java - 问题，如何修复android中从URL获取JSON？，Onclicklistener？异步任务？执行后？

Question

/////////////////////////////第一次尝试，第一次尝试://///////////////////////

大家好，我是第一次制作 Android 应用程序，只是测试一下它是否有效，所以我的问题是这样的:我在 iOS 中创建了一个应用程序，将某人的参数发送到一个 URL，我返回一个 Json 字符串值，只有一个值链，我的 iOS 代码是:

 URL = [[self replaceRealURL:[self GetUrlForRegisterWithName:NameValue Mail:MailValue Language:Language Country:Country]]stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding];
    NSURL *Filtro = [NSURL URLWithString:URL];

    NSLog(@"%@",URL);


    dispatch_async(HILO_REGISTRO, ^{

        NSData *data = [[NSData alloc] initWithContentsOfURL:Filtro];

        [self performSelectorOnMainThread:@selector(fetchedData:)withObject:data waitUntilDone:YES];
        //[self fetchedData:data];
    });

- (void)fetchedData:(NSData *)responseData {

NSError* error;

NSDictionary* json = [NSJSONSerialization

                      JSONObjectWithData:responseData

                      options:kNilOptions

                      error:&error];


NSString *CodigoDeError = [json objectForKey:@"error"];

if ([CodigoDeError isEqualToString:@"1"])
{
    // Existe
    NSLog(@"%@",json);
    [progressUpload hide:YES];
    UIAlertView *YaExiste = [[UIAlertView alloc] initWithTitle:@"Usuario registrado"
                                                       message:@"Este usuario ya ha sido registrado"
                                                      delegate:self
                                             cancelButtonTitle:@"OK"
                                             otherButtonTitles:nil];
    [YaExiste show];
}
else if ([CodigoDeError isEqualToString:@"2"])
{
    // Argumentos Invalidos
    NSLog(@"%@",json);
    [progressUpload hide:YES];
    UIAlertView *NoValidos = [[UIAlertView alloc] initWithTitle:@"Su email no es válido"
                                                        message:@"Por favor ingrese un email válido"
                                                       delegate:self
                                              cancelButtonTitle:@"OK"
                                              otherButtonTitles:nil];
    [NoValidos show];
}    }
-(NSString*)GetUrlForRegisterWithName:(NSString*)name Mail:(NSString*)mail Language:(NSString*)language Country:(NSString*)country
{
NSString *PushToURL = [NSString stringWithFormat:@"http://MIPAGINA.com/PRUEBA/regiphone/?name=%@&email=%@&lang=%@&country=%@",name,mail,language,country];
return PushToURL;
 }

它工作得很好，但在 Android 中我在我的 Activity 中使用此代码:

textNombre = URLEncoder.encode(textNombre,"utf-8");
                    textMail = URLEncoder.encode(textMail,"utf-8");
                    Idioma = URLEncoder.encode(Idioma,"utf-8");
                    Pais = URLEncoder.encode(Pais,"utf-8");


                    JSONUrl = "http://MIPAGINA.com/PRUEBA/regiphone/?name="+textNombre+"&email="+textMail+"&lang="+Idioma+"&country="+Pais;

                /*  Toast msg = Toast.makeText(getBaseContext(),
                             JSONUrl, Toast.LENGTH_LONG);
                            msg.show();*/
                    JSONParser jParser = new JSONParser();

                    // getting JSON string from URL
                    JSONObject json = jParser.getJSONFromUrl(JSONUrl);

                    Toast msg = Toast.makeText(getBaseContext(),
                             JSONUrl, Toast.LENGTH_LONG);
                            msg.show();

                            try {


                                String CodigoDeError = jsonobject.getString("error");

                                if(CodigoDeError.equals("1"))
                                {
                                    String Mensaje = "Este usuario ya ha sido registrado";
                                    Toast msge = Toast.makeText(getBaseContext(),
                                             Mensaje, Toast.LENGTH_LONG);
                                            msge.show();
                                }
                                else if (CodigoDeError.equals("2")) 
                                {
                                    String Mensaje = "Por favor ingrese un email válido";
                                    Toast msge = Toast.makeText(getBaseContext(),
                                             Mensaje, Toast.LENGTH_LONG);
                                            msge.show();
                                }
                                else
                                {
                                    CodigoDeError = jsonobject.getString("id");
                                    String NSLOG = "Nslog";
                                    Log.i(NSLOG, CodigoDeError.toString());
                                    String Mensaje = "Muchas gracias por registrarse";
                                    Toast msge = Toast.makeText(getBaseContext(),
                                             Mensaje, Toast.LENGTH_LONG);
                                            msge.show();
                                }


