最近反复研究日常经典必用的几个android app，从主界面带来的交互方式入手进行分析，我将其大致分为三类。今天记录第一种方式，即主界面下面有几个tab页，最上端是标题栏，tab页和tab页之间不是通过滑动切换的，而是通过点击切换tab页。早期这种架构一直是使用tabhost+activitygroup来使用，随着fragment的出现及google官方也大力推荐使用fragment，后者大有代替前者之势。本文也使用fragment进行搭建，标题中的“经典”指这种交互经典，非本文的代码框架结构，欢迎大家提出指出不足，帮助完善。文中的fragment部分参考了郭神的博文(链接1 链接2 链接3)，代码也是在郭神代码基础上加入了自己对框架的理解。

再次重申下这种主界面交互的特点:1,多个tab，不能滑动切换只能点击切换；2，上有标题栏。这种模式也是目前app中使用最多的。如qq、百度云盘、招商银行、微博、支付宝。几个月前支付宝还是能滑动切换的，后来取消了。视图如下:

下面本文从底部控制栏、顶部控制栏及中间的内容显示载体fragment三部分叙述。

一、底部控制栏

底部控制栏里每个控件都不是单一基础控件，上面是图片、下面是文字，右上角是红点，当有更新时红点显示，否则隐藏。另外像qq的右上角还能显示未读消息的个数，我的参考链接里是通过大量的layout一点一点搭出来的，这样的好处是方便控制比较直观，另外是可以利用Linearlayout里的layout_weight这个属性，让底部的这些item均匀分布，缺点是代码上有很多重复，维护起来不方便。既然是整理app的通用模板框架，因此我将每个item视为一个对象，然后将其放在底部就ok了。本代码里只封装了上面是图片下面是文字，右上角的红点么有封装进来。

ImageText.java就作了这样一件事:

package org.yanzi.ui;

import org.yanzi.constant.Constant;

import android.content.Context;
import android.graphics.Color;
import android.util.AttributeSet;
import android.view.LayoutInflater;
import android.view.MotionEvent;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageView;
import android.widget.LinearLayout;
import android.widget.TextView;

import com.example.fragmentproject.R;


public class ImageText extends LinearLayout{
	private Context mContext = null;
	private ImageView mImageView = null;
	private TextView mTextView = null;
	private final static int DEFAULT_IMAGE_WIDTH = 64;
	private final static int DEFAULT_IMAGE_HEIGHT = 64;
	private int CHECKED_COLOR = Color.rgb(29, 118, 199); //选中蓝色
	private int UNCHECKED_COLOR = Color.GRAY;   //自然灰色
	public ImageText(Context context) {
		super(context);
		// TODO Auto-generated constructor stub
		mContext = context;
	}

	public ImageText(Context context, AttributeSet attrs) {
		super(context, attrs);
		// TODO Auto-generated constructor stub
		mContext = context;
		LayoutInflater inflater = (LayoutInflater) mContext.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
		View parentView = inflater.inflate(R.layout.image_text_layout, this, true);
		mImageView = (ImageView)findViewById(R.id.image_iamge_text);
		mTextView = (TextView)findViewById(R.id.text_iamge_text);
	}
	public void setImage(int id){
		if(mImageView != null){
			mImageView.setImageResource(id);
			setImageSize(DEFAULT_IMAGE_WIDTH, DEFAULT_IMAGE_HEIGHT);
		}
	}

	public void setText(String s){
		if(mTextView != null){
			mTextView.setText(s);
			mTextView.setTextColor(UNCHECKED_COLOR);
		}
	}

	@Override
	public boolean onInterceptTouchEvent(MotionEvent ev) {
		// TODO Auto-generated method stub
		return true;
	}
	private void setImageSize(int w, int h){
		if(mImageView != null){
			ViewGroup.LayoutParams params = mImageView.getLayoutParams();
			params.width = w;
			params.height = h;
			mImageView.setLayoutParams(params);
		}
	}
	public void setChecked(int itemID){
		if(mTextView != null){
			mTextView.setTextColor(CHECKED_COLOR);
		}
		int checkDrawableId = -1;
		switch (itemID){
		case Constant.BTN_FLAG_MESSAGE:
			checkDrawableId = R.drawable.message_selected;
			break;
		case Constant.BTN_FLAG_CONTACTS:
			checkDrawableId = R.drawable.contacts_selected;
			break;
		case Constant.BTN_FLAG_NEWS:
			checkDrawableId = R.drawable.news_selected;
			break;
		case Constant.BTN_FLAG_SETTING:
			checkDrawableId = R.drawable.setting_selected;
			break;
		default:break;
		}
		if(mImageView != null){
			mImageView.setImageResource(checkDrawableId);
		}
	}


	


}

<?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" >

    <ImageView
        android:id="@+id/image_iamge_text"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center_horizontal" />

    <TextView
        android:id="@+id/text_iamge_text"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center_horizontal" />

</LinearLayout>

package org.yanzi.constant;

public class Constant {
	//Btn的标识
	public static final int BTN_FLAG_MESSAGE = 0x01;
	public static final int BTN_FLAG_CONTACTS = 0x01 << 1;
	public static final int BTN_FLAG_NEWS = 0x01 << 2;
	public static final int BTN_FLAG_SETTING = 0x01 << 3;
	
	//Fragment的标识
	public static final String FRAGMENT_FLAG_MESSAGE = "消息"; 
	public static final String FRAGMENT_FLAG_CONTACTS = "联系人"; 
	public static final String FRAGMENT_FLAG_NEWS = "新闻"; 
	public static final String FRAGMENT_FLAG_SETTING = "设置"; 
	public static final String FRAGMENT_FLAG_SIMPLE = "simple"; 
	
	
}

完成了ImageText之后，下面就是将4个这样的控件放到一个布局里。为了控制方便，我们将底部栏抽象为一个对象BottomControlPanel.java，这样在维护底部栏相关内容时直接找他就行了。BottomControlPanel继承自RelativeLayout，先来看它的布局:

bottom_panel_layout.xml

<?xml version="1.0" encoding="utf-8"?>
<org.yanzi.ui.BottomControlPanel xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="60dp"
    android:layout_alignParentBottom="true"
    android:gravity="center_vertical"
    android:paddingLeft="20dp"
    android:paddingRight="20dp" >

    <org.yanzi.ui.ImageText
        android:id="@+id/btn_message"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentLeft="true" />

    <org.yanzi.ui.ImageText
        android:id="@+id/btn_contacts"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_toRightOf="@id/btn_message" />

    <org.yanzi.ui.ImageText
        android:id="@+id/btn_news"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_toRightOf="@id/btn_contacts" />

    <org.yanzi.ui.ImageText
        android:id="@+id/btn_setting"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentRight="true" />

</org.yanzi.ui.BottomControlPanel>

BottomControlPanel.java

package org.yanzi.ui;

import java.util.ArrayList;
import java.util.List;

import org.yanzi.constant.Constant;

import android.content.Context;
import android.graphics.Color;
import android.util.AttributeSet;
import android.util.Log;
import android.view.View;
import android.widget.RelativeLayout;

import com.example.fragmentproject.R;

public class BottomControlPanel extends RelativeLayout implements View.OnClickListener {
	private Context mContext;
	private ImageText mMsgBtn = null;
	private ImageText mContactsBtn = null;
	private ImageText mNewsBtn = null;
	private ImageText mSettingBtn = null;
	private int DEFALUT_BACKGROUND_COLOR = Color.rgb(243, 243, 243); //Color.rgb(192, 192, 192)
	private BottomPanelCallback mBottomCallback = null;
	private List<ImageText> viewList = new ArrayList<ImageText>();

	public interface BottomPanelCallback{
		public void onBottomPanelClick(int itemId);
	}
	public BottomControlPanel(Context context, AttributeSet attrs) {
		super(context, attrs);
		// TODO Auto-generated constructor stub
	}
	@Override
	protected void onFinishInflate() {
		// TODO Auto-generated method stub
		mMsgBtn = (ImageText)findViewById(R.id.btn_message);
		mContactsBtn = (ImageText)findViewById(R.id.btn_contacts);
		mNewsBtn = (ImageText)findViewById(R.id.btn_news);
		mSettingBtn = (ImageText)findViewById(R.id.btn_setting);
		setBackgroundColor(DEFALUT_BACKGROUND_COLOR);
		viewList.add(mMsgBtn);
		viewList.add(mContactsBtn);
		viewList.add(mNewsBtn);
		viewList.add(mSettingBtn);

	}
	public void initBottomPanel(){
		if(mMsgBtn != null){
			mMsgBtn.setImage(R.drawable.message_unselected);
			mMsgBtn.setText("消息");
		}
		if(mContactsBtn != null){
			mContactsBtn.setImage(R.drawable.contacts_unselected);
			mContactsBtn.setText("联系人");
		}
		if(mNewsBtn != null){
			mNewsBtn.setImage(R.drawable.news_unselected);
			mNewsBtn.setText("新闻");
		}
		if(mSettingBtn != null){
			mSettingBtn.setImage(R.drawable.setting_unselected);
			mSettingBtn.setText("设置");
		}
		setBtnListener();

