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; } }; }