Android Permissions with Google Play Permissions policy

Remember that as of Android 6.0 (API level 23), users grant permissions ( risky permissions to apps while running, not when they install the app.

In the case of permissions related to the SMS messages :

These are considered risky permissions

  

risky permissions may allow the app to access information   confidential of the user. If your app has a normal permission in its   manifest, the system grants permission automatically. If you have   a dangerous permit, the user must explicitly authorize your   app.

therefore must be manually requested at runtime

This is an example, you can request permissions within the onCreate() method of your main Activity:

@Override
protected void onCreate(Bundle savedInstanceState) {
    ...
    ...

    ActivityCompat.requestPermissions(this,
            new String[]{Manifest.permission.READ_SMS,Manifest.permission.RECEIVE_SMS,Manifest.permission.SEND_SMS},
            255);

     ...
     ...
    }

and add the onRequestPermissionsResult() method:

@Override
public void onRequestPermissionsResult(int requestCode, String permissions[], int[] grantResults) {
    switch (requestCode) {
        case 255: {
            if (grantResults.length > 0
                    && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
            } else {
                Toast.makeText(this, "Permiso denegado", Toast.LENGTH_SHORT).show();
            }
            return;
        }
    }
}

This way, when starting the application, the permissions will be required: