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Android 异步任务上的JSON？

android json

Android 异步任务上的JSON？,android,json,android-asynctask,httpclient,Android,Json,Android Asynctask,Httpclient,我正在制作一个Android程序，从互联网上获取JSON数据。JSON文本来自网页的源代码（使用HttpClient），然后解析它并将其显示到TextView。这是对Froyo的工作，但我需要它是对蜂窝和以上的工作任务 因为这个问题，我现在很困惑。我尝试并遵循了一些教程，但这与我想要做的不同。我只是犯了一些错误，我很沮丧。谢谢你的帮助！：） 这是我在MainActivity类上的方法： private void jsonStuffs() { // TODO Auto-ge

我正在制作一个Android程序，从互联网上获取JSON数据。JSON文本来自网页的源代码（使用HttpClient），然后解析它并将其显示到TextView。这是对Froyo的工作，但我需要它是对蜂窝和以上的工作任务

因为这个问题，我现在很困惑。我尝试并遵循了一些教程，但这与我想要做的不同。我只是犯了一些错误，我很沮丧。谢谢你的帮助！：）

这是我在MainActivity类上的方法：

private void jsonStuffs() {
            // TODO Auto-generated method stub
        //JSON PARSER & HOME PAGE TEXTVIEWS

            client = new DefaultHttpClient();
            //new Read().execute("id");
            //http client codes only no parser !!
            GetMethodEx test = new GetMethodEx();
            String returned;
            try {
                returned = test.getInternetData();
            } catch (Exception e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }

            try{
                String jsonStr = test.getInternetData(); //go to GetMethodEx
                    JSONObject obj = new JSONObject(jsonStr);

                    //find temperature on JSON on webpage
                    String temperature = obj.getString("temperature");
                    TextView tvTemp = (TextView)findViewById(R.id.temp);
                    tvTemp.setText(temperature);

            }
            //catch (JSONException e) {
                 // e.printStackTrace();
                //} 
            catch (Exception e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
        }
这是我的GetMethodEx类：

public class GetMethodEx extends Activity {
public String getInternetData() throws Exception{

    BufferedReader in = null;
    String data = null;
    //

    try{
        HttpClient client = new DefaultHttpClient();
        URI website = new URI("http://nhjkv.comuf.com/json_only.php");
        HttpGet request = new HttpGet();
        request.setURI(website);
        HttpResponse response = client.execute(request);
        in = new BufferedReader(new InputStreamReader(response.getEntity().getContent()));
        StringBuffer sb = new StringBuffer("");
        String l = "";
        String nl = System.getProperty("line.separator");
        while ((l = in.readLine()) !=null){
            sb.append(l + nl);
        }
        in.close();
        data = sb.toString();
        return data;
    }finally {
        if (in !=null){
            try{
                in.close();
                return data;
            } catch (Exception e){
                e.printStackTrace();
            }
        }
    }
}
}
将您的连接部分作为一个单独的类，并将下面的代码放入其中

public String getInternetData() throws Exception{

BufferedReader in = null;
String data = null;
//

try{
    HttpClient client = new DefaultHttpClient();
    URI website = new URI("http://nhjkv.comuf.com/json_only.php");
    HttpGet request = new HttpGet();
    request.setURI(website);
    HttpResponse response = client.execute(request);
    in = new BufferedReader(new InputStreamReader(response.getEntity().getContent()));
    StringBuffer sb = new StringBuffer("");
    String l = "";
    String nl = System.getProperty("line.separator");
    while ((l = in.readLine()) !=null){
        sb.append(l + nl);
    }
    in.close();
    data = sb.toString();
    return data;
}finally {
    if (in !=null){
        try{
            in.close();
            return data;
        } catch (Exception e){
            e.printStackTrace();
        }
    }
}
}
使用该类作为您的服务

public class TaskAsync extends AsyncTask<String, String, String> {

private String response = null;

@Override
protected String doInBackground(String... params) {
    response = new ClassName().getInternetData();
    return response;
}

}
将您的连接部分作为一个单独的类，并将下面的代码放入其中

public String getInternetData() throws Exception{

BufferedReader in = null;
String data = null;
//

try{
    HttpClient client = new DefaultHttpClient();
    URI website = new URI("http://nhjkv.comuf.com/json_only.php");
    HttpGet request = new HttpGet();
    request.setURI(website);
    HttpResponse response = client.execute(request);
    in = new BufferedReader(new InputStreamReader(response.getEntity().getContent()));
    StringBuffer sb = new StringBuffer("");
    String l = "";
    String nl = System.getProperty("line.separator");
    while ((l = in.readLine()) !=null){
        sb.append(l + nl);
    }
    in.close();
    data = sb.toString();
    return data;
}finally {
    if (in !=null){
        try{
            in.close();
            return data;
        } catch (Exception e){
            e.printStackTrace();
        }
    }
}
}
使用该类作为您的服务

public class TaskAsync extends AsyncTask<String, String, String> {

private String response = null;

