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;

        }

 

}

}