LogCat输出：
10-15 21:57:58.557 10666-10666/com.example.bilal.myapp D/OpenGLRenderer﹕ Enabling debug mode 0
10-15 21:57:58.687 10666-10666/com.example.bilal.myapp E/Qmage﹕ onDecode : QmageDecodeFrame 20140421 Rev.6376
10-15 21:57:58.687 10666-10666/com.example.bilal.myapp E/Qmage﹕ This is decoding
10-15 21:57:58.687 10666-10666/com.example.bilal.myapp E/Qmage﹕ decoding stream->hasLength()
10-15 21:57:58.687 10666-10666/com.example.bilal.myapp E/Qmage﹕ onDecode : QmageDecParseHeader call : QM
10-15 21:57:58.687 10666-10666/com.example.bilal.myapp E/Qmage﹕ Qmage parsing for decoding ok
10-15 21:57:58.687 10666-10666/com.example.bilal.myapp E/Qmage﹕ onDecode : QmageHeader.NinePatched 0
10-15 21:57:58.687 10666-10666/com.example.bilal.myapp E/Qmage﹕ onDecode : QmageHeader Height() 32 Width() : 32 sampleSize : 1
10-15 21:57:58.687 10666-10666/com.example.bilal.myapp E/Qmage﹕ Qmage Make Color table
10-15 21:57:58.687 10666-10666/com.example.bilal.myapp E/Qmage﹕ SkBitmap::kIndex8_Config == config && 1 == sampleSize
10-15 21:57:58.687 10666-10666/com.example.bilal.myapp E/Qmage﹕ onDecode : return true QM
10-15 21:57:59.908 10666-10685/com.example.bilal.myapp I/System.out﹕ [{"username":"bilal","title":"bilaltitle","description":"descrip","discount":"10","image1":"IMG_0477. JPG","image2":"IMG_0530.JPG","image3":"IMG_0490.JPG","image4":"IMG_0528.JPG","expiry_duration":"2014- 10-14","date_posted":"2014-10-12 13:38:34"},{"username":"bilal","title":"offer 2","description":"des 2","discount":"20","image1":"","image2":"IMG_0489.JPG","image3":"","image4":"","expiry_duration":"201 4-10-14","date_posted":"2014-10-12 20:24:01"}]
10-15 21:57:59.938 10666-10685/com.example.bilal.myapp E/OfferFetcher﹕ Failed due to: java.lang.NullPointerException: storage == null
我的JSON由网络服务器上的android收到
[
{
"username":"bilal",
"title":"bilaltitle",
"description":"descrip",
"discount":"10",
"image1":"IMG_0477.JPG",
"image2":"IMG_0530.JPG",
"image3":"IMG_0490.JPG",
"image4":"IMG_0528.JPG",
"expiry_duration":"2014-10-14",
"date_posted":"2014-10-12 13:38:34"
}
]
主要活动中的OfferFetcher方法接收JSON并使用GSON
private class OffersFetcher extends AsyncTask<Void, Void, String> {
private static final String TAG = "OfferFetcher";
public static final String SERVER_URL ="http://192.168.0.107/webservice/listoffers.php";
@Override
protected String doInBackground(Void... params) {
try {
StringBuilder builder = new StringBuilder();
// create an HTTP client
HttpClient client = new DefaultHttpClient();
HttpPost httpPost = new HttpPost(SERVER_URL);
// perform the request and check the status code
HttpResponse response = client.execute(httpPost);
StatusLine statusline = response.getStatusLine();
if(statusline.getStatusCode() == 200) {
HttpEntity entity = response.getEntity();
InputStream content = entity.getContent();
try {
// read the server response and attempt to parse it as JSON
BufferedReader b_reader = new BufferedReader(new InputStreamReader(content));
Reader reader = new InputStreamReader(content);
String line;
while((line = b_reader.readLine()) != null) {
builder.append(line);
System.out.println(line);
}
GsonBuilder gsonbuilder = new GsonBuilder();
Gson gson = gsonbuilder.create();
List<Offer> offers;
offers = Arrays.asList(gson.fromJson(reader, Offer[].class));
} catch (Exception ex) {
Log.e(TAG, "Failed due to: " + ex);
failedLoadingOffers1();
}
} else {
Log.e(TAG, "Server responded with status code: " + statusline.getStatusCode());
failedLoadingOffers2();
}
return builder.toString();
} catch (Exception ex) {
Log.e(TAG, "Failed to send HTTP POST request due to: " + ex);
failedLoadingOffers3();
}
return null;
}
}
}
我的商品类（Offer.java）
public class Offer {
// @SerializedName("username")
public String username;
// @SerializedName("title")
public String title;
// @SerializedName("description")
public String description;
@SerializedName("discount")
public String discount;
// @SerializedName("image1")
public String image1;
// @SerializedName("image2")
public String image2;
// @SerializedName("image3")
public String image3;
// @SerializedName("image4")
public String image4;
// @SerializedName("expiry_duration")
public String expiry_duration;
// @SerializedName("date_posted")
public String date_posted;
}
我的PHP代码在这里转发JSON：
$j_response["Offer"] = array();
foreach ($row as $row) {
$offer = array();
$offer['username'] = $row['username'];
$offer['title'] = $row['title'];
$offer['description'] = $row['description'];
$offer['discount'] = $row['discount'];
$offer['image1'] = $row['image1'];
$offer['image2'] = $row['image2'];
$offer['image3'] = $row['image3'];
$offer['image4'] = $row['image4'];
$offer['expiry_duration'] = $row['expiry_duration'];
$offer['date_posted'] = $row['date_posted'];
// update our JSON data
array_push($j_response["Offer"], $offer);
}
$json = json_encode($j_response["Offer"]);
echo $json;
我的代码抛出错误 E / OfferFetcher：由于以下原因无法解析JSON：java.lang.NullPointerException：storage == null
答案 0 :(得分：0)
尝试这样做
Type listType = new TypeToken<ArrayList<Offer>>() {}.getType();
List<Offer> list = new Gson().fromJson(line, listType);
要逐个访问每个对象，您可以执行此操作，
for(Offer offer : list) {
//Do your thing
}
答案 1 :(得分：0)
你的问题就在这一行：
offers = Arrays.asList(gson.fromJson(reader, Offer[].class));
gson.fromJson将第一个参数作为字符串 你发给读者了！试试这个：
offers = Arrays.asList(gson.fromJson(builder, Offer[].class));
答案 2 :(得分：0)
感谢 dandoonian
当我使用＆＃34; builder.toString（）＆＃34;
这项工作：
List<Offer> offers;
offers = Arrays.asList(gson.fromJson(builder.toString(), Offer[].class));
for(Offer offer : offers) {
System.out.println(offer.getUsername());
System.out.println(offer.getTitle());
}