Android 使用FragmentTabHost实现底部菜单功能

前言

现在大部分App底部都有一个菜单，实现这个功能也有好多办法：

- TabHost+Fragment
- RadioGroup+Fragment
- FragmentTabHost+Fragment
- 5.0以后有个新控件，BottomNavigator

这篇主要介绍下FragmentTabHost配合Fragment使用

运行效果图

效果图分析

FragmentTabHost简单介绍

首先我们看下官方文档的介绍

OK，接着官方还给出了一份使用的代码，我们也来看下

Activity中使用

import com.example.android.supportv4.R;
import android.os.Bundle;
import android.support.v4.app.FragmentActivity;
import android.support.v4.app.FragmentTabHost;
/**
* This demonstrates how you can implement switching between the tabs of a
* TabHost through fragments, using FragmentTabHost.
*/
public class FragmentTabs extends FragmentActivity {
private FragmentTabHost mTabHost;
@Override
protected void onCreate(Bundle savedInstanceState) {
 super.onCreate(savedInstanceState);
 setContentView(R.layout.fragment_tabs);
 mTabHost = (FragmentTabHost)findViewById(android.R.id.tabhost);
 mTabHost.setup(this, getSupportFragmentManager(), R.id.realtabcontent);
 mTabHost.addTab(mTabHost.newTabSpec("simple").setIndicator("Simple"),
   FragmentStackSupport.CountingFragment.class, null);
 mTabHost.addTab(mTabHost.newTabSpec("contacts").setIndicator("Contacts"),
   LoaderCursorSupport.CursorLoaderListFragment.class, null);
 mTabHost.addTab(mTabHost.newTabSpec("custom").setIndicator("Custom"),
   LoaderCustomSupport.AppListFragment.class, null);
 mTabHost.addTab(mTabHost.newTabSpec("throttle").setIndicator("Throttle"),
   LoaderThrottleSupport.ThrottledLoaderListFragment.class, null);
}
}

Fragment中使用

import com.example.android.supportv4.R;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentTabHost;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
public class FragmentTabsFragmentSupport extends Fragment {
private FragmentTabHost mTabHost;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
  Bundle savedInstanceState) {
 mTabHost = new FragmentTabHost(getActivity());
 mTabHost.setup(getActivity(), getChildFragmentManager(), R.id.fragment1);
 mTabHost.addTab(mTabHost.newTabSpec("simple").setIndicator("Simple"),
   FragmentStackSupport.CountingFragment.class, null);
 mTabHost.addTab(mTabHost.newTabSpec("contacts").setIndicator("Contacts"),
   LoaderCursorSupport.CursorLoaderListFragment.class, null);
 mTabHost.addTab(mTabHost.newTabSpec("custom").setIndicator("Custom"),
   LoaderCustomSupport.AppListFragment.class, null);
 mTabHost.addTab(mTabHost.newTabSpec("throttle").setIndicator("Throttle"),
   LoaderThrottleSupport.ThrottledLoaderListFragment.class, null);
 return mTabHost;
}
@Override
public void onDestroyView() {
 super.onDestroyView();
 mTabHost = null;
}
}

FragmentTabHost 布局问题

官方在给出例子的时候，并没有贴出对应的布局文件，这个布局文件有一些要求，所以我就把我自己写的贴出来吧，方便大家观看

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
tools:context="com.study.buttomtabdemo.MainActivity">
<FrameLayout
 android:id="@+id/flayout_content"
 android:layout_width="match_parent"
 android:layout_height="0dp"
 android:layout_weight="1"/>
<com.study.buttomtabdemo.widget.FragmentTabHost
 android:id="@android:id/tabhost"
 android:layout_width="match_parent"
 android:layout_height="wrap_content"
 android:background="#ffffff">
 <FrameLayout
  android:id="@android:id/tabcontent"
  android:layout_width="0dp"
  android:layout_height="0dp"
  android:layout_weight="0"/>
</com.study.buttomtabdemo.widget.FragmentTabHost>
</LinearLayout>

这里要注意以下几点：

1.我自己自定义了一个FragmentTabHost，因为原来的FragmentTabHost每次切换Fragment事都会走一遍onCreateView（）和onResume（）方法；

2.id必须是android:id=”@android:id/tabhost”这个；

3.里面的FrameLayout的id必须是android:id=”@android:id/tabcontent”

