NewProductActivity.java上的運行時錯誤

Question

我需要使用xampp連接並使用php測試我的應用程序。所以我提到這個http://www.androidhive.info/2012/05/how-to-connect-android-with-php-mysql/tutorial。最後我得到一個logcat錯誤。

我不知道如何解決這個問題。對於添加產品，我只需要這樣做。因此我將該鏈接更改爲本地主機。

我指出了以下代碼中的錯誤行。

堆棧跟蹤：

10-21 02:40:54.739: E/Buffer Error(2680): Error converting result java.lang.NullPointerException: lock == null 
10-21 02:40:54.739: E/JSON Parser(2680): Error parsing data org.json.JSONException: End of input at character 0 of 
10-21 02:40:54.739: W/dalvikvm(2680): threadid=12: thread exiting with uncaught exception (group=0xb3a9fba8) 
10-21 02:40:54.849: E/AndroidRuntime(2680): FATAL EXCEPTION: AsyncTask #2 
10-21 02:40:54.849: E/AndroidRuntime(2680): Process: com.steve.test, PID: 2680 
10-21 02:40:54.849: E/AndroidRuntime(2680): java.lang.RuntimeException: An error occured while executing doInBackground() 
10-21 02:40:54.849: E/AndroidRuntime(2680):  at android.os.AsyncTask$3.done(AsyncTask.java:300) 
10-21 02:40:54.849: E/AndroidRuntime(2680):  at java.util.concurrent.FutureTask.finishCompletion(FutureTask.java:355) 
10-21 02:40:54.849: E/AndroidRuntime(2680):  at java.util.concurrent.FutureTask.setException(FutureTask.java:222) 
10-21 02:40:54.849: E/AndroidRuntime(2680):  at java.util.concurrent.FutureTask.run(FutureTask.java:242) 
10-21 02:40:54.849: E/AndroidRuntime(2680):  at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:231) 
10-21 02:40:54.849: E/AndroidRuntime(2680):  at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112) 
10-21 02:40:54.849: E/AndroidRuntime(2680):  at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587) 
10-21 02:40:54.849: E/AndroidRuntime(2680):  at java.lang.Thread.run(Thread.java:841) 
10-21 02:40:54.849: E/AndroidRuntime(2680): Caused by: java.lang.NullPointerException 
10-21 02:40:54.849: E/AndroidRuntime(2680):  at com.steve.test.NewProductActivity$CreateNewProduct.doInBackground(NewProductActivity.java:99) 
10-21 02:40:54.849: E/AndroidRuntime(2680):  at com.steve.test.NewProductActivity$CreateNewProduct.doInBackground(NewProductActivity.java:1) 
10-21 02:40:54.849: E/AndroidRuntime(2680):  at android.os.AsyncTask$2.call(AsyncTask.java:288) 
10-21 02:40:54.849: E/AndroidRuntime(2680):  at java.util.concurrent.FutureTask.run(FutureTask.java:237) 
10-21 02:40:54.849: E/AndroidRuntime(2680):  ... 4 more 
10-21 02:40:55.679: I/Choreographer(2680): Skipped 98 frames! The application may be doing too much work on its main thread. 
10-21 02:40:56.419: I/Choreographer(2680): Skipped 167 frames! The application may be doing too much work on its main thread. 
10-21 02:40:56.599: I/Choreographer(2680): Skipped 46 frames! The application may be doing too much work on its main thread. 
10-21 02:40:56.849: I/Choreographer(2680): Skipped 62 frames! The application may be doing too much work on its main thread. 
10-21 02:40:57.819: D/dalvikvm(2680): GC_FOR_ALLOC freed 210K, 7% free 4050K/4336K, paused 196ms, total 207ms 
10-21 02:40:57.819: E/WindowManager(2680): android.view.WindowLeaked: Activity com.steve.test.NewProductActivity has leaked window com.android.internal.policy.impl.PhoneWindow$DecorView{b3db5a78 V.E..... R.....ID 0,0-329,175} that was originally added here 
10-21 02:40:57.819: E/WindowManager(2680): at android.view.ViewRootImpl.<init>(ViewRootImpl.java:348) 
10-21 02:40:57.819: E/WindowManager(2680): at android.view.WindowManagerGlobal.addView(WindowManagerGlobal.java:248) 
10-21 02:40:57.819: E/WindowManager(2680): at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:69) 
10-21 02:40:57.819: E/WindowManager(2680): at android.app.Dialog.show(Dialog.java:286) 
10-21 02:40:57.819: E/WindowManager(2680): at com.steve.test.NewProductActivity$CreateNewProduct.onPreExecute(NewProductActivity.java:76) 
10-21 02:40:57.819: E/WindowManager(2680): at android.os.AsyncTask.executeOnExecutor(AsyncTask.java:587) 
10-21 02:40:57.819: E/WindowManager(2680): at android.os.AsyncTask.execute(AsyncTask.java:535) 
10-21 02:40:57.819: E/WindowManager(2680): at com.steve.test.NewProductActivity$1.onClick(NewProductActivity.java:56) 
10-21 02:40:57.819: E/WindowManager(2680): at android.view.View.performClick(View.java:4438) 
10-21 02:40:57.819: E/WindowManager(2680): at android.view.View$PerformClick.run(View.java:18422) 
10-21 02:40:57.819: E/WindowManager(2680): at android.os.Handler.handleCallback(Handler.java:733) 
10-21 02:40:57.819: E/WindowManager(2680): at android.os.Handler.dispatchMessage(Handler.java:95) 
10-21 02:40:57.819: E/WindowManager(2680): at android.os.Looper.loop(Looper.java:136) 
10-21 02:40:57.819: E/WindowManager(2680): at android.app.ActivityThread.main(ActivityThread.java:5017) 
10-21 02:40:57.819: E/WindowManager(2680): at java.lang.reflect.Method.invokeNative(Native Method) 
10-21 02:40:57.819: E/WindowManager(2680): at java.lang.reflect.Method.invoke(Method.java:515) 
10-21 02:40:57.819: E/WindowManager(2680): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779) 
10-21 02:40:57.819: E/WindowManager(2680): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595) 
10-21 02:40:57.819: E/WindowManager(2680): at dalvik.system.NativeStart.main(Native Method) 

