我有一个异步任务，可以从服务器加载信息并在UI上显示数据。突然，异步任务下载数据并格式化JSON数据，但它会完全冻结UI。
这是基础下载类
public class GetRawData {
private static String LOG_TAG = GetRawData.class.getSimpleName();
private String mRawURL;
private List<NameValuePair> mRawParams = null;
private String mRawData;
private DownloadStatus mDownloadStatus;
public GetRawData(String mRawURL) {
this.mRawURL = mRawURL;
this.mRawParams = null;
this.mDownloadStatus = DownloadStatus.IDLE;
}
public String getRawData() {
return mRawData;
}
public void setRawURL(String mRawURL) {
this.mRawURL = mRawURL;
}
public List<NameValuePair> getRawParams() {
return mRawParams;
}
public void setRawParams(List<NameValuePair> mParams) {
this.mRawParams = mParams;
}
public DownloadStatus getDownloadStatus() {
return mDownloadStatus;
}
public void reset() {
this.mRawURL = null;
this.mRawData = null;
this.mDownloadStatus = DownloadStatus.IDLE;
}
public void execute() {
this.mDownloadStatus = DownloadStatus.PROCESSING;
DownloadRawData mDownloadRawData = new DownloadRawData();
mDownloadRawData.execute(mRawURL);
}
public class DownloadRawData extends AsyncTask<String, Void, String> {
@Override
protected String doInBackground(String... params) {
// Create URL and Reader instances.
HttpURLConnection urlConnection = null;
BufferedReader reader = null;
//If no parameter has been provided, return null.
if (params == null)
return null;
try {
// Get URL entered by the user.
URL mURL = new URL(params[0]);
urlConnection = (HttpURLConnection) mURL.openConnection();
urlConnection.setDoOutput(true);
urlConnection.setRequestMethod("POST");
urlConnection.setUseCaches(false);
urlConnection.setConnectTimeout(10000);
urlConnection.setReadTimeout(10000);
urlConnection.setRequestProperty("Content-Type","application/json");
//urlConnection.setRequestProperty("Host", "android.schoolportal.gr");
urlConnection.connect();
// validate and add parameters if available.
if (mRawParams != null && mRawParams.size()>0){
JSONObject jsonParam = new JSONObject();
for (NameValuePair pair : mRawParams) {
jsonParam.put(pair.getName().toString(), pair.getValue().toString());
}
String jsonparams = jsonParam.toString();
// Send POST output.
DataOutputStream printout;
printout = new DataOutputStream(urlConnection.getOutputStream());
printout.writeBytes(jsonparams);
printout.flush();
printout.close();
}
int HttpResult =urlConnection.getResponseCode();
StringBuffer buffer = new StringBuffer();
if(HttpResult ==HttpURLConnection.HTTP_OK){
InputStream inputStream = urlConnection.getInputStream();
if (inputStream == null) {
return null;
}
reader = new BufferedReader(new InputStreamReader(inputStream));
String line;
while ((line = reader.readLine()) != null) {
buffer.append(line + "\n");
}
System.out.println(""+buffer.toString());
}else{
InputStream errorStream = urlConnection.getErrorStream();
if (errorStream == null) {
return null;
}
reader = new BufferedReader(new InputStreamReader(errorStream));
String line;
while ((line = reader.readLine()) != null) {
buffer.append(line + "\n");
}
System.out.println(urlConnection.getResponseMessage());
}
return buffer.toString();
} catch (IOException e) {
Log.d("IOException", e.toString());
return null;
} catch (JSONException j) {
Log.d("JSONException", j.toString());
return null;
} finally {
if (urlConnection != null) {
urlConnection.disconnect();
}
if (reader != null) {
try {
reader.close();
} catch (IOException e) {
Log.d("IOException", "unable to close the reader");
}
}
}
}
@Override
protected void onPostExecute(String result) {
super.onPostExecute(result);
mRawData = result;
//Log.d("onPostExecute", result);
if (mRawData == null) {
if (mRawURL == null) {
mDownloadStatus = DownloadStatus.NOT_INITIALIZED;
} else {
mDownloadStatus = DownloadStatus.FAILED_OR_EMPTY;
}
} else {
mDownloadStatus = DownloadStatus.PROCESSED;
}
}
private String getQuery(List<NameValuePair> params) throws UnsupportedEncodingException {
StringBuilder result = new StringBuilder();
boolean first = true;
for (NameValuePair pair : params) {
if (first)
first = false;
else
result.append("&");
result.append(URLEncoder.encode(pair.getName(), "UTF-8"));
result.append("=");
result.append(URLEncoder.encode(pair.getValue(), "UTF-8"));
}
return result.toString();
}
}
}
enum DownloadStatus {
IDLE,
PROCESSING,
NOT_INITIALIZED,
FAILED_OR_EMPTY,
PROCESSED
}
以下是扩展到类
之上的特定数据格式化类public class GetJobCardJsonData extends GetRawData {
private static String LOG_TAG = GetAuthenticationJsonData.class.getSimpleName();
private static String JOBCARD_SERVICE_URL = "http://www.appservice.com/appservice/jobcardinfoservice.asmx/GetJobCardInfo";
private List<JobCard> mJobCardList;
private CarcalDownloadListener mListener;
public GetJobCardJsonData(String CurrentDate, int DealershipID) {
super(null);
List<NameValuePair> mParams = new ArrayList<NameValuePair>();
mParams.add(new BasicNameValuePair("JobCardDate", CurrentDate));
mParams.add(new BasicNameValuePair("DealershipID", String.valueOf(DealershipID)));
this.setRawParams(mParams);
}
public List<JobCard> getJobCardList() {
return mJobCardList;
}
public void getjobcards() {
super.setRawURL(JOBCARD_SERVICE_URL);
DownloadJobCardJsonData mDownloadJobCardJsonData = new DownloadJobCardJsonData();
mDownloadJobCardJsonData.execute(JOBCARD_SERVICE_URL);
}
public void setOnCarcalDownloadListener(CarcalDownloadListener onCarcalDownloadListener) {
this.mListener = onCarcalDownloadListener;
}
private void processResult() {
if (getDownloadStatus() != DownloadStatus.PROCESSED) {
Log.e(LOG_TAG, "Error Downloading the raw file.");
return;
}
if (mJobCardList == null){
mJobCardList = new ArrayList<JobCard>();
}
final String JOBCARD_JOBCARDID = "JobCardID";
final String JOBCARD_GETSTOCKNUMBER_WITH_DELIVERYTIME = "StockNumberWithDeliveryTime";
final String JOBCARD_CUSTOMERNAME = "CustomerName";
final String JOBCARD_MODELNUMBER = "ModelNumber";
final String JOBCARD_COLOR = "Color";
final String JOBCARD_SALEEXECUTIVE = "SaleExecutive";
final String JOBCARD_ORDERSTATUS = "OrderStatus";
final String JOBCARD_SHOWROOMSTATUS = "ShowRoomStatus";
try {
JSONArray jsonArray = new JSONArray(getRawData());
for (int i = 0; i < jsonArray.length(); i++) {
JSONObject jobcarditem = jsonArray.optJSONObject(i);
Long JOBCARDID = jobcarditem.getLong(JOBCARD_JOBCARDID);
String STOCKWITHDELIVERY = jobcarditem.getString(JOBCARD_GETSTOCKNUMBER_WITH_DELIVERYTIME);
String CUSTOMERNAME = jobcarditem.getString(JOBCARD_CUSTOMERNAME);
String MODELNUMBER = jobcarditem.getString(JOBCARD_MODELNUMBER);
String COLOR = jobcarditem.getString(JOBCARD_COLOR);
String SALEEXECUTIVE = jobcarditem.getString(JOBCARD_SALEEXECUTIVE);
int ORDERSTATUS = jobcarditem.getInt(JOBCARD_ORDERSTATUS);
int SHOWROOMSTATUS = jobcarditem.getInt(JOBCARD_SHOWROOMSTATUS);
JobCard mJobCard = new JobCard(JOBCARDID, STOCKWITHDELIVERY, CUSTOMERNAME, MODELNUMBER, COLOR, SALEEXECUTIVE, ORDERSTATUS, SHOWROOMSTATUS);
mJobCardList.add(mJobCard);
}
} catch (JSONException jsone) {
jsone.printStackTrace();
Log.e(LOG_TAG, "Error processing json data.");
}
}
public class DownloadJobCardJsonData extends DownloadRawData {
@Override
protected String doInBackground(String... params) {
return super.doInBackground(params[0]);
}
@Override
protected void onPostExecute(String result) {
super.onPostExecute(result);
processResult();
mListener.OnDownloadCompleted();
}
}
}
以下是在活动
上调用的代码private JobCardRecyclerViewAdapter mJobCardRecyclerViewAdapter;
private GetJobCardJsonData mGetJobCardJsonData;
SessionManager session;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_job_card_calender);
activateToolbarWithHomeEnabled();
String formattedDate="";
if (session.getCurrentDate() == ""){
Calendar c = Calendar.getInstance();
SimpleDateFormat df = new SimpleDateFormat("MM/dd/yyyy");
formattedDate = df.format(c.getTime());
currentDateTextView.setText(formattedDate);
}else {
formattedDate = session.getCurrentDate();
currentDateTextView.setText(formattedDate);
}
// Fetch data for current date.
mGetJobCardJsonData = new GetJobCardJsonData(formattedDate, session.getDealershipID());
mGetJobCardJsonData.getjobcards();
mGetJobCardJsonData.setOnCarcalDownloadListener(new CarcalDownloadListener() {
@Override
public void OnDownloadCompleted() {
List<JobCard> mJobCards = mGetJobCardJsonData.getJobCardList();
mJobCardRecyclerViewAdapter = new JobCardRecyclerViewAdapter(mJobCards, JobCardCalenderActivity.this);
mRecyclerView.setAdapter(mJobCardRecyclerViewAdapter);
}
});
}
任何人都可以帮助解决我正在做错的事情，这会冻结用户界面。它之前工作正常并且已经开始突然冻结UI。
答案 0 :(得分：0)
我能够解决问题，问题不在于Async任务，而在于布局。我意外地用回滚视图包裹了回收者视图。这导致UI冻结。滚动视图导致整个UI线程冻结，这看起来很奇怪。但这是我的解决方案
<ScrollView
android:layout_width="match_parent"
android:layout_height="match_parent">
<view
android:id="@+id/jobCardRecyclerView"
class="android.support.v7.widget.RecyclerView"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_below="@id/jobCardHeader"
android:scrollbars="vertical"></view>
</ScrollView>
将其更改为
<view
android:id="@+id/jobCardRecyclerView"
class="android.support.v7.widget.RecyclerView"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_below="@id/jobCardHeader"
android:scrollbars="vertical"></view>
希望它对面临同样问题的其他人有所帮助。