Android入门第十二篇之Gallery

Android的Gallery控件是个很不错的看图控件，大大减轻了开发者对于看图功能的开发，而且效果也比较美观。本文介绍Gallery的用法，用反射机制来动态读取资源中的图片。

       本文的效果图：

main.xml源码:

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<?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" 
    > 
<Gallery android:id="@+id/gallery" android:layout_height="fill_parent" android:layout_width="fill_parent"></Gallery> 
</LinearLayout> 
<?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"
    >
<Gallery android:id="@+id/gallery" android:layout_height="fill_parent" android:layout_width="fill_parent"></Gallery>
</LinearLayout>
 

程序源码：

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package com.testImageView;  
 
import java.lang.reflect.Field;  
import java.util.ArrayList;  
 
import android.app.Activity;  
import android.content.Context;  
import android.graphics.Bitmap;  
import android.graphics.BitmapFactory;  
import android.os.Bundle;  
import android.view.View;  
import android.view.ViewGroup;  
import android.widget.AdapterView;  
import android.widget.BaseAdapter;  
import android.widget.Gallery;  
import android.widget.ImageView;  
import android.widget.AdapterView.OnItemClickListener;  
 
public class testImageView extends Activity {  
    private Gallery mGallery;  
    @Override 
    public void onCreate(Bundle savedInstanceState) {  
        super.onCreate(savedInstanceState);  
        setContentView(R.layout.main);  
          
        mGallery = (Gallery)findViewById(R.id.gallery);  
        try {  
            mGallery.setAdapter(new ImageAdapter(this));  
        } catch (IllegalArgumentException e) {  
            // TODO Auto-generated catch block  
            e.printStackTrace();  
        } catch (IllegalAccessException e) {  
            // TODO Auto-generated catch block  
            e.printStackTrace();  
        }  
        mGallery.setOnItemClickListener(new OnItemClickListener() {  
            public void onItemClick(AdapterView parent, View v, int position, long id) {  
                testImageView.this.setTitle(String.valueOf(position));  
            }  
        });  
    }  
      
    /* 
     * class ImageAdapter is used to control gallery source and operation. 
     */ 
    private class ImageAdapter extends BaseAdapter{  
        private Context mContext;  
        private ArrayList<Integer> imgList=new ArrayList<Integer>();  
        private ArrayList<Object> imgSizes=new ArrayList<Object>();  
        public ImageAdapter(Context c) throws IllegalArgumentException, IllegalAccessException{  
            mContext = c;  
              
            //用反射机制来获取资源中的图片ID和尺寸  
            Field[] fields = R.drawable.class.getDeclaredFields();  
            for (Field field : fields)  
            {  
                if (!"icon".equals(field.getName()))//除了icon之外的图片  
                {     
                    int index=field.getInt(R.drawable.class);  
                    //保存图片ID  
                    imgList.add(index);  
                    //保存图片大小  
                    int size[]=new int[2];  
                    Bitmap bmImg=BitmapFactory.decodeResource(getResources(),index);  
                    size[0]=bmImg.getWidth();size[1]=bmImg.getHeight();  
                    imgSizes.add(size);  
                }  
            }  
        }  
        @Ove