Android实现Gallery相册组件开发

[align=left]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。[/align] [align=left]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。[/align] [align=left]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）。[/align] [align=left]最终效果图如下：[/align]


[align=left]一、Layout布局文件[/align] [align=left]A:主界面布局文件[/align] [align=left] [/align] [align=left]

<?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>

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[align=left]B:显示Gallery和ImageSwitcher的布局文件[/align] [align=left]

<?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>

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[align=left] C:String文件[/align] [align=left]

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

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[align=left] 二、设置图片资源[/align] [align=left]在drawable-hdpi文件夹下放置10个要显示的图片，如下图[/align] [align=left] [/align]


[align=left] 三、主Activity类[/align] [align=left] [/align] [align=left]

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;          }     }  }

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[align=left] [/align] [align=left] [/align] 本文出自 “Android小子的” 博客，请务必保留此出处http://androidrigl.blog.51cto.com/7531835/1249453