@Override
protected String doInBackground(String... params) {
    response = new ClassName().getInternetData();
    return response;
}

}
将代码更改为使用AsyncTask进行webserivce调用：

private void jsonStuffs() {
            // TODO Auto-generated method stub

            try{

               new InternetDataOperation().execute("");

            }
            //catch (JSONException e) {
                 // e.printStackTrace();
                //} 
            catch (Exception e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
        }

private class InternetDataOperation extends AsyncTask<String, Void, String> {

      @Override
      protected void onPreExecute() {
      }

      @Override
      protected String doInBackground(String... params) {
        client = new DefaultHttpClient();

        GetMethodEx test = new GetMethodEx();
        String jsonStr = test.getInternetData(); //go to GetMethodEx
            return jsonStr;
      }      

      @Override
      protected void onPostExecute(String result) {  
         JSONObject obj = new JSONObject(result);

         //find temperature on JSON on webpage
         String temperature = obj.getString("temperature");
         TextView tvTemp = (TextView)findViewById(R.id.temp);
         tvTemp.setText(temperature);             
      }


}

private void jsonStuffs（）{
//TODO自动生成的方法存根
试一试{
新建InternetDataOperation（）。执行（“”）；
}
//捕获（JSONException e）{
//e.printStackTrace（）；
//} 
捕获（例外e）{
//TODO自动生成的捕捉块
e、 printStackTrace（）；
}
}
私有类InternetDataOperation扩展了异步任务{
@凌驾
受保护的void onPreExecute（）{
}
@凌驾
受保护的字符串doInBackground（字符串…参数）{
client=新的DefaultHttpClient（）；
GetMethodEx测试=新的GetMethodEx（）；
字符串jsonStr=test.getInternetData（）；//转到GetMethodEx
返回jsonStr；
}      
@凌驾
受保护的void onPostExecute（字符串结果）{
JSONObject obj=新JSONObject（结果）；
//在网页上的JSON上查找温度
字符串温度=对象获取字符串（“温度”）；
TextView tvTemp=（TextView）findViewById（R.id.temp）；
tvTemp.setText（温度）；
}
}
将您的代码更改为使用AsyncTask进行webserivce调用：

private void jsonStuffs() {
            // TODO Auto-generated method stub

            try{

               new InternetDataOperation().execute("");

            }
            //catch (JSONException e) {
                 // e.printStackTrace();
                //} 
            catch (Exception e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
        }

private class InternetDataOperation extends AsyncTask<String, Void, String> {

      @Override
      protected void onPreExecute() {
      }

      @Override
      protected String doInBackground(String... params) {
        client = new DefaultHttpClient();

        GetMethodEx test = new GetMethodEx();
        String jsonStr = test.getInternetData(); //go to GetMethodEx
            return jsonStr;
      }      

      @Override
      protected void onPostExecute(String result) {  
         JSONObject obj = new JSONObject(result);

         //find temperature on JSON on webpage
         String temperature = obj.getString("temperature");
         TextView tvTemp = (TextView)findViewById(R.id.temp);
         tvTemp.setText(temperature);             
      }


}

private void jsonStuffs（）{
//TODO自动生成的方法存根
试一试{
新建InternetDataOperation（）。执行（“”）；
}
//捕获（JSONException e）{
//e.printStackTrace（）；
//} 
捕获（例外e）{
//TODO自动生成的捕捉块
e、 printStackTrace（）；
}
}
私有类InternetDataOperation扩展了异步任务{
@凌驾
受保护的void onPreExecute（）{
}
@凌驾
受保护的字符串doInBackground（字符串…参数）{
client=新的DefaultHttpClient（）；
GetMethodEx测试=新的GetMethodEx（）；
字符串jsonStr=test.getInternetData（）；//转到GetMethodEx
返回jsonStr；
}      
@凌驾
受保护的void onPostExecute（字符串结果）{
JSONObject obj=新JSONObject（结果）；
//在网页上的JSON上查找温度
字符串温度=对象获取字符串（“温度”）；
TextView tvTemp=（TextView）findViewById（R.id.temp）；
tvTemp.setText（温度）；
}
}
您不能在doInBackground方法中使用findViewByID和textView。您可以在onPostExecute中使用textView

修改方法“jsonStuffs（）”以便返回字符串。您不必将getInternetData（）放到另一个活动类中

它是MainActivity.class中修改的方法

private String jsonStuffs() {
            // TODO Auto-generated method stub
        //JSON PARSER & HOME PAGE TEXTVIEWS

            client = new DefaultHttpClient();
            //new Read().execute("id");
            //http client codes only no parser !!

