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Android底部菜单 Android底部菜单简单应用

vampire2777 人气:0
想了解Android底部菜单简单应用的相关内容吗,vampire2777在本文为您仔细讲解Android底部菜单的相关知识和一些Code实例,欢迎阅读和指正,我们先划重点:Android,底部菜单,下面大家一起来学习吧。

在Android中实现菜单功能有多种方法。
Options Menu:用户按下menu Button时显示的菜单。
Context Menu:用户长时间按下屏幕,所显示出来的菜单也称为上下文菜单。
Submenu:子菜单。
但是有时候这些内置的菜单并不能满足我们功能,这就需要自己自定义一种菜单。接下来我说的这种就是通过TabHost与RadioGroup结合完成的菜单。这也是很常用的一种底部菜单做法。先上图:

Xml代码

<?xml version="1.0" encoding="UTF-8"?> 
<TabHost android:id="@android:id/tabhost" android:layout_width="fill_parent" android:layout_height="fill_parent" 
 xmlns:android="http://schemas.android.com/apk/res/android"> 
  <LinearLayout  
    android:orientation="vertical"  
    android:layout_width="fill_parent"  
    android:layout_height="fill_parent"> 
    <FrameLayout  
      android:id="@android:id/tabcontent"  
      android:layout_width="fill_parent"  
      android:layout_height="0.0dip"  
      android:layout_weight="1.0" /> 
    <TabWidget  
      android:id="@android:id/tabs"  
      android:visibility="gone"  
      android:layout_width="fill_parent"  
      android:layout_height="wrap_content"  
      android:layout_weight="0.0" /> 
    <RadioGroup  
      android:gravity="center_vertical"  
      android:layout_gravity="bottom"  
      android:orientation="horizontal"  
      android:id="@+id/main_radio"  
      android:background="@drawable/maintab_toolbar_bg"  
      android:layout_width="fill_parent"  
      android:layout_height="wrap_content"> 
      <RadioButton  
        android:id="@+id/radio_button0"  
        android:tag="radio_button0"  
        android:layout_marginTop="2.0dip"  
        android:text="@string/alarm"  
        android:drawableTop="@drawable/icon_1"  
        style="@style/main_tab_bottom" /> 
      <RadioButton  
        android:id="@+id/radio_button1"  
        android:tag="radio_button1"  
        android:layout_marginTop="2.0dip"  
        android:text="@string/message"  
        android:drawableTop="@drawable/icon_2"  
        style="@style/main_tab_bottom" /> 
      <RadioButton  
        android:id="@+id/radio_button2"  
        android:tag="radio_button2"  
        android:layout_marginTop="2.0dip"  
        android:text="@string/photo"  
        android:drawableTop="@drawable/icon_3"  
        style="@style/main_tab_bottom" /> 
      <RadioButton  
        android:id="@+id/radio_button3"  
        android:tag="radio_button3"  
        android:layout_marginTop="2.0dip"  
        android:text="@string/music"  
        android:drawableTop="@drawable/icon_4"  
        style="@style/main_tab_bottom" /> 
      <RadioButton  
        android:id="@+id/radio_button4"  
        android:tag="radio_button4"  
        android:layout_marginTop="2.0dip"  
        android:text="@string/setting"  
        android:drawableTop="@drawable/icon_5"  
        style="@style/main_tab_bottom" /> 
    </RadioGroup> 
  </LinearLayout> 
</TabHost> 

需要注意的是,如果用TabHost这个控件,其中有几个ID是必须这么写的,android:id=”@android:id/tabhost ;android:id=”@android:id/tabcontent” ;android:id=”@android:id/tabs” ;之所以要这么写是因为在TabHost这个类中。需要实例化上述这个ID的控件。看源码:

在TabActivity中有么个方法:

@Override 
  public void onContentChanged() { 
    super.onContentChanged(); 
    mTabHost = (TabHost) findViewById(com.android.internal.R.id.tabhost); 

    if (mTabHost == null) { 
      throw new RuntimeException( 
          "Your content must have a TabHost whose id attribute is " + 
          "'android.R.id.tabhost'"); 
    } 
    mTabHost.setup(getLocalActivityManager()); 
  } 

  private void ensureTabHost() { 
    if (mTabHost == null) { 
      this.setContentView(com.android.internal.R.layout.tab_content); 
    } 
  } 

