doInBackground执行错误-Distance-Matrix-API和Places API

Question

MainActivity.java

AutoCompleteTextView location, destination;
public Places place1, place2;
Button calculate;
TextView result_a, result_b;
String result_main;
//default values for taxi fare
int basePrice = 10;
double priceMeter = 5.80;
double fare;
int parseFare;
int roundedValue;
String textvalue;
String actual_distance;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    location=(AutoCompleteTextView)findViewById(R.id.locale);
    location.setAdapter(new PlacesAutoCompleteAdapter(this, R.layout.list_item));
    location.setOnItemClickListener(new OnItemClickListener()
    {

    @Override
    public void onItemClick(AdapterView<?> adapterView, View view, int position, long id) {
            // TODO Auto-generated method stub
            place1 = (Places) adapterView.getItemAtPosition(position);
            location.setText(place1.description);
            //location.clearFocus();
            Log.d("AutoCompleteTask", location.getText().toString());
                }
    });

    destination = (AutoCompleteTextView)findViewById(R.id.destination);
    destination.setAdapter(new PlacesAutoCompleteAdapter(this, R.layout.list_item));
    destination.setOnItemClickListener(new OnItemClickListener() 
    {

    @Override
    public void onItemClick(AdapterView<?> adapterView, View view, int position, long id) {
                // TODO Auto-generated method stub
            place2 = (Places) adapterView.getItemAtPosition(position);
            destination.setText(place2.description);
            //destination.clearFocus();
            Log.d("AutoCompleteTask2", destination.getText().toString());
                }
    });



    calculate = (Button)findViewById(R.id.calculate);

    calculate.setOnClickListener(new View.OnClickListener() {

        @Override
        public void onClick(View v) {
            // TODO Auto-generated method stub
        new ReadDistanceJSONFeedTask().execute("http://maps.googleapis.com/maps/api/distancematrix/json?origins="+location.getText().toString()+"&destinations="+destination.getText().toString()+"&sensor=false&units=metric&mode=driving");
        //result_a.setText("ROUTE A "+result_main +"\n"+ "The estimated fare is Rs."+textvalue);
        }
    });
}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    // Inflate the menu; this adds items to the action bar if it is present.
    getMenuInflater().inflate(R.menu.activity_main, menu);
    return true;
}


private class ReadDistanceJSONFeedTask extends AsyncTask<String, Void, String>
{       
        @Override
        protected String doInBackground(String... urls) {
            // TODO Auto-generated method stub
            return readJSONFeed(urls[0]);
        }

        @Override
        protected void onPostExecute(String result)
        {
            try
            {   //Accessing the JSON Results
                JSONObject jsonObject = new JSONObject(result);

                JSONArray rows = jsonObject.getJSONArray("rows");
                Log.i("json", rows.toString());

                JSONObject obj = rows.getJSONObject(0);

                JSONArray elements = obj.getJSONArray("elements");

                JSONObject ini_dis = elements.getJSONObject(0);

                JSONObject distance = ini_dis.getJSONObject("distance");
                Log.i("json", distance.toString());

                //Distance to send
                actual_distance = distance.getString("text");

                //Calculation part
                String solve = distance.getString("value");
                int parseFare = Integer.parseInt(solve);
                fare = basePrice + ((parseFare/200)*priceMeter);
                roundedValue = (int)Math.round(fare);

                //another activity
                Intent i = new Intent(MainActivity.this,ResultsDisplay.class);
                i.putExtra("Display",actual_distance);
                i.putExtra("Display_b",textvalue);
                startActivity(i);

            }
            catch(Exception e)
            {
                Log.d("ReadDistanceJSONFeedTask", e.getLocalizedMessage());
            }
        }

            public String readJSONFeed(String URL){
            //Initial steps to getting the JSON Result
            StringBuilder stringBuilder = new StringBuilder();
            HttpClient httpClient = new DefaultHttpClient();
            HttpGet httpGet = new HttpGet(URL);
            try
            {
                HttpResponse response = httpClient.execute(httpGet);
                StatusLine statusLine = response.getStatusLine();
                int statusCode = statusLine.getStatusCode();
                //statusCodes at 200 are OK_Statuses
                if(statusCode==200)
                {
                    HttpEntity entity = response.getEntity();
                    InputStream inputStream = entity.getContent();
                    BufferedReader reader = new BufferedReader(new InputStreamReader(inputStream));
                    String line;
                    while((line=reader.readLine())!=null)
                    {
                        stringBuilder.append(line);

                    }
                    inputStream.close();
                }
                else
                {
                    Log.d("readJSONFeed","Failed to download file");
                }
            }
            catch(Exception e)
            {
                Log.d("readJSONFeed", e.getLocalizedMessage());
            }
                return stringBuilder.toString();
        }

