本文实例介绍的Android的Gallery控件是个很不错的看图控件，可以大大减轻开发者对于看图功能的开发，并且效果也很美观。本文实例中的Gallery的用法，主要实现用反射机制来动态读取资源中的图片。
该实例代码运行的效果图如下：
main.xml源码如下:
Java程序源码如下：
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 imgList=new ArrayList();
private ArrayList imgSizes=new ArrayList();
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;
}
};
}