	}
	private void setBtnListener(){
		int num = this.getChildCount();
		for(int i = 0; i < num; i++){
			View v = getChildAt(i);
			if(v != null){
				v.setOnClickListener(this);
			}
		}
	}
	public void setBottomCallback(BottomPanelCallback bottomCallback){
		mBottomCallback = bottomCallback;
	}
	@Override
	public void onClick(View v) {
		// TODO Auto-generated method stub
		initBottomPanel();
		int index = -1;
		switch(v.getId()){
		case R.id.btn_message:
			index = Constant.BTN_FLAG_MESSAGE;
			mMsgBtn.setChecked(Constant.BTN_FLAG_MESSAGE);
			break;
		case R.id.btn_contacts:
			index = Constant.BTN_FLAG_CONTACTS;
			mContactsBtn.setChecked(Constant.BTN_FLAG_CONTACTS);
			break;
		case R.id.btn_news:
			index = Constant.BTN_FLAG_NEWS;
			mNewsBtn.setChecked(Constant.BTN_FLAG_NEWS);
			break;
		case R.id.btn_setting:
			index = Constant.BTN_FLAG_SETTING;
			mSettingBtn.setChecked(Constant.BTN_FLAG_SETTING);
			break;
		default:break;
		}
		if(mBottomCallback != null){
			mBottomCallback.onBottomPanelClick(index);
		}
	}
	public void defaultBtnChecked(){
		if(mMsgBtn != null){
			mMsgBtn.setChecked(Constant.BTN_FLAG_MESSAGE);
		}
	}
	@Override
	protected void onLayout(boolean changed, int left, int top, int right, int bottom) {
		// TODO Auto-generated method stub
		super.onLayout(changed, left, top, right, bottom);
		layoutItems(left, top, right, bottom);
	}
	/**最左边和最右边的view由母布局的padding进行控制位置。这里需对第2、3个view的位置重新设置
	 * @param left
	 * @param top
	 * @param right
	 * @param bottom
	 */
	private void layoutItems(int left, int top, int right, int bottom){
		int n = getChildCount();
		if(n == 0){
			return;
		}
		int paddingLeft = getPaddingLeft();
		int paddingRight = getPaddingRight();
		Log.i("yanguoqi", "paddingLeft = " + paddingLeft + " paddingRight = " + paddingRight);
		int width = right - left;
		int height = bottom - top;
		Log.i("yanguoqi", "width = " + width + " height = " + height);
		int allViewWidth = 0;
		for(int i = 0; i< n; i++){
			View v = getChildAt(i);
			Log.i("yanguoqi", "v.getWidth() = " + v.getWidth());
			allViewWidth += v.getWidth();
		}
		int blankWidth = (width - allViewWidth - paddingLeft - paddingRight) / (n - 1);
		Log.i("yanguoqi", "blankV = " + blankWidth );

		LayoutParams params1 = (LayoutParams) viewList.get(1).getLayoutParams();
		params1.leftMargin = blankWidth;
		viewList.get(1).setLayoutParams(params1);

		LayoutParams params2 = (LayoutParams) viewList.get(2).getLayoutParams();
		params2.leftMargin = blankWidth;
		viewList.get(2).setLayoutParams(params2);
	}



}

这里定义了

public interface BottomPanelCallback{
public void onBottomPanelClick(int itemId);
}这个接口，通过传递Id来通知Activity。defaultBtnChecked()函数是apk初次打开后，默认切换到第一个消息fragment上。

这里有个地方需要注意，就是虽然ImageText和BottomControlPanel都是自定义控件，但两者在方式上是有区别的。在ImageText的构造函数里通过inflater将布局加载进来，它对应的布局是个普通的布局。而BottomControlPanel对应的布局文件里，直接使用了定义的BottomControlPanel，在onFinishInflate函数里实例化孩子View。前者是inflate之后实例化的。在使用ImageText到一个新的母布局时是通过<org.yanzi.ui.ImageText />这种方式进行的，那么使用BottomControlPanel有何区别，请见下文介绍Activity的布局时。

二、顶部控制栏

有了底部控制栏，顶部控制栏就可以如法炮制了。这里先交代几句，虽然Android3.0 后Google推出的有ActionBar来做顶部导航栏，参见郭神的这篇博文。但我发现，本文最前面贴图的几款应用应该都没有使用ActionBar，因为它不够灵活。ActionBar使用起来什么样，大家看看微信就知道了，那个的顶部控制栏就是ActionBar做的，这个应该没跑。

