尝试执行 httppost 时应用程序崩溃

Question

我确实向服务器发送 json 请求并使用 Asyntask 接收它，并且我在 doInBackground 中执行 httppost，如下所示：

HttpResponse httpResponse = httpClient.execute(httpPost);

如果我在等待服务器响应时禁用互联网连接，应用程序将崩溃！问题是我不知道如何处理这个异常（RuntimeException） 当然我会在我的应用程序中处理这些异常：

ConnectionTimeoutException、SocketTimeoutException、NetworkOnMainThreadException、IllegalStateException、IOException、 UnsupportedEncodingException , ClientProtocolException

public class GetJSON extends AsyncTask<String, Void, String> {
String username;
String password;
Context context;
ArrayList<NameValuePair> valuesForServer =new ArrayList<NameValuePair>();
InputStream inputStream = null;
String result = "";


public GetJSON(Context context,String username, String password){
    this.username=username;
    this.password=password;
    this.context=context;
    valuesForServer.add(new BasicNameValuePair("api_key", "teroapi_php_java_1395"));
    valuesForServer.add(new BasicNameValuePair("api_function", "login"));
    valuesForServer.add(new BasicNameValuePair("username",this.username));
    valuesForServer.add(new BasicNameValuePair("password",this.password));
}

@Override
protected String doInBackground(String... urls) {
    try {
        String url=urls[0];
        // Set up HTTP post
        // HttpClient is more then less deprecated. Need to change to URLConnection
        HttpParams httpParameters = new BasicHttpParams();
        HttpConnectionParams.setConnectionTimeout(httpParameters, 10000);
        HttpConnectionParams.setSoTimeout(httpParameters, 10000);
        DefaultHttpClient httpClient = new DefaultHttpClient(httpParameters);

        HttpPost httpPost = new HttpPost(url);
        httpPost.setEntity(new UrlEncodedFormEntity(valuesForServer));
        HttpResponse httpResponse = httpClient.execute(httpPost);
        HttpEntity httpEntity = httpResponse.getEntity();

        StatusLine statusLine = httpResponse.getStatusLine();
        if (statusLine.getStatusCode() == HttpStatus.SC_OK) {
            // Read content & Log
            inputStream = httpEntity.getContent();
        }else{
            return null;
        }

    }catch(ConnectTimeoutException e5){
        Toast.makeText(this.context, e5 + "", Toast.LENGTH_SHORT).show();
        e5.printStackTrace();
        return null;
    }catch (NetworkOnMainThreadException e7){
        Toast.makeText(this.context, e7 + "", Toast.LENGTH_SHORT).show();
        e7.printStackTrace();
        return null;
    } catch(SocketTimeoutException e6){
        Toast.makeText(this.context, e6 + "", Toast.LENGTH_SHORT).show();
        e6.printStackTrace();
        return null;
    } catch (UnsupportedEncodingException e1) {
        Toast.makeText(this.context, e1 + "", Toast.LENGTH_SHORT).show();
        e1.printStackTrace();
        return null;
    } catch (ClientProtocolException e2) {
        Toast.makeText(this.context,e2+"",Toast.LENGTH_SHORT).show();
        e2.printStackTrace();
        return null;
    } catch (IllegalStateException e3) {
        Toast.makeText(this.context,e3+"",Toast.LENGTH_SHORT).show();
        e3.printStackTrace();
        return null;
    } catch (IOException e4) {
        Toast.makeText(this.context,e4+"",Toast.LENGTH_SHORT).show();
        e4.printStackTrace();
        return null;
    }
    // Convert response to string using String Builder
    if(inputStream!=null) {
        try {
            BufferedReader bReader = new BufferedReader(new InputStreamReader(inputStream, "utf-8"), 8);
            StringBuilder sBuilder = new StringBuilder();

            String line = null;
            while ((line = bReader.readLine()) != null) {
                sBuilder.append(line + "\n");
            }

            inputStream.close();
            result = sBuilder.toString();

        } catch (Exception e) {
            Toast.makeText(this.context, e + "", Toast.LENGTH_SHORT).show();
            return null;
        }
    }else {
        return null;
    }
    return result;
}

