android 消费REST webservice

本文记录阅读《Android多媒体开发高级编程——为智能手机和平板电脑开发图形、音乐、视频和富媒体应用》第十二章“使用web服务的媒体消费和发布”，通过调用Flickr的REST API，生成照片列表的应用。在线照片地址：
效果图如下：



我们需要在flickr上获取一个app secret。这里不过多描述。下面直接贴代码：

常量Constants.java中定义了API_KEY等信息：

package flickr;

public class Constants {

    public static final String API_KEY = "465257bbc0011ba13bb6437c545bd6ec";
    public static final String API_SECRET = "4a34e548c49499ca";
    public static final String USER_ID = "94448382@N04";
    public static final String REST_URL_ROOT = "";
    public static final String PHOTO_URL_ROOT = "";
    //29096781@N02/3606436456/
    //user id(owner)/photo id/
}

layout文件：包括主界面和每一行的布局定义。

主界面：包含一个ListView，如下photolist_main.xml：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    xmlns:android=""
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:background="#FFFFFF">

     <ListView
        android:id="@+id/photoListView"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent" />

</LinearLayout>

行布局 photolist_item_row.xml 定义了每一行的布局，包含一个显示图片的ImageView和一个显示文本的TextView：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    xmlns:android=""
    android:orientation="horizontal"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:padding="10dp">

     <ImageView
         android:id="@+id/photoView"
        android:layout_width="64dp"
        android:layout_height="64dp"
        android:gravity="center_vertical"
        android:layout_marginRight="15dp"
        android:layout_marginTop="5dp"
        android:layout_marginBottom="5dp"
         />

     <TextView android:id="@+id/photoTitle"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:gravity="center_vertical"
        android:textStyle="bold"
        android:textColor="#000000"
        android:layout_marginTop="5dp"
        android:layout_marginBottom="5dp" />

</LinearLayout>

通过Flickr响应的json数据抽象出来的数据模型FlickrPhoto.java

package flickr;

public class FlickrPhoto {

    private String id;
    private String owner;
    private String secret;
    private String server;
    private String title;
    private String farm;
    public String getId() {
        return id;
    }
    public void setId(String id) {
        this.id = id;
    }
    public String getOwner() {
        return owner;
    }
    public void setOwner(String owner) {
        this.owner = owner;
    }
    public String getSecret() {
        return secret;
    }
    public void setSecret(String secret) {
        this.secret = secret;
    }
    public String getServer() {
        return server;
    }
    public void setServer(String server) {
        this.server = server;
    }
    public String getTitle() {
        return title;
    }
    public void setTitle(String title) {
        this.title = title;
    }
    public String getFarm() {
        return farm;
    }
    public void setFarm(String farm) {
        this.farm = farm;
    }

    public String makeURL(){
        return ""+farm+".static.flickr.com/"+server+"/"+id+"_"+secret+"_m.jpg";
    }


}

图片列表Activity对应的java类MmActivity.java

package flickr;

import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;

import android.app.Activity;
import android.os.Bundle;
import android.util.Log;
import android.widget.ListView;

import com.example.twiter.R;
import com.github.kevinsawicki.http.HttpRequest;

public class MmActivity extends Activity {
    private static final String TAG = "MmActivity";

    FlickrPhoto[] photos;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.photolist_main);

        String getPublicPhotos = Constants.REST_URL_ROOT + "&method=flickr.people.getPublicPhotos&api_key=" +
        Constants.API_KEY + "&user_id=" +
        Constants.USER_ID +"&format=json&per_page=500";
        String response = HttpRequest.get(getPublicPhotos).body();
        response = response.substring("jsonFlickrApi(".length(), response.length()-1);

        Log.d(TAG,"log..." + getPublicPhotos);
        Log.d(TAG, response);
        if(response!=null && !"".equals(response)){
            try {
                JSONObject thedata = new JSONObject(response);

                JSONObject photoData = thedata.getJSONObject("photos");
                JSONArray photoArr = photoData.getJSONArray("photo");
                int len = photoArr.length();
                photos = new FlickrPhoto[len];

                for(int i=0; i<len; i++){
                    FlickrPhoto tempPhoto = new FlickrPhoto();//这一句放在for前面导致严重错误
                    JSONObject photoObj = photoArr.getJSONObject(i);
                    tempPhoto.setId(photoObj.getString("id"));
                    tempPhoto.setOwner(photoObj.getString("owner"));
                    tempPhoto.setTitle(photoObj.getString("title"));
                    tempPhoto.setFarm(photoObj.getString("farm"));
                    tempPhoto.setSecret(photoObj.getString("secret"));
                    tempPhoto.setServer(photoObj.getString("server"));
                    Log.d(TAG,"PHOTO i:"+ i +"  id:"+ photoObj.getString("id"));
                    photos[i] = tempPhoto;
                }

            } catch (JSONException e) {
                e.printStackTrace();
                Log.e(TAG, "响应的不是json格式，"+e.getMessage());
            }

            ListView photoListView = (ListView)this.findViewById(R.id.photoListView);
            photoListView.setAdapter(new FlickrGalleryAdapter(this,photos));
        }
        /*
        &method=flickr.people.getPublicPhotos&api_key=4ef2fe2affcdd6e13218f5ddd0e2500d&user_id=29096781@N02&format=json
        */
    }


