【Android UI设计与开发】5.底部菜单栏（二）使用Fragment实现底部菜单栏

既然 Fragment 取代了TabActivity，当然 TabActivity 的能实现的菜单栏，Fragment 当然也能实现。主要其实就是通过菜单栏的点击事件切换 Fragment 的显示和隐藏。

来看看栗子吧：

1.效果图来了：

2.代码具体实现

2.1 自定义底部菜单栏实现方式

(1)对应的 Fragment 编辑代码和布局实现在前面的 Fragment介绍和简单实现  中已经有提及，代码中没复杂的地方，此处略过，具体可看实例代码。

(2)菜单栏实现，这里使用代码实现的，其实也可以用布局文件实现，代码如下：

package com.yanis.yc_ui_fragment_menu;

import android.content.Context;
import android.graphics.Color;
import android.util.AttributeSet;
import android.util.TypedValue;
import android.view.Gravity;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.ImageView;
import android.widget.LinearLayout;
import android.widget.TextView;

/**
 * 
 * @author YeChao
 * @功能描述：自定义底部工具栏
 *
 */
public class ViewIndicator extends LinearLayout implements OnClickListener {
    private int mDefaultIndicator = 0; // 默认的选定View

    private static int mCurIndicator; // 当前选定View

    private static View[] mIndicators; // View集合

    private OnIndicateListener mOnIndicateListener; // 对应的监听器
    // 对应的图标Tag
    private static final String TAG_ICON_0 = "icon_tag_0";
    private static final String TAG_ICON_1 = "icon_tag_1";
    private static final String TAG_ICON_2 = "icon_tag_2";
    private static final String TAG_ICON_3 = "icon_tag_3";
    private static final String TAG_ICON_4 = "icon_tag_4";
    // 对应的文字Tag
    private static final String TAG_TEXT_0 = "text_tag_0";
    private static final String TAG_TEXT_1 = "text_tag_1";
    private static final String TAG_TEXT_2 = "text_tag_2";
    private static final String TAG_TEXT_3 = "text_tag_3";
    private static final String TAG_TEXT_4 = "text_tag_4";
    // 未选中状态
    private static final int COLOR_UNSELECT = Color.argb(100, 0xff, 0xff, 0xff);
    // 选中状态
    private static final int COLOR_SELECT = Color.WHITE;

    // 构造函数
    public ViewIndicator(Context context) {
        super(context);
    }

    public ViewIndicator(Context context, AttributeSet attrs) {
        super(context, attrs);
        mCurIndicator = mDefaultIndicator;
        setOrientation(LinearLayout.HORIZONTAL);// 水平布局
        init();
    }

    /**
     * 菜单视图布局
     * 
     * @param iconResID
     *            图片资源ID
     * @param stringResID
     *            文字资源ID
     * @param stringColor
     *            颜色资源ID
     * @param iconTag
     *            图片标签
     * @param textTag
     *            文字标签
     * @return
     */
    private View createIndicator(int iconResID, int stringResID,
            int stringColor, String iconTag, String textTag) {
        // 实例一个LinearLayout
        LinearLayout view = new LinearLayout(getContext());
        view.setOrientation(LinearLayout.VERTICAL);// 垂直布局
        // 设置宽高和权重
        view.setLayoutParams(new LinearLayout.LayoutParams(
                LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT, 1));
        view.setGravity(Gravity.CENTER_HORIZONTAL);
        view.setBackgroundResource(R.drawable.main_tab_item_bg_normal);
        // 实例一个ImageView
        ImageView iconView = new ImageView(getContext());
        // 设置与该ImageView视图相关联的标记
        iconView.setTag(iconTag);
        // 设置宽高和权重
        iconView.setLayoutParams(new LinearLayout.LayoutParams(
                LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT, 1));
        iconView.setImageResource(iconResID);// 设置图片资源
        // 实例一个TextView
        TextView textView = new TextView(getContext());
        // 设置与该TextView视图相关联的标记
        textView.setTag(textTag);
        // 设置宽高和权重
        textView.setLayoutParams(new LinearLayout.LayoutParams(
                LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT, 1));
        // 设置文字颜色
        textView.setTextColor(stringColor);
        // 设置文字大小
        textView.setTextSize(TypedValue.COMPLEX_UNIT_SP, 16);
        // 设置文字资源
        textView.setText(stringResID);
        // 添加视图到布局中
        view.addView(iconView);
        view.addView(textView);
        // 返回布局视图
        return view;

    }

    /**
     * 初始化视图
     */
    private void init() {
        mIndicators = new View[5];// 5个View
        // 第一个为默认选中的
        // 主页main_tab_item_bg_normal
        mIndicators[0] = createIndicator(R.drawable.main_tab_item_home_focus,
                R.string.tab_item_home, COLOR_SELECT, TAG_ICON_0, TAG_TEXT_0);
        mIndicators[0].setBackgroundResource(R.drawable.main_tab_item_bg);
        mIndicators[0].setTag(Integer.valueOf(0));
        mIndicators[0].setOnClickListener(this);
        addView(mIndicators[0]);
        // 分类
        mIndicators[1] = createIndicator(
                R.drawable.main_tab_item_category_normal,
                R.string.tab_item_category, COLOR_UNSELECT, TAG_ICON_1,
                TAG_TEXT_1);
        mIndicators[1].setBackgroundResource(R.drawable.main_tab_item_bg);
        mIndicators[1].setTag(Integer.valueOf(1));
        mIndicators[1].setOnClickListener(this);
        addView(mIndicators[1]);
        // 下载
        mIndicators[2] = createIndicator(R.drawable.main_tab_item_down_normal,
                R.string.tab_item_down, COLOR_UNSELECT, TAG_ICON_2, TAG_TEXT_2);
        mIndicators[2].setBackgroundResource(R.drawable.main_tab_item_bg);
        mIndicators[2].setTag(Integer.valueOf(2));
        mIndicators[2].setOnClickListener(this);
        addView(mIndicators[2]);
        // 我的
        mIndicators[3] = createIndicator(R.drawable.main_tab_item_user_normal,
                R.string.tab_item_user, COLOR_UNSELECT, TAG_ICON_3, TAG_TEXT_3);
        mIndicators[3].setBackgroundResource(R.drawable.main_tab_item_bg);
        mIndicators[3].setTag(Integer.valueOf(3));
        mIndicators[3].setOnClickListener(this);
        addView(mIndicators[3]);
        // 设置
        mIndicators[4] = createIndicator(
                R.drawable.main_tab_item_setting_normal,
                R.string.tab_item_setting, COLOR_UNSELECT, TAG_ICON_4,
                TAG_TEXT_4);
        mIndicators[4].setBackgroundResource(R.drawable.main_tab_item_bg);
        mIndicators[4].setTag(Integer.valueOf(4));
        mIndicators[4].setOnClickListener(this);
        addView(mIndicators[4]);
    }

    public static void setIndicator(int which) {
        // /////////////////清除之前的状态/////////////////////////////////
        // mIndicators[mCurIndicator].setBackgroundResource(R.drawable.main_tab_item_bg_normal);
        ImageView prevIcon;
        TextView prevText;
        switch (mCurIndicator) {
        case 0:
            prevIcon = (ImageView) mIndicators[mCurIndicator]
                    .findViewWithTag(TAG_ICON_0);
            prevIcon.setImageResource(R.drawable.main_tab_item_home);
            prevText = (TextView) mIndicators[mCurIndicator]
                    .findViewWithTag(TAG_TEXT_0);
            prevText.setTextColor(COLOR_UNSELECT);
            break;
        case 1:
            prevIcon = (ImageView) mIndicators[mCurIndicator]
                    .findViewWithTag(TAG_ICON_1);
            prevIcon.setImageResource(R.drawable.main_tab_item_category);
            prevText = (TextView) mIndicators[mCurIndicator]
                    .findViewWithTag(TAG_TEXT_1);
            prevText.setTextColor(COLOR_UNSELECT);
            break;
        case 2:
            prevIcon = (ImageView) mIndicators[mCurIndicator]
                    .findViewWithTag(TAG_ICON_2);
            prevIcon.setImageResource(R.drawable.main_tab_item_down);
            prevText = (TextView) mIndicators[mCurIndicator]
                    .findViewWithTag(TAG_TEXT_2);
            prevText.setTextColor(COLOR_UNSELECT);
            break;
        case 3:
            prevIcon = (ImageView) mIndicators[mCurIndicator]
                    .findViewWithTag(TAG_ICON_3);
            prevIcon.setImageResource(R.drawable.main_tab_item_user);
            prevText = (TextView) mIndicators[mCurIndicator]
                    .findViewWithTag(TAG_TEXT_3);
            prevText.setTextColor(COLOR_UNSELECT);
            break;
        case 4:
            prevIcon = (ImageView) mIndicators[mCurIndicator]
                    .findViewWithTag(TAG_ICON_4);
            prevIcon.setImageResource(R.drawable.main_tab_item_setting);
            prevText = (TextView) mIndicators[mCurIndicator]
                    .findViewWithTag(TAG_TEXT_4);
            prevText.setTextColor(COLOR_UNSELECT);
            break;
        }
        // /////////////////更新前状态/////////////////////////////////
        // mIndicators[which].setBackgroundResource(R.drawable.main_tab_item_bg_focus);
        ImageView currIcon;
        TextView currText;
        /**
         * 设置选中状态
         */
        switch (which) {
        case 0:
            currIcon = (ImageView) mIndicators[which]
                    .findViewWithTag(TAG_ICON_0);
            currIcon.setImageResource(R.drawable.main_tab_item_home_focus);
            currText = (TextView) mIndicators[which]
                    .findViewWithTag(TAG_TEXT_0);
            currText.setTextColor(COLOR_SELECT);
            break;
        case 1:
            currIcon = (ImageView) mIndicators[which]
                    .findViewWithTag(TAG_ICON_1);
            currIcon.setImageResource(R.drawable.main_tab_item_category_focus);
            currText = (TextView) mIndicators[which]
                    .findViewWithTag(TAG_TEXT_1);
            currText.setTextColor(COLOR_SELECT);
            break;
        case 2:
            currIcon = (ImageView) mIndicators[which]
                    .findViewWithTag(TAG_ICON_2);
            currIcon.setImageResource(R.drawable.main_tab_item_down_focus);
            currText = (TextView) mIndicators[which]
                    .findViewWithTag(TAG_TEXT_2);
            currText.setTextColor(COLOR_SELECT);
            break;
        case 3:
            currIcon = (ImageView) mIndicators[which]
                    .findViewWithTag(TAG_ICON_3);
            currIcon.setImageResource(R.drawable.main_tab_item_user_focus);
            currText = (TextView) mIndicators[which]
                    .findViewWithTag(TAG_TEXT_3);
            currText.setTextColor(COLOR_SELECT);
            break;
        case 4:
            currIcon = (ImageView) mIndicators[which]
                    .findViewWithTag(TAG_ICON_4);
            currIcon.setImageResource(R.drawable.main_tab_item_setting_focus);
            currText = (TextView) mIndicators[which]
                    .findViewWithTag(TAG_TEXT_4);
            currText.setTextColor(COLOR_SELECT);
            break;
        }

        mCurIndicator = which;
    }

    public interface OnIndicateListener {
        public void onIndicate(View v, int which);
    }

    public void setOnIndicateListener(OnIndicateListener listener) {
        mOnIndicateListener = listener;
    }

    @Override
    public void onClick(View v) {
        if (mOnIndicateListener != null) {
            int tag = (Integer) v.getTag();
            switch (tag) {
            case 0:
                if (mCurIndicator != 0) {
                    mOnIndicateListener.onIndicate(v, 0);
                    setIndicator(0);
                }
                break;
            case 1:
                if (mCurIndicator != 1) {
                    mOnIndicateListener.onIndicate(v, 1);
                    setIndicator(1);
                }
                break;
            case 2:
                if (mCurIndicator != 2) {
                    mOnIndicateListener.onIndicate(v, 2);
                    setIndicator(2);
                }
                break;
            case 3:
                if (mCurIndicator != 3) {
                    mOnIndicateListener.onIndicate(v, 3);
                    setIndicator(3);
                }
                break;
            case 4:
                if (mCurIndicator != 4) {
                    mOnIndicateListener.onIndicate(v, 4);
                    setIndicator(4);
                }
                break;
            default:
                break;
            }
        }
    }
}

(3)最后就是主界面代码，切换 Fragment 的显示和隐藏以及菜单栏的选中状态

package com.yanis.yc_ui_fragment_menu;

import com.yanis.yc_ui_fragment_menu.ViewIndicator.OnIndicateListener;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentActivity;
import android.view.View;

public class MainActivity extends FragmentActivity {
     public static Fragment[] mFragments;  
     
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        
        setFragmentIndicator(0);  
    }
    
     /** 
     * 初始化fragment 
     */  
    private void setFragmentIndicator(int whichIsDefault) { 
        //实例化 Fragment 集合
         mFragments = new Fragment[5];  
         mFragments[0] = getSupportFragmentManager().findFragmentById(R.id.fragment_home);  
         mFragments[1] = getSupportFragmentManager().findFragmentById(R.id.fragment_category);  
         mFragments[2] = getSupportFragmentManager().findFragmentById(R.id.fragment_down);  
         mFragments[3] = getSupportFragmentManager().findFragmentById(R.id.fragment_user);  
         mFragments[4] = getSupportFragmentManager().findFragmentById(R.id.fragment_setting);  
         //显示默认的Fragment
         getSupportFragmentManager().beginTransaction().hide(mFragments[0])  
                 .hide(mFragments[1]).hide(mFragments[2]).hide(mFragments[3]).hide(mFragments[4]).show(mFragments[whichIsDefault]).commit(); 
         //绑定自定义的菜单栏组件
        ViewIndicator mIndicator = (ViewIndicator) findViewById(R.id.indicator);  
        ViewIndicator.setIndicator(whichIsDefault);  
        mIndicator.setOnIndicateListener(new OnIndicateListener() {  
            @Override  
            public void onIndicate(View v, int which) {  
                //显示指定的Fragment
                  getSupportFragmentManager().beginTransaction()  
                  .hide(mFragments[0]).hide(mFragments[1])  
                  .hide(mFragments[2]).hide(mFragments[3]).hide(mFragments[4]).show(mFragments[which]).commit(); 
            }  
        });  
    }  
}

源代码地址：https://github.com/YeXiaoChao/Yc_ui_fragment_menu

---

2.2 使用 Fragment+FragmentTabHost 来实现底部菜单栏方式

效果是一样的，只是在上面的基础上使用 FragmentTabHost 来实现底部菜单栏，直接通过 FragmentTabHost 来切换 Fragment 的显示 ，而不是自定义的布局。

（1）修改主布局代码，加入了FragmentTabHost 组件

<?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="fill_parent"
    android:orientation="vertical" >

    <FrameLayout
        android:id="@+id/realtabcontent"
        android:layout_width="fill_parent"
        android:layout_height="0dip"
        android:layout_weight="1" />

    <android.support.v4.app.FragmentTabHost
        android:id="@android:id/tabhost"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content" 
        android:background="@drawable/main_tab_item_bg">

        <FrameLayout
            android:id="@android:id/tabcontent"
            android:layout_width="0dp"
            android:layout_height="0dp"
            android:layout_weight="0" />            
    </android.support.v4.app.FragmentTabHost>

</LinearLayout>

（2）单独为Tab按钮选项布局

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

    <ImageView
        android:id="@+id/imageview"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:focusable="false"
        android:padding="3dp" 
        android:src="@drawable/main_tab_item_home">
    </ImageView>

    <TextView
        android:id="@+id/textview"       
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" 
        android:textSize="12sp"
        android:textColor="#ffffff">
    </TextView>

</LinearLayout>

(3) fragment布局界面和之前一样，就不再赘述

(4) Tab选项的自定义按钮中图片资源文件，列出其中一个按钮，指定了按钮的选中状态和不选中状态不同的图片显示

<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">

    <item android:drawable="@drawable/main_tab_item_home_focus" android:state_selected="true"/>
    <item android:drawable="@drawable/main_tab_item_home_normal"/>

</selector>

(5) Tab选项按钮背景资源文件，指定了点击的效果

<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">

    <!-- pressed -->
    <item android:drawable="@drawable/main_tab_item_bg_focus" android:state_enabled="true" android:state_pressed="true"/>

    <!-- focused -->
    <item android:drawable="@drawable/main_tab_item_bg_focus" android:state_enabled="true" android:state_focused="true"/>

    <!-- normal -->
    <item android:drawable="@drawable/main_tab_item_bg_normal" android:state_enabled="true"/>

</selector>

（6） 最后就是主界面代码的改变

package com.yanis.yc_ui_fragment_tabhost;

import android.os.Bundle;
import android.support.v4.app.FragmentActivity;
import android.support.v4.app.FragmentTabHost;
import android.view.LayoutInflater;
import android.view.View;
import android.widget.ImageView;
import android.widget.TabHost.TabSpec;
import android.widget.TextView;

/**
 * 
 * @author yechao
 * @功能说明 自定义TabHost
 *
 */
public class MainActivity extends FragmentActivity {
    // 定义FragmentTabHost对象
    private FragmentTabHost mTabHost;

    // 定义一个布局
    private LayoutInflater layoutInflater;

    // 定义数组来存放Fragment界面
    private Class fragmentArray[] = { FragmentHome.class,
            FragmentCategory.class, FragmentDown.class, FragmentUser.class,
            FragmentSetting.class };

    // 定义数组来存放按钮图片
    private int mImageViewArray[] = { R.drawable.main_tab_item_home,
            R.drawable.main_tab_item_category, R.drawable.main_tab_item_down,
            R.drawable.main_tab_item_user, R.drawable.main_tab_item_setting };

    // Tab选项卡的文字
    private String mTextviewArray[] = { "主页", "分类", "下载", "我的", "设置" };

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

        initView();
    }

    /**
     * 初始化组件
     */
    private void initView() {
        // 实例化布局对象
        layoutInflater = LayoutInflater.from(this);

        // 实例化TabHost对象，得到TabHost
        mTabHost = (FragmentTabHost) findViewById(android.R.id.tabhost);
        mTabHost.setup(this, getSupportFragmentManager(), R.id.realtabcontent);

        // 得到fragment的个数
        int count = fragmentArray.length;

        for (int i = 0; i < count; i++) {
            // 为每一个Tab按钮设置图标、文字和内容
            TabSpec tabSpec = mTabHost.newTabSpec(mTextviewArray[i])
                    .setIndicator(getTabItemView(i));
            // 将Tab按钮添加进Tab选项卡中
            mTabHost.addTab(tabSpec, fragmentArray[i], null);
            // 设置Tab按钮的背景
            mTabHost.getTabWidget().getChildAt(i)
                    .setBackgroundResource(R.drawable.main_tab_item_bg);
        }
    }

    /**
     * 给Tab按钮设置图标和文字
     */
    private View getTabItemView(int index) {
        View view = layoutInflater.inflate(R.layout.tab_item_view, null);

        ImageView imageView = (ImageView) view.findViewById(R.id.imageview);
        imageView.setImageResource(mImageViewArray[index]);

        TextView textView = (TextView) view.findViewById(R.id.textview);
        textView.setText(mTextviewArray[index]);

        return view;
    }
}

源代码地址：https://github.com/YeXiaoChao/Yc_ui_fragment_tabhost