Android实现Gallery相册组件开发

Gallery组件主要用于横向显示图像列表，不过按常规做法。Gallery组件只能有限地显示指定的图像。

也就是说，如果为Gallery组件指定了10张图像，那么当Gallery组件显示到第10张时，就不会再继续显示了。这虽然在大多数时候没有什么关系，但在某些情况下，我们希望图像显示到最后一张时再重第1张开始显示，也就是循环显示。要实现这种风格的Gallery组件，就需要对Gallery的Adapter对象进行一番改进。

以下通过Gallery模拟循环显示图像，在单击某一个Gallery组件中的图像时在下方显示一个放大的图像（使用ImageSwitcher组件）。

最终效果图如下：

一、Layout布局文件

A:主界面布局文件

 

<?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">
    <ImageButton android:id="@+id/ibtnHead"
    
android:layout_height="60px" android:layout_width="60px"
    android:src="@drawable/icon" android:scaleType="fitXY"></ImageButton>
</LinearLayout>

B:显示Gallery和ImageSwitcher的布局文件

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout 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/img_gallery" 
android:layout_width="fill_parent"
     
   android:layout_height="110px" android:layout_marginTop="2px"
        android:layout_alignParentLeft="true"></Gallery>
    
<ImageSwitcher 
android:id="@+id/img_switcher"
        android:layout_width="90px" android:layout_height="90px"
        android:layout_centerHorizontal="true" android:layout_below="@+id/img_gallery"
        ></ImageSwitcher>
</RelativeLayout>

C:String文件

 

<?xml version="1.0" encoding="utf-8"?>
<resources>
    
<string name="addContact_PleaseChooseImg">请选择图像</string>
</resources>

二、设置图片资源

在drawable-hdpi文件夹下放置10个要显示的图片，如下图

 

三、主Activity类

 

package cn.moon.contact;
import android.app.Activity;
import android.app.AlertDialog;
import android.content.Context;
import android.content.DialogInterface;
import android.content.DialogInterface.OnClickListener;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.view.ViewGroup.LayoutParams;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemSelectedListener;
import android.widget.BaseAdapter;
import android.widget.Gallery;
import android.widget.ImageButton;
import android.widget.ImageSwitcher;
import android.widget.ImageView;
import android.widget.ImageView.ScaleType;
import android.widget.ViewSwitcher.ViewFactory;

publicclass AddContactActivity extends Activity {
    ImageButton ibtnImgChoose;
    AlertDialog imgChooseDialog;
    Gallery gallery;
  
  ImageSwitcher imageSwitcher;
    int selectedImage;

    privateint[] images = { R.drawable.png0001, R.drawable.png0002,
            R.drawable.png0003, R.drawable.png0004, R.drawable.png0005,
            R.drawable.png0006, R.drawable.png0007, R.drawable.png0008,
            R.drawable.png0009, R.drawable.png0010, 
};

    publicvoid onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
     
   setContentView(R.layout.addcontact);
     
   System.out.println("AddContact");
     
   ibtnImgChoose = (ImageButton) findViewById(R.id.ibtnHead);
     
   ibtnImgChoose.setOnClickListener(new View.OnClickListener() {
            publicvoid onClick(View v) {
                
initImageChoose();
                imgChooseDialog.show();
           
}
        });
    }

    privatevoid initImageChoose() {
     
   LayoutInflater layoutInflater = LayoutInflater.from(this);
        View view = layoutInflater.inflate(R.layout.userheadchoose, null);
        gallery = (Gallery) view.findViewById(R.id.img_gallery);
        gallery.setAdapter(new imageAdapter(this));
     
   gallery.setSelection(images.length /2);
     
   imageSwitcher = (ImageSwitcher) view.findViewById(R.id.img_switcher);
     
   imageSwitcher.setFactory(new switcherFactory(this));
     
   gallery.setOnItemSelectedListener(new OnItemSelectedListener() {


            publicvoid onItemSelected(AdapterView<?> arg0, View arg1,int arg2, long arg3) {
                
imageSwitcher.setImageResource(images[arg2]);
                selectedImage = arg2;
           
}

    publicvoid onNothingSelected(AdapterView<?> arg0) {
                // TODO Auto-generated method stub

            }
        });
     
   AlertDialog.Builder builder =new AlertDialog.Builder(this);
  
      builder.setTitle("请选择图像");
     
   builder.setPositiveButton("确认", new OnClickListener() {

           
publicvoid onClick(DialogInterface dialog, int which) {
                
ibtnImgChoose.setImageResource(images[selectedImage]);
            }
     
   });
        builder.setNegativeButton("取消", new OnClickListener() {

            publicvoid onClick(DialogInterface dialog, 
int which) {

           
}
        });
        builder.setView(view);
        imgChooseDialog = builder.create();
    
}

    class imageAdapter extends BaseAdapter {
     
   private Context context;

        public imageAdapter(Context context) {
            super();
            this.context = context;
        }

     
   publicint getCount() {
            return images.length;
        }

  
      public Object getItem(int arg0) {
        
    // TODO Auto-generated 
method stub
           
returnnull;
        }

     
   publiclong getItemId(int position) {
            // TODO Auto-generated method 
stub
           
　　return0;
        }

        public View getView(int position, View convertView, ViewGroup parent) {
            ImageView imageView =new ImageView(context);// 构造一个ImageView
  
          imageView.setImageResource(images[position]);// 设置ImageView图片源
           
　　　　　　imageView.setAdjustViewBounds(true);
           
　　　　　　imageView.setScaleType(ScaleType.FIT_XY);// 自适应高和宽
           
　　　　　　imageView.setLayoutParams(new Gallery.LayoutParams(80, 80));// 设置显示图处的大小
           
　　　　　　imageView.setPadding(10, 5, 10, 5);// 
设置四边的距离
           
return imageView;
     
   }
    }

    class switcherFactory implements ViewFactory {
        private Context context;

        public switcherFactory(Context context) 
{
            super();
  
          this.context = context;
        }
 
      public View makeView() 
{
            ImageView imageView =new ImageView(context);
            imageView.setLayoutParams(new ImageSwitcher.LayoutParams(90, 90));
            return imageView;
        }
 
}
}