package com.example.project;
import android.app.Activity;
import android.os.Bundle;
import android.view.Menu;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
public class MainActivity extends Activity {
 TextView tv;
 int Num=0;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        setTitle("색종이 맞추기");
       
        Button btn1 =(Button)findViewById(R.id.button1);
    tv =(TextView)findViewById(R.id.TextView1);
    
        View.OnClickListener a;
        a=new View.OnClickListener() {
   public void onClick(View v) {
       Num=(int)(Math.random()*9)+1;
          tv.setText(Num);  
   }
  };btn1.setOnClickListener(a);
   
       
       
    }
    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }
   
}
 
버튼을 누르면 TextView 를 셋해주고 싶은데 오류가 뜨네요.
어느부분이 문제가 있는지 알려주시면 감사하겠습니다 ^^