Android中ActivityGroup + GridView 实现Tab分页标签

本文来自http://blog.csdn.net/hellogv/ ,引用必须注明出处!

      很多客户端软件和浏览器软件都喜欢用Tab分页标签来搭建界面框架。读者也许会马上想到使用TabHost  TabActivity的组合,其实最常用的不是它们,而是由GridViewActivityGroup的组合。每当用户在GridView选中一项,ActivityGroup就把该项对应的ActivityWindow作为View添加到ActivityGroup所指定的容器(LinearLayout)中。

接下来贴出本例运行的效果图
Android中ActivityGroup + GridView 实现Tab分页标签

ImageAdapter是本实例的关键之一,它继承于BaseAdapter,并加入一些自定义的方法。ImageAdapter的源码如下:

package com.ActivityGroupDemo;  
  
import android.content.Context;  
import android.graphics.drawable.ColorDrawable;  
import android.view.View;  
import android.view.ViewGroup;  
import android.widget.BaseAdapter;  
import android.widget.GridView;  
import android.widget.ImageView;  
/** 
 *  
 * @author GV 
 * 
 */  
public class ImageAdapter extends BaseAdapter {  
    private Context mContext;   
    private ImageView[] imgItems;  
    private int selResId;  
    public ImageAdapter(Context c,int[] picIds,int width,int height,int selResId) {   
        mContext = c;   
        this.selResId=selResId;  
        imgItems=new ImageView[picIds.length];  
        for(int i=0;i<picIds.length;i++)  
        {  
            imgItems[i] = new ImageView(mContext);   
            imgItems[i].setLayoutParams(new GridView.LayoutParams(width, height));//设置ImageView宽高   
            imgItems[i].setAdjustViewBounds(false);   
            //imgItems[i].setScaleType(ImageView.ScaleType.CENTER_CROP);   
            imgItems[i].setPadding(2, 2, 2, 2);   
            imgItems[i].setImageResource(picIds[i]);   
        }  
    }   
   
    public int getCount() {   
        return imgItems.length;   
    }   
   
    public Object getItem(int position) {   
        return position;   
    }   
   
    public long getItemId(int position) {   
        return position;   
    }   
   
    /**  
     * 设置选中的效果  
     */    
    public void SetFocus(int index)    
    {    
        for(int i=0;i<imgItems.length;i++)    
        {    
            if(i!=index)    
            {    
                imgItems[i].setBackgroundResource(0);//恢复未选中的样式  
            }    
        }    
        imgItems[index].setBackgroundResource(selResId);//设置选中的样式  
    }    
      
    public View getView(int position, View convertView, ViewGroup parent) {   
        ImageView imageView;   
        if (convertView == null) {   
            imageView=imgItems[position];  
        } else {   
            imageView = (ImageView) convertView;   
        }   
        return imageView;   
    }   
}   

 
 
SetFocus(int)这个方法是个关键点,即实现选中的效果。例如有ABCD4Item,其中C被选中了,那么除C以外的Item都被设置为未被选中的样式,而C则设置为选中的样式。

 

接下来就开始写主Activity,主Activity包含GridView控件,名为gvTopBar,有2点是需要注意一下的。

  • SetNumColumns():必须要使用setNumColumns来设置列数,因为这个GridView只有一行,即所有的Item都在同一行,Item数量即为列数。
  • setSelector(new ColorDrawable(Color.TRANSPARENT)):把系统默认选中的背景色透明化,因为我们已经在BaseAdapter中加入了SetFocus()来改变选中的样式。 
package com.ActivityGroupDemo;  
  
import android.app.Activity;  
import android.app.ActivityGroup;  
import android.content.BroadcastReceiver;  
import android.content.Context;  
import android.content.Intent;  
import android.content.IntentFilter;  
import android.graphics.Color;  
import android.graphics.drawable.ColorDrawable;  
import android.os.Bundle;  
import android.util.Log;  
import android.view.Gravity;  
import android.view.View;  
import android.view.Window;  
import android.view.ViewGroup.LayoutParams;  
import android.widget.AdapterView;  
import android.widget.GridView;  
import android.widget.LinearLayout;  
import android.widget.Toast;  
import android.widget.AdapterView.OnItemClickListener;  
/** 
 *  
 * @author GV 
 * 
 */  
public class ActivityGroupDemo extends ActivityGroup {  
  
    private GridView gvTopBar;  
    private ImageAdapter topImgAdapter;  
    public LinearLayout container;// 装载sub Activity的容器  
  