                            } catch (JSONException e) {
                                Log.e("Error", e.getMessage());
                                e.printStackTrace();
                            }

我不知道我是否做错了什么，或者应该从我创建的 url 接收 json，两者的代码都在 Ibaction 和 OnClickListener 中运行，但是出了什么问题？应用程序崩溃并显示:

Logcat 向我展示了这个，是 URL 吗？来自http请求？:

请从 Url 获取简单的 Json 来提供帮助吗？我所使用的 Java Android Eclipse 代码位于本教程中的 android hive 中:http://www.androidhive.info/2012/01/android-json-parsing-tutorial/

               //------------------------------------------//
               //           THANKS StackOverFlow           //
               //          GRETTINGS FROM BOLIVIA          //
               //             ROCK ON!!!! n_n'             //
               //------------------------------------------//

//////////////////////////////编辑////////////////////////////////////

/////////////////////////////第二次尝试，第二次尝试://///////////////////////

好吧，有些 Commrads 推荐我使用 AsyncTask 并更改我的代码，如下:

  registrarseBtn.setOnClickListener(new OnClickListener()
    {
    public void onClick(View v)
    {
        new Registration().execute();
    }

  class Registration extends AsyncTask<Void,String, JSONObject> {

        @Override
        protected void onPreExecute() {
            super.onPreExecute();
            // Create a progressdialog
            mProgressDialog = new ProgressDialog(MainActivity.this);
            // Set progressdialog title
            mProgressDialog.setTitle("Auto Venta");
            // Set progressdialog message
            mProgressDialog.setMessage("Registrando...");
            mProgressDialog.setIndeterminate(false);
            // Show progressdialog
            mProgressDialog.show();
        }


        @Override
        protected JSONObject doInBackground(Void... params) 
        {
            String textNombre;
            String textMail;
            String Idioma;
            String Pais;
            //-------Validando Nombre -----//
             // String textNombre;

              if (nombreTextField.getText().toString().length() <= 0) 
              {
                nombreTextField.setError("Accept Alphabets Only.");
                textNombre = null;
            } else if (!nombreTextField.getText().toString().matches("[a-zA-Z ]+")) 
            {
                nombreTextField.setError("Accept Alphabets Only.");
                textNombre = null;
            } else 
            {
                textNombre=nombreTextField.getText().toString();
            }
              //-------- Validando eMail --------//

              //String textMail;
              if (mailTextField.getText().toString() == null) {
                mailTextField.setError("Invalid Email Address");
                textMail = null;
            } else if (isEmailValid(mailTextField.getText().toString()) == false) {
                mailTextField.setError("Invalid Email Address");
                textMail = null;
            } else {
                textMail = mailTextField.getText().toString();
            }

            //-------Armando Cadena para URL------// 


              Idioma = Locale.getDefault().getLanguage();
              TelephonyManager tm = (TelephonyManager)getSystemService(Context.TELEPHONY_SERVICE);
              Pais = tm.getSimCountryIso();

                        try {

                            textNombre = URLEncoder.encode(textNombre,"utf-8");
                            textMail = URLEncoder.encode(textMail,"utf-8");
                            Idioma = URLEncoder.encode(Idioma,"utf-8");
                            Pais = URLEncoder.encode(Pais,"utf-8");


                            JSONUrl = "http://MIPAGINA.com/PRUEBA/websites/regiphone/?name="+textNombre+"&email="+textMail+"&lang="+Idioma+"&country="+Pais;

                        } catch (UnsupportedEncodingException e1) {
                            // TODO Auto-generated catch block
                            e1.printStackTrace();
                        }

            JSONParser jParser = new JSONParser();

             // getting JSON string from URL
             JSONObject json = jParser.getJSONFromUrl(JSONUrl);

             return json;
        }
        protected void onPostExecute(JSONObject json) 
        {

