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ActivityGroup + GridView 实现Tab分页标签
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本文转自http://blog.csdn.net/hellogv/       

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

 

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>  

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JavaGG
发帖于7年前 1回/1K+阅
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