Android webapi

Android call web api (Json)

  (2013-11-15 23:10:53)

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分类： 软件开发

Source code:

a.        Web API:   https://github.com/tonglanli/WebAPIForAndroidSample/  (Open with visual studio 2013)

b.        Android Calling Web API:  https://github.com/tonglanli/AndroidCallingWebApiSample (Open with Eclipse ADT)

 

Summary:

1.        Publish Web API in your local (the project use VS2013)

2.        Change the web API Url of the Android Calling Web API Project to your local address:

Be attention, the localhost should be set as 10.0.2.2.

 

public class ServiceUrl {

    public static final String REST_SERVICE_URL = "http://10.0.2.2:10081/api/";

    public static final String PRODUCT = REST_SERVICE_URL + "products";

}

 

 

External JARs:

Gson (https://code.google.com/p/google-gson/)  can convert Json string to Class object automatically.  

new GsonBuilder().create().fromJson(resultString, objectClass);

 

WebAPI JSon data:

http://localhost:10081/api/products

[{"Id":1,"Name":"Tomato Soup","Category":"Groceries","Price":1.0},{"Id":2,"Name":"Yo-yo","Category":"Toys","Price":3.75},{"Id":3,"Name":"Hammer","Category":"Hardware","Price":16.99}]

 

Android window:

 

Reference:

How to call .NET Web Api from Android App：

http://www.youtube.com/watch?v=aQ8Mu7-s_Xk

How to call ASP.Net Web API service from Android?：

http://hintdesk.com/how-to-call-asp-net-web-api-service-from-android/

Getting Started with ASP.NET Web API 2 (C#)：

http://www.asp.net/web-api/overview/getting-started-with-aspnet-web-api/tutorial-your-first-web-api

 

Steps:

Create Web API:

1.        Set config to use Jason:

a.        Global.asax.cs:

 

protected void Application_Start()

        {

            GlobalConfiguration.Configure(WebApiConfig.Register);

            ConfigureApi(GlobalConfiguration.Configuration);

        }

 

        void ConfigureApi(HttpConfiguration config)

        {

            // Remove the JSON formatter

            //config.Formatters.Remove(config.Formatters.JsonFormatter);

 

            // or

 

            // Remove the XML formatter

            config.Formatters.Remove(config.Formatters.XmlFormatter);

        }

 

The Setup Steps for Android calling Web Api (JSon):

1.        Create an Android Application.

2.        Add ListView to layout view.

 

3.        Create productrow.xml in layout view.

                                                android:paddingLeft="4dp" android:layout_width="wrap_content"

                                                android:layout_height="wrap_content">

                                               

                                                                         android:id="@+id/product_id" android:layout_alignParentLeft="true" android:src="@drawable/blank" android:layout_centerVertical="true">

                                               

                                               

                                                                        android:layout_width="wrap_content" android:layout_height="wrap_content"

                                                                        android:textStyle="bold" android:textColor="#777777"

                                                                        android:shadowColor="@color/black" android:shadowRadius="0.5"

                                                                        android:shadowDx="0" android:shadowDy="0" android:layout_toRightOf="@+id/product_id" android:layout_marginLeft="4dip">

                                               

                                                                        android:layout_height="wrap_content" android:layout_toRightOf="@+id/product_id" android:layout_below="@id/product_name">

                       

4.        Create ProductRowHolder in MainActivity:

public static class ProductRowHolder {

        public TextView productId, productName, productPrice;

    }

 

5.        Create JSONHttpClient.java:

combine Gson (https://code.google.com/p/google-gson/) with generic class to build a .net equivalent HttpClient for Android. 

public class JSONHttpClient {

    public T PostObject(final String url, final T object, final Class objectClass) {

        DefaultHttpClient defaultHttpClient = new DefaultHttpClient();

        HttpPost httpPost = new HttpPost(url);

        try {

 

            StringEntity stringEntity = new StringEntity(new GsonBuilder().create().toJson(object));

            httpPost.setEntity(stringEntity);

            httpPost.setHeader("Accept", "application/json");

            httpPost.setHeader("Content-type", "application/json");

            httpPost.setHeader("Accept-Encoding", "gzip");

 

            HttpResponse httpResponse = defaultHttpClient.execute(httpPost);

            HttpEntity httpEntity = httpResponse.getEntity();

            if (httpEntity != null) {

                InputStream inputStream = httpEntity.getContent();

                Header contentEncoding = httpResponse.getFirstHeader("Content-Encoding");

                if (contentEncoding != null && contentEncoding.getValue().equalsIgnoreCase("gzip")) {

                    inputStream = new GZIPInputStream(inputStream);

                }

 

                String resultString = convertStreamToString(inputStream);

                inputStream.close();

                return new GsonBuilder().create().fromJson(resultString, objectClass);

 

            }

 

        } catch (UnsupportedEncodingException e) {

            e.printStackTrace();  //To change body of catch statement use File | Settings | File Templates.