NewProductActivity.java：

package com.example.test; ------>1st line 

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://localhost/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(); --------->56th line 
      } 
     }); 
    } 

    /** 
    * 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();    ------->76th line 
     } 

     /** 
     * 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 for response 
      Log.d("Create Response", json.toString()); ----->99th line 

      // 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(); 
     } 

    } 
} 

JsonParser.class：

public class JSONParser { 

    static InputStream is = null; 
    static JSONObject jObj = null; 
    static String json = ""; 

    // constructor 
    public JSONParser() { 

    } 

    // function get json from url 
    // by making HTTP POST or GET mehtod 
    public JSONObject makeHttpRequest(String url, String method, 
      List<NameValuePair> params) { 

     // Making HTTP request 
     try { 

      // check for request method 
      if(method.equals("POST")){ 


       Log.d("Steve Response",method); 
       // 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.equals("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; 

    } 
} 

清單：

<?xml version="1.0" encoding="utf-8"?> 
<manifest xmlns:android="http://schemas.android.com/apk/res/android" 
    package="com.example.test" 
    android:versionCode="1" 
    android:versionName="1.0" > 

    <uses-sdk 
     android:minSdkVersion="8" 
     android:targetSdkVersion="19" /> 

    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" /> 
    <uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" /> 
    <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" /> 
    <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" /> 
    <uses-permission android:name="android.permission.ACCESS_WIFI_STATE" /> 
    <uses-permission android:name="android.permission.INTERNET" /> 


    <application 
     android:allowBackup="true" 
     android:icon="@drawable/ic_launcher" 
     android:label="@string/app_name" 
     android:theme="@style/AppTheme" > 
     <activity 
      android:name=".MainScreenActivity" 
      android:label="@string/app_name" > 
      <intent-filter> 
       <action android:name="android.intent.action.MAIN" /> 

       <category android:name="android.intent.category.LAUNCHER" /> 
      </intent-filter> 
     </activity> 
     <activity 
      android:name="com.example.test.NewProductActivity" /> 

     <activity android:name="com.example.test.EditProductActivity" /> 
     <activity android:name="com.example.test.AllProductsActivity" /> 
    </application> 

</manifest> 

Answer 1

更改您的本地主機的IP地址。

private static String url_create_product = "http://127.0.0.1/android_connect/create_product.php"; 

Answer 2

你可以在你的URL中給你的IP而不是本地主機。

192.xxx.xx.xxx:80

EG- 「http://192.xxx.xx.xxx:80/android_connect/create_product.php」

這裏80爲端口號。

由於URL沒有響應或返回任何JSONObject，您正在獲取LogCat錯誤。

還要確保你的'create_product.php'給出了正確的響應。

更好地添加php代碼與問題。

希望它有幫助