BroadCast onReceive() yönteminden bir düğmeyi nasıl etkinleştirir veya devre dışı bırakırım

Question

Çevrimdışı çevrimdışı gibi bir ağ durumu göstergesi olarak işlev gören bir düğme var. Sorum şu: broadcast receiver'un genişlediği WifiStatusReceiver sınıfına sahibim. WifiStatusReceiver sınıfından bir düğmeyi etkinleştirmek veya devre dışı bırakmak istiyorum. Bunu nasıl yapabilirim ?? i bir düğmeye arka plan ayarlamak çalışırsanız

public class Wifi extends BroadcastReceiver implements ActionBar.TabListener{ 
ActionBar actionBar; 
@Override 
public void onReceive(Context context, Intent intent) { 
    Toast.makeText(context, "Intent Detected.", Toast.LENGTH_LONG).show(); 

    ConnectivityManager connectivityManager = 
      (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE); 
    NetworkInfo activeNetInfo = connectivityManager.getActiveNetworkInfo(); 

    if (activeNetInfo != null 
      && activeNetInfo.getType() == ConnectivityManager.TYPE_WIFI) { 
     Toast.makeText(context, "Wifi Connected!", Toast.LENGTH_SHORT).show(); 
     actionBar.setCustomView(R.layout.header); 
     actionBar.getCustomView().findViewById(R.id.btn_onlinestatus).setBackground(context.getResources().getDrawable(R.drawable.onlinestaticon)); 
    } else { 
     Toast.makeText(context, "Wifi Not Connected!", Toast.LENGTH_SHORT).show(); 

     actionBar.setCustomView(R.layout.header); 
     actionBar.getCustomView().findViewById(R.id.btn_onlinestatus).setBackground(context.getResources().getDrawable(R.drawable.offlinestaticon)); 
    } 
} 

onun "java.lang.RuntimeException belirten bir boş gösterici durum atma: alıcı com.balaji.example.Operations.Wifi başlatılamıyor: java.lang Eğer registerReceiver OnCreate - - .NullPointerException"

Answer 1

Main Activity 

    package com.checkisonline; 

    import android.net.ConnectivityManager; 
    import android.net.NetworkInfo; 
    import android.os.Bundle; 
    import android.os.Handler; 
    import android.os.Message; 
    import android.app.Activity; 
    import android.content.BroadcastReceiver; 
    import android.content.Context; 
    import android.content.Intent; 
    import android.content.IntentFilter; 
    import android.graphics.Color; 
    import android.view.Menu; 
    import android.widget.Button; 

    public class MainActivity extends Activity { 

     Button wifiState; 
     private IntentFilter intfilt; 
     private boolean enableOrDisable=false; 

     BroadcastReceiver enableDisableBrodcastRecr = new BroadcastReceiver() 
     { 

      @Override 
      public void onReceive(Context arg0, Intent arg1) { 


       enableOrDisable=arg1.getExtras().getBoolean("enableordisable");//enableordisable is Key which is passed inside onReceive method of Wifi 

       handler.sendEmptyMessage(0); 

      } 
     }; 

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

      intfilt = new IntentFilter(); 
      intfilt.addAction("EnableDisableAction"); 

      registerReceiver(enableDisableBrodcastRecr, intfilt); 

      wifiState=(Button)findViewById(R.id.state); 

     } 

     @Override 
     protected void onResume() { 
      // TODO Auto-generated method stub 
      super.onResume(); 


      if(checkWifiState()==true) 
       { 

       wifiState.setText("Wifi-ON"); 
       wifiState.setTextColor(Color.GREEN); 
       }else 
       { 

        wifiState.setText("Wifi-OFF"); 
        wifiState.setTextColor(Color.RED); 
       } 
     } 

     @Override 
     protected void onPause() { 
      // TODO Auto-generated method stub 
      super.onPause(); 

     } 

     @Override 
     protected void onDestroy() { 
      // TODO Auto-generated method stub 
      super.onDestroy(); 

      unregisterReceiver(enableDisableBrodcastRecr); 
     } 

     private Handler handler = new Handler() { 
      @Override 
      public void handleMessage(Message msg) { 

       if(enableOrDisable==true) 
       { 

       wifiState.setText("Wifi-ON"); 
       wifiState.setTextColor(Color.GREEN); 
       }else 
       { 

        wifiState.setText("Wifi-OFF"); 
        wifiState.setTextColor(Color.RED); 
       } 

      } 
    }; 

     @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_main, menu); 
      return true; 
     } 


     public boolean checkWifiState() 
     { 
      boolean wifistate; 
      ConnectivityManager connectivityManager = 
        (ConnectivityManager)getSystemService(Context.CONNECTIVITY_SERVICE); 
      NetworkInfo activeNetInfo = connectivityManager.getActiveNetworkInfo(); 


      if (activeNetInfo != null 
        && activeNetInfo.getType() == ConnectivityManager.TYPE_WIFI) {   
       wifistate=true; 

      } else { 
       wifistate=false; 
      } 

      return wifistate; 
     } 



    } 

    Wifi Receiver 

    package com.checkisonline; 

    import android.content.BroadcastReceiver; 
    import android.content.Context; 
    import android.content.Intent; 
    import android.net.ConnectivityManager; 
    import android.net.NetworkInfo; 



     public class WifiReceiver extends BroadcastReceiver { 

       @Override 
       public void onReceive(Context context, Intent intent) { 

        ConnectivityManager connectivityManager = 
          (ConnectivityManager)context.getSystemService(Context.CONNECTIVITY_SERVICE); 
        NetworkInfo activeNetInfo = connectivityManager.getActiveNetworkInfo(); 

        Intent broadcastIntent = new Intent(); 
        broadcastIntent.setAction("EnableDisableAction"); 
        if (activeNetInfo != null 
          && activeNetInfo.getType() == ConnectivityManager.TYPE_WIFI) { 

         broadcastIntent.putExtra("enableordisable", true); 

        } else { 

         broadcastIntent.putExtra("enableordisable", false); 

        } 
        context.sendBroadcast(broadcastIntent); 
       } 
     } 

    activity_main.xml 

     <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" 
      android:layout_width="fill_parent" 
      android:layout_height="fill_parent" > 

      <Button 
       android:id="@+id/state" 
       android:layout_width="wrap_content" 
       android:layout_height="wrap_content" 
       android:layout_alignParentTop="true" 
       android:layout_centerHorizontal="true" 
       android:layout_marginTop="176dp" 
       android:textSize="20dp" 

       /> 

     </RelativeLayout> 

    Manifest.xml 

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

     <uses-sdk 
      android:minSdkVersion="8" 
      android:targetSdkVersion="17" /> 

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

     <application 
      android:allowBackup="true" 
      android:icon="@drawable/ic_launcher" 
      android:label="@string/app_name" 
      android:theme="@style/AppTheme" > 
      <activity 
       android:name="com.checkisonline.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> 

      <receiver android:name="com.checkisonline.WifiReceiver" android:enabled="true"> 
      <intent-filter> 
       <action android:name="android.net.wifi.WIFI_STATE_CHANGED" /> 
       <action android:name="android.net.conn.CONNECTIVITY_CHANGE"/> 
      </intent-filter> 
     </receiver> 


     </application> 

    </manifest> 

Now as you required use ActionBar object wherever I used Button. 
Enjoy.... 

Answer 2

Ben bu duruma için LocalBroadCast kullanmak gerektiğini düşünüyorum bunun olmasına istemiyorsanız Düğme İşleyici size kaydını ve isterseniz tekrar sicil - OnPause veya OnStop (belki) kayıt olup olmadığını kontrol edin> unreg isterReceiver Kişisel Gereklilik/Tasarım sen unRegisterReceiver alışkanlık Niyet gönderilen Broadcast dinlemek mümkün çağrılıp çağrılmadığını

Bu yüzden dikkatli olmak da onCreate()-onDestroy() veya onStart()-onStop() içine kayıt ve kaydını silmek Alıcı olabilir dayanarak

Answer 3

public class Wifi extends BroadcastReceiver { 

    @Override 
    public void onReceive(Context context, Intent intent) { 
     Toast.makeText(context, "Intent Detected.", Toast.LENGTH_LONG).show(); 

     ConnectivityManager connectivityManager = 
       (ConnectivityManager)context.getSystemService(Context.CONNECTIVITY_SERVICE); 
     NetworkInfo activeNetInfo = connectivityManager.getActiveNetworkInfo(); 

     Intent broadcastIntent = new Intent(); 
     broadcastIntent.setAction("EnableDisableAction"); 
     if (activeNetInfo != null 
       && activeNetInfo.getType() == ConnectivityManager.TYPE_WIFI) {   

     Toast.makeText(context, "WifiConnected!",Toast.LENGTH_SHORT).show(); 
     broadcastIntent.putExtra("enableordisable", true); 


     } else { 
      Toast.makeText(context, "Wifi Not Connected!", Toast.LENGTH_SHORT).show(); 
      broadcastIntent.putExtra("enableordisable", false); 
     } 
     arg0.sendBroadcast(broadcastIntent); 
    } 

Now in your activity 

private IntentFilter intfilt; 
private boolean enableOrDisable=false; 
private ActionBar actionBar; 
BroadcastReceiver enableDisableBrodcastRecr = new BroadcastReceiver() 
    { 

     @Override 
     public void onReceive(Context arg0, Intent arg1) { 

      enableOrDisable=arg1.getExtras().getBoolean("enableordisable");//enableordisable is Key which is passed inside onReceive method of Wifi 

      // For Refreshing The message 

     } 
    }; 

onCreate() 
{ 
    intfilt = new IntentFilter(); 
    intfilt.addAction("EnableDisableAction"); 
} 

onResume() 
{ 
registerReceiver(enableDisableBrodcastRecr, intfilt); 

if(enableOrDisable==true) 

    { 
actionBar.setCustomView(R.layout.header); 
     actionBar.getCustomView().findViewById(R.id.btn_onlinestatus).setBackground(context.getResources().getDrawable(R.drawable.onlinestaticon)); 

    }else 
    { 
actionBar.setCustomView(R.layout.header); 
     actionBar.getCustomView().findViewById(R.id.btn_onlinestatus).setBackground(context.getResources().getDrawable(R.drawable.offlinestaticon)); 
    } 

} 

onPause() 
{ 
     unregisterReceiver(enableDisableBrodcastRecr); 
} 

Not: Her zaman UI iş parçacığı dışındaki kullanıcı arabirimini güncellememelisiniz