}

为主界面ListView提供数据的Adapter FlickrGalleryAdapter.java

package flickr;

import java.io.IOException;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;

import android.app.Activity;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.ImageView;
import android.widget.TextView;

import com.example.twiter.R;

public class FlickrGalleryAdapter extends BaseAdapter {

    private Context context;
    private FlickrPhoto[] photos;

    LayoutInflater inflater;

    public FlickrGalleryAdapter(Context context, FlickrPhoto[] photos){
        this.context = context;
        this.photos = photos;
    }

    @Override
    public int getCount() {

        return photos.length;
    }

    @Override
    public Object getItem(int position) {
        return photos[position];
    }

    @Override
    public long getItemId(int position) {
        return position;
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        /*LayoutInflater inflater = (LayoutInflater) context
                .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        View photoRow = inflater.inflate(R.layout.photolist_item_row, parent,false);
        ImageView photoView = (ImageView)photoRow.findViewById(R.id.photoView);
        TextView photoTitle = (TextView)photoRow.findViewById(R.id.photoTitle);

        String url = photos[position].makeURL();
        Log.d("URL", "_______________"+url);
        photoView.setImageBitmap(getImgFromURL(url));

        photoTitle.setText(photos[position].getTitle());
        return photoRow;
        */


        View row = convertView;
        PhotoHolder holder = null;

        if (row == null) {
            LayoutInflater inflater = ((Activity) context).getLayoutInflater();
            //generate view from a row layout xml
            row = inflater.inflate(R.layout.photolist_item_row, parent, false);

            holder = new PhotoHolder();
            holder.photoView = (ImageView) row.findViewById(R.id.photoView);
            holder.photoTitle = (TextView) row.findViewById(R.id.photoTitle);

            row.setTag(holder);
        } else {
            holder = (PhotoHolder) row.getTag();//the Object stored in this view as a tag
        }

        FlickrPhoto photo = photos[position];
        holder.photoTitle.setText(photo.getTitle());
        holder.photoView.setImageBitmap(getImgFromURL(photo.makeURL()));

        Log.d("POSITION", "_______________"+position);
        Log.d("URL", "_______________"+photo.makeURL());
        Log.d("photo.getTitle()", "_______________"+photo.getTitle());


        return row;
    }

    public Bitmap getImgFromURL(String url){
        Bitmap bitMapImg = null;
        URL photoUrl = null;
            try {
                photoUrl = new URL(url);
                HttpURLConnection httpConn = (HttpURLConnection) photoUrl.openConnection();
                httpConn.setDoInput(true);
                httpConn.connect();
                InputStream is = httpConn.getInputStream();
                bitMapImg = BitmapFactory.decodeStream(is);

            } catch (MalformedURLException e) {

                bitMapImg = Bitmap.createBitmap(50,50,Bitmap.Config.ARGB_8888);
            } catch (IOException e) {

            }
            return bitMapImg;
    }

    static class PhotoHolder {
        ImageView photoView;
        TextView photoTitle;
    }


}

服务端响应的json数据：

{"photos":{"page":1, "pages":1, "perpage":500, "total":"11", "photo":[{"id":"8614366579", "owner":"94448382@N04", "secret":"18f9546601", "server":"8402", "farm":9, "title":"MOVIE", "ispublic":1, "isfriend":0, "isfamily":0}, {"id":"8615474674", "owner":"94448382@N04", "secret":"befe943159", "server":"8126", "farm":9, "title":"xiaofeixing4", "ispublic":1, "isfriend":0, "isfamily":0}, {"id":"8614366639", "owner":"94448382@N04", "secret":"6b5000040b", "server":"8102", "farm":9, "title":"xiaofeixing3", "ispublic":1, "isfriend":0, "isfamily":0}, {"id":"8615474714", "owner":"94448382@N04", "secret":"ce0abaee44", "server":"8530", "farm":9, "title":"xiaofeixing2", "ispublic":1, "isfriend":0, "isfamily":0}, {"id":"8614366749", "owner":"94448382@N04", "secret":"4e1179ccf0", "server":"8398", "farm":9, "title":"xiaofeixing1", "ispublic":1, "isfriend":0, "isfamily":0}, {"id":"8615474746", "owner":"94448382@N04", "secret":"41f15d9df5", "server":"8541", "farm":9, "title":"xiaofeixing", "ispublic":1, "isfriend":0, "isfamily":0}, {"id":"8615474782", "owner":"94448382@N04", "secret":"656bdb2cb4", "server":"8395", "farm":9, "title":"movie2", "ispublic":1, "isfriend":0, "isfamily":0}, {"id":"8615474790", "owner":"94448382@N04", "secret":"9aa25ecd9c", "server":"8101", "farm":9, "title":"movie1", "ispublic":1, "isfriend":0, "isfamily":0}, {"id":"8614366763", "owner":"94448382@N04", "secret":"f03c1d90e7", "server":"8528", "farm":9, "title":"movie", "ispublic":1, "isfriend":0, "isfamily":0}, {"id":"8597609376", "owner":"94448382@N04", "secret":"259e77d927", "server":"8230", "farm":9, "title":"weather", "ispublic":1, "isfriend":0, "isfamily":0}, {"id":"8597609382", "owner":"94448382@N04", "secret":"06a2e4d618", "server":"8383", "farm":9, "title":"list0", "ispublic":1, "isfriend":0, "isfamily":0}]}, "stat":"ok"}

依赖项：
json/gson
com.github.kevinsawicki.http.HttpRequest