressLint;
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.support.v7.app.ActionBarActivity;
import android.view.Menu;
import android.view.View;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.ListView;

public class MainActivity extends ActionBarActivity {
    WifiManager wifi;
    WifiScanReceiver wifireciever;
    Button scan;
    List<ScanResult> wifilist;
    ListView list;
    String wifis[];

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

        list=(ListView)findViewById(R.id.listView1);
        scan=(Button)findViewById(R.id.button1);


        scan.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub
                wifi=(WifiManager)getSystemService(Context.WIFI_SERVICE);

                if (wifi.isWifiEnabled()==false){
                    wifi.setWifiEnabled(true);

                }

                wifireciever = new WifiScanReceiver();
                registerReceiver(wifireciever, new IntentFilter(WifiManager.SCAN_RESULTS_AVAILABLE_ACTION));
                wifi.startScan();

            }
        });


    }

    protected void onPause() {
          unregisterReceiver(wifireciever);
          super.onPause();
       }

    protected void onResume() {
          registerReceiver(wifireciever, new IntentFilter(WifiManager.SCAN_RESULTS_AVAILABLE_ACTION));
          super.onResume();
       }

    class WifiScanReceiver extends BroadcastReceiver {
          @SuppressLint("UseValueOf")
          public void onReceive(Context c, Intent intent) {
             List<ScanResult> wifilist = wifi.getScanResults();
             wifis = new String[wifilist.size()];
             for(int i = 0; i < wifilist.size(); i++){
                wifis[i] = ((wifilist.get(i)).toString());
             }

             list.setAdapter(new ArrayAdapter<String>(getApplicationContext(),
             android.R.layout.simple_list_item_1,wifis));
          }
       }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {

        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }   
}

fragment_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"
    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="com.example.wifiscanner.MainActivity$PlaceholderFragment" >

    <ListView
        android:id="@+id/listView1"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_below="@+id/button1"
        android:layout_centerHorizontal="true" >
    </ListView>

    <Button
        android:id="@+id/button1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignLeft="@+id/listView1"
        android:layout_alignParentTop="true"
        android:layout_marginLeft="34dp"
        android:layout_marginTop="37dp"
        android:minWidth="@dimen/abc_action_bar_stacked_tab_max_width"
        android:text="Scan" />

</RelativeLayout>

Log cat：

05-26 09:41:49.840: D/AndroidRuntime(11186): Shutting down VM
05-26 09:41:49.840: W/dalvikvm(11186): threadid=1: thread exiting with uncaught exception (group=0x414f82a0)
05-26 09:41:49.861: E/AndroidRuntime(11186): FATAL EXCEPTION: main
05-26 09:41:49.861: E/AndroidRuntime(11186): java.lang.SecurityException: WifiService: Neither user 10105 nor current process has android.permission.ACCESS_WIFI_STATE.
05-26 09:41:49.861: E/AndroidRuntime(11186):    at android.os.Parcel.readException(Parcel.java:1425)
05-26 09:41:49.861: E/AndroidRuntime(11186):    at android.os.Parcel.readException(Parcel.java:1379)
05-26 09:41:49.861: E/AndroidRuntime(11186):    at android.net.wifi.IWifiManager$Stub$Proxy.getWifiEnabledState(IWifiManager.java:900)
05-26 09:41:49.861: E/AndroidRuntime(11186):    at android.net.wifi.WifiManager.getWifiState(WifiManager.java:1078)
05-26 09:41:49.861: E/AndroidRuntime(11186):    at android.net.wifi.WifiManager.isWifiEnabled(WifiManager.java:1090)
05-26 09:41:49.861: E/AndroidRuntime(11186):    at com.example.wifiscanner.MainActivity$1.onClick(MainActivity.java:44)
05-26 09:41:49.861: E/AndroidRuntime(11186):    at android.view.View.performClick(View.java:4262)
05-26 09:41:49.861: E/AndroidRuntime(11186):    at android.view.View$PerformClick.run(View.java:17421)
05-26 09:41:49.861: E/AndroidRuntime(11186):    at android.os.Handler.handleCallback(Handler.java:615)
05-26 09:41:49.861: E/AndroidRuntime(11186):    at android.os.Handler.dispatchMessage(Handler.java:92)
05-26 09:41:49.861: E/AndroidRuntime(11186):    at android.os.Looper.loop(Looper.java:137)
05-26 09:41:49.861: E/AndroidRuntime(11186):    at android.app.ActivityThread.main(ActivityThread.java:4947)
05-26 09:41:49.861: E/AndroidRuntime(11186):    at java.lang.reflect.Method.invokeNative(Native Method)
05-26 09:41:49.861: E/AndroidRuntime(11186):    at java.lang.reflect.Method.invoke(Method.java:511)
05-26 09:41:49.861: E/AndroidRuntime(11186):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1038)
05-26 09:41:49.861: E/AndroidRuntime(11186):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:805)
05-26 09:41:49.861: E/AndroidRuntime(11186):    at dalvik.system.NativeStart.main(Native Method)
05-26 09:41:49.941: D/dalvikvm(11186): GC_CONCURRENT freed 203K, 15% free 6966K/8135K, paused 12ms+9ms, total 73ms
05-26 09:42:00.201: I/Process(11186): Sending signal. PID: 11186 SIG: 9

我的Manifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.wifiscanner"
    android:versionCode="1"
    android:versionName="1.0" >

    <uses-sdk
        android:minSdkVersion="8"
        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.wifiscanner.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>

一旦我按下扫描按钮，它就会停止工作。如果有人能帮助我，我会很感激。

Answer 1

你logcat清楚地说过

java.lang.SecurityException: WifiService: Neither user 10105 nor current process has android.permission.ACCESS_WIFI_STATE.
05-26 09:41:49.861: E/AndroidRuntime(11186):    at android.os.Parcel.readException(Parcel.java:1425)

在android.permission.ACCESS_WIFI_STATE

中添加manifest.xml

Answer 2

您需要将以下权限添加到清单文件中：

    <uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />

这些需要在应用程序标记之外添加。（在之前或之后）

您的清单文件位于项目的主文件夹中，名称为：AndroidManifest.xml。

不幸的是，Wifi扫描仪已停止

2 个答案: