title: Android - Check Permission
body: <p>This code is for testing whether application has Permission after being checked would be returned true if you have permission, and false otherwise .</p>
  
  <p>But it is not working when I run application stops working , so I wonder why it's not working , if this missing something in the code:</p>
  
  <p>EDIT2 - Made some corrections with suggestions, but still didn't work:</p>
  
  <pre><code> public class CheckPermission extends Activity {
      private final Context context;
      private static final String MNC = "MNC";
      int permReq = 0;
      String permMan = "";
  
      public CheckPermission(Context context) {
          this.context = context;
      }
  
      //perMan can be any code number higher than 0
      public void requestPermission(String permRequested){
          switch (permRequested) {
              case "CAMERA":
                  //Request for Camera
                  this.permReq =  ContextCompat.checkSelfPermission(context, Manifest.permission.CAMERA);
                  this.permMan = Manifest.permission.CAMERA;
                  break;
              case "INTERNET":
                  //Requesr for Internet
                  this.permReq =  ContextCompat.checkSelfPermission(context, Manifest.permission.INTERNET);
                  this.permMan = Manifest.permission.INTERNET;
                  break;
              case "STORAGE":
                  //Request for group Storage - Read_External_Storage &amp; Write_External_Storage
                  this.permReq =  ContextCompat.checkSelfPermission(context, Manifest.permission_group.STORAGE);
                  this.permMan = Manifest.permission_group.STORAGE;
                  break;
              case "MICROPHONE":
                  //Request for group Microphone - Record_Audio
                  this.permReq =  ContextCompat.checkSelfPermission(context, Manifest.permission_group.MICROPHONE);
                  this.permMan = Manifest.permission_group.MICROPHONE;
                  break;
              case "LOCATION":
                  //Request for group Location - Acess_Fine_Location &amp; Acess_Coarse_Location
                  this.permReq =  ContextCompat.checkSelfPermission(context, Manifest.permission_group.LOCATION);
                  this.permMan = Manifest.permission_group.LOCATION;
                  break;
              case "CALL":
                  //Requesr for call
                  this.permReq = ContextCompat.checkSelfPermission(context, Manifest.permission.CALL_PHONE);
                  this.permMan = Manifest.permission.CALL_PHONE;
                  break;
              default:
                  break;
          }
      }
  
      public boolean hasPermission( String permRequested){
          final PackageManager pm = context.getPackageManager();
  
          if(isMNC_Or_Higher()) {
              requestPermission(permRequested);
              Toast.makeText(this.context, "Is MNC - permMan: " + this.permMan + " Perm required: " + permReq, Toast.LENGTH_SHORT).show();
  
              if (permReq != pm.PERMISSION_GRANTED) {
                  ActivityCompat.requestPermissions(this, new String[]{this.permMan}, this.permReq);
                  return false;
              }
          }
          return true;
      }
  
      //check if is 6.0 or higher
      public boolean isMNC_Or_Higher(){
          if (Build.VERSION.SDK_INT &gt;= Build.VERSION_CODES.M) {
              return true;
          }
          return false;
      }
  
      @Override
      public void onRequestPermissionsResult(int requestCode, String[] permissions, int[] grantResults) {
  
          if (requestCode == this.permReq) {
              if (grantResults.length == 1 &amp;&amp;
                      grantResults[0] == PackageManager.PERMISSION_GRANTED) {
                  Toast.makeText(this, "Permissão concedida", Toast.LENGTH_SHORT).show();
              } else {
                  Toast.makeText(this, "Permissão negada", Toast.LENGTH_SHORT).show();
              }
          } else {
              super.onRequestPermissionsResult(requestCode, permissions, grantResults);
          }
      }
  }
  </code></pre>
  
  <p>ERROR:</p>
  
  <p>PID: 25504
                                                                                     java.lang.NullPointerException: Attempt to invoke virtual method 'android.content.Context android.content.Context.getApplicationContext()' on a null object reference
                                                                                         at android.content.ContextWrapper.getApplicationContext(ContextWrapper.java:107)
                                                                                         at com.dev.kamui.patrulhacomunitaria.CheckPermission.hasPermission(CheckPermission.java:68)
                                                                                         at com.dev.kamui.patrulhacomunitaria.Pagina_Principal$1.onClick(Pagina_Principal.java:47)
                                                                                         at android.view.View.performClick(View.java:5198)
                                                                                         at android.view.View$PerformClick.run(View.java:21147)
                                                                                         at android.os.Handler.handleCallback(Handler.java:739)
                                                                                         at android.os.Handler.dispatchMessage(Handler.java:95)
                                                                                         at android.os.Looper.loop(Looper.java:148)
                                                                                         at android.app.ActivityThread.main(ActivityThread.java:5417)
                                                                                         at java.lang.reflect.Method.invoke(Native Method)
                                                                                         at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
                                                                                         at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)</p>