所以我现在有一个运行的AsyncTask类，当我点击一个按钮时，我的服务器发布了POST数据（效果很好）。
我现在要做的是处理当用户未连接到互联网时会发生什么。所以我已经设置了这些类，以便在互联网连接时通知应用程序，以便数据可以自动发送到服务器。
AsyncTask类（内部类）
private class HttpAsyncTask extends AsyncTask<String, Void, String> {
ProgressDialog dialog = new ProgressDialog(getActivity());
final AlertDialog finishedDialog = new AlertDialog.Builder(getActivity())
.setCancelable(false)
.setPositiveButton(android.R.string.ok, null)
.create();
@Override
protected String doInBackground(String... urls) {
onProgressUpdate("Uploading Data...");
return POST(urls[0]);
}
@Override
protected void onPreExecute() {
this.dialog.show();
finishedDialog.setOnShowListener(new DialogInterface.OnShowListener(){
@Override
public void onShow(DialogInterface dialog) {
Button b = finishedDialog.getButton(AlertDialog.BUTTON_POSITIVE);
b.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
// navigate to match summary.....
finishedDialog.dismiss();
}
});
}
});
}
protected void onProgressUpdate(String msg) {
dialog.setMessage(msg);
}
// onPostExecute displays the results of the AsyncTask.
@Override
protected void onPostExecute(String result) {
if (result != ""){
finishedDialog.setTitle("Upload Complete!");
finishedDialog.setMessage("Data Sent Successfully");
finishedDialog.show();
dialog.dismiss();
editor.clear();
editor.commit();
//Toast.makeText(getActivity().getBaseContext(), result, Toast.LENGTH_LONG).show();
}else
{
Handler handler = new Handler();
handler.postDelayed(new Runnable() {
public void run() {
finishedDialog.setTitle("Upload Failed!");
finishedDialog.setMessage("Data Will Automatically Be Uploaded When Internet Connection Is Available");
finishedDialog.show();
dialog.dismiss();
}}, 1000);
setFlag(true);
}
}
}
public static boolean getFlag() {
return flag;
}
public void setFlag(boolean flag) {
this.flag = flag;
}
public String POST(String url){
InputStream inputStream = null;
String result = "";
try {
// 1. create HttpClient
HttpClient httpclient = new DefaultHttpClient();
// 2. make POST request to the given URL
HttpPost httpPost = new HttpPost(url);
if(adapter.updateNeeded()){
JSONObject main = new JSONObject(exmaplePrefs.getString("jsonString", "cant find json"));
JSONObject dbUpdates = new JSONObject(exmaplePrefs.getString("ChangesJSON", "cant find Changejson"));
main.put("Team_Updates", dbUpdates);
json = main.toString();
}else{
json = exmaplePrefs.getString("jsonString", "cant find json");
// String json = "{\"twitter\":\"test\",\"country\":\"test\",\"name\":\"test\"}";
}
// 5. set json to StringEntity
StringEntity se = new StringEntity(json);
se.setContentType("application/json;charset=UTF-8");
// 6. set httpPost Entity
httpPost.setEntity(se);
// 7. Set some headers to inform server about the type of the content
// httpPost.setHeader("Accept", "application/json");
// httpPost.setHeader("Content-type", "application/json");
// httpPost.setHeader("json", json);
// 8. Execute POST request to the given URL
HttpResponse httpResponse = httpclient.execute(httpPost);
// 9. receive response as inputStream
inputStream = httpResponse.getEntity().getContent();
String status = httpResponse.getStatusLine().toString();
// 10. convert inputstream to string
if (!status.equals("HTTP/1.1 500 Internal Server Error")){
if(inputStream != null){
result = convertInputStreamToString(inputStream);
}
else{
result = "Did not work!";
}
}else{
System.out.println("500 Error");
}
} catch (Exception e) {
Log.d("InputStream", e.getLocalizedMessage());
