我试着制作一个应用程序并将其连接到我的数据库（MySQL wamp）。我已经制作了我的php文件，这是给出错误的NewProductActivity.java文件。我已经做了一个样本。我收到了here
的代码 package com.example.abc.androidhive;
import java.util.ArrayList;
import java.util.List;
import org.apache.http.NameValuePair;
import org.apache.http.message.BasicNameValuePair;
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;
public class NewProductActivity extends Activity {
// Progress Dialog
-private ProgressDialog pDialog;
JSONParser jsonParser = new JSONParser();
EditText inputName;
EditText inputPrice;
EditText inputDesc;
// url to create new product
private static String url_create_product = "http://api.androidhive.info/android_connect/create_product.php";
// JSON Node names
private static final String TAG_SUCCESS = "success";
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.add_product);
// Edit Text
inputName = (EditText) findViewById(R.id.inputName);
inputPrice = (EditText) findViewById(R.id.inputPrice);
inputDesc = (EditText) findViewById(R.id.inputDesc);
// Create button
Button btnCreateProduct = (Button) findViewById(R.id.btnCreateProduct);
// button click event
btnCreateProduct.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
// creating new product in background thread
new CreateNewProduct().execute();
}
});
}
/**
* Background Async Task to Create new product
* */
class CreateNewProduct extends AsyncTask<String, String, String> {
/**
* Before starting background thread Show Progress Dialog
* */
@Override
protected void onPreExecute() {
super.onPreExecute();
pDialog = new ProgressDialog(NewProductActivity.this);
pDialog.setMessage("Creating Product..");
pDialog.setIndeterminate(false);
pDialog.setCancelable(true);
pDialog.show();
}
/**
* Creating product
* */
protected String doInBackground(String... args) {
String name = inputName.getText().toString();
String price = inputPrice.getText().toString();
String description = inputDesc.getText().toString();
// Building Parameters
List<NameValuePair> params = new ArrayList<NameValuePair>();
params.add(new BasicNameValuePair("name", name));
params.add(new BasicNameValuePair("price", price));
params.add(new BasicNameValuePair("description", description));
// getting JSON Object
// Note that create product url accepts POST method
JSONObject json = jsonParser.makeHttpRequest(url_create_product,
"POST", params);
// check log cat fro response
Log.d("Create Response", json.toString());
// check for success tag
try {
int success = json.getInt(TAG_SUCCESS);
if (success == 1) {
// successfully created product
Intent i = new Intent(getApplicationContext(), AllProductsActivity.class);
startActivity(i);
// closing this screen
finish();
} else {
// failed to create product
}
} catch (JSONException e) {
e.printStackTrace();
}
return null;
}
/**
* After completing background task Dismiss the progress dialog
* **/
protected void onPostExecute(String file_url) {
// dismiss the dialog once done
pDialog.dismiss();
}
}
}
产生错误的部分是：
protected String doInBackground(String... args) {
String name = inputName.getText().toString();
String price = inputPrice.getText().toString();
String description = inputDesc.getText().toString();
// Building Parameters
List<NameValuePair> params = new ArrayList<NameValuePair>();
params.add(new BasicNameValuePair("name", name));
params.add(new BasicNameValuePair("price", price));
params.add(new BasicNameValuePair("description", description));
我的Logcat是：
03-03 04:06:10.552 1944-1967/? E/JSON Parser: Error parsing data org.json.JSONException: Value Unknown of type java.lang.String cannot be converted to JSONObject
03-03 04:06:10.552 1944-1967/? W/dalvikvm: threadid=15: thread exiting with uncaught exception (group=0xb17d3678)
03-03 04:06:10.552 1944-1967/? E/AndroidRuntime: FATAL EXCEPTION: AsyncTask #5
03-03 04:06:10.552 1944-1967/? E/AndroidRuntime: java.lang.RuntimeException: An error occured while executing doInBackground()
03-03 04:06:10.552 1944-1967/? E/AndroidRuntime: at android.os.AsyncTask$3.done(AsyncTask.java:299)
03-03 04:06:10.552 1944-1967/? E/AndroidRuntime: at java.util.concurrent.FutureTask.finishCompletion(FutureTask.java:352)
03-03 04:06:10.552 1944-1967/? E/AndroidRuntime: at java.util.concurrent.FutureTask.setException(FutureTask.java:219)
03-03 04:06:10.552 1944-1967/? E/AndroidRuntime: at java.util.concurrent.FutureTask.run(FutureTask.java:239)
03-03 04:06:10.552 1944-1967/? E/AndroidRuntime: at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:230)
03-03 04:06:10.552 1944-1967/? E/AndroidRuntime: at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1080)
03-03 04:06:10.552 1944-1967/? E/AndroidRuntime: at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:573)
03-03 04:06:10.552 1944-1967/? E/AndroidRuntime: at java.lang.Thread.run(Thread.java:841)
03-03 04:06:10.552 1944-1967/? E/AndroidRuntime: Caused by: java.lang.NullPointerException
03-03 04:06:10.552 1944-1967/? E/AndroidRuntime: at com.example.abc.androidhive.NewProductActivity$CreateNewProduct.doInBackground(NewProductActivity.java:100)
03-03 04:06:10.552 1944-1967/? E/AndroidRuntime: at com.example.abc.androidhive.NewProductActivity$CreateNewProduct.doInBackground(NewProductActivity.java:64)
03-03 04:06:10.552 1944-1967/? E/AndroidRuntime: at android.os.AsyncTask$2.call(AsyncTask.java:287)
03-03 04:06:10.552 1944-1967/? E/AndroidRuntime: at java.util.concurrent.FutureTask.run(FutureTask.java:234)
03-03 04:06:10.552 1944-1967/? E/AndroidRuntime: at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:230)
03-03 04:06:10.552 1944-1967/? E/AndroidRuntime: at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1080)
03-03 04:06:10.552 1944-1967/? E/AndroidRuntime: at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:573)
03-03 04:06:10.552 1944-1967/? E/AndroidRuntime: at java.lang.Thread.run(Thread.java:841)
请告诉我可能的纠正措施。
答案 0 :(得分：0)
问题是你的服务器返回它不是一个有效的json。你应该检查一下这个电话的响应是什么
我尝试使用休闲参数（name = a，price = b，description = c）并且服务器返回
未知数据库'download_androidhive'
这是一个字符串，99％是您发出问题的原因。
答案 1 :(得分：0)
这不是因为这个课程，这是JSONParser课程中出现这些行的错误
// 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;
我想建议你，它根本不是一个JsonObject。所以，试着替换这一行
jObj = new JSONObject(json);
<强>与
JSONArray jsonArray = new JSONArray(json);
JSONObject jObj = jsonArray.getJSONObject(0);