大家好，我正在构建一个android应用程序，它使用json从数据库加载数据。当互联网速度快（3g或4g或wifi）时，它可以正常加载，但是当人们使用2g时，加载应用崩溃的时间就非常长。在长时间等待后，如何捕获异常并像Playstore一样创建重试按钮？
我的代码是：
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
listView = (ListView) findViewById(R.id.listView1);
ConnectivityManager cm = (ConnectivityManager) getSystemService(CONNECTIVITY_SERVICE);
NetworkInfo activeNetwork = cm.getActiveNetworkInfo();
boolean network_connected = activeNetwork != null
&& activeNetwork.isAvailable();
if (!network_connected) {
onDetectNetworkState().show();
} else {
accessWebService();
registerCallClickBack();
}
}
private class JsonReadTask extends AsyncTask<String, Void, String> {
@Override
protected void onPreExecute() {
super.onPreExecute();
pDialog = new ProgressDialog(MainActivity.this);
pDialog.setTitle(R.string.waiting);
pDialog.setMessage(getString(R.string.get_stocks));
pDialog.setCancelable(false);
pDialog.show();
}
@Override
protected String doInBackground(String... params) {
HttpClient httpclient = new DefaultHttpClient();
HttpPost httppost = new HttpPost(params[0]);
try {
HttpResponse response = httpclient.execute(httppost);
jsonResult = inputStreamToString(
response.getEntity().getContent()).toString();
}
catch (ClientProtocolException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
return null;
}
private StringBuilder inputStreamToString(InputStream is) {
String rLine = "";
StringBuilder answer = new StringBuilder();
BufferedReader rd = new BufferedReader(new InputStreamReader(is));
try {
while ((rLine = rd.readLine()) != null) {
answer.append(rLine);
}
}
catch (IOException e) {
// e.printStackTrace();
Toast.makeText(getApplicationContext(),
"Error..." + e.toString(), Toast.LENGTH_LONG).show();
}
return answer;
}
@Override
protected void onPostExecute(String result) {
ListDrwaer();
pDialog.dismiss();
}
}// end async task
public void accessWebService() {
JsonReadTask task = new JsonReadTask();
// passes values for the urls string array
task.execute(new String[] { url });
}
我检查了网络连接，以了解其是否已连接，但是当它长时间连接时崩溃了，我该如何解决？例如，我希望它等待10-15秒，然后显示一个重试按钮，因此用户重试。
任何帮助将不胜感激。提前致谢。
您可以将计时器设置为5000毫秒，然后查看是否通过了此计时器，在doInBackgroundFunction中还返回null，还可以初始化reload = false;。如果计时器已结束reload = true;在onPostExecute检查中
if(reload)
{new JsonReadTask().execute(); }
在这里编辑
@Override
protected String doInBackground(String... params) {
boolean reload =false;
long waitTime = 5000;// or whatever you want the timeout length to be long
curWaitTime = 0;
while (!reload && curWaitTime < waitTime)
HttpResponse response;
{ // put your network
HttpClient httpclient = new DefaultHttpClient();
HttpPost httppost = new HttpPost(params[0]);
try {
response = httpclient.execute(httppost);
jsonResult = inputStreamToString(
response.getEntity().getContent()).toString();
//test if jsonResult have the correct data if yes reload=true;
}
catch (ClientProtocolException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
curWaitTime += 100;
}
return null;
}
private StringBuilder inputStreamToString(InputStream is) {
String rLine = "";
StringBuilder answer = new StringBuilder();
BufferedReader rd = new BufferedReader(new InputStreamReader(is));
try {
while ((rLine = rd.readLine()) != null) {
answer.append(rLine);
}
}
catch (IOException e) {
// e.printStackTrace();
Toast.makeText(getApplicationContext(),
"Error..." + e.toString(), Toast.LENGTH_LONG).show();
}
return answer;
}
@Override
protected void onPostExecute(String result) {
ListDrwaer();
pDialog.dismiss();
if(!reload){
accessWebService();
}
}
}// end async task
public void accessWebService() {
JsonReadTask task = new JsonReadTask();
// passes values for the urls string array
task.execute(new String[] { url });
}
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