            String returned;
            try {
                returned = getInternetData();
            } catch (Exception e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }

            try{
                String jsonStr = test.getInternetData(); //go to GetMethodEx
                    JSONObject obj = new JSONObject(jsonStr);

                    //find temperature on JSON on webpage
                    String temperature = obj.getString("temperature");
                    return temperature

            }
            //catch (JSONException e) {
                 // e.printStackTrace();
                //} 
            catch (Exception e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                    return null;
                }
        }

public String getInternetData() throws Exception{

    BufferedReader in = null;
    String data = null;
    //

    try{
        HttpClient client = new DefaultHttpClient();
        URI website = new URI("http://nhjkv.comuf.com/json_only.php");
        HttpGet request = new HttpGet();
        request.setURI(website);
        HttpResponse response = client.execute(request);
        in = new BufferedReader(new InputStreamReader(response.getEntity().getContent()));
        StringBuffer sb = new StringBuffer("");
        String l = "";
        String nl = System.getProperty("line.separator");
        while ((l = in.readLine()) !=null){
            sb.append(l + nl);
        }
        in.close();
        data = sb.toString();
        return data;
    }finally {
        if (in !=null){
            try{
                in.close();
                return data;
            } catch (Exception e){
                e.printStackTrace();
            }
        }
    }
}
}
然后创建如下异步任务：

public class JsonDownloaderTask extends AsyncTask<Void, Void, String>{


    @Override
    protected Void doInBackground(Void... params) {
        return jsonStuff()
    }

    @Override
    protected void onPostExecute(String result){
        if(result != null){
            //DO YOUR STUFF WITH TEXTVIEW
        }
    }

}

公共类JsonDownloaderTask扩展了异步任务{
@凌驾
受保护的Void doInBackground（Void…参数）{
返回jsonstaff（）
}
@凌驾
受保护的void onPostExecute（字符串结果）{
如果（结果！=null）{
//使用TEXTVIEW完成您的工作
}
}
}
您需要在MainActivity.class中的onCreate（）或onResume（）方法中初始化textView。您不能在doInBackground方法中使用findViewByID和textView。您可以在onPostExecute中使用textView

private String jsonStuffs() {
            // TODO Auto-generated method stub
        //JSON PARSER & HOME PAGE TEXTVIEWS

            client = new DefaultHttpClient();
            //new Read().execute("id");
            //http client codes only no parser !!

            String returned;
            try {
                returned = getInternetData();
            } catch (Exception e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }

            try{
                String jsonStr = test.getInternetData(); //go to GetMethodEx
                    JSONObject obj = new JSONObject(jsonStr);

                    //find temperature on JSON on webpage
                    String temperature = obj.getString("temperature");
                    return temperature

            }
            //catch (JSONException e) {
                 // e.printStackTrace();
                //} 
            catch (Exception e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                    return null;
                }
        }

public String getInternetData() throws Exception{

    BufferedReader in = null;
    String data = null;
    //

    try{
        HttpClient client = new DefaultHttpClient();
        URI website = new URI("http://nhjkv.comuf.com/json_only.php");
        HttpGet request = new HttpGet();
        request.setURI(website);
        HttpResponse response = client.execute(request);
        in = new BufferedReader(new InputStreamReader(response.getEntity().getContent()));
        StringBuffer sb = new StringBuffer("");
        String l = "";
        String nl = System.getProperty("line.separator");
        while ((l = in.readLine()) !=null){
            sb.append(l + nl);
        }
        in.close();
        data = sb.toString();
        return data;
    }finally {
        if (in !=null){
            try{
                in.close();
                return data;
            } catch (Exception e){
                e.printStackTrace();
            }
        }
    }
}
}
修改方法“jsonStuffs（）”以便返回字符串。您不必将getInternetData（）放到另一个活动类中

它是MainActivity.class中修改的方法

private String jsonStuffs() {
            // TODO Auto-generated method stub
        //JSON PARSER & HOME PAGE TEXTVIEWS

            client = new DefaultHttpClient();
            //new Read().execute("id");
            //http client codes only no parser !!

