我正在编写一个扫描可用无线网络的应用程序但是,当我运行我的应用程序时,它甚至在显示主要活动之前就崩溃了。我也在寻找如何使用扫描结果,但我不确定我使用它的方式是否正确。 我读到了广播接收器,但我没有找到任何如何使用它的例子。 这是我的代码,非常感谢任何帮助
package com.example.wizer2;
import java.util.List;
import android.net.wifi.ScanResult;
import android.net.wifi.WifiInfo;
import android.net.wifi.WifiManager;
import android.os.Bundle;
import android.app.Activity;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.view.Menu;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
public class Wizer extends Activity {
WifiManager Wifi;
BroadcastReceiver receiver;
List<ScanResult> results;
Button bt1; //Current status
TextView t1; //for current status result
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_wizer);
//GUI
bt1=(Button)findViewById(R.id.b1);
t1=(TextView)findViewById(R.id.t1);
// to enable wifi service
Wifi = (WifiManager) getSystemService(Context.WIFI_SERVICE);
bt1.setOnClickListener(new View.OnClickListener() {
public void onClick(View arg0) {
WifiInfo info = Wifi.getConnectionInfo();
if (info.getBSSID()==null)
{
t1.setText("You are currently not connected to any wireless network.\n");
}
else
{
t1.append("Current Status:\n");
t1.append("Network Name :"+info.getSSID().toString()+"\n");
t1.append("RSSI :"+info.getRssi()+"\n");
}
}
});
Wifi.startScan();
// Register Broadcast Receiver
if (receiver == null)
receiver = new BroadcastReceiver() {
@Override
public void onReceive(Context context, Intent intent) {
results =Wifi.getScanResults();
// Intent I1 =new Intent();
}
};
registerReceiver(receiver, new IntentFilter( WifiManager.SCAN_RESULTS_AVAILABLE_ACTION));
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.activity_wizer, menu);
return true;
}
public void onStop() {
unregisterReceiver(receiver);
}
}
答案 0 :(得分:0)
确保您已添加
uses-permission android:name =“android.permission.CHANGE_WIFI_STATE” uses-permission android:name =“android.permission.ACCESS_WIFI_STATE”
您的Manifest xml文件中的权限。
答案 1 :(得分:0)
除了在清单文件中添加权限外,我只使用了您的代码而不更改任何内容。它为我工作检查代码
public class MainActivity extends Activity { WifiManager Wifi;
BroadcastReceiver receiver;
List<ScanResult> results; @Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
//GUI
bt1=(Button)findViewById(R.id.btn1);
t1=(TextView)findViewById(R.id.txt1);
// to enable wifi service
Wifi = (WifiManager) getSystemService(Context.WIFI_SERVICE);
bt1.setOnClickListener(new View.OnClickListener() { public void onClick(View arg0) {
WifiInfo info = Wifi.getConnectionInfo();
if (info.getBSSID()==null)
{
t1.setText("You are currently not connected to any wireless network.\n");
}
else
{
t1.append("Current Status:\n");
t1.append("Network Name :"+info.getSSID().toString()+"\n");
t1.append("RSSI :"+info.getRssi()+"\n");
}
}
}); Wifi.startScan();
// Register Broadcast Receiver
if (receiver == null)
receiver = new BroadcastReceiver() {
@Override
public void onReceive(Context context, Intent intent) {
results =Wifi.getScanResults();
// Intent I1 =new Intent();
}
};
registerReceiver(receiver, new IntentFilter( WifiManager.SCAN_RESULTS_AVAILABLE_ACTION));
}
/*@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.activity_wizer, menu);
return true;
}*/
public void onStop() {
unregisterReceiver(receiver);
} }
的Manifest.xml
<?xml version="1.0" encoding="utf-8"?> <manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.textoverlay"
android:versionCode="1"
android:versionName="1.0" > <uses-sdk
android:minSdkVersion="8"
android:targetSdkVersion="17" />
<uses-permission android:name="android.permission.CHANGE_WIFI_STATE"/>
<uses-permission android:name="android.permission.ACCESS_WIFI_STATE"/>
<application
android:allowBackup="true"
android:icon="@drawable/ic_launcher"
android:label="@string/app_name"
android:theme="@style/AppTheme" > <activity
android:name="com.example.textoverlay.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>