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，希望对大家有所帮助，如果大家有任何疑问请给我留言，小编会及时回复大家的。在此也非常感谢大家对我们网站的支持！

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