            Toast msg = Toast.makeText(getBaseContext(),
                    JSONUrl, Toast.LENGTH_LONG);
                   msg.show();

                   try {


                       String CodigoDeError = jsonobject.getString("error");

                       if(CodigoDeError.equals("1"))
                       {
                           String Mensaje = "Este usuario ya ha sido registrado";
                           Toast msge = Toast.makeText(getBaseContext(),
                                    Mensaje, Toast.LENGTH_LONG);
                                   msge.show();
                       }
                       else if (CodigoDeError.equals("2")) 
                       {
                           String Mensaje = "Por favor ingrese un email válido";
                           Toast msge = Toast.makeText(getBaseContext(),
                                    Mensaje, Toast.LENGTH_LONG);
                                   msge.show();
                       }
                       else
                       {
                           CodigoDeError = jsonobject.getString("id");
                           String NSLOG = "Nslog";
                           Log.i(NSLOG, CodigoDeError.toString());
                           String Mensaje = "Muchas gracias por registrarse";
                           Toast msge = Toast.makeText(getBaseContext(),
                                    Mensaje, Toast.LENGTH_LONG);
                                   msge.show();
                       }


                   } catch (JSONException e) {
                       Log.e("Error", e.getMessage());
                       e.printStackTrace();
                   }
        }
    }

    boolean isEmailValid(CharSequence email)
    {
        return android.util.Patterns.EMAIL_ADDRESS.matcher(email).matches();
    } 
     });



