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;

	@Override
	protected void onCreate(Bundle savedInstanceState) {
		// TODO Auto-generated method stub
		super.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TabSpec
		TabSpec 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";

	@Override
	protected void onCreate(Bundle savedInstanceState) {
		// TODO Auto-generated method stub
		super.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";

	@Override
	protected void onCreate(Bundle savedInstanceState) {
		// TODO Auto-generated method stub
		super.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";

	@Override
	protected void onCreate(Bundle savedInstanceState) {
		// TODO Auto-generated method stub
		super.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";

	@Override
	protected void onCreate(Bundle savedInstanceState) {
		// TODO Auto-generated method stub
		super.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