android加了button 运行会闪退

Question

加了BUTTON后 哪怕不加监听事件他都闪退 去掉BUTTON就正常 为什么呀

 /**
 * 
 */
package com.nav.gamepack;


import com.nav.gamepack.puzzle.jigsaw.JigsawBoardView;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;

/**
 * @author Administrator
 *
 */
public class welcomeclass extends Activity {
    public Button trans =(Button)findViewById(R.id.button1);
    @Override
    public void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.start);

  //trans.setOnClickListener(new OnClickListener(){} );
  trans.setOnClickListener(new OnClickListener() {
      @Override
      public void onClick(View v) {

          //startActivity(new Intent("GamePackActivity"));  
      }
  });


    }

Answer 1

绑定完布局文件后在进行控件实例化