Android初学者请教问题。

package gzy.secret;

import android.content.Context;
import android.content.SharedPreferences;

public class Config {
    public static final String KEY_TOKEN="token";
    public static final String APP_ID="gzy.secret";
    public static String getCachedTOken(Context context){
        return context.getSharedPreferences(APP_ID,Context.MODE_PRIVATE).getString(KEY_TOKEN,null);
    }
    public  static void cacheToken(Context context,String token){
        SharedPreferences.Editor e=context.getSharedPreferences(APP_ID,Context.MODE_PRIVATE).edit();
        ();
    }
}

package gzy.secret;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;

public class MainActivity extends Activity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        String token = Config.getCachedTOken(this);
        if (token != null) {
            Intent i = new Intent(this, AtyTimeLine.class);
            i.putExtra(Config.KEY_TOKEN, token);
            startActivity(i);
        }else{
            startActivity(new Intent(this,AtyLogin.class));
        }
    }
}