通过观察，顶部控制栏除了标题居中外，在右上角通常会再放一个按钮。不是ImageView就是TextView，这里我为了方便放的是两个TextView，右侧的按钮效果可以再TextView上弄个背景来实现。

HeadControlPanel.java

package org.yanzi.ui;

import org.yanzi.constant.Constant;

import com.example.fragmentproject.R;

import android.content.Context;
import android.graphics.Color;
import android.util.AttributeSet;
import android.widget.RelativeLayout;
import android.widget.TextView;

public class HeadControlPanel extends RelativeLayout {

	private Context mContext;
	private TextView mMidleTitle;
	private TextView mRightTitle;
	private static final float middle_title_size = 20f; 
	private static final float right_title_size = 17f; 
	private static final int default_background_color = Color.rgb(23, 124, 202);
	
	public HeadControlPanel(Context context, AttributeSet attrs) {
		super(context, attrs);
		// TODO Auto-generated constructor stub
	}

	@Override
	protected void onFinishInflate() {
		// TODO Auto-generated method stub
		mMidleTitle = (TextView)findViewById(R.id.midle_title);
		mRightTitle = (TextView)findViewById(R.id.right_title);
		setBackgroundColor(default_background_color);
	}
	public void initHeadPanel(){
		
		if(mMidleTitle != null){
			setMiddleTitle(Constant.FRAGMENT_FLAG_MESSAGE);
		}
	}
	public void setMiddleTitle(String s){
		mMidleTitle.setText(s);
		mMidleTitle.setTextSize(middle_title_size);
	}
	

}

<?xml version="1.0" encoding="utf-8"?>
<org.yanzi.ui.HeadControlPanel xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="50dp"
    android:layout_alignParentTop="true">
    <TextView 
        android:id="@+id/midle_title"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerInParent="true"
        android:textColor="@android:color/white"/>
    <TextView 
         android:id="@+id/right_title"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentRight="true"
        android:textColor="@android:color/white"/>
        
</org.yanzi.ui.HeadControlPanel>

三、总控中心Activity和Fragment

先交代下Fragment的使用大致分两种，一种是将Fragment作为一个View写死在布局中，布局里使用android:name来告诉它对应的是哪个实体Fragment。这种添加fragment的方式不能delete和replace掉。另一种是通过获得activity的fragmentmanager和fragmentTransaction和进行动态的添加。这种方式更加灵活，一般使用此种方法。

先看Activity的布局activity_main.xml:

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/root_layout"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="org.yanzi.fragmentproject.MainActivity" >

    <include
        android:id="@+id/bottom_layout"
        layout="@layout/bottom_panel_layout" />

    <View
        android:layout_width="match_parent"
        android:layout_height="1dip"
        android:layout_above="@id/bottom_layout"
        android:background="#FFE7E7E7" />

    <include
        android:id="@+id/head_layout"
        layout="@layout/head_panel_layout" />

    <View
        android:layout_width="match_parent"
        android:layout_height="1dip"
        android:layout_below="@id/head_layout"
        android:background="#FFE7E7E7" />
    <FrameLayout
        android:id="@+id/fragment_content"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_below="@id/head_layout"
        android:layout_above="@id/bottom_layout" >
    </FrameLayout>

</RelativeLayout>

在放Fragment的时候需要注意，究竟是否要将顶部控制栏放到各自的fragment里合适还是放到Activity里合适要看具体情况，如果顶部栏里多是显示标题这种功能或少量的点击事件，应该放到Activity里，即顶部栏的事务逻辑和当前fragment的事务逻辑耦合的不是很紧。举个例子，比如微信的顶部栏，不管你处在哪个Tab页(聊天、发现、通讯录)，点击顶部栏里的按钮都呈现出同样的内容。但反过来讲，如果顶部栏里的事务逻辑和fragment耦合很紧，即在不同的fragment，顶部栏呈现的内容都不一样，且点击后处理的事务也和当前fragment紧密联系一起，那就应该一个fragment配套一个顶部栏，方便控制。本文是将两者分开的。所以让fragment的容器在顶部栏之下，底部栏之上，不这样写的话，就会遮挡。

    <FrameLayout
        android:id="@+id/fragment_content"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_below="@id/head_layout"
        android:layout_above="@id/bottom_layout" >
    </FrameLayout>

