How get permission for camera in android.(Specifically Marshmallow)

Question

First check if the user has granted the permission:

if (ContextCompat.checkSelfPermission(context, Manifest.permission.CAMERA)
    == PackageManager.PERMISSION_DENIED)

Then, you could use this to request to the user:

ActivityCompat.requestPermissions(activity, new String[] {Manifest.permission.CAMERA}, requestCode);

And in Marshmallow, it will appear in a dialog

You can try the following code to request camera permission in marshmallow. First check if the user grant the permission. If user has not granted the permission, then request the camera permission:

private static final int MY_CAMERA_REQUEST_CODE = 100;

if (checkSelfPermission(Manifest.permission.CAMERA) != PackageManager.PERMISSION_GRANTED) {
    requestPermissions(new String[]{Manifest.permission.CAMERA}, MY_CAMERA_REQUEST_CODE);
}

After requesting the permission, dialog will display to ask permission containing allow and deny options. After clicking action we can get result of the request with the following method:

@Override
public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
    super.onRequestPermissionsResult(requestCode, permissions, grantResults);
    if (requestCode == MY_CAMERA_REQUEST_CODE) {
        if (grantResults[0] == PackageManager.PERMISSION_GRANTED) {
            Toast.makeText(this, "camera permission granted", Toast.LENGTH_LONG).show();
        } else {
            Toast.makeText(this, "camera permission denied", Toast.LENGTH_LONG).show();
        }
    }
}

This works for me, the source is here

int MY_PERMISSIONS_REQUEST_CAMERA=0;
// Here, this is the current activity
if (ContextCompat.checkSelfPermission(this, Manifest.permission.CAMERA) != PackageManager.PERMISSION_GRANTED)
{
     if (ActivityCompat.shouldShowRequestPermissionRationale(this, Manifest.permission.CAMERA))
     {

     }
     else
     {
          ActivityCompat.requestPermissions(this,new String[]{Manifest.permission.CAMERA}, MY_PERMISSIONS_REQUEST_CAMERA );
          // MY_PERMISSIONS_REQUEST_READ_CONTACTS is an
          // app-defined int constant. The callback method gets the
          // result of the request.
      }
}

check using this
if (ContextCompat.checkSelfPermission(this, android.Manifest.permission.CAMERA)
            == PackageManager.PERMISSION_DENIED)

and

Requesting Permissions In the following code, we will ask for camera permission:

in java

EasyPermissions is a wrapper library to simplify basic system permissions logic when targeting Android M or higher.

Installation EasyPermissions is installed by adding the following dependency to your build.gradle file:

dependencies {

    // For developers using AndroidX in their applications
    implementation 'pub.devrel:easypermissions:3.0.0'

    // For developers using the Android Support Library
    implementation 'pub.devrel:easypermissions:2.0.1'

}


private void askAboutCamera(){

        EasyPermissions.requestPermissions(
                this,
                "A partir deste ponto a permissão de câmera é necessária.",
                CAMERA_REQUEST_CODE,
                Manifest.permission.CAMERA );
}

click here for full source code and learn more.

Before get permission you can check api version,

  if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M)
  {
      if (ContextCompat.checkSelfPermission(MainActivity.this, Manifest.permission.READ_EXTERNAL_STORAGE) == PackageManager.PERMISSION_GRANTED) {

      } 
      else
      {
         ActivityCompat.requestPermissions(MainActivity.this, new String[]{Manifest.permission.READ_EXTERNAL_STORAGE}, 401);
      }
  }
  else
  {
    // if version is below m then write code here,          
  }

Get the Result of the permission dialog,

@Override
public void onRequestPermissionsResult(int requestCode, String[] permissions, int[] grantResults) {
    super.onRequestPermissionsResult(requestCode, permissions, grantResults);
    if (requestCode == 401) {
        if (grantResults.length == 0 || grantResults == null) {

        } else if (grantResults[0] == PackageManager.PERMISSION_GRANTED) {
            openGallery();
        } else if (grantResults[0] == PackageManager.PERMISSION_DENIED) {
        }
    } else if (requestCode == 402) {
        if (grantResults.length == 0 || grantResults == null) {

        } else if (grantResults[0] == PackageManager.PERMISSION_GRANTED) {

        } else if (grantResults[0] == PackageManager.PERMISSION_DENIED) {
        }
    }
} 

I try to add following code:

private static final int MY_CAMERA_REQUEST_CODE = 100;

@RequiresApi(api = Build.VERSION_CODES.M)

if (checkSelfPermission(Manifest.permission.CAMERA) != PackageManager.PERMISSION_GRANTED) {
        requestPermissions(new String[]{Manifest.permission.CAMERA}, MY_CAMERA_REQUEST_CODE);
    }

On onCreate Function and this following code:

@Override
public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
    super.onRequestPermissionsResult(requestCode, permissions, grantResults);
    if (requestCode == MY_CAMERA_REQUEST_CODE) {
        if (grantResults[0] == PackageManager.PERMISSION_GRANTED) {
            Toast.makeText(this, "camera permission granted", Toast.LENGTH_LONG).show();
        } else {
            Toast.makeText(this, "camera permission denied", Toast.LENGTH_LONG).show();
        }
    }
}

And this worked for me :)