即使import没漏，依然找不到findViewbyId

1.import不少:
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.view.Window;
import android.view.WindowManager;
import android.view.Menu;
import android.view.MenuItem;
import android.os.PowerManager;
import android.content.Context;
import android.widget.Button;
import android.util.Log;

2.问题在这里:
/MainActivity.java:39: cannot find symbol
symbol : method findViewbyId(int)
location: c.MainActivity
Button myButton = findViewbyId(R.id.button_poweroff);

答案很简单：findViewbyId should be findViewById
大小写的问题，汗!