@Override
public void onPostExecute(String result) {
    if (result != null) {
        MainActivity.analizeData(result);
        if (MainActivity.success.equals("1")) {
            MainActivity.teamsFragment.parseJSON();
            MainActivity.projectsFragment.parseJSON();
            MainActivity.dutiesFragment.parseJSON();
            insertToDb(result);
            try {
                Picasso.with(context)
                        .load("http://teroject.com/upload/avatars/" + MainActivity.information.getString("profilepicurl") + ".jpg")
                        .error(R.drawable.avatar)
                        .into(MainActivity.navProfilePic);
            } catch (JSONException e) {
                Toast.makeText(this.context,e+"",Toast.LENGTH_SHORT).show();
                e.printStackTrace();
            }
        } else if (MainActivity.success.equals("0")) {
            Intent intent = new Intent(context, LoginActivity.class);
            context.startActivity(intent);
            Toast.makeText(context, "لطفا مجددا وارد شوید",
                    Toast.LENGTH_LONG).show();
            ((Activity) context).overridePendingTransition(R.anim.fade_in, R.anim.fade_out);
            ((Activity) context).finish();
            SharedPreferences sharedPreferences = context.getSharedPreferences(TeroSession.TEROPREFS, context.MODE_PRIVATE);
            SharedPreferences.Editor editor = sharedPreferences.edit();
            editor.clear();
            editor.apply();
            deleteFromDb();
        }
    }else {
        Toast.makeText(this.context,"مشکلی در برقراری ارتباط بوجود آمده \n" +
                "لطفا مجددا تلاش کنید",Toast.LENGTH_LONG).show();
    }
}

}

我的日志：

07-24 02:52:27.591 3601-3723/com.teroject.teroject E/AndroidRuntime: FATAL EXCEPTION: AsyncTask #1
                                                                 Process: com.teroject.teroject, PID: 3601
                                                                 java.lang.RuntimeException: An error occured while executing doInBackground()
                                                                     at android.os.AsyncTask$3.done(AsyncTask.java:300)
                                                                     at java.util.concurrent.FutureTask.finishCompletion(FutureTask.java:355)
                                                                     at java.util.concurrent.FutureTask.setException(FutureTask.java:222)
                                                                     at java.util.concurrent.FutureTask.run(FutureTask.java:242)
                                                                     at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:231)
                                                                     at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112)
                                                                     at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587)
                                                                     at java.lang.Thread.run(Thread.java:818)
                                                                  Caused by: java.lang.RuntimeException: Can't create handler inside thread that has not called Looper.prepare()
                                                                     at android.os.Handler.<init>(Handler.java:200)
                                                                     at android.os.Handler.<init>(Handler.java:114)
                                                                     at android.widget.Toast$TN.<init>(Toast.java:353)
                                                                     at android.widget.Toast.<init>(Toast.java:108)
                                                                     at android.widget.Toast.makeText(Toast.java:267)
                                                                     at com.teroject.teroject.GetJSON.doInBackground(GetJSON.java:116)
                                                                     at com.teroject.teroject.GetJSON.doInBackground(GetJSON.java:48)
                                                                     at android.os.AsyncTask$2.call(AsyncTask.java:288)
                                                                     at java.util.concurrent.FutureTask.run(FutureTask.java:237)
                                                                     at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:231) 
                                                                     at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112) 
                                                                     at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587) 
                                                                     at java.lang.Thread.run(Thread.java:818) 

非常感谢您抽出宝贵时间！

Answer 1

这基本上意味着您不能从后台线程进行Toasts（或进行任何其他 UI 修改），而是从 UI 线程。有两种方法可以解决这个问题：

• 将每个Toast 转换为Log.i("some tag", e + "")，因为您使用Toasts 来捕获错误，而Log 是一种更好的方法。这些日志将出现在您的 Android 监视器中（您可以使用 CTRL+F 搜索它们）

• 您也可以使用Activity.runOnUiThread() 并以这种方式发布Toasts，这将是一个更糟糕的选择，因为您并不真正需要它们，您只是将它们用于调试。