用Fragment实现如新浪微博一样的底部菜单的切换

像我这个有强迫症的人来说，自从TabActivity抛弃之后，再使用看到一个个警告和一条条划着的横线，心里很不舒服，现在终于下定决心用Fragment来替换掉TabActivity了！我的研究成果如下：

首先是MainActivity，它需要继承FragmentActivity(这里是指：版本是3.0之前的继承FragmentActivity，3.0版本之后的继承Activity就可以)，对于FragmentActivity的声明周期我就不过多介绍了，和Activity差不了多少，自己也能弄明白！下边是MainActivity的代码：

package net.loonggg.fragment;

import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentActivity;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentTransaction;
import android.view.Window;
import android.widget.RadioButton;
import android.widget.RadioGroup;
import android.widget.RadioGroup.OnCheckedChangeListener;

public class MainActivity extends FragmentActivity {
	private Fragment[] mFragments;
	private RadioGroup bottomRg;
	private FragmentManager fragmentManager;
	private FragmentTransaction fragmentTransaction;
	private RadioButton rbOne, rbTwo, rbThree, rbFour;

	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		requestWindowFeature(Window.FEATURE_NO_TITLE);
		setContentView(R.layout.activity_main);
		mFragments = new Fragment[3];
		fragmentManager = getSupportFragmentManager();
		mFragments[0] = fragmentManager.findFragmentById(R.id.fragement_main);
		mFragments[1] = fragmentManager.findFragmentById(R.id.fragement_search);
		mFragments[2] = fragmentManager
				.findFragmentById(R.id.fragement_setting);
		fragmentTransaction = fragmentManager.beginTransaction()
				.hide(mFragments[0]).hide(mFragments[1]).hide(mFragments[2]);
		fragmentTransaction.show(mFragments[0]).commit();
		setFragmentIndicator();
	}

	private void setFragmentIndicator() {

		bottomRg = (RadioGroup) findViewById(R.id.bottomRg);
		rbOne = (RadioButton) findViewById(R.id.rbOne);
		rbTwo = (RadioButton) findViewById(R.id.rbTwo);
		rbThree = (RadioButton) findViewById(R.id.rbThree);

		bottomRg.setOnCheckedChangeListener(new OnCheckedChangeListener() {

			@Override
			public void onCheckedChanged(RadioGroup group, int checkedId) {
				fragmentTransaction = fragmentManager.beginTransaction()
						.hide(mFragments[0]).hide(mFragments[1])
						.hide(mFragments[2]);
				switch (checkedId) {
				case R.id.rbOne:
					fragmentTransaction.show(mFragments[0]).commit();
					break;

				case R.id.rbTwo:
					fragmentTransaction.show(mFragments[1]).commit();
					break;

				case R.id.rbThree:
					fragmentTransaction.show(mFragments[2]).commit();
					break;

				default:
					break;
				}
			}
		});
	}

}

下边对应的是MainActivity的布局文件activity_main.xml：

<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:background="@drawable/activity_bg"
    android:orientation="vertical" >

    <!-- 上边主页面 -->

    <fragment
        android:id="@+id/fragement_main"
        android:name="net.loonggg.fragment.FragmentMain"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        android:layout_weight="10" />

    <fragment
        android:id="@+id/fragement_search"
        android:name="net.loonggg.fragment.FragmentSearch"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        android:layout_weight="10" />

    <fragment
        android:id="@+id/fragement_setting"
        android:name="net.loonggg.fragment.FragmentSetting"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        android:layout_weight="10" />

    <!-- 底部菜单页面 -->

    <RadioGroup
        android:id="@+id/bottomRg"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:layout_weight="0.5"
        android:background="@drawable/tab_footer_bg"
        android:orientation="horizontal" >

        <RadioButton
            android:id="@+id/rbOne"
            style="@style/rg_btn_style"
            android:checked="true"
            android:drawableTop="@drawable/rb_one_btn_selector"
            android:text="首页" />

        <RadioButton
            android:id="@+id/rbTwo"
            style="@style/rg_btn_style"
            android:drawableTop="@drawable/rb_two_btn_selector"
            android:text="搜索" />

        <RadioButton
            android:id="@+id/rbThree"
            style="@style/rg_btn_style"
            android:drawableTop="@drawable/rb_three_btn_selector"
            android:text="设置" />
    </RadioGroup>

</LinearLayout>

这里为了大家方便，展示一下项目的布局图：

再下边是要设计的首页界面，它是继承的Fragment，具体看代码：

package net.loonggg.fragment;

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.TextView;

public class FragmentMain extends Fragment {
	private TextView tv;

	@Override
	public View onCreateView(LayoutInflater inflater, ViewGroup container,
			Bundle savedInstanceState) {
		return inflater.inflate(R.layout.fragment_main, container, false);
	}

	@Override
	public void onActivityCreated(Bundle savedInstanceState) {
		super.onActivityCreated(savedInstanceState);
		tv = (TextView) getView().findViewById(R.id.titleTv);
		tv.setText("首页");
	}
}

接着是对应的布局文件代码fragment_main.xml：

<?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" >

    <include
        android:id="@+id/one_title"
        layout="@layout/title_bar" />

    <TextView
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        android:gravity="center"
        android:text="这是首页"
        android:textColor="#000000" />

</LinearLayout>

再接着是：搜索界面的代码：

package net.loonggg.fragment;

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.TextView;

public class FragmentSearch extends Fragment {
	private TextView tv;

	@Override
	public View onCreateView(LayoutInflater inflater, ViewGroup container,
			Bundle savedInstanceState) {
		return inflater.inflate(R.layout.fragment_search, container, false);
	}

	@Override
	public void onActivityCreated(Bundle savedInstanceState) {
		super.onActivityCreated(savedInstanceState);
		tv = (TextView) getView().findViewById(R.id.titleTv);
		tv.setText("搜索");

	}

	@Override
	public void onPause() {
		super.onPause();
	}

}

如上是对应的布局文件的代码fragment_search.xml：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:orientation="vertical" >

    <include layout="@layout/title_bar" />

    <TextView
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        android:gravity="center"
        android:text="这是搜索界面"
        android:textColor="#000000" />

</LinearLayout>

紧跟着是：设置界面的代码：

package net.loonggg.fragment;

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.TextView;

public class FragmentSetting extends Fragment {
	private TextView tv;

	@Override
	public View onCreateView(LayoutInflater inflater, ViewGroup container,
			Bundle savedInstanceState) {
		return inflater.inflate(R.layout.fragment_setting, container, false);
	}

	@Override
	public void onActivityCreated(Bundle savedInstanceState) {
		super.onActivityCreated(savedInstanceState);
		tv = (TextView) getView().findViewById(R.id.titleTv);
		tv.setText("设置");
	}
}

当然一样，下边对应的是设置界面的布局文件代码fragment_setting.xml：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:orientation="vertical" >

    <include layout="@layout/title_bar" />

    <TextView
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        android:gravity="center"
        android:text="这是设置页面"
        android:textColor="#000000" />

</LinearLayout>

最后是我用的title_bar.xml文件，这个文件是嵌入到各个界面中的那个顶部的标题的布局文件，代码如下：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:background="@drawable/title_bg"
    android:gravity="center"
    android:orientation="vertical" >

    <TextView
        android:id="@+id/titleTv"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center"
        android:gravity="center"
        android:textColor="#ffffff"
        android:textSize="20sp" />

</LinearLayout>

到这里就基本完成了！！！你会了吗?