1、使用Fragment 可以方便的替代TabActivity、ViewGroup

2、同时也省去了在AndroidManifest.xml文件中 添加相应的Activity

3、Fragment 是3.0之后的功能，如果想向下兼容我们在导包时一定要注意了，该导入 import android.support.v4.app.FragmentActivity; 而不是 import android.app.Fragment;

4、同时向下兼容我们的Activity 要继承 FragmentActivity 而不是 Activity

5、核心代码：

package com.example.testdialog;

import android.annotation.SuppressLint;

import android.os.Bundle;

import android.support.v4.app.FragmentActivity;

import android.support.v4.app.FragmentManager;

import android.support.v4.app.FragmentTransaction;

import android.view.View;

import android.view.View.OnClickListener;

import android.widget.TextView;

@SuppressLint("NewApi")

public class MainActivity extends FragmentActivity implements OnClickListener {

    private TextView tab1 = null;

    private TextView tab2 = null;

    private FragmentManager fm = null;

    private FragmentTransaction ft = null;

    @Override

    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_main);

        findViewById();

        fm = getSupportFragmentManager();

    }

    private void findViewById() {

        this.tab1 = (TextView) this.findViewById(R.id.tab1);

        this.tab2 = (TextView) this.findViewById(R.id.tab2);

        this.tab1.setOnClickListener(this);

        this.tab2.setOnClickListener(this);

    }

    @Override

    public void onClick(View v) {

        ft = fm.beginTransaction();

        switch (v.getId()) {

        case R.id.tab1:

            ft.replace(R.id.content, new MyFragment1());

            break;

        case R.id.tab2:

            ft.replace(R.id.content, new MyFragment2());

            break;

        default:

            break;

        }

        ft.commit();

    }

}

activity_main.xml 文件：

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"

    xmlns:tools="http://schemas.android.com/tools"

    android:layout_width="match_parent"

    android:layout_height="match_parent"

    android:orientation="vertical"

    tools:context=".MainActivity" >

    <LinearLayout

        android:layout_width="match_parent"

        android:layout_height="wrap_content"

        android:orientation="horizontal" >

        <TextView

            android:id="@+id/tab1"

            android:layout_width="0dip"

            android:layout_height="wrap_content"

            android:layout_weight="1"

            android:gravity="center"

            android:text="Tab1" />

        <TextView

            android:id="@+id/tab2"

            android:layout_width="0dip"

            android:layout_height="wrap_content"

            android:layout_weight="1"

            android:gravity="center"

            android:text="Tab2" />

        <TextView

            android:id="@+id/tab3"

            android:layout_width="0dip"

            android:layout_height="wrap_content"

            android:layout_weight="1"

            android:gravity="center"

            android:text="Tab3" />

        <TextView

            android:id="@+id/tab4"

            android:layout_width="0dip"

            android:layout_height="wrap_content"

            android:layout_weight="1"

            android:gravity="center"

            android:text="Tab2" />

    </LinearLayout>

    <LinearLayout

        android:id="@+id/content"

        android:layout_width="match_parent"

        android:layout_height="match_parent"

        android:layout_marginTop="20dip"

        android:orientation="horizontal" >

    </LinearLayout>

</LinearLayout>

MyFragment1.java

package com.example.testdialog;

import android.annotation.SuppressLint;

import android.os.Bundle;

import android.support.v4.app.Fragment;

import android.view.LayoutInflater;

import android.view.View;

import android.view.ViewGroup;

import android.widget.Button;

@SuppressLint("NewApi")

public class MyFragment1 extends Fragment {

    private Button button1 = null;

    @Override

    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {

        View view = inflater.inflate(R.layout.fragment1, null);

        button1 = (Button) view.findViewById(R.id.button1);

        return view;

    }

}

6、这样我们就可以在相应的 Fragment 中做我们的UI设计了