android之Gallery

业务层提供数据：

实体类：

package com.ghg.Entity;import android.graphics.Bitmap;public class BitmapInfo {private String path;private String title;private Bitmap bitmap;public String getPath() {return path;}public void setPath(String path) {this.path = path;}public String getTitle() {return title;}public void setTitle(String title) {this.title = title;}public Bitmap getBitmap() {return bitmap;}public void setBitmap(Bitmap bitmap) {this.bitmap = bitmap;}}

构造数据源：

package com.ghg.Bitmapbiz;import java.io.File;import java.util.ArrayList;import android.graphics.BitmapFactory;import com.ghg.BitmapService.BitmapService;import com.ghg.Entity.BitmapInfo;/** * 从文件中读取所有图片添加到list集合中，构成数据源 * @author gaohong * */public class BitmapBiz {public ArrayList<BitmapInfo> getBitmapInfos(String pathName){ArrayList<BitmapInfo> list=null;if(pathName!=null){//根据路径创建文件File dir=new File(pathName);if (dir.exists()&&dir.isDirectory()) {list=new ArrayList<BitmapInfo>();//初始化list集合String[] files=dir.list();//获取目录下所有文件名//遍历files并依次构建BitmapInfo对象for(String file:files){BitmapInfo info=new BitmapInfo();info.setTitle(file.substring(0, file.lastIndexOf(".")));info.setPath(pathName+file);info.setBitmap(BitmapService.getBitmap(info.getPath(), 80, 80));list.add(info);}}}return list;}}

工具类提供bitmap：

package com.ghg.BitmapService;import android.graphics.Bitmap;import android.graphics.BitmapFactory;import android.graphics.BitmapFactory.Options;public class BitmapService {//通过路径名获得位图public static Bitmap getBitmap(String pathName){return BitmapFactory.decodeFile(pathName);}//通过路径名获得位图的缩略图public static Bitmap getBitmap(String pathName,int scale){Options opts=new Options();opts.inSampleSize=scale;return BitmapFactory.decodeFile(pathName, opts);}//通过文件名获得缩略图，指定缩略后的尺寸，宽，高各为多少public static Bitmap getBitmap(String pathName,int width,int height){Options opts=new Options();opts.inJustDecodeBounds=true;//仅读取边界信息BitmapFactory.decodeFile(pathName, opts);//读完后的信息保存到opts对象中int x=opts.outWidth/width;int y=opts.outHeight/height;int scale=x>y?x:y;opts.inJustDecodeBounds=false;return getBitmap(pathName, scale);}}

适配器提供视图项：

package com.ghg.BitmapAdapter;import java.util.ArrayList;import com.ghg.Entity.BitmapInfo;import com.ghg.Gallery.R;import android.content.Context;import android.view.LayoutInflater;import android.view.View;import android.view.ViewGroup;import android.widget.BaseAdapter;import android.widget.ImageView;import android.widget.TextView;public class Adapter extends BaseAdapter {private ArrayList<BitmapInfo> list;private LayoutInflater inflater;public Adapter(Context context,ArrayList<BitmapInfo> list){this.inflater=LayoutInflater.from(context);this.list=list;}@Overridepublic int getCount() {// TODO Auto-generated method stubreturn list.size();}@Overridepublic Object getItem(int position) {// TODO Auto-generated method stubreturn list.get(position);}@Overridepublic long getItemId(int position) {// TODO Auto-generated method stubreturn position;}@Overridepublic View getView(int position, View convertView, ViewGroup parent) {ViewHolder holder=null;if (convertView==null) {//系统不提示自定义的资源，可以导入自己R资源，R前面加上R所在的包名；convertView=inflater.inflate(R.layout.item, null);holder=new ViewHolder();holder.galleryItem=(ImageView) convertView.findViewById(R.id.iv_calleryItem);holder.pictureTitle=(TextView) convertView.findViewById(R.id.tv_title);convertView.setTag(holder);}else {holder=(ViewHolder) convertView.getTag();}//从数据源读取数据，绘制Gallery的item项；BitmapInfo info=list.get(position);holder.galleryItem.setImageBitmap(info.getBitmap());holder.pictureTitle.setText(info.getTitle());return convertView;} class ViewHolder{private ImageView galleryItem;private TextView pictureTitle;}}

activity中显示Gallery：

package com.ghg.Gallery;import com.ghg.BitmapAdapter.Adapter;import com.ghg.BitmapService.BitmapService;import com.ghg.Bitmapbiz.BitmapBiz;import com.ghg.Entity.BitmapInfo;import android.app.Activity;import android.graphics.Bitmap;import android.os.Bundle;import android.view.View;import android.widget.AdapterView;import android.widget.AdapterView.OnItemSelectedListener;import android.widget.Gallery;import android.widget.ImageView;public class Day0704_GalleryDemoActivity extends Activity {private static final String PATHNAME="/mnt/sdcard/imgs/";    /** Called when the activity is first created. */    @Override    public void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.main);        initView();        initListener();    }        ImageView imageView;    private void initListener() {    imageView=(ImageView) findViewById(R.id.iv_topPic);gallery.setOnItemSelectedListener(new OnItemSelectedListener() {@Overridepublic void onItemSelected(AdapterView<?> parent, View view,int position, long id) {// TODO Auto-generated method stubBitmapInfo info=(BitmapInfo) adapter.getItem(position);Bitmap bm=BitmapService.getBitmap(info.getPath());imageView.setImageBitmap(bm);}@Overridepublic void onNothingSelected(AdapterView<?> parent) {// TODO Auto-generated method stub}});}    Gallery gallery;    BitmapBiz biz;    Adapter adapter;private void initView() {// TODO Auto-generated method stubgallery=(Gallery) findViewById(R.id.gallery);biz=new BitmapBiz();adapter=new Adapter(this, biz.getBitmapInfos(PATHNAME));gallery.setAdapter(adapter);}}

用到的布局文件：

main.xml

<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"    android:layout_width="fill_parent"    android:layout_height="fill_parent"    android:orientation="vertical" >    <ImageView         android:id="@+id/iv_topPic"        android:layout_width="fill_parent"        android:layout_height="0dp"        android:layout_weight="1.0"        />    <Gallery         android:id="@+id/gallery"        android:layout_width="fill_parent"        android:layout_height="wrap_content"        android:spacing="10dp"        /></LinearLayout>

item.xml

<?xml version="1.0" encoding="utf-8"?><FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"    android:layout_width="80dp"    android:layout_height="80dp" >    <ImageView         android:id="@+id/iv_calleryItem"        android:layout_width="80dp"        android:layout_height="80dp"        android:scaleType="fitCenter"        />    <TextView         android:id="@+id/tv_title"        android:layout_width="80dp"        android:layout_height="wrap_content"        android:layout_gravity="bottom"        android:gravity="center_horizontal"        /></FrameLayout>

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