Android入门第十二篇之Gallery

 

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

       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:

<?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：

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);  
                }  
            }  
        }  
        @Override  
        public int getCount() {  
            // TODO Auto-generated method stub   
  
            return imgList.size();  
        }  
  
        @Override  
        public Object getItem(int position) {  
            // TODO Auto-generated method stub   
  
            return position;  
        }  
  
        @Override  
        public long getItemId(int position) {  
            // TODO Auto-generated method stub   
  
            return position;  
        }  
  
        @Override  
        public View getView(int position, View convertView, ViewGroup parent) {  
            // TODO Auto-generated method stub   
  
            ImageView i = new ImageView (mContext);  
            //从imgList取得图片ID   
            i.setImageResource(imgList.get(position).intValue());  
            i.setScaleType(ImageView.ScaleType.FIT_XY);  
            //从imgSizes取得图片大小   
            int size[]= new int[2];  
            size=(int[]) imgSizes.get(position);  
            i.setLayoutParams(new Gallery.LayoutParams(size[0], size[1]));  
            return i;  
        }  
          
    };  
}