MainActivity.java代码：

package org.yanzi.activity;

import org.yanzi.constant.Constant;
import org.yanzi.fragment.BaseFragment;
import org.yanzi.fragment.ContactsFragment;
import org.yanzi.fragment.MessageFragment;
import org.yanzi.fragment.NewsFragment;
import org.yanzi.fragment.SettingFragment;
import org.yanzi.ui.BottomControlPanel;
import org.yanzi.ui.BottomControlPanel.BottomPanelCallback;
import org.yanzi.ui.HeadControlPanel;

import android.app.Activity;
import android.app.Fragment;
import android.app.FragmentManager;
import android.app.FragmentTransaction;
import android.os.Bundle;
import android.text.TextUtils;
import android.util.Log;
import android.view.Menu;
import android.widget.Toast;

import com.example.fragmentproject.R;

public class MainActivity extends Activity implements BottomPanelCallback {
	BottomControlPanel bottomPanel = null;
	HeadControlPanel headPanel = null;
	
	private FragmentManager fragmentManager = null;
	private FragmentTransaction fragmentTransaction = null;
	
/*	private MessageFragment messageFragment;
	private ContactsFragment contactsFragment;
	private NewsFragment newsFragment;
	private SettingFragment settingFragment;*/
	
	public static String currFragTag = "";
	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);
		initUI();
		fragmentManager = getFragmentManager();
		setDefaultFirstFragment(Constant.FRAGMENT_FLAG_MESSAGE);
	}

	@Override
	public boolean onCreateOptionsMenu(Menu menu) {
		// Inflate the menu; this adds items to the action bar if it is present.
		getMenuInflater().inflate(R.menu.main, menu);
		return true;
	}
	private void initUI(){
		bottomPanel = (BottomControlPanel)findViewById(R.id.bottom_layout);
		if(bottomPanel != null){
			bottomPanel.initBottomPanel();
			bottomPanel.setBottomCallback(this);
		}
		headPanel = (HeadControlPanel)findViewById(R.id.head_layout);
		if(headPanel != null){
			headPanel.initHeadPanel();
		}
	}

	/* 处理BottomControlPanel的回调
	 * @see org.yanzi.ui.BottomControlPanel.BottomPanelCallback#onBottomPanelClick(int)
	 */
	@Override
	public void onBottomPanelClick(int itemId) {
		// TODO Auto-generated method stub
		String tag = "";
		if((itemId & Constant.BTN_FLAG_MESSAGE) != 0){
			tag = Constant.FRAGMENT_FLAG_MESSAGE;
		}else if((itemId & Constant.BTN_FLAG_CONTACTS) != 0){
			tag = Constant.FRAGMENT_FLAG_CONTACTS;
		}else if((itemId & Constant.BTN_FLAG_NEWS) != 0){
			tag = Constant.FRAGMENT_FLAG_NEWS;
		}else if((itemId & Constant.BTN_FLAG_SETTING) != 0){
			tag = Constant.FRAGMENT_FLAG_SETTING;
		}
		setTabSelection(tag); //切换Fragment
		headPanel.setMiddleTitle(tag);//切换标题 
	}
	
	private void setDefaultFirstFragment(String tag){
		Log.i("yan", "setDefaultFirstFragment enter... currFragTag = " + currFragTag);
		setTabSelection(tag);
		bottomPanel.defaultBtnChecked();
		Log.i("yan", "setDefaultFirstFragment exit...");
	}
	
	private void commitTransactions(String tag){
		if (fragmentTransaction != null && !fragmentTransaction.isEmpty()) {
			fragmentTransaction.commit();
			currFragTag = tag;
			fragmentTransaction = null;
		}
	}
	
	private FragmentTransaction ensureTransaction( ){
		if(fragmentTransaction == null){
			fragmentTransaction = fragmentManager.beginTransaction();
			fragmentTransaction
			.setTransition(FragmentTransaction.TRANSIT_FRAGMENT_FADE);
			
		}
		return fragmentTransaction;
		
	}
	
	private void attachFragment(int layout, Fragment f, String tag){
		if(f != null){
			if(f.isDetached()){
				ensureTransaction();
				fragmentTransaction.attach(f);
				
			}else if(!f.isAdded()){
				ensureTransaction();
				fragmentTransaction.add(layout, f, tag);
			}
		}
	}
	
	private Fragment getFragment(String tag){
		
		Fragment f = fragmentManager.findFragmentByTag(tag);
		
		if(f == null){
			Toast.makeText(getApplicationContext(), "fragment = null tag = " + tag, Toast.LENGTH_SHORT).show();
			f = BaseFragment.newInstance(getApplicationContext(), tag);
		}
		return f;
		
