android应用开发揭秘examples_04-17笔记(Gallery的使用)

这个例子的截图：

 

//--------Activity01.java-----------
package com.yarin.android.Examples_04_17;

import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.widget.AdapterView;
import android.widget.Gallery;
import android.widget.Toast;
import android.widget.AdapterView.OnItemClickListener;

public class Activity01 extends Activity
{
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        //获得Gallery对象
        Gallery g = (Gallery) findViewById(R.id.Gallery01);

        //添加ImageAdapter给Gallery对象
        g.setAdapter(new ImageAdapter(this));

        //设置Gallery的背景
        g.setBackgroundResource(R.drawable.bg0);
       
        //设置Gallery的事件监听
        g.setOnItemClickListener(new OnItemClickListener() {
            public void onItemClick(AdapterView<?> parent, View v, int position, long id)
            {
                Toast.makeText(Activity01.this,"你选择了"+(position+1)+" 号图片",
                    Toast.LENGTH_SHORT).show();
            }
        });
    }
}

//-----------ImageAdapter.java---------------------
package com.yarin.android.Examples_04_17;

import android.content.Context;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.Gallery;
import android.widget.ImageView;

public class ImageAdapter extends BaseAdapter
{
    // 定义Context
    private Context        mContext;       
    // 定义整型数组 即图片源
    private Integer[]    mImageIds =
    {                        
            R.drawable.img1,
            R.drawable.img2,
            R.drawable.img3,
            R.drawable.img4,
            R.drawable.img5,
            R.drawable.img6,
            R.drawable.img7,
            R.drawable.img8,   
            R.drawable.img_cat
    };

    // 声明 ImageAdapter
    public ImageAdapter(Context c)
    {
        mContext = c;
    }

    // 获取图片的个数
    public int getCount()
    {
        return mImageIds.length;
    }

    // 获取图片在库中的位置
    public Object getItem(int position)
    {
        return position;
    }

    // 获取图片ID
    public long getItemId(int position)
    {
        return position;
    }

    public View getView(int position, View convertView, ViewGroup parent)
    {
        ImageView imageview = new ImageView(mContext);

        // 给ImageView设置资源
        imageview.setImageResource(mImageIds[position]);
        // 设置布局 图片120×120显示
        imageview.setLayoutParams(new Gallery.LayoutParams(120, 120));
        // 设置显示比例类型
        imageview.setScaleType(ImageView.ScaleType.FIT_CENTER);
        return imageview;
    }
}