使用setContentView进行两个互相界面的跳转出现问题

[halo_frrrank]

代码：package com.siren.calc;

import android.app.Activity;
import android.content.Intent;
import android.support.v7.app.AppCompatActivity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.view.Menu;
import android.view.Window;

import android.widget.Button;

public class MainActivity extends AppCompatActivity {

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
this.requestWindowFeature(Window.FEATURE_NO_TITLE);
setContentView(R.layout.activity_main);

Button button1=(Button) this.findViewById(R.id.button1);
button1.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
setContentView(R.layout.life);
}
});
Button button2=(Button) this.findViewById(R.id.button2);
button2.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
setContentView(R.layout.qinshu);
}
});
}
}

public void goTOLayout1(){
//将layout由activity_main切换到life
setContentView(R.layout.life);
Button button_life=(Button) this.findViewById(R.id.button_life);
button_life.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
goTOLayoutMain();
}
});
}

public void goTOLayoutMain(){
//由life切换到activity_main
setContentView(R.layout.activity_main);

Button button1=(Button) this.findViewById(R.id.button1);
button1.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
goTOLayout1();
}
});
}

错误：Error:(47, 5) 错误: 需要class, interface或enum
希望各位大牛们可以帮忙解答一下小白的疑惑，谢谢

[魑魅魍魉9527]

//由life切换到activity_main 之后 Button button2=(Button) this.findViewById(R.id.button2); 需要重新绑定

[Jing丶無雙]

表示很难理解，为什么要这么做。不过还是说下原因，setContentView 后整个Activity的View会被重建，相关控件（如这里的Button按钮）都需要重新从相应的布局里找到（即findViewById）并绑定相应的事件。参考这里http://bbs.csdn.net/topics/350073783