    /** 顶部按钮图片 **/  
    int[] topbar_image_array = { R.drawable.topbar_home,  
            R.drawable.topbar_user, R.drawable.topbar_shoppingcart,  
            R.drawable.topbar_note };  
  
    @Override  
    public void onCreate(Bundle savedInstanceState) {  
        super.onCreate(savedInstanceState);  
        setContentView(R.layout.main);  
        gvTopBar = (GridView) this.findViewById(R.id.gvTopBar);  
        gvTopBar.setNumColumns(topbar_image_array.length);// 设置每行列数  
        gvTopBar.setSelector(new ColorDrawable(Color.TRANSPARENT));// 选中的时候为透明色  
        gvTopBar.setGravity(Gravity.CENTER);// 位置居中  
        gvTopBar.setVerticalSpacing(0);// 垂直间隔  
        int width = this.getWindowManager().getDefaultDisplay().getWidth()  
                / topbar_image_array.length;  
        topImgAdapter = new ImageAdapter(this, topbar_image_array, width, 48,  
                R.drawable.topbar_itemselector);  
        gvTopBar.setAdapter(topImgAdapter);// 设置菜单Adapter  
        gvTopBar.setOnItemClickListener(new ItemClickEvent());// 项目点击事件  
        container = (LinearLayout) findViewById(R.id.Container);  
        SwitchActivity(0);//默认打开第0页  
    }  
  
    class ItemClickEvent implements OnItemClickListener {  
  
        public void onItemClick(AdapterView<?> arg0, View arg1, int arg2,  
                long arg3) {  
            SwitchActivity(arg2);  
        }  
    }  
    /** 
     * 根据ID打开指定的Activity 
     * @param id GridView选中项的序号 
     */  
    void SwitchActivity(int id)  
    {  
        topImgAdapter.SetFocus(id);//选中项获得高亮  
        container.removeAllViews();//必须先清除容器中所有的View  
        Intent intent =null;  
        if (id == 0 || id == 2) {  
            intent = new Intent(ActivityGroupDemo.this, ActivityA.class);  
        } else if (id == 1 || id == 3) {  
            intent = new Intent(ActivityGroupDemo.this, ActivityB.class);  
        }   
        intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);  
        //Activity 转为 View  
        Window subActivity = getLocalActivityManager().startActivity(  
                "subActivity", intent);  
        //容器添加View  
        container.addView(subActivity.getDecorView(),  
                LayoutParams.FILL_PARENT, LayoutParams.FILL_PARENT);  
    }  
  
}  

 主Activity的布局XML文件源码如下:

<?xml version="1.0" encoding="utf-8"?>  
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"  
    android:orientation="vertical" android:layout_width="fill_parent"  
    android:layout_height="fill_parent">  
    <RelativeLayout android:layout_height="fill_parent"  
        android:layout_width="fill_parent">  
        <GridView android:layout_height="wrap_content" android:id="@+id/gvTopBar"  
            android:layout_alignParentTop="true" android:layout_width="fill_parent"  
            android:fadingEdgeLength="5dip" android:fadingEdge="vertical">  
        </GridView>  
        <LinearLayout android:id="@+id/Container"  
            android:layout_below="@+id/gvTopBar" android:layout_width="fill_parent"  
            android:layout_height="fill_parent">  
        </LinearLayout>  
    </RelativeLayout>  
</LinearLayout>  

 提示:

问:getLocalActivityManager()这个怎么报错啊

答:必须继承ActivityGroup才有这个方法,一般的Activity没有此方法

 

新建一个ClassA类    代码如下:

public class ActivityA extends Activity {
	 public void onCreate(Bundle savedInstanceState) {
	        super.onCreate(savedInstanceState);
	        setContentView(R.layout.activitya);
	 }
}

 新建一个ClassA类    代码如下:

public class ActivityB extends Activity {
	 public void onCreate(Bundle savedInstanceState) {
	        super.onCreate(savedInstanceState);
	        setContentView(R.layout.activityb);
	 }
}

 activitya.xml布局文件代码如下:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical" >
    
	<TextView 
	    android:text="ActivityA"
	    android:layout_width="fill_parent"
	    android:layout_height="fill_parent"
	    />
</LinearLayout>

 

activityb.xml的代码如下:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical" >

    <TextView
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        android:text="ActivityB" />

</LinearLayout>

 最后需要在AndroidManifest.xml中声明这两个activity,内容为:

 

<activity 
            android:name=".ActivityA"
            ></activity>
        <activity 
            android:name=".ActivityB"
            ></activity>

 

 

 

 

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