这一段代码setContentView(R.layout.activity_main);这一行报错,底下所有id下也有下划线
package com.example.keyboardscan;
import android.app.Activity;
import android.content.Context;
import android.os.Bundle;
import android.widget.Button;
import android.widget.TextView;
public class MainActivity extends Activity {
private TextView Letter;
private TextView ASCNumber;
private TextView ScanNumber;
private Button A,B,C,D,E,F,G,H,I,J,K,L,M,N,O,P,Q,R,S,
T,U,V,W,X,Y,Z,Space,Comma,Period;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Letter = (TextView)findViewById(R.id.Letter);
ASCNumber = (TextView)findViewById(R.id.ASCNumber);
ScanNumber = (TextView)findViewById(R.id.ScanNumber);
如果把上面定义Button的那两行去掉就没问题,这是怎么回事呢?