Android入门教程(二十六)------之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 与 TabActivity的组合，其实最常用的不是它们，而是由GridView与ActivityGroup的组合。每当用户在GridView选中一项，ActivityGroup就把该项对应的Activity的Window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;
    }
}

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ABCD4个Item，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);
    }

}

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>