	}
	private void detachFragment(Fragment f){
		
		if(f != null && !f.isDetached()){
			ensureTransaction();
			fragmentTransaction.detach(f);
		}
	}
	/**切换fragment 
	 * @param tag
	 */
	private  void switchFragment(String tag){
		if(TextUtils.equals(tag, currFragTag)){
			return;
		}
		//把上一个fragment detach掉 
		if(currFragTag != null && !currFragTag.equals("")){
			detachFragment(getFragment(currFragTag));
		}
		attachFragment(R.id.fragment_content, getFragment(tag), tag);
		commitTransactions( tag);
	} 
	
	/**设置选中的Tag
	 * @param tag
	 */
	public  void setTabSelection(String tag) {
		// 开启一个Fragment事务
		fragmentTransaction = fragmentManager.beginTransaction();
/*		 if(TextUtils.equals(tag, Constant.FRAGMENT_FLAG_MESSAGE)){
		   if (messageFragment == null) {
				messageFragment = new MessageFragment();
			} 
			
		}else if(TextUtils.equals(tag, Constant.FRAGMENT_FLAG_CONTACTS)){
			if (contactsFragment == null) {
				contactsFragment = new ContactsFragment();
			} 
			
		}else if(TextUtils.equals(tag, Constant.FRAGMENT_FLAG_NEWS)){
			if (newsFragment == null) {
				newsFragment = new NewsFragment();
			}
			
		}else if(TextUtils.equals(tag,Constant.FRAGMENT_FLAG_SETTING)){
			if (settingFragment == null) {
				settingFragment = new SettingFragment();
			}
		}else if(TextUtils.equals(tag, Constant.FRAGMENT_FLAG_SIMPLE)){
			if (simpleFragment == null) {
				simpleFragment = new SimpleFragment();
			} 
			
		}*/
		 switchFragment(tag);
		 
	}

	@Override
	protected void onStop() {
		// TODO Auto-generated method stub
		super.onStop();
		currFragTag = "";
	}

	@Override
	protected void onSaveInstanceState(Bundle outState) {
		// TODO Auto-generated method stub
	}

}

/* private MessageFragment messageFragment;
private ContactsFragment contactsFragment;
private NewsFragment newsFragment;
private SettingFragment settingFragment;*/
这些内容，因为Fragment的生成是通过BaseFragment.newInstance()来生成的，传进去Tag生成相应的Fragment。所有的Fragment，ContactsFragment、MessageFragment、NewsFragment、SettingFragment都继承自BaseFragment，通过BaseFragment里的newInstance()接口进行实例化对应的fragment。优点是方便管理，缺点么也有，因为java继承继承一个类，不能同时继承两个类。所以如ListFragment这些，就没法同时继承了。不过好在有listview这些，也妨碍不了我们做到同样的效果。

Activity里事件的入口是在onBottomPanelClick()监听点击了谁，然后：

setTabSelection(tag); //切换Fragment

headPanel.setMiddleTitle(tag);//切换标题 

先切换Fragment再切换顶部栏的标题。setTabSelection()里直接调switchFragment(),在switchFragment函数里先判断标签是否一样，一样则意外着无需切换，否则的话就先把当前Fragment找到然后detach掉，之后进到attachFragment()函数里。在这里，先判断这个fragment是不是被detach掉的，如果是的话意味着之前曾被add过，所以只需attach就ok了。否则的话，意味着这是第一次，进行add.这里记录下Fragment的声明周期:

MessageFragment正常打开：
Line 155: 01-04 11:50:46.688 E/MessageFragment( 2546): onAttach-----
Line 159: 01-04 11:50:46.688 E/MessageFragment( 2546): onCreate------
Line 161: 01-04 11:50:46.693 D/MessageFragment( 2546): onCreateView---->
Line 165: 01-04 11:50:46.694 E/MessageFragment( 2546): onActivityCreated-------
Line 169: 01-04 11:50:46.694 E/MessageFragment( 2546): onStart----->
Line 173: 01-04 11:50:46.694 E/MessageFragment( 2546): onresume---->
返回键退出：
Line 183: 01-04 11:52:26.506 E/MessageFragment( 2546): onpause
Line 259: 01-04 11:52:27.131 E/MessageFragment( 2546): onStop
Line 263: 01-04 11:52:27.132 E/MessageFragment( 2546): ondestoryView
Line 269: 01-04 11:52:27.134 E/MessageFragment( 2546): ondestory
Line 271: 01-04 11:52:27.135 D/MessageFragment( 2546): onDetach------