        } catch (ClientProtocolException e) {

            e.printStackTrace();  //To change body of catch statement use File | Settings | File Templates.

        } catch (IOException e) {

            e.printStackTrace();  //To change body of catch statement use File | Settings | File Templates.

        }

        return null;

    }

 

    public T PostParams(String url, final List params, final Class objectClass) {

        String paramString = URLEncodedUtils.format(params, "utf-8");

        url += "?" + paramString;

        return PostObject(url, null, objectClass);

    }

 

    private String convertStreamToString(InputStream inputStream) {

        BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(inputStream));

        StringBuilder stringBuilder = new StringBuilder();

        String line = null;

        try {

            while ((line = bufferedReader.readLine()) != null) {

                stringBuilder.append(line + " ");

            }

        } catch (IOException e) {

            e.printStackTrace();  //To change body of catch statement use File | Settings | File Templates.

        } finally {

            try {

                inputStream.close();

            } catch (IOException e) {

                e.printStackTrace();  //To change body of catch statement use File | Settings | File Templates.

            }

        }

 

        return stringBuilder.toString();

    }

 

    public T Get(String url, List params, final Class objectClass) {

        DefaultHttpClient defaultHttpClient = new DefaultHttpClient();

        String paramString = URLEncodedUtils.format(params, "utf-8");

        url += "?" + paramString;

        HttpGet httpGet = new HttpGet(url);

        try {

 

            httpGet.setHeader("Accept", "application/json");

            httpGet.setHeader("Accept-Encoding", "gzip");

 

            HttpResponse httpResponse = defaultHttpClient.execute(httpGet);

            HttpEntity httpEntity = httpResponse.getEntity();

            if (httpEntity != null) {

                InputStream inputStream = httpEntity.getContent();

                Header contentEncoding = httpResponse.getFirstHeader("Content-Encoding");

                if (contentEncoding != null && contentEncoding.getValue().equalsIgnoreCase("gzip")) {

                    inputStream = new GZIPInputStream(inputStream);

                }

 

                String resultString = convertStreamToString(inputStream);

                inputStream.close();

                return new GsonBuilder().create().fromJson(resultString, objectClass);

 

            }

 

        } catch (UnsupportedEncodingException e) {

            e.printStackTrace();  //To change body of catch statement use File | Settings | File Templates.

        } catch (ClientProtocolException e) {

            e.printStackTrace();  //To change body of catch statement use File | Settings | File Templates.

        } catch (IOException e) {

            e.printStackTrace();  //To change body of catch statement use File | Settings | File Templates.

        }

        return null;

    }

 

    public boolean Delete(String url, final List params) {

        DefaultHttpClient defaultHttpClient = new DefaultHttpClient();

        String paramString = URLEncodedUtils.format(params, "utf-8");

        url += "?" + paramString;

        HttpDelete httpDelete = new HttpDelete(url);

 

        HttpResponse httpResponse = null;

        try {

            httpResponse = defaultHttpClient.execute(httpDelete);

            return httpResponse.getStatusLine().getStatusCode() == HttpStatus.SC_NO_CONTENT;

        } catch (IOException e) {

            e.printStackTrace();  //To change body of catch statement use File | Settings | File Templates.

        }

 

        return false;

    }

}

6.        Create LoadAllProductsTask.java

package com.example.androidcallingwebapi.tasks;

 

import java.util.ArrayList;

import java.util.List;

 

import org.apache.http.NameValuePair;

 

import com.example.androidcallingwebapi.JSONHttpClient;

import com.example.androidcallingwebapi.models.Product;

import com.example.androidcallingwebapi.util.ServiceUrl;

 

import android.app.ProgressDialog;

import android.content.Context;

import android.os.AsyncTask;

 

public class LoadAllProductsTask extends AsyncTask {

 

                        public Context context;

                        private ProgressDialog progressDialog;

                       

                        public LoadAllProductsTask(Context context) {

                                                super();

                                                this.context = context;

                        }

 

    @Override

    protected Product[] doInBackground(String... params) {

        List nameValuePairs = new ArrayList();

        JSONHttpClient jsonHttpClient = new JSONHttpClient();

        Product[] products = jsonHttpClient.Get(ServiceUrl.PRODUCT, nameValuePairs, Product[].class);

       

        return products;

    }

 

    @Override

    protected void onPreExecute() {

        super.onPreExecute();    //To change body of overridden methods use File | Settings | File Templates.

        progressDialog = new ProgressDialog(context);

        progressDialog.setMessage("Loading products. Please wait...");

        progressDialog.show();

