Android中选项卡TabHost的实际应用篇

       

   上一次学习了TabHost的基本使用(Android中选项卡TabHost的基本使用),今天学习一下实际稍微高级的应用, 例如在微博等等客户端中经常看到界面底部的那一排控件；

先看下Demo效果截图下:

要做出这样的效果，其实难度不大 总体使用一个TabHost,  Tabhost上面使用RadioGroup和RadioButton的组件,然后每一个选项

对应一个Activity,点击跳转相应的Activity.

下面来看下TabHost的布局文件:

  

<?xml version="1.0" encoding="utf-8"?><TabHost xmlns:android="http://schemas.android.com/apk/res/android"    android:id="@android:id/tabhost"    android:layout_width="fill_parent"    android:layout_height="fill_parent"    android:background="#65a083"    android:orientation="horizontal" >    <!-- 注意Id -->    <TabWidget        android:id="@android:id/tabs"        android:layout_width="fill_parent"        android:layout_height="wrap_content"        android:visibility="gone" >    </TabWidget>    <!-- 注意Id -->    <FrameLayout        android:id="@android:id/tabcontent"        android:layout_width="fill_parent"        android:layout_height="fill_parent" >    </FrameLayout>    <RadioGroup        android:id="@+id/rg_main_btns"        android:layout_width="fill_parent"        android:layout_height="wrap_content"        android:layout_gravity="bottom"        android:background="@drawable/title_header_fu"        android:gravity="center_vertical"        android:orientation="horizontal" >        <!-- android:drawableTop="@drawable/at_icon" 这句的意思是在文字上面放入图片 -->        <RadioButton            android:id="@+id/first"            style="@style/main_style "            android:layout_width="wrap_content"            android:layout_height="wrap_content"            android:drawableTop="@drawable/first_icon"            android:text="第一个" >        </RadioButton>        <RadioButton            android:id="@+id/second"            style="@style/main_style "            android:layout_width="wrap_content"            android:layout_height="wrap_content"            android:drawableTop="@drawable/second_icon"            android:text="第二个" >        </RadioButton>        <RadioButton            android:id="@+id/third"            style="@style/main_style "            android:layout_width="wrap_content"            android:layout_height="wrap_content"            android:drawableTop="@drawable/third_icon"            android:text="第三个" >        </RadioButton>        <RadioButton            android:id="@+id/four"            style="@style/main_style "            android:layout_width="wrap_content"            android:layout_height="wrap_content"            android:drawableTop="@drawable/four_icon"            android:text="第四个" >        </RadioButton>    </RadioGroup></TabHost>

上面布局文中的 style="@style/main_style"是用的自定义样式，里面主要定义一些文字大小，和布局，还有点击的时候图片改变

<?xml version="1.0" encoding="utf-8"?><resources>    <style name="main_style ">        <item name="android:button">@null</item>        <item name="android:textSize">10dp</item>        <item name="android:textColor">#ffffff</item>        <item name="android:gravity">center_horizontal</item>        <item name="android:layout_width">fill_parent</item>        <item name="android:layout_height">wrap_content</item>        <item name="android:drawablePadding">4dip</item>        <item name="android:layout_weight">1.0</item>        <!-- 下面引用Button按下的效果xml文件, 在 drawable文件下面 -->        <item name="android:background">@drawable/main_bg_d</item>    </style></resources>

接下来看总的MainActivity :

  

package com.android.tabhost;import com.android.R;import android.app.TabActivity;import android.content.Intent;import android.os.Bundle;import android.widget.RadioGroup;import android.widget.TabHost;import android.widget.RadioGroup.OnCheckedChangeListener;import android.widget.TabHost.TabSpec;public class MainActivity extends TabActivity {private static final String FISRT = "first";private static final String SECOND = "second";private static final String THIRD = "third";private static final String FOUR = "four";private TabHost tabHost;@Overrideprotected void onCreate(Bundle savedInstanceState) {// TODO Auto-generated method stubsuper.onCreate(savedInstanceState);setContentView(R.layout.main_tabhost);tabHost = this.getTabHost();// 点击相应选项选项，跳转到相应的Activity,创建TabSpecTabSpec homeSpec = tabHost.newTabSpec(FISRT).setIndicator(FISRT).setContent(new Intent(this, FirstActivity.class));TabSpec atSpec = tabHost.newTabSpec(SECOND).setIndicator(SECOND).setContent(new Intent(this, SecondActivity.class));TabSpec msgSpec = tabHost.newTabSpec(THIRD).setIndicator(THIRD).setContent(new Intent(this, ThirdActivtiy.class));TabSpec moreSpec = tabHost.newTabSpec(FOUR).setIndicator(FOUR).setContent(new Intent(this, FourActivity.class));// 添加TabSpec 到选项卡中tabHost.addTab(homeSpec);tabHost.addTab(atSpec);tabHost.addTab(msgSpec);tabHost.addTab(moreSpec);RadioGroup radioGroup = (RadioGroup) this.findViewById(R.id.rg_main_btns);radioGroup.setOnCheckedChangeListener(new OnCheckedChangeListener() {/** * 响应点击事件 */public void onCheckedChanged(RadioGroup group, int checkedId) {switch (checkedId) {case R.id.first:tabHost.setCurrentTabByTag(FISRT);break;case R.id.second:tabHost.setCurrentTabByTag(SECOND);break;case R.id.third:tabHost.setCurrentTabByTag(THIRD);break;case R.id.four:tabHost.setCurrentTabByTag(FOUR);break;}}});}}

下面对应四个Activity:

 

package com.android.tabhost;import com.android.R;import android.app.Activity;import android.os.Bundle;import android.util.Log;public class FirstActivity extends Activity {private static final String TAG = "FirstActivity";@Overrideprotected void onCreate(Bundle savedInstanceState) {// TODO Auto-generated method stubsuper.onCreate(savedInstanceState);setContentView(R.layout.first);System.out.println("FirstActivity....");}}

package com.android.tabhost;import com.android.R;import android.app.Activity;import android.os.Bundle;import android.util.Log;public class SecondActivity extends Activity {private static final String TAG = "SecondActivity";@Overrideprotected void onCreate(Bundle savedInstanceState) {// TODO Auto-generated method stubsuper.onCreate(savedInstanceState);setContentView(R.layout.second);System.out.println("SecondActivity。。。。");}}

package com.android.tabhost;import com.android.R;import android.app.Activity;import android.os.Bundle;import android.util.Log;public class ThirdActivtiy extends Activity {private static final String TAG = "ThirdActivtiy";@Overrideprotected void onCreate(Bundle savedInstanceState) {// TODO Auto-generated method stubsuper.onCreate(savedInstanceState);setContentView(R.layout.third);System.out.println("ThirdActivtiy....");}}

package com.android.tabhost;import com.android.R;import android.app.Activity;import android.os.Bundle;import android.util.Log;public class FourActivity extends Activity {private static final String TAG = "FourActivity";@Overrideprotected void onCreate(Bundle savedInstanceState) {// TODO Auto-generated method stubsuper.onCreate(savedInstanceState);setContentView(R.layout.four);System.out.println("FourActivity.....");}}

  下面看下这样去使用还有一个体现Android性能的地方，当我们点击下面四个选项的时候，点击点击完成之后Activity将会被onCreate() 但是当点击一次之后，接下去再去点击，会发现不会去执行onCreate(),这样其实Activity只会被创建一次，这样效率高了很多:

  

上面当点击到点第三个Activity还可以创建

然后继续点击第四个，---->点击第一个看效果，下面就没有输出了

   好了今天就写到这里，继续学习了