我正在尝试根据条形码编号从mysql数据库中获取产品。我检查了他们正在使用的PHP代码,但在android方面我犯了一个错误。 这是我的GetProductDetails类(我认为这部分没问题);
import java.util.ArrayList;
import java.util.List;
import org.apache.http.NameValuePair;
import org.apache.http.message.BasicNameValuePair;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import android.app.Activity;
import android.app.ProgressDialog;
import android.content.Intent;
import android.os.AsyncTask;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;
public class Query_product extends Activity {
EditText txtId, txtName, txtPrice, txtDesc;
Button btnSave, btnDelete;
String ID = "";
String pid;
// Progress Dialog
private ProgressDialog pDialog;
// Creating JSON Parser object
JSONParser jsonParser = new JSONParser();
// url to get all products list
private static final String url_product_details = "http://10.0.2.2/ssa/get_product_details.php";
private static final String url_update_product = "http://10.0.2.2/ssa/update_product.php";
private static final String url_delete_product = "http://10.0.2.2/ssa/delete_product.php";
// JSON Node names
private static final String TAG_SUCCESS = "success";
private static final String TAG_PRODUCT = "product";
private static final String TAG_PID = "barcode";
private static final String TAG_NAME = "name";
private static final String TAG_PRICE = "price";
private static final String TAG_DESCRIPTION = "description";
// products JSONArray
JSONArray products = null;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.query_prod);
btnSave = (Button) findViewById(R.id.btnSave);
btnDelete = (Button) findViewById(R.id.btnDelete);
ID += " " + getIntent().getExtras().getString(Constants.ID);
pid = ID;
new GetProductDetails().execute();
btnSave.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View arg0) {
// starting background task to update product
new SaveProductDetails().execute();
}
});
// Delete button click event
btnDelete.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View arg0) {
// deleting product in background thread
new DeleteProduct().execute();
}
});
}
class GetProductDetails extends AsyncTask<String, String, String> {
@Override
protected void onPreExecute() {
super.onPreExecute();
pDialog = new ProgressDialog(Query_product.this);
pDialog.setMessage("Loading product details. Please wait...");
pDialog.setIndeterminate(false);
pDialog.setCancelable(true);
pDialog.show();
}
protected String doInBackground(String... params) {
// updating UI from Background Thread
runOnUiThread(new Runnable() {
public void run() {
// Check for success tag
int success;
try {
// Building Parameters
List<NameValuePair> params = new ArrayList<NameValuePair>();
params.add(new BasicNameValuePair(TAG_PID, pid));
// getting product details by making HTTP request
// Note that product details url will use GET request
JSONObject json = jsonParser.makeHttpRequest(
url_product_details, "GET", params);
// check your log for json response
Log.d("Single Product Details", json.toString());
// json success tag
success = json.getInt(TAG_SUCCESS);
if (success == 1) {
// successfully received product details
JSONArray productObj = json
.getJSONArray(TAG_PRODUCT); // JSON Array
// get first product object from JSON Array
JSONObject product = productObj.getJSONObject(0);
// product with this pid found
// Edit Text
txtId = (EditText) findViewById(R.id.inputId);
txtName = (EditText) findViewById(R.id.inputName);
txtPrice = (EditText) findViewById(R.id.inputPrice);
txtDesc = (EditText) findViewById(R.id.inputDesc);
// display product data in EditText
txtId.setText(product.getString(TAG_PID));
txtName.setText(product.getString(TAG_NAME));
txtPrice.setText(product.getString(TAG_PRICE));
txtDesc.setText(product.getString(TAG_DESCRIPTION));
}
else
{
String error = "Not found!";
Toast.makeText(Query_product.this, error, Toast.LENGTH_LONG).show();
}
} catch (JSONException e) {
e.printStackTrace();
}
}
});
return null;
}
这里是makeHttpRequest类;
public JSONObject makeHttpRequest (String url, String method,
List<NameValuePair> params) {
// Making HTTP request
try {
// check for request method
if(method == "POST"){
// request method is POST
// defaultHttpClient
DefaultHttpClient httpClient = new DefaultHttpClient();
HttpPost httpPost = new HttpPost(url);
httpPost.setEntity(new UrlEncodedFormEntity(params));
HttpResponse httpResponse = httpClient.execute(httpPost);
HttpEntity httpEntity = httpResponse.getEntity();
is = httpEntity.getContent();
}else if(method == "GET"){
// request method is GET
DefaultHttpClient httpClient = new DefaultHttpClient();