}

我正在创建一个应用程序，接受用户输入的位置和目的地，并向他们返回路径之间的距离以及预计的出租车费 。 该程序中还具有利用Google-Places API的自动完成文本查看功能。 此应用程序使用的是Direction-Matrix-API ，其中我当前在AsyncTask上存在问题... logcat在'doInBackGround（）'方法中执行时生成错误...请帮助。

LogCat错误

03-27 09：29：03.785：I / Choreographer（3468）：跳了123帧！ 该应用程序可能在其主线程上做太多工作。 03-27 09：29：05.485：W / dalvikvm（3468）：threadid = 12：线程以未捕获的异常退出（group = 0x40a71930）03-27 09：29：05.525：E / AndroidRuntime（3468）：致命异常：AsyncTask ＃2 03-27 09：29：05.525：E / AndroidRuntime（3468）：java.lang.RuntimeException：执行doInBackground（）03-27 09：29：05.525：E / AndroidRuntime（3468）时发生错误.os.AsyncTask $ 3.done（AsyncTask.java:299）03-27 09：29：05.525：E / AndroidRuntime（3468）：at java.util.concurrent.FutureTask.finishCompletion（FutureTask.java:352）03-27 09：29：05.525：E / AndroidRuntime（3468）：在java.util.concurrent.FutureTask.setException（FutureTask.java:219）03-27 09：29：05.525：E / AndroidRuntime（3468）：在java.util .concurrent.FutureTask.run（FutureTask.java:239）03-27 09：29：05.525：E / AndroidRuntime（3468）：at android.os.AsyncTask $ SerialExecutor $ 1.run（AsyncTask.java:230）03-27 09：29：05.525：E / AndroidRuntime（3468）：位于java.util.concurrent.ThreadPoolExecutor.runWorker（ThreadPoolExecutor.java:1080）03-27 09：29：05.525：E / AndroidR untime（3468）：在java.util.concurrent.ThreadPoolExecutor $ Worker.run（ThreadPoolExecutor.java:573）03-27 09：29：05.525：E / AndroidRuntime（3468）：在java.lang.Thread.run（Thread .java：856）03-27 09：29：05.525：E / AndroidRuntime（3468）：原因：java.lang.IllegalArgumentException：索引73处查询中的非法字符： http ://maps.googleapis.com/maps/ api / distancematrix / json？origins = Lagankhel Rd，Patan，中部地区，尼泊尔＆目的地= Thamel，加德满都，中部地区，尼泊尔＆sensor = false＆units = metric＆mode = driving 03-27 09：29：05.525：E / AndroidRuntime（3468）：at java .net.URI.create（URI.java:727）03-27 09：29：05.525：E / AndroidRuntime（3468）：位于org.apache.http.client.methods.HttpGet。（HttpGet.java:75）03 -27 09：29：05.525：E / AndroidRuntime（3468）：位于com.example.calculator_taxi_fare.MainActivity $ ReadDistanceJSONFeedTask.readJSONFeed（MainActivity.java:159）03-27 09：29：05.525：E / AndroidRuntime（3468）：在com.example.calculator_taxi_fare.MainActivity $ ReadDistanceJSONFeedTask.doInBackground（MainActivity.ja va：111）03-27 09：29：05.525：E / AndroidRuntime（3468）：at com.example.calculator_taxi_fare.MainActivity $ ReadDistanceJSONFeedTask.doInBackground（MainActivity.java:1）03-27 09：29：05.525：E / AndroidRuntime（3468）：位于android.os.AsyncTask $ 2.call（AsyncTask.java:287）03-27 09：29：05.525：E / AndroidRuntime（3468）：位于java.util.concurrent.FutureTask.run（FutureTask。 java：234）03-27 09：29：05.525：E / AndroidRuntime（3468）：...还有4个

Answer 1

在这里

@Override
        public void onClick(View v) {
            // TODO Auto-generated method stub
        new ReadDistanceJSONFeedTask().execute("your url");
        ....
        startActivity(i); //<<<<<

}

您将在执行ReadDistanceJSONFeedTask AsyncTask之后开始下一个Activity。 因为AsyncTask在单独的线程中执行，并且控件无需等待AsyncTask结果即可到达下一行。

移动活动启动内侧部分onPostExecute其执行对UI线程时后仅doInBackground执行完毕：

@Override
        protected void onPostExecute(String result)
        {
           ///....your code here..
           // start next Activity here..
           Intent i = new Intent(MainActivity.this,ResultsDisplay.class);
           i.putExtra("Display",actual_distance);
           i.putExtra("Display_b",textvalue);
           startActivity(i);
        }

编辑：您还需要在发送HttpGet参数之前使用URLEncoder.encode

String strparams="origins="+location.getText().toString()+"&
                       destinations="+destination.getText().toString()+
                       "&sensor=false&units=metric&mode=driving";
String encodedurl = URLEncoder.encode(strparams,"UTF-8");
new ReadDistanceJSONFeedTask().execute("http://maps.googleapis.com/maps
                                        /api/distancematrix/json?"+encodedurl);