import android.os.Bundle;import android.app.Activity;import android.app.FragmentManager;import android.app.FragmentTransaction;import android.view.Menu;import android.view.View;import android.view.View.OnClickListener;import android.widget.Button;public class MainActivity extends Activity implements OnClickListener {    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        // [1]找到我们关心的控件        Button btn_contact = (Button) findViewById(R.id.btn_contact);        Button btn_discover = (Button) findViewById(R.id.btn_discover);        Button btn_me = (Button) findViewById(R.id.btn_me);        Button btn_wx = (Button) findViewById(R.id.btn_wx);        // [2]给按钮设置点击事件        btn_contact.setOnClickListener(this);        btn_discover.setOnClickListener(this);        btn_me.setOnClickListener(this);        btn_wx.setOnClickListener(this);    }    @Override    public void onClick(View v) {                // [3]具体判断一下我点击的是哪个按钮                //[4]获取fragment的管理者         FragmentManager fragmentManager = getFragmentManager();        //[5]开启事物         FragmentTransaction transaction = fragmentManager.beginTransaction();                switch (v.getId()) {        case R.id.btn_wx: // 说明点击了微信按钮            transaction.replace(R.id.ll, new WxFragment());            break;        case R.id.btn_contact: // 说明点击了微信按钮            transaction.replace(R.id.ll, new ContactFragment());            break;        case R.id.btn_discover: // 说明点击了微信按钮            transaction.replace(R.id.ll, new DiscoverFragment());            break;        case R.id.btn_me: // 说明点击了微信按钮            transaction.replace(R.id.ll, new MeFragment());            break;        }        //[6]最后一布 记得 提交事物         transaction.commit();    }

import android.app.Fragment;import android.os.Bundle;import android.view.LayoutInflater;import android.view.View;import android.view.View.OnClickListener;import android.view.ViewGroup;public class WxFragment extends Fragment {    @Override    public View onCreateView(LayoutInflater inflater, ViewGroup container,            Bundle savedInstanceState) {        View view = inflater.inflate(R.layout.fragment_wx, null);        view.findViewById(R.id.btn_test).setOnClickListener(new OnClickListener() {                        @Override            public void onClick(View v) {                System.out.println("哈哈哈 我被点击了");            }        });                return view;     }    }

<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"    android:layout_width="match_parent"    android:layout_height="match_parent"    android:orientation="vertical" >    <TextView        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:text="这是微信模块" />    <Button        android:id="@+id/btn_test"        android:layout_width="wrap_content"        android:layout_height="wrap_content"         android:text="test"        /></LinearLayout>