按home按键退出:
Line 97: 01-05 05:06:15.659 E/MessageFragment(18835): onpause
Line 215: 01-05 05:06:16.292 E/MessageFragment(18835): onStop
再次打开：
Line 81: 01-05 05:07:02.408 E/MessageFragment(18835): onStart----->
Line 85: 01-05 05:07:02.408 E/MessageFragment(18835): onresume---->

通过detach的方式切换至其他Fragment：
Line 69: 01-04 11:53:33.381 E/MessageFragment( 2546): onpause
Line 73: 01-04 11:53:33.382 E/MessageFragment( 2546): onStop
Line 77: 01-04 11:53:33.382 E/MessageFragment( 2546): ondestoryView
再次切换过来:
Line 55: 01-04 11:54:59.462 D/MessageFragment( 2546): onCreateView---->
Line 59: 01-04 11:54:59.463 E/MessageFragment( 2546): onActivityCreated-------
Line 63: 01-04 11:54:59.463 E/MessageFragment( 2546): onStart----->
Line 67: 01-04 11:54:59.464 E/MessageFragment( 2546): onresume---->

四、适配器和MessageBean

本来要连数据库的，时间原因用个简单的MessageBean代替了。一个消息分联系人头像、名字、消息正文和时间四部分组成，封装到一个MessageBean里。

MessageBean.java

package org.yanzi.bean;

public class MessageBean {
	private int PhotoDrawableId;
	private String MessageName;
	private String MessageContent;
	private String MessageTime;
	
	public MessageBean(){
		
	}
	
	public MessageBean(int photoDrawableId, String messageName,
			String messageContent, String messageTime) {
		super();
		PhotoDrawableId = photoDrawableId;
		MessageName = messageName;
		MessageContent = messageContent;
		MessageTime = messageTime;
	}

	public int getPhotoDrawableId() {
		return PhotoDrawableId;
	}
	public void setPhotoDrawableId(int mPhotoDrawableId) {
		this.PhotoDrawableId = mPhotoDrawableId;
	}
	public String getMessageName() {
		return MessageName;
	}
	public void setMessageName(String messageName) {
		MessageName = messageName;
	}
	public String getMessageContent() {
		return MessageContent;
	}
	public void setMessageContent(String messageContent) {
		MessageContent = messageContent;
	}
	public String getMessageTime() {
		return MessageTime;
	}
	public void setMessageTime(String messageTime) {
		MessageTime = messageTime;
	}
	@Override
	public String toString() {
		return "MessageBean [mPhotoDrawableId=" + PhotoDrawableId
				+ ", MessageName=" + MessageName + ", MessageContent="
				+ MessageContent + ", MessageTime=" + MessageTime + "]";
	}
	
	
	
}

package org.yanzi.fragment.adapter;

import java.util.List;

import org.yanzi.bean.MessageBean;

import com.example.fragmentproject.R;

import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.ImageView;
import android.widget.TextView;

public class MessageAdapter extends BaseAdapter {
	private List<MessageBean> mListMsgBean = null;
	private Context mContext;
	private LayoutInflater mInflater;
	public MessageAdapter(List<MessageBean> listMsgBean, Context context){
		mListMsgBean = listMsgBean;
		mContext = context;
		mInflater = LayoutInflater.from(mContext);
	}
	@Override
	public int getCount() {
		// TODO Auto-generated method stub
		return mListMsgBean.size();
	}

	@Override
	public Object getItem(int position) {
		// TODO Auto-generated method stub
		return mListMsgBean.get(position);
	}

	@Override
	public long getItemId(int position) {
		// TODO Auto-generated method stub
		return position;
	}

	@Override
	public View getView(int position, View convertView, ViewGroup parent) {
		// TODO Auto-generated method stub
		View v = mInflater.inflate(R.layout.message_item_layout, null);
		
		ImageView imageView = (ImageView) v.findViewById(R.id.img_msg_item);
		imageView.setImageResource(mListMsgBean.get(position).getPhotoDrawableId());
		
		TextView nameMsg = (TextView)v.findViewById(R.id.name_msg_item);
		nameMsg.setText(mListMsgBean.get(position).getMessageName());

		TextView contentMsg = (TextView)v.findViewById(R.id.content_msg_item);
		contentMsg.setText(mListMsgBean.get(position).getMessageContent());
		