System.out.println("eerroorr "+e);
}
// 11. return result
System.out.println(result);
return result;
}
private static String convertInputStreamToString(InputStream inputStream) throws IOException{
BufferedReader bufferedReader = new BufferedReader( new InputStreamReader(inputStream));
String line = "";
String result = "";
while((line = bufferedReader.readLine()) != null)
result += line;
inputStream.close();
return result;
}
}
NetworkUtil类
public class NetworkUtil {
public static int TYPE_WIFI = 1;
public static int TYPE_MOBILE = 2;
public static int TYPE_NOT_CONNECTED = 0;
public static int getConnectivityStatus(Context context) {
ConnectivityManager cm = (ConnectivityManager) context
.getSystemService(Context.CONNECTIVITY_SERVICE);
NetworkInfo activeNetwork = cm.getActiveNetworkInfo();
if (null != activeNetwork) {
if(activeNetwork.getType() == ConnectivityManager.TYPE_WIFI)
return TYPE_WIFI;
if(activeNetwork.getType() == ConnectivityManager.TYPE_MOBILE)
return TYPE_MOBILE;
}
return TYPE_NOT_CONNECTED;
}
public static String getConnectivityStatusString(Context context) {
int conn = NetworkUtil.getConnectivityStatus(context);
String status = null;
if (conn == NetworkUtil.TYPE_WIFI) {
status = "Wifi enabled";
} else if (conn == NetworkUtil.TYPE_MOBILE) {
status = "Mobile data enabled";
} else if (conn == NetworkUtil.TYPE_NOT_CONNECTED) {
status = "Not connected to Internet";
}
return status;
}
}
BroadcastReceiver类
public class NetworkChangeReceiver extends BroadcastReceiver {
@Override
public void onReceive(final Context context, final Intent intent) {
intent.getExtras();
String status = NetworkUtil.getConnectivityStatusString(context);
Toast.makeText(context, status, Toast.LENGTH_LONG).show();
if(MatchFragment.getFlag()){
//send data
}
}
}
因此，在BroadcastReceiver类中，当应用程序尝试发送数据但没有Internet（AsyncTask类中的onPostExecute）时，我会检查设置为true的标志。
所以想要做的是如何调用POST方法。我是否必须创建一个新的Async任务类？我有点难过。
谢谢
答案 0 :(得分：12)
在AsyncTask中使用BroadcastReceiver是糟糕的做法。
您应该使用Service，因为Android操作系统可能会终止您的进程，或者onReceive()可能会在asyncTask返回结果之前运行完成，因此无法保证您将获得预期的结果。
答案 1 :(得分：5)
您不应在Broadcast Receiver中使用AsyncTask，因为系统可能会在从onReceive方法返回后终止您的进程（如果没有任何活动服务或活动）。 Proof link
针对此类案例的官方文档recommends IntentService（请参阅有关广播接收器的段落）。
答案 2 :(得分：3)
其他答案不正确according to Google's documentation。如果您先致电AsyncTask并将状态报告给BroadcastReceiver <中的待处理结果，则广播接收人开发人员指南会明确指出您可以使用goAsync()中的AsyncTask s / p>
因此，您不应该从广播接收器开始长时间运行后台线程。在onReceive（）之后，系统可以随时终止进程以回收内存，并且这样做会终止在进程中运行的生成线程。 要避免这种情况，您应该调用goAsync（）（如果您想要更多时间在后台线程中处理广播），或者使用JobScheduler从接收方安排JobService，这样系统就知道了该过程继续执行积极的工作。
后来它澄清了你实际得到多少时间：
在接收者的onReceive（）方法中调用goAsync（）并传递 BroadcastReceiver.PendingResult到后台线程。这保持不变 从onReceive（）返回后广播活动。但是，甚至 使用这种方法，系统希望您完成广播 很快（不到10秒）。它确实允许你将工作转移到 另一个线程，以避免故障主线程。
public class MyBroadcastReceiver extends BroadcastReceiver {
private static final String TAG = "MyBroadcastReceiver";
@Override
public void onReceive(final Context context, final Intent intent) {
final PendingResult pendingResult = goAsync();
AsyncTask<String, Integer, String> asyncTask = new AsyncTask<String, Integer, String>() {
@Override
protected String doInBackground(String... params) {
StringBuilder sb = new StringBuilder();
sb.append("Action: " + intent.getAction() + "\n");
sb.append("URI: " + intent.toUri(Intent.URI_INTENT_SCHEME).toString() + "\n");
Log.d(TAG, log);
// Must call finish() so the BroadcastReceiver can be recycled.
pendingResult.finish();
return data;
}
};
asyncTask.execute();
}
}