FragmentTabHost 使用

下面就到了具体使用的过程了

1.定义Tab类

因为它属于Tab的一个组合吧，里面包含好多个Tab，所以我们先定义一个Tab类

/**
* 主页TAB对应实体
* Created by HFS on 2017/5/7.
*/
public class Tab {
private int title; // 文字
private int icon; // 图标
private Class fragment; // 对应fragment
public Tab(Class fragment,int title, int icon ) {
 this.title = title;
 this.icon = icon;
 this.fragment = fragment;
}
public int getTitle() {
 return title;
}
public void setTitle(int title) {
 this.title = title;
}
public int getIcon() {
 return icon;
}
public void setIcon(int icon) {
 this.icon = icon;
}
public Class getFragment() {
 return fragment;
}
public void setFragment(Class fragment) {
 this.fragment = fragment;
}
}

这里面要对应相应的Fragment，所以需要一个Fragment对象

2.初始化Tab集合

有几个Tab就往Tab集合添加几个Tab   

Tab tab_home = new Tab(HomeFragment.class,R.string.home,R.drawable.selector_icon_home);
 Tab tab_hot = new Tab(HotFragment.class,R.string.hot,R.drawable.selector_icon_hot);
 Tab tab_category = new   Tab(CategoryFragment.class,R.string.catagory,R.drawable.selector_icon_category);
 Tab tab_cart = new Tab(CartFragment.class,R.string.cart,R.drawable.selector_icon_cart);
 Tab tab_mine = new Tab(MineFragment.class,R.string.mine,R.drawable.selector_icon_mine);
 mTabs.add(tab_home);
 mTabs.add(tab_hot);
 mTabs.add(tab_category);
 mTabs.add(tab_cart);
 mTabs.add(tab_mine);

3.setUp

找到该控件之后，就要调用对应的这个方法

mInflater = LayoutInflater.from(this);
 mTabhost = (FragmentTabHost) this.findViewById(android.R.id.tabhost);
 mTabhost.setup(this,getSupportFragmentManager(),R.id.flayout_content);

4.添加TabSpec

到这一步就要添加TabSpec了，有几个Tab，就添加几个TabSpec        

for (Tab tab : mTabs){
  TabHost.TabSpec tabSpec = mTabhost.newTabSpec(getString(tab.getTitle()));
  tabSpec.setIndicator(buildIndicator(tab));
  mTabhost.addTab(tabSpec,tab.getFragment(),null);
 }
 //构建Indicator
 private View buildIndicator(Tab tab){
  View view =mInflater.inflate(R.layout.tab_indicator,null);
  ImageView img = (ImageView) view.findViewById(R.id.icon_tab);
  TextView text = (TextView) view.findViewById(R.id.txt_indicator);
  img.setBackgroundResource(tab.getIcon());
  text.setText(tab.getTitle());
 return view;
}

5.设置默认显示第一个

mTabhost.setCurrentTab(0);

6.设置没有分割线

mTabhost.getTabWidget().setShowDividers(LinearLayout.SHOW_DIVIDER_NONE);

自定义FragmentTabHost类

package com.study.buttomtabdemo.widget;
/**
* Created by monkey
* on 2014/9/24
* 功能描述：修改过的FragmentTabHost,保存fragment实例不销毁
*/
/*
* Copyright (C) 2012 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
*  http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
 import java.util.ArrayList;
 import android.content.Context;
 import android.content.res.TypedArray;
 import android.os.Bundle;
 import android.os.Parcel;
 import android.os.Parcelable;
 import android.support.v4.app.Fragment;
 import android.support.v4.app.FragmentManager;
 import android.support.v4.app.FragmentTransaction;
 import android.util.AttributeSet;
 import android.view.View;
 import android.view.ViewGroup;
 import android.widget.FrameLayout;
 import android.widget.LinearLayout;
 import android.widget.TabHost;
 import android.widget.TabWidget;
/**
* Special TabHost that allows the use of {@link Fragment} objects for its tab
* content. When placing this in a view hierarchy, after inflating the hierarchy
* you must call {@link #setup(Context, FragmentManager, int)} to complete the
* initialization of the tab host.
*
* <p>
* Here is a simple example of using a FragmentTabHost in an Activity:
*
* {@sample
* development/samples/Support4Demos/src/com/example/android/supportv4/app/
* FragmentTabs.java complete}
*
* <p>
* This can also be used inside of a fragment through fragment nesting:
*
* {@sample
* development/samples/Support4Demos/src/com/example/android/supportv4/app/
* FragmentTabsFragmentSupport.java complete}
*/
public class FragmentTabHost extends TabHost implements
 TabHost.OnTabChangeListener {
private final ArrayList<TabInfo> mTabs = new ArrayList<TabInfo>();
private FrameLayout mRealTabContent;
private Context mContext;
private FragmentManager mFragmentManager;
private int mContainerId;
private OnTabChangeListener mOnTabChangeListener;
private TabInfo mLastTab;
private boolean mAttached;
static final class TabInfo {
 private final String tag;
 private final Class<?> clss;
 private final Bundle args;
 private Fragment fragment;
 TabInfo(String _tag, Class<?> _class, Bundle _args) {
  tag = _tag;
  clss = _class;
  args = _args;
 }
}
static class DummyTabFactory implements TabContentFactory {
 private final Context mContext;
 public DummyTabFactory(Context context) {
  mContext = context;
 }
 @Override
 public View createTabContent(String tag) {
  View v = new View(mContext);
  v.setMinimumWidth(0);
  v.setMinimumHeight(0);
  return v;
 }
}
static class SavedState extends BaseSavedState {
 String curTab;
 SavedState(Parcelable superState) {
  super(superState);
 }
 private SavedState(Parcel in) {
  super(in);
  curTab = in.readString();
 }
 @Override
 public void writeToParcel(Parcel out, int flags) {
  super.writeToParcel(out, flags);
  out.writeString(curTab);
 }
 @Override
 public String toString() {
  return "FragmentTabHost.SavedState{"
    + Integer.toHexString(System.identityHashCode(this))
    + " curTab=" + curTab + "}";
 }
 public static final Creator<SavedState> CREATOR = new Creator<SavedState>() {
  public SavedState createFromParcel(Parcel in) {
   return new SavedState(in);
  }
  public SavedState[] newArray(int size) {
   return new SavedState[size];
  }
 };
}
public FragmentTabHost(Context context) {
 // Note that we call through to the version that takes an AttributeSet,
 // because the simple Context construct can result in a broken object!
 super(context, null);
 initFragmentTabHost(context, null);
}
public FragmentTabHost(Context context, AttributeSet attrs) {
 super(context, attrs);
 initFragmentTabHost(context, attrs);
}
private void initFragmentTabHost(Context context, AttributeSet attrs) {
 TypedArray a = context.obtainStyledAttributes(attrs,
   new int[] { android.R.attr.inflatedId }, 0, 0);
 mContainerId = a.getResourceId(0, 0);
 a.recycle();
 super.setOnTabChangedListener(this);
}
private void ensureHierarchy(Context context) {
 // If owner hasn't made its own view hierarchy, then as a convenience
 // we will construct a standard one here.
 if (findViewById(android.R.id.tabs) == null) {
  LinearLayout ll = new LinearLayout(context);
  ll.setOrientation(LinearLayout.VERTICAL);
  addView(ll, new LayoutParams(
    ViewGroup.LayoutParams.MATCH_PARENT,
    ViewGroup.LayoutParams.MATCH_PARENT));
  TabWidget tw = new TabWidget(context);
  tw.setId(android.R.id.tabs);
  tw.setOrientation(TabWidget.HORIZONTAL);
  ll.addView(tw, new LinearLayout.LayoutParams(
    ViewGroup.LayoutParams.MATCH_PARENT,
    ViewGroup.LayoutParams.WRAP_CONTENT, 0));
  FrameLayout fl = new FrameLayout(context);
  fl.setId(android.R.id.tabcontent);
  ll.addView(fl, new LinearLayout.LayoutParams(0, 0, 0));
  mRealTabContent = fl = new FrameLayout(context);
  mRealTabContent.setId(mContainerId);
  ll.addView(fl, new LinearLayout.LayoutParams(
    LinearLayout.LayoutParams.MATCH_PARENT, 0, 1));
 }
}
/**
 * @deprecated Don't call the original TabHost setup, you must instead call