		TextView timeMsg = (TextView)v.findViewById(R.id.time_msg_item);
		timeMsg.setText(mListMsgBean.get(position).getMessageTime());

		return v;
	}

}

MessageFragment.java代码：

package org.yanzi.fragment;

import java.util.ArrayList;
import java.util.List;

import org.yanzi.activity.MainActivity;
import org.yanzi.bean.MessageBean;
import org.yanzi.constant.Constant;
import org.yanzi.fragment.adapter.MessageAdapter;

import android.app.Activity;
import android.os.Bundle;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.Toast;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.ListView;

import com.example.fragmentproject.R;

public class MessageFragment extends BaseFragment {

	private static final String TAG = "MessageFragment";
	private MainActivity mMainActivity ;
	private ListView mListView;
	private MessageAdapter mMsgAdapter;
	private List<MessageBean> mMsgBean = new ArrayList<MessageBean>();
	public View onCreateView(LayoutInflater inflater, ViewGroup container,
			Bundle savedInstanceState) {
		View messageLayout = inflater.inflate(R.layout.message_layout,
				container, false);
		Log.d(TAG, "onCreateView---->");
		mMainActivity = (MainActivity) getActivity();
		mFragmentManager = getActivity().getFragmentManager();
		mListView = (ListView)messageLayout.findViewById(R.id.listview_message);
		mMsgAdapter = new MessageAdapter(mMsgBean, mMainActivity);
		mListView.setAdapter(mMsgAdapter);
		mListView.setOnItemClickListener(new OnItemClickListener() {

			@Override
			public void onItemClick(AdapterView<?> parent, View view,
					int position, long id) {
				// TODO Auto-generated method stub
				Toast.makeText(mMainActivity, mMsgBean.get(position).toString(),
						Toast.LENGTH_SHORT).show();
			}

		});
		return messageLayout;
	}


	@Override
	public void onAttach(Activity activity) {
		// TODO Auto-generated method stub
		super.onAttach(activity);
		Log.e(TAG, "onAttach-----");

	}
	@Override
	public void onCreate(Bundle savedInstanceState) {
		// TODO Auto-generated method stub
		super.onCreate(savedInstanceState);
		Log.e(TAG, "onCreate------");
		mMsgBean.add(new MessageBean(R.drawable.ic_photo_1, "张三", "吃饭没?", "昨天"));
		mMsgBean.add(new MessageBean(R.drawable.ic_photo_2, "李四", "哈哈", "昨天"));
		mMsgBean.add(new MessageBean(R.drawable.ic_photo_3, "小明", "吃饭没?", "昨天"));
		mMsgBean.add(new MessageBean(R.drawable.ic_photo_4, "王五", "吃饭没?", "昨天"));
		mMsgBean.add(new MessageBean(R.drawable.ic_photo_5, "Jack", "吃饭没?", "昨天"));
		mMsgBean.add(new MessageBean(R.drawable.ic_photo_6, "Jone", "吃饭没?", "昨天"));
		mMsgBean.add(new MessageBean(R.drawable.ic_photo_7, "Jone", "吃饭没?", "昨天"));
		mMsgBean.add(new MessageBean(R.drawable.ic_photo_8, "Jone", "吃饭没?", "昨天"));
		mMsgBean.add(new MessageBean(R.drawable.ic_photo_9, "Jone", "吃饭没?", "昨天"));
	}

	@Override
	public void onActivityCreated(Bundle savedInstanceState) {
		// TODO Auto-generated method stub
		super.onActivityCreated(savedInstanceState);
		Log.e(TAG, "onActivityCreated-------");
	}

	@Override
	public void onStart() {
		// TODO Auto-generated method stub
		super.onStart();

		Log.e(TAG, "onStart----->");
	}

	@Override
	public void onResume() {
		// TODO Auto-generated method stub
		super.onResume();
		Log.e(TAG, "onresume---->");
		MainActivity.currFragTag = Constant.FRAGMENT_FLAG_MESSAGE;
	}

	@Override
	public void onPause() {
		// TODO Auto-generated method stub
		super.onPause();
		Log.e(TAG, "onpause");
	}

	@Override
	public void onStop() {
		// TODO Auto-generated method stub
		super.onStop();
		Log.e(TAG, "onStop");
	}

	@Override
	public void onDestroyView() {
		// TODO Auto-generated method stub
		super.onDestroyView();
		Log.e(TAG, "ondestoryView");
	}
	@Override
	public void onDestroy() {
		// TODO Auto-generated method stub
		super.onDestroy();
		Log.e(TAG, "ondestory");
	}

	@Override
	public void onDetach() {
		// TODO Auto-generated method stub
		super.onDetach();
		Log.d(TAG, "onDetach------");

	}



}

横屏情况下:

--------------本文系原创，转载请注明作者yanzi1225627

Android应用经典主界面框架之一:仿QQ (使用Fragment, 附源码),布布扣,bubuko.com

Android应用经典主界面框架之一:仿QQ (使用Fragment, 附源码)