if the IF statement is true view new activity

                   if(res.equals("5510"))
                    checkback.setText("Correct version");
               //
                else
                    开发者_如何学JAVAcheckback.setText("Incorrect version, please update. \n Your current version is " + getString(R.string.versioncode)); 

How do i get it so that if the IF statement is true then it'll start and view mainactivity.class?

I put intent in but when i did it showed up with a bunch of errors

Try this, but replace "CurrentActivity.this" with the name of the activity your calling it from.

if(res.equals("5510")){
    checkback.setText("Correct version");
    Intent i = new Intent(CurrentActiviy.this, mainactivity.class);
        startActivity(i);
}else{
    checkback.setText("Incorrect version, please update. \n Your current version is " + getString(R.string.versioncode));
}

If you still get errors then post the errors you get - it makes it a million times easier to work out where the issue is!