 *    {@link #setup(Context, FragmentManager)} or
 *    {@link #setup(Context, FragmentManager, int)}.
 */
@Override
@Deprecated
public void setup() {
 throw new IllegalStateException(
   "Must call setup() that takes a Context and FragmentManager");
}
public void setup(Context context, FragmentManager manager) {
 ensureHierarchy(context); // Ensure views required by super.setup()
 super.setup();
 mContext = context;
 mFragmentManager = manager;
 ensureContent();
}
public void setup(Context context, FragmentManager manager, int containerId) {
 ensureHierarchy(context); // Ensure views required by super.setup()
 super.setup();
 mContext = context;
 mFragmentManager = manager;
 mContainerId = containerId;
 ensureContent();
 mRealTabContent.setId(containerId);
 // We must have an ID to be able to save/restore our state. If
 // the owner hasn't set one at this point, we will set it ourself.
 if (getId() == View.NO_ID) {
  setId(android.R.id.tabhost);
 }
}
private void ensureContent() {
 if (mRealTabContent == null) {
  mRealTabContent = (FrameLayout) findViewById(mContainerId);
  if (mRealTabContent == null) {
   throw new IllegalStateException(
     "No tab content FrameLayout found for id "
       + mContainerId);
  }
 }
}
@Override
public void setOnTabChangedListener(OnTabChangeListener l) {
 mOnTabChangeListener = l;
}
public void addTab(TabSpec tabSpec, Class<?> clss, Bundle args) {
 tabSpec.setContent(new DummyTabFactory(mContext));
 String tag = tabSpec.getTag();
 TabInfo info = new TabInfo(tag, clss, args);
 if (mAttached) {
  // If we are already attached to the window, then check to make
  // sure this tab's fragment is inactive if it exists. This shouldn't
  // normally happen.
  info.fragment = mFragmentManager.findFragmentByTag(tag);
  if (info.fragment != null && !info.fragment.isDetached()) {
   FragmentTransaction ft = mFragmentManager.beginTransaction();
//    ft.detach(info.fragment);
   ft.hide(info.fragment);
   ft.commit();
  }
 }
 mTabs.add(info);
 addTab(tabSpec);
}
@Override
protected void onAttachedToWindow() {
 super.onAttachedToWindow();
 String currentTab = getCurrentTabTag();
 // Go through all tabs and make sure their fragments match
 // the correct state.
 FragmentTransaction ft = null;
 for (int i = 0; i < mTabs.size(); i++) {
  TabInfo tab = mTabs.get(i);
  tab.fragment = mFragmentManager.findFragmentByTag(tab.tag);
//   if (tab.fragment != null && !tab.fragment.isDetached()) {
  if (tab.fragment != null) {
   if (tab.tag.equals(currentTab)) {
    // The fragment for this tab is already there and
    // active, and it is what we really want to have
    // as the current tab. Nothing to do.
    mLastTab = tab;
   } else {
    // This fragment was restored in the active state,
    // but is not the current tab. Deactivate it.
    if (ft == null) {
     ft = mFragmentManager.beginTransaction();
    }
//     ft.detach(tab.fragment);
    ft.hide(tab.fragment);
   }
  }
 }
 // We are now ready to go. Make sure we are switched to the
 // correct tab.
 mAttached = true;
 ft = doTabChanged(currentTab, ft);
 if (ft != null) {
  ft.commitAllowingStateLoss();
  mFragmentManager.executePendingTransactions();
 }
}
@Override
protected void onDetachedFromWindow() {
 super.onDetachedFromWindow();
 mAttached = false;
}
@Override
protected Parcelable onSaveInstanceState() {
 Parcelable superState = super.onSaveInstanceState();
 SavedState ss = new SavedState(superState);
 ss.curTab = getCurrentTabTag();
 return ss;
}
@Override
protected void onRestoreInstanceState(Parcelable state) {
 SavedState ss = (SavedState) state;
 super.onRestoreInstanceState(ss.getSuperState());
 setCurrentTabByTag(ss.curTab);
}
@Override
public void onTabChanged(String tabId) {
 if (mAttached) {
  FragmentTransaction ft = doTabChanged(tabId, null);
  if (ft != null) {
   ft.commit();
  }
 }
 if (mOnTabChangeListener != null) {
  mOnTabChangeListener.onTabChanged(tabId);
 }
}
private FragmentTransaction doTabChanged(String tabId,
           FragmentTransaction ft) {
 TabInfo newTab = null;
 for (int i = 0; i < mTabs.size(); i++) {
  TabInfo tab = mTabs.get(i);
  if (tab.tag.equals(tabId)) {
   newTab = tab;
  }
 }
 if (newTab == null) {
  throw new IllegalStateException("No tab known for tag " + tabId);
 }
 if (mLastTab != newTab) {
  if (ft == null) {
   ft = mFragmentManager.beginTransaction();
  }
  if (mLastTab != null) {
   if (mLastTab.fragment != null) {
//     ft.detach(mLastTab.fragment);
    ft.hide(mLastTab.fragment);
   }
  }
  if (newTab != null) {
   if (newTab.fragment == null) {
    newTab.fragment = Fragment.instantiate(mContext,
      newTab.clss.getName(), newTab.args);
    ft.add(mContainerId, newTab.fragment, newTab.tag);
   } else {
//     ft.attach(newTab.fragment);
    ft.show(newTab.fragment);
   }
  }
  mLastTab = newTab;
 }
 return ft;
}
}

总结

以上所述是小编给大家介绍的Android 使用FragmentTabHost实现底部菜单功能网站的支持！

来源：http://blog.csdn.net/Greathfs/article/details/71336423