}

问题与应用程序崩溃相同，我不知道出了什么问题，如果我要更改代码中的某些内容？ logcat 告诉我这个？

 11-13 09:37:42.840: E/AndroidRuntime(1200): FATAL EXCEPTION: AsyncTask #1
11-13 09:37:42.840: E/AndroidRuntime(1200): Process: com.example.prototipo, PID: 1200
11-13 09:37:42.840: E/AndroidRuntime(1200): java.lang.RuntimeException: An error occured while executing doInBackground()
11-13 09:37:42.840: E/AndroidRuntime(1200):     at android.os.AsyncTask$3.done(AsyncTask.java:300)
11-13 09:37:42.840: E/AndroidRuntime(1200):     at java.util.concurrent.FutureTask.finishCompletion(FutureTask.java:355)
11-13 09:37:42.840: E/AndroidRuntime(1200):     at java.util.concurrent.FutureTask.setException(FutureTask.java:222)
11-13 09:37:42.840: E/AndroidRuntime(1200):     at java.util.concurrent.FutureTask.run(FutureTask.java:242)
11-13 09:37:42.840: E/AndroidRuntime(1200):     at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:231)
11-13 09:37:42.840: E/AndroidRuntime(1200):     at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112)
11-13 09:37:42.840: E/AndroidRuntime(1200):     at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587)
11-13 09:37:42.840: E/AndroidRuntime(1200):     at java.lang.Thread.run(Thread.java:841)
11-13 09:37:42.840: E/AndroidRuntime(1200): Caused by: java.lang.SecurityException: Permission denied (missing INTERNET permission?)
11-13 09:37:42.840: E/AndroidRuntime(1200):     at java.net.InetAddress.lookupHostByName(InetAddress.java:418)
11-13 09:37:42.840: E/AndroidRuntime(1200):     at java.net.InetAddress.getAllByNameImpl(InetAddress.java:236)
11-13 09:37:42.840: E/AndroidRuntime(1200):     at java.net.InetAddress.getAllByName(InetAddress.java:214)
11-13 09:37:42.840: E/AndroidRuntime(1200):     at org.apache.http.impl.conn.DefaultClientConnectionOperator.openConnection(DefaultClientConnectionOperator.java:137)
11-13 09:37:42.840: E/AndroidRuntime(1200):     at org.apache.http.impl.conn.AbstractPoolEntry.open(AbstractPoolEntry.java:164)
11-13 09:37:42.840: E/AndroidRuntime(1200):     at org.apache.http.impl.conn.AbstractPooledConnAdapter.open(AbstractPooledConnAdapter.java:119)
11-13 09:37:42.840: E/AndroidRuntime(1200):     at org.apache.http.impl.client.DefaultRequestDirector.execute(DefaultRequestDirector.java:360)
11-13 09:37:42.840: E/AndroidRuntime(1200):     at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:555)
11-13 09:37:42.840: E/AndroidRuntime(1200):     at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:487)
11-13 09:37:42.840: E/AndroidRuntime(1200):     at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:465)
11-13 09:37:42.840: E/AndroidRuntime(1200):     at com.example.prototipo.JSONParser.getJSONFromUrl(JSONParser.java:38)
11-13 09:37:42.840: E/AndroidRuntime(1200):     at com.example.prototipo.MainActivity$1$Registration.doInBackground(MainActivity.java:153)
11-13 09:37:42.840: E/AndroidRuntime(1200):     at com.example.prototipo.MainActivity$1$Registration.doInBackground(MainActivity.java:1)
11-13 09:37:42.840: E/AndroidRuntime(1200):     at android.os.AsyncTask$2.call(AsyncTask.java:288)
11-13 09:37:42.840: E/AndroidRuntime(1200):     at java.util.concurrent.FutureTask.run(FutureTask.java:237)
11-13 09:37:42.840: E/AndroidRuntime(1200):     ... 4 more
11-13 09:37:42.840: E/AndroidRuntime(1200): Caused by: libcore.io.GaiException: getaddrinfo failed: EAI_NODATA (No address associated with hostname)
11-13 09:37:42.840: E/AndroidRuntime(1200):     at libcore.io.Posix.getaddrinfo(Native Method)
11-13 09:37:42.840: E/AndroidRuntime(1200):     at libcore.io.ForwardingOs.getaddrinfo(ForwardingOs.java:61)
11-13 09:37:42.840: E/AndroidRuntime(1200):     at java.net.InetAddress.lookupHostByName(InetAddress.java:405)
11-13 09:37:42.840: E/AndroidRuntime(1200):     ... 18 more
11-13 09:37:42.840: E/AndroidRuntime(1200): Caused by: libcore.io.ErrnoException: getaddrinfo failed: EACCES (Permission denied)
11-13 09:37:42.840: E/AndroidRuntime(1200):     ... 21 more
11-13 09:37:45.580: E/WindowManager(1200): android.view.WindowLeaked: Activity com.example.prototipo.MainActivity has leaked window com.android.internal.policy.impl.PhoneWindow$DecorView{b4150488 V.E..... R......D 0,0-480,243} that was originally added here
11-13 09:37:45.580: E/WindowManager(1200):  at android.view.ViewRootImpl.<init>(ViewRootImpl.java:346)
11-13 09:37:45.580: E/WindowManager(1200):  at android.view.WindowManagerGlobal.addView(WindowManagerGlobal.java:248)
11-13 09:37:45.580: E/WindowManager(1200):  at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:69)
11-13 09:37:45.580: E/WindowManager(1200):  at android.app.Dialog.show(Dialog.java:286)
11-13 09:37:45.580: E/WindowManager(1200):  at com.example.prototipo.MainActivity$1$Registration.onPreExecute(MainActivity.java:89)
11-13 09:37:45.580: E/WindowManager(1200):  at android.os.AsyncTask.executeOnExecutor(AsyncTask.java:587)
11-13 09:37:45.580: E/WindowManager(1200):  at android.os.AsyncTask.execute(AsyncTask.java:535)
11-13 09:37:45.580: E/WindowManager(1200):  at com.example.prototipo.MainActivity$1.onClick(MainActivity.java:73)
11-13 09:37:45.580: E/WindowManager(1200):  at android.view.View.performClick(View.java:4424)
11-13 09:37:45.580: E/WindowManager(1200):  at android.view.View$PerformClick.run(View.java:18383)
11-13 09:37:45.580: E/WindowManager(1200):  at android.os.Handler.handleCallback(Handler.java:733)
11-13 09:37:45.580: E/WindowManager(1200):  at android.os.Handler.dispatchMessage(Handler.java:95)
11-13 09:37:45.580: E/WindowManager(1200):  at android.os.Looper.loop(Looper.java:137)
11-13 09:37:45.580: E/WindowManager(1200):  at android.app.ActivityThread.main(ActivityThread.java:4998)
11-13 09:37:45.580: E/WindowManager(1200):  at java.lang.reflect.Method.invokeNative(Native Method)
11-13 09:37:45.580: E/WindowManager(1200):  at java.lang.reflect.Method.invoke(Method.java:515)
11-13 09:37:45.580: E/WindowManager(1200):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:777)
11-13 09:37:45.580: E/WindowManager(1200):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:593)
11-13 09:37:45.580: E/WindowManager(1200):  at dalvik.system.NativeStart.main(Native Method)
11-13 09:37:46.390: I/Process(1200): Sending signal. PID: 1200 SIG: 9

请帮忙!

