用Fragment来代替过期的Tabhost和ActivityGroup

首先布局xml中加入一个RelativeLayout来作为Fragment的容器，相当于Tabhost中的tabcontent；加入RadioGroup来作为选项卡，相当于Tabhost中的TabWidget。具体如下：

其次，在当前Activity中加入默认Fragment，并且通过RadioGroup的监听来进行切换Fragment。具体Activity代码如下：

package com.kenneth.blogtabfragment;

import android.app.Activity;
import android.app.Fragment;
import android.app.FragmentManager;
import android.app.FragmentTransaction;
import android.content.Context;
import android.os.Bundle;
import android.view.Menu;
import android.widget.RadioButton;
import android.widget.RadioGroup;
import android.widget.RadioGroup.OnCheckedChangeListener;

/**
 * @author Kenneth 2014-2-11 上午10:26:06
 */
public class MainActivity extends Activity implements OnCheckedChangeListener {
	public static final String TAG = MainActivity.class.getSimpleName();
	private Context mContext = this;
	private FragmentManager fm;
	private RadioGroup radioGroup1;
	private RadioButton radio0;
	private RadioButton radio1;
	private RadioButton radio2;

	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);
		initView();
		initData();
		initListener();
	}

	@Override
	public boolean onCreateOptionsMenu(Menu menu) {
		getMenuInflater().inflate(R.menu.main, menu);
		return true;
	}

	private void initView() {
		radioGroup1 = (RadioGroup) findViewById(R.id.radioGroup1);
		radio0 = (RadioButton) findViewById(R.id.radio0);
		radio1 = (RadioButton) findViewById(R.id.radio1);
		radio2 = (RadioButton) findViewById(R.id.radio2);
	}

	private void initData() {
		fm = getFragmentManager();// 获取fragment管理工具类
		replace(new FirstFragment());//默认选第一个
	}

	private void initListener() {
		radioGroup1.setOnCheckedChangeListener(this);
	}

	@Override
	public void onCheckedChanged(RadioGroup group, int checkedId) {
		switch (checkedId) {
		case R.id.radio0:
			replace(new FirstFragment());
			break;
		case R.id.radio1:
			replace(new SecondFragment());

			break;
		case R.id.radio2:
			replace(new ThirdFragment());

			break;

		default:
			break;
		}
	}

	private void replace(Fragment fragment) {//替换当前容器中的Fragment
		FragmentTransaction beginTransaction = fm.beginTransaction();
		beginTransaction.replace(R.id.content, fragment);
		beginTransaction.commit();
	}
}

以上，就是用Fragment来实现Tabhost效果的主要代码。如果是api11以下，请把getFragmentManager替换为getSupportFragmentManager,其他Fragment相关的请引v4支持包中的。

用多了你就会发现Fragment要比Tabhost，ActivityGroup好用太多了。