    }

 

}

 

7.        Create ProductAdapter.java:

 

package com.example.androidcallingwebapi.adapters;

 

 

import com.example.androidcallingwebapi.MainActivity;

import com.example.androidcallingwebapi.MainActivity.ProductRowHolder;

import com.example.androidcallingwebapi.models.Product;

 

import com.example.androidcallingwebapi.R;

import android.view.LayoutInflater;

import android.view.View;

import android.view.View.OnClickListener;

import android.view.ViewGroup;

import android.widget.BaseAdapter;

import android.widget.TextView;

 

public class ProductAdapter extends BaseAdapter implements OnClickListener {

 

                        private LayoutInflater layoutInflater;

                        private Product[] products;

                       

    public ProductAdapter (MainActivity a, LayoutInflater l, Product[] data)

    {

                      this.layoutInflater = l;

                      this.products = data;

    }

   

                        @Override

                        public int getCount() {

                                                return this.products.length;

                        }

 

                        @Override

                        public Object getItem(int position) {

                                                return null;

                        }

 

                        @Override

                        public long getItemId(int position) {

                                                // TODO Auto-generated method stub

                                                return 0;

                        }

 

                        @Override

                        public View getView(int pos, View convertView, ViewGroup parent) {

                                                ProductRowHolder holder;

                                               

        if (convertView == null) {

            convertView = layoutInflater.inflate(R.layout.productrow, parent, false);

            holder = new ProductRowHolder();

            holder.productId = (TextView) convertView.findViewById(R.id.product_id);

            holder.productName = (TextView) convertView.findViewById(R.id.product_name);

            holder.productPrice = (TextView) convertView.findViewById(R.id.product_price);

            convertView.setTag(holder);

        }

        else {

            holder = (ProductRowHolder) convertView.getTag();

        }

       

                                               convertView.setOnClickListener(this);

                                              

                                               Product product = products[pos];

                                               holder.product = product;

                                               holder.productId.setText(product.getId());

                                               holder.productName.setText(product.getName());

                                               holder.productPrice.setText(product.getPrice() + "");

                                              

        return convertView;

                        }

 

                        @Override

                        public void onClick(View v) {

                                                // TODO Auto-generated method stub

                                               

                        }

 

}

8.        Load Data in Main:

 

package com.example.androidcallingwebapi;

 

 

import java.util.concurrent.ExecutionException;

 

import com.example.androidcallingwebapi.adapters.ProductAdapter;

import com.example.androidcallingwebapi.models.Product;

import com.example.androidcallingwebapi.tasks.LoadAllProductsTask;

 

import android.os.Bundle;

import android.app.Activity;

import android.view.LayoutInflater;

import android.view.Menu;

import android.widget.ListView;

import android.widget.TextView;

 

public class MainActivity extends Activity {

 

                       

                        private ListView productList;

                        @Override

                        protected void onCreate(Bundle savedInstanceState) {

                                                super.onCreate(savedInstanceState);

                                                setContentView(R.layout.activity_main);

                                                this.productList = (ListView) findViewById(R.id.product_list);

                                                LoadAllProductsTask loadAllProductsTask = new LoadAllProductsTask(MainActivity.this.getApplicationContext());

                                                Product[] products = null;

                                                try {

                                                                        loadAllProductsTask.execute();

        }

        catch (Exception e)

        {

                    loadAllProductsTask.cancel(true);

            //alert (getResources().getString(R.string.no_products));

        }

                                                try {

                                                                        products = loadAllProductsTask.get();

                                                } catch (InterruptedException e) {

                                                                        // TODO Auto-generated catch block

                                                                        e.printStackTrace();

                                                } catch (ExecutionException e) {

                                                                        // TODO Auto-generated catch block

                                                                        e.printStackTrace();

                                                }

                                                if(products != null)

                                                {

                                                                        this.productList.setAdapter(new ProductAdapter(this,LayoutInflater.from(this), products));

                                                }

                        }

 

                        @Override

                        public boolean onCreateOptionsMenu(Menu menu) {

                                                // Inflate the menu; this adds items to the action bar if it is present.

                                                getMenuInflater().inflate(R.menu.main, menu);

                                                return true;

                        }

 

    public static class ProductRowHolder {

        public TextView productId, productName, productPrice;

        public Product product;

    }

}

 

 

9.        Add config into AndroidManifest.xml for access internet:

10.     Create ServiceUrl:

Be attention, the localhost should be set as 10.0.2.2.

 

public class ServiceUrl {

    public static final String REST_SERVICE_URL = "http://10.0.2.2:10081/api/";

    public static final String PRODUCT = REST_SERVICE_URL + "products";

}