当我使用asynctask方法时，活动指示器不起作用。 AsyncTask方法用于从URL下载图像并放入手机内存。以下是我的代码
btnSubmit.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
AsyncCallWS aws = new AsyncCallWS();
try {
retData = aws.execute().get();
Log.d(TAG, "STATUS is " + retData);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (ExecutionException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
// Close the window and go back to login page
Intent intent = new Intent(launchar.this, arcamera.class);
intent.putExtra("url", url_);
intent.putExtra(Strings.USERNAME, mUsername);
intent.putExtra(Strings.PASSWORD, mPassword);
intent.putExtra(Strings.COMP_ID, mCompId);
startActivity(intent);
}
});
我的异步方法如下：
private class AsyncCallWS extends AsyncTask<String, Void, String> {
@Override
protected String doInBackground(String... params) {
// Call the service
HttpConnectionHelper helper = new HttpConnectionHelper(
Constants.SERVICE_GETAR_URL);
final String REQUEST_DATA = String.format(
"<ReqData xmlns=\"http://www.ceolution.com/phone\"> "
+ "<key>%s|%s|%s</key>" + "</ReqData>", mUsername,
mPassword, mCompId);
try {
helper.setRequestMethod(HttpPost.METHOD_NAME);
helper.setPostData(REQUEST_DATA);
helper.setHeader("Content-Type", "application/xml");
int code = helper.getResponseCode();
if (Constants.LOