畫廊(Gallery)

前文網格視圖(GridView)闡釋了網格視圖, 本文會演示另一種常用於以水平滾動方式顯示項目列的視圖, 畫廊(Gallery).



可以比較這篇文章和網格視圖(GridView)的源碼的區別, 主要是在getView()之上.

先創建一個文件夾/res/drawable, 並複製一些PNG圖形到/res/drawable內. 我使用的文件名為a01.png~a15.png.

修改main.xml, 使用Gallery.

<?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_width="fill_parent"
android:layout_height="100dp"
android:spacing="10dp"
   />
</LinearLayout>

修改源碼.

package com.AndroidGallery;

import android.app.Activity;
import android.content.Context;
import android.os.Bundle;
import android.view.View;
import android.view.ViewGroup;
import android.view.ViewGroup.LayoutParams;
import android.widget.BaseAdapter;
import android.widget.Gallery;
import android.widget.ImageView;

public class AndroidGallery extends Activity {
   /** Called when the activity is first created. */
   @Override
   public void onCreate(Bundle savedInstanceState) {
       super.onCreate(savedInstanceState);
       setContentView(R.layout.main);
      
       Gallery myGallery = (Gallery)findViewById(R.id.gallery);
       myGallery.setAdapter(new ImageAdapter(this));
   }
  
   public class ImageAdapter extends BaseAdapter{
    private Context context;
   
    private Integer[] mThumbIds = {
      R.drawable.a01,
      R.drawable.a02,
      R.drawable.a03,
      R.drawable.a04,
      R.drawable.a05,
      R.drawable.a06,
      R.drawable.a07,
      R.drawable.a08,
      R.drawable.a09,
      R.drawable.a10,
      R.drawable.a11,
      R.drawable.a12,
      R.drawable.a13,
      R.drawable.a14,
      R.drawable.a15,
    };
   
    public ImageAdapter(Context c){
     context = c;
    }
   
 @Override
 public int getCount() {
  // TODO Auto-generated method stub
  return mThumbIds.length;
 }

 @Override
 public Object getItem(int position) {
  // TODO Auto-generated method stub
  return mThumbIds[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 imageView;
        if (convertView == null) {
         // if it's not recycled, initialize some attributes
            imageView = new ImageView(context);
            imageView.setLayoutParams(new Gallery.LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT));
            imageView.setScaleType(ImageView.ScaleType.CENTER_CROP);
            imageView.setPadding(8, 8, 8, 8);
        } else {
            imageView = (ImageView) convertView;
        }

        imageView.setImageResource(mThumbIds[position]);
        return imageView;
 }

   
   }
}

下一篇文章: 實現Gallery的OnItemSelectedListener.