String paramString = URLEncodedUtils.format(params, "utf-8");
url += "?" + paramString;
HttpGet httpGet = new HttpGet(url);
HttpResponse httpResponse = httpClient.execute(httpGet);
HttpEntity httpEntity = httpResponse.getEntity();
is = httpEntity.getContent();
}
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
} catch (ClientProtocolException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
try {
BufferedReader reader = new BufferedReader(new InputStreamReader(
is, "iso-8859-1"), 8);
StringBuilder sb = new StringBuilder();
String line = null;
while ((line = reader.readLine()) != null) {
sb.append(line + "\n");
}
is.close();
json = sb.toString();
} catch (Exception e) {
Log.e("Buffer Error", "Error converting result " + e.toString());
}
// try parse the string to a JSON object
try {
jObj = new JSONObject(json);
} catch (JSONException e) {
Log.e("JSON Parser", "Error parsing data " + e.toString());
}
// return JSON String
return jObj;
}
}
我无法解决问题。程序一直运行到这一行;
HttpResponse httpResponse = httpClient.execute(httpGet);
Logcat错误;
12-14 18:05:30.994:E / AndroidRuntime(986):致命异常:主要 12-14 18:05:30.994:E / AndroidRuntime(986):android.os.NetworkOnMainThreadException 12-14 18:05:30.994:E / AndroidRuntime(986):在android.os.StrictMode $ AndroidBlockGuardPolicy.onNetwork(StrictMode.java:1117) 12-14 18:05:30.994:E / AndroidRuntime(986):at libcore.io.BlockGuardOs.connect(BlockGuardOs.java:84) 12-14 18:05:30.994:E / AndroidRuntime(986):at libcore.io.IoBridge.connectErrno(IoBridge.java:127) 12-14 18:05:30.994:E / AndroidRuntime(986):at libcore.io.IoBridge.connect(IoBridge.java:112) 12-14 18:05:30.994:E / AndroidRuntime(986):at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:192) 12-14 18:05:30.994:E / AndroidRuntime(986):at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:459) 12-14 18:05:30.994:E / AndroidRuntime(986):at java.net.Socket.connect(Socket.java:842) 12-14 18:05:30.994:E / AndroidRuntime(986):at org.apache.http.conn.scheme.PlainSocketFactory.connectSocket(PlainSocketFactory.java:119) 12-14 18:05:30.994:E / AndroidRuntime(986):at org.apache.http.impl.conn.DefaultClientConnectionOperator.openConnection(DefaultClientConnectionOperator.java:144) 12-14 18:05:30.994:E / AndroidRuntime(986):at org.apache.http.impl.conn.AbstractPoolEntry.open(AbstractPoolEntry.java:164) 12-14 18:05:30.994:E / AndroidRuntime(986):at org.apache.http.impl.conn.AbstractPooledConnAdapter.open(AbstractPooledConnAdapter.java:119) 12-14 18:05:30.994:E / AndroidRuntime(986):at org.apache.http.impl.client.DefaultRequestDirector.execute(DefaultRequestDirector.java:360) 12-14 18:05:30.994:E / AndroidRuntime(986):at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:555) 12-14 18:05:30.994:E / AndroidRuntime(986):at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:487) 12-14 18:05:30.994:E / AndroidRuntime(986):at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:465) 12-14 18:05:30.994:E / AndroidRuntime(986):at com.example.ssa.JSONParser.makeHttpRequest(JSONParser.java:66) 12-14 18:05:30.994:E / AndroidRuntime(986):at com.example.ssa.Query_product $ GetProductDetails $ 1.run(Query_product.java:134) 12-14 18:05:30.994:E / AndroidRuntime(986):在android.os.Handler.handleCallback(Handler.java:725) 12-14 18:05:30.994:E / AndroidRuntime(986):在android.os.Handler.dispatchMessage(Handler.java:92) 12-14 18:05:30.994:E / AndroidRuntime(986):在android.os.Looper.loop(Looper.java:137) 12-14 18:05:30.994:E / AndroidRuntime(986):在android.app.ActivityThread.main(ActivityThread.java:5041) 12-14 18:05:30.994:E / AndroidRuntime(986):at java.lang.reflect.Method.invokeNative(Native Method) 12-14 18:05:30.994:E / AndroidRuntime(986):at java.lang.reflect.Method.invoke(Method.java:511) 12-14 18:05:30.994:E / AndroidRuntime(986):at com.android.internal.os.ZygoteInit $ MethodAndArgsCaller.run(ZygoteInit.java:793) 12-14 18:05:30.994:E / AndroidRuntime(986):at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560) 12-14 18:05:30.994:E / AndroidRuntime(986):at dalvik.system.NativeStart.main(Native Method) 12-14 18:10:31.483:I / Process(986):发送信号。 PID:986 SIG:9 12-14 18:10:33.372:D / gralloc_goldfish(1025):未检测到GPU仿真的仿真器。
答案 0 :(得分:3)
您无法在主线程上执行网络任务,因为如果网络任务需要很长时间,它可能会阻止您的应用程序。您需要使用AsyncTask
在后台运行此类任务。
答案 1 :(得分:1)
尝试在setContentView()
下方的主要活动中使用以下代码,以避免networkOnmainThread
例外..
if (android.os.Build.VERSION.SDK_INT > 9) {
StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder().permitAll().build();
StrictMode.setThreadPolicy(policy);
}
答案 2 :(得分:0)
看起来错误不是json。 您正试图从主线程中调用一个不允许从android 4.0中获取的URL 尝试使用AsynTask或从辅助线程调用url。