Gallery的使用(一)

Gallerty组件一般用于显示图像列表，Gallery只能水平显示一行，而且支持水平滑动效果。单击、选中或拖动Gallerty中的图像，Gallery中的图像列表会根据不同的情况向左或向右移动，直到显示到最后一个图像为止。

package com.example.androidtest;

import android.os.Bundle;
import android.app.Activity;
import android.content.Context;
import android.content.res.TypedArray;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.BaseAdapter;
import android.widget.Gallery;
import android.widget.ImageView;
import android.widget.Toast;

public class MainActivity extends Activity {

	Integer[] imageIDs = {R.drawable.ic_launcher,
						R.drawable.ic_launcher,
						R.drawable.ic_launcher,
						R.drawable.ic_launcher,
						R.drawable.ic_launcher,
						R.drawable.ic_launcher,
						R.drawable.ic_launcher};
	
	public void onCreate(Bundle savedInstanceState)
	{
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);
		
		Gallery gallery = (Gallery)findViewById(R.id.gallery1);
		
		gallery.setAdapter(new ImageAdapter(this));
		gallery.setOnItemClickListener(new OnItemClickListener() {
			public void onItemClick(AdapterView<?> parent, View v, int position, long id)
			{
				Toast.makeText(getBaseContext(), "pic" + (position + 1) + " selected", 
						Toast.LENGTH_SHORT).show();
				ImageView imageView = (ImageView)findViewById(R.id.image1);
				imageView.setImageResource(imageIDs[position]);
			}
		});
	}	
	
	public class ImageAdapter extends BaseAdapter
	{
		private Context context;
		private int itemBackground;
		
		public ImageAdapter(Context c)
		{
			context = c;
			TypedArray a = obtainStyledAttributes(R.styleable.Gallery1);
			itemBackground = a.getResourceId(R.styleable.Gallery1_android_galleryItemBackground, 0);
			a.recycle();
		}
		
		public int getCount()
		{
			return imageIDs.length;
		}
		
		public Object getItem(int position)
		{
			return position;
		}
		
		public long getItemId(int position)
		{
			return position;
		}
		
		public View getView(int position, View convertView, ViewGroup parent)
		{
			ImageView imageView = new ImageView(context);
			imageView.setImageResource(imageIDs[position]);
			imageView.setScaleType(ImageView.ScaleType.FIT_XY);
			imageView.setLayoutParams(new Gallery.LayoutParams(150, 120));
			imageView.setBackgroundResource(itemBackground);
			return imageView;
		}
	}
}
	
	

在res/values下添加styleable.xml文件：

<?xml version="1.0" encoding="UTF-8"?>
<resources> 
    <declare-styleable name="Gallery1"> 
        <attr name="android:galleryItemBackground" /> 
    </declare-styleable> 
</resources>

activity_main.xml:

<?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">
    <TextView
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
       	android:text="Images of San Francisco"/>
    <Gallery
        android:id="@+id/gallery1"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"/>
    <ImageView
        android:id="@+id/image1"
        android:layout_width="320px"
        android:layout_height="250px"
        android:scaleType="fitXY"/>
        
</LinearLayout>