当内容发生改变时它会调用这个方法,来更新列表或者其他视图,而这个方法中需要实例化TabHost,所以必须通过ID为tabhost实例化。

再看看TabHost这个类中

public void setup() { 
   mTabWidget = (TabWidget) findViewById(com.android.internal.R.id.tabs); 
   if (mTabWidget == null) { 
     throw new RuntimeException( 
         "Your TabHost must have a TabWidget whose id attribute is 'android.R.id.tabs'"); 
   } 

   // KeyListener to attach to all tabs. Detects non-navigation keys 
   // and relays them to the tab content. 
   mTabKeyListener = new OnKeyListener() { 
     public boolean onKey(View v, int keyCode, KeyEvent event) { 
       switch (keyCode) { 
         case KeyEvent.KEYCODE_DPAD_CENTER: 
         case KeyEvent.KEYCODE_DPAD_LEFT: 
         case KeyEvent.KEYCODE_DPAD_RIGHT: 
         case KeyEvent.KEYCODE_DPAD_UP: 
         case KeyEvent.KEYCODE_DPAD_DOWN: 
         case KeyEvent.KEYCODE_ENTER: 
           return false; 

       } 
       mTabContent.requestFocus(View.FOCUS_FORWARD); 
       return mTabContent.dispatchKeyEvent(event); 
     } 

   }; 

   mTabWidget.setTabSelectionListener(new TabWidget.OnTabSelectionChanged() { 
     public void onTabSelectionChanged(int tabIndex, boolean clicked) { 
       setCurrentTab(tabIndex); 
       if (clicked) { 
         mTabContent.requestFocus(View.FOCUS_FORWARD); 
       } 
     } 
   }); 

   mTabContent = (FrameLayout) findViewById(com.android.internal.R.id.tabcontent); 
   if (mTabContent == null) { 
     throw new RuntimeException( 
         "Your TabHost must have a FrameLayout whose id attribute is " 
             + "'android.R.id.tabcontent'"); 
   } 
 } 

这个方法,是在增加选项卡之前由系统调用。在这个方法中需要通过tabs 这个ID实例化一个TabWidget,通过tabcontent这个ID实例化一个FrameLayout,用来放置选项卡内容。所以这两个ID也是固定的。

在上述布局文件中隐藏了系统默认的Widget,取而代之的是带有图片的Button。

看一下主要代码:

package com.iteye.androidtoast; 

import android.app.TabActivity; 
import android.content.Intent; 
import android.os.Bundle; 
import android.widget.RadioGroup; 
import android.widget.RadioGroup.OnCheckedChangeListener; 
import android.widget.TabHost; 

public class MainActivity extends TabActivity implements OnCheckedChangeListener{ 
  /** Called when the activity is first created. */ 
  private TabHost mHost; 
  private RadioGroup radioderGroup; 
  @Override 
  public void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.maintabs); 
    //实例化TabHost 
    mHost=this.getTabHost(); 

    //添加选项卡 
    mHost.addTab(mHost.newTabSpec("ONE").setIndicator("ONE") 
          .setContent(new Intent(this,OneActivity.class))); 
    mHost.addTab(mHost.newTabSpec("TWO").setIndicator("TWO") 
        .setContent(new Intent(this,TwoActivity.class))); 
    mHost.addTab(mHost.newTabSpec("THREE").setIndicator("THREE") 
        .setContent(new Intent(this,ThreeActivity.class))); 
    mHost.addTab(mHost.newTabSpec("FOUR").setIndicator("FOUR") 
        .setContent(new Intent(this,FourActivity.class))); 
    mHost.addTab(mHost.newTabSpec("FIVE").setIndicator("FIVE") 
        .setContent(new Intent(this,FiveActivity.class))); 

    radioderGroup = (RadioGroup) findViewById(R.id.main_radio); 
    radioderGroup.setOnCheckedChangeListener(this); 
  } 
  @Override 
  public void onCheckedChanged(RadioGroup group, int checkedId) { 
    switch(checkedId){ 
    case R.id.radio_button0: 
      mHost.setCurrentTabByTag("ONE"); 
      break; 
    case R.id.radio_button1: 
      mHost.setCurrentTabByTag("TWO"); 
      break; 
    case R.id.radio_button2: 
      mHost.setCurrentTabByTag("THREE"); 
      break; 
    case R.id.radio_button3: 
      mHost.setCurrentTabByTag("FOUR"); 
      break; 
    case R.id.radio_button4: 
      mHost.setCurrentTabByTag("FIVE"); 
      break; 
    }     
  } 
} 

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