使用Retrofit，PHP，JSON和WAMP从Android应用程序获取Mysql数据库的信息

PHP file stored in www directory of WAMP

<?php
//Response array JSON
$response = array();

//Connexion to the db local in WAMP
include("connexion_db.php");
$idcom = connexobject("database_app_android","myparam");

$sql = "SELECT * FROM products";

$result = $idcom->query($sql);

if(!$result)
{
    //Cannot read
    $response["success"] = 0;
    $response["mesage"] = "SQL query has timed out";
}
else
{
    if($result->num_rows > 0)
    {
        //Products founds
        $response["products"] = array();

        while($row = $result->fecth_object())
        {
            $product = array();
            foreach ($row as $key => $value)
            {
                $product[$key] = $value;
            }

            //Add product to the response JSON array
            array_push($response["products"], $product);
        }

        $response["success"] = 1;
    }
    else
    {
        //0 product found
        $response["success"] = 0;
        $response["mesage"] = "No products found";
    }
}

//Encode and send response in JSON format
echo(json_encode($response));

$response->free();
$result->free();
$idcom->close();
?>

Android API

public interface CatalogAPI {
    @GET("/products")
    Call<List<Product>> getProductList();

    @GET("/products/{product}")
    Call<Product> getProduct(@Path("product") int productId);
}

Android part using retrofit

//Retrofit
Retrofit retrofit = new Retrofit.Builder()
        .baseUrl("http://10.0.2.2:3000/MyAndroidApp/get_all_product.php")
        .addConverterFactory(GsonConverterFactory.create())
        .build();
CatalogAPI service = retrofit.create(CatalogAPI.class);
service.getProductList().enqueue(new Callback<List<Product>>() {
    @Override
    public void onResponse(Call<List<Product>> call, Response<List<Product>> response) {
        Log.i("retrofit","DOWNLOAD OK");
        for (Product p : response.body())
        {
            Log.i("retrofit","Product : " + p.getName());
            catalog.add(p);
        }
    }

    @Override
    public void onFailure(Call<List<Product>> call, Throwable t) {

    }
});

Please, why this doesn't work ? I use the Android studio emulator. The php script encode to json all products founds in the mysql database. The MySQL database is on a local server wamp

Please add logging interceptor to your retrofit client, this would help to find where is the problem .

Gradle Change

compile 'com.squareup.okhttp3:logging-interceptor:3.3.1'  

Code Change

HttpLoggingInterceptor logging = new HttpLoggingInterceptor();  
// set your desired log level
logging.setLevel(Level.BODY);

OkHttpClient.Builder httpClient = new OkHttpClient.Builder();  
// add your other interceptors …

// add logging as last interceptor
httpClient.addInterceptor(logging);  // <-- this is the important line!

Retrofit retrofit = new Retrofit.Builder()  
   .baseUrl(API_BASE_URL)
   .addConverterFactory(GsonConverterFactory.create())
   .client(httpClient.build())
   .build();

In php file write

while($row = $result->**fetch**_object())

instead of

while($row = $result->**fecth**_object())

Good day, i know this is coming late though, but the problem seems to come from the way PHP encodes into json array. PHP adds extra features like " " and more to encode into json array, which is totally different from what Retrofit 2 is expecting. Retrofit 2 expects something like:

[ 
{ "name": "John Doe", "address": "60, station road", "mobile": "1" }, 
{ "name": "Doe Chujwu", "address": "6, Morgan Estate", "mobile": "2" }
 ].

Hence change your output to echo the above give format and then would your code work. I hope it helps. NB: also test that you can access your server homepage on the emulators browser. (This is to ensure that your are using the right ipaddress to connect).