            String returned;
            try {
                returned = getInternetData();
            } catch (Exception e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }

            try{
                String jsonStr = test.getInternetData(); //go to GetMethodEx
                    JSONObject obj = new JSONObject(jsonStr);

                    //find temperature on JSON on webpage
                    String temperature = obj.getString("temperature");
                    return temperature

            }
            //catch (JSONException e) {
                 // e.printStackTrace();
                //} 
            catch (Exception e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                    return null;
                }
        }

public String getInternetData() throws Exception{

    BufferedReader in = null;
    String data = null;
    //

    try{
        HttpClient client = new DefaultHttpClient();
        URI website = new URI("http://nhjkv.comuf.com/json_only.php");
        HttpGet request = new HttpGet();
        request.setURI(website);
        HttpResponse response = client.execute(request);
        in = new BufferedReader(new InputStreamReader(response.getEntity().getContent()));
        StringBuffer sb = new StringBuffer("");
        String l = "";
        String nl = System.getProperty("line.separator");
        while ((l = in.readLine()) !=null){
            sb.append(l + nl);
        }
        in.close();
        data = sb.toString();
        return data;
    }finally {
        if (in !=null){
            try{
                in.close();
                return data;
            } catch (Exception e){
                e.printStackTrace();
            }
        }
    }
}
}
然后创建如下异步任务：

public class JsonDownloaderTask extends AsyncTask<Void, Void, String>{


    @Override
    protected Void doInBackground(Void... params) {
        return jsonStuff()
    }

    @Override
    protected void onPostExecute(String result){
        if(result != null){
            //DO YOUR STUFF WITH TEXTVIEW
        }
    }

}

公共类JsonDownloaderTask扩展了异步任务{
@凌驾
受保护的Void doInBackground（Void…参数）{
返回jsonstaff（）
}
@凌驾
受保护的void onPostExecute（字符串结果）{
如果（结果！=null）{
//使用TEXTVIEW完成您的工作
}
}
}
您需要在MainActivity.class中的onCreate（）或onResume（）方法中初始化textView。例如，我尝试将此代码放在AsyncTask类声明
textView TVTEM=（textView）findViewById（R.id.textView）下面，我得到一个错误
类型loadSomeStuff的findViewById（int）方法未定义。如果我把它放在onCreate方法上，它就不起作用了。它表示无法在onPostExecute（）上解析TVTEM。我了解一点AsyncTask的逻辑，但我不太擅长Java编码。@KkeevvSienaAlejandrino:查看我的答案，将AsyncTask作为活动的内部类，而不是在单独的文件中创建它，如果要在单独的文件中创建它，则将活动上下文传递给它例如，我尝试将此代码放在AsyncTask类声明
TextView tvTemp=（TextView）findViewById（R.id.TextView）下面，我得到一个错误
类型loadSomeStuff的findViewById（int）方法未定义。如果我把它放在onCreate方法上，它就不起作用了。上面说TVTEM不能在onPostExecute（）上解析。我理解AsyncTask的一点逻辑，但我不太擅长Java编码。@KkeevvSienaAlejandrino:看到我的答案了吗

private String jsonStuffs() {
            // TODO Auto-generated method stub
        //JSON PARSER & HOME PAGE TEXTVIEWS

            client = new DefaultHttpClient();
            //new Read().execute("id");
            //http client codes only no parser !!

            String returned;
            try {
                returned = getInternetData();
            } catch (Exception e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }

            try{
                String jsonStr = test.getInternetData(); //go to GetMethodEx
                    JSONObject obj = new JSONObject(jsonStr);

                    //find temperature on JSON on webpage
                    String temperature = obj.getString("temperature");
                    return temperature

            }
            //catch (JSONException e) {
                 // e.printStackTrace();
                //} 
            catch (Exception e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                    return null;
                }
        }

public String getInternetData() throws Exception{

    BufferedReader in = null;
    String data = null;
    //

    try{
        HttpClient client = new DefaultHttpClient();
        URI website = new URI("http://nhjkv.comuf.com/json_only.php");
        HttpGet request = new HttpGet();
        request.setURI(website);
        HttpResponse response = client.execute(request);
        in = new BufferedReader(new InputStreamReader(response.getEntity().getContent()));
        StringBuffer sb = new StringBuffer("");
        String l = "";
        String nl = System.getProperty("line.separator");
        while ((l = in.readLine()) !=null){
            sb.append(l + nl);
        }
        in.close();
        data = sb.toString();
        return data;
    }finally {
        if (in !=null){
            try{
                in.close();
                return data;
            } catch (Exception e){
                e.printStackTrace();
            }
        }
    }
}
}