Android入门户十二篇之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。

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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>  

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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;          }                };  }  

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