Android入门第十二篇之Gallery

               

 本文来自http://blog.youkuaiyun.com/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;        }            };}