/////////////////////////////第三次尝试，第三次尝试://///////////////////////

谢谢:

@popovitsj, @Phil, @printemps, @aegean, @Wang, 

但是我添加了

 <uses-permission android:name="android.permission.INTERNET" /> 

到我的manifest.xml 文件，应用程序也崩溃了，logcat 现在向我显示:

11-13 10:06:03.450: E/AndroidRuntime(1256): FATAL EXCEPTION: main
11-13 10:06:03.450: E/AndroidRuntime(1256): Process: com.example.prototipo, PID: 1256
11-13 10:06:03.450: E/AndroidRuntime(1256): java.lang.NullPointerException
11-13 10:06:03.450: E/AndroidRuntime(1256):     at com.example.prototipo.MainActivity$1$Registration.onPostExecute(MainActivity.java:167)
11-13 10:06:03.450: E/AndroidRuntime(1256):     at com.example.prototipo.MainActivity$1$Registration.onPostExecute(MainActivity.java:1)
11-13 10:06:03.450: E/AndroidRuntime(1256):     at android.os.AsyncTask.finish(AsyncTask.java:632)
11-13 10:06:03.450: E/AndroidRuntime(1256):     at android.os.AsyncTask.access$600(AsyncTask.java:177)
11-13 10:06:03.450: E/AndroidRuntime(1256):     at android.os.AsyncTask$InternalHandler.handleMessage(AsyncTask.java:645)
11-13 10:06:03.450: E/AndroidRuntime(1256):     at android.os.Handler.dispatchMessage(Handler.java:102)
11-13 10:06:03.450: E/AndroidRuntime(1256):     at android.os.Looper.loop(Looper.java:137)
11-13 10:06:03.450: E/AndroidRuntime(1256):     at android.app.ActivityThread.main(ActivityThread.java:4998)
11-13 10:06:03.450: E/AndroidRuntime(1256):     at java.lang.reflect.Method.invokeNative(Native Method)
11-13 10:06:03.450: E/AndroidRuntime(1256):     at java.lang.reflect.Method.invoke(Method.java:515)
11-13 10:06:03.450: E/AndroidRuntime(1256):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:777)
11-13 10:06:03.450: E/AndroidRuntime(1256):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:593)
11-13 10:06:03.450: E/AndroidRuntime(1256):     at dalvik.system.NativeStart.main(Native Method)
11-13 10:06:06.000: I/Process(1256): Sending signal. PID: 1256 SIG: 9

好的，寄存器终于运行了，所以，现在的问题出在 onPostExecute 中，问题是当我在 URL 中插入数据时，它返回错误代码或只是 JSON 中记录的 id，如下所示:

{
  error:1
}

或

{
 id:123
}

但是在我的 asyncTask 中出了什么问题？？？请帮助大家!!!

Answer 1

Logcat 应该显示一些内容。尝试重新连接设备并检查您是否在 DDMS 视角中选择了正确的设备。

//编辑

您正在尝试在 UI 线程上运行网络调用。尝试使用 AsyncTask 进行后台调用。 AsyncTask

类似这样的事情:

new AsyncTask<JSONURL, Integer, JSONObject> {
 protected JSONObject doInBackground(JSONURL... urls) {
     JSONParser jParser = new JSONParser();

     // getting JSON string from URL
     JSONObject json = jParser.getJSONFromUrl(JSONUrl);

     return json;
 }

 protected void onPostExecute(JSONObject json) {
     Toast msg = Toast.makeText(getBaseContext(),
                         JSONUrl, Toast.LENGTH_LONG);
                        msg.show();

                        try {


                            String CodigoDeError = jsonobject.getString("error");

                            if(CodigoDeError.equals("1"))
                            {
                                String Mensaje = "Este usuario ya ha sido registrado";
                                Toast msge = Toast.makeText(getBaseContext(),
                                         Mensaje, Toast.LENGTH_LONG);
                                        msge.show();
                            }
                            else if (CodigoDeError.equals("2")) 
                            {
                                String Mensaje = "Por favor ingrese un email válido";
                                Toast msge = Toast.makeText(getBaseContext(),
                                         Mensaje, Toast.LENGTH_LONG);
                                        msge.show();
                            }
                            else
                            {
                                CodigoDeError = jsonobject.getString("id");
                                String NSLOG = "Nslog";
                                Log.i(NSLOG, CodigoDeError.toString());
                                String Mensaje = "Muchas gracias por registrarse";
                                Toast msge = Toast.makeText(getBaseContext(),
                                         Mensaje, Toast.LENGTH_LONG);
                                        msge.show();
                            }


                        } catch (JSONException e) {
                            Log.e("Error", e.getMessage());
                            e.printStackTrace();
                        }
        }
 }.execute(JSONURL);

这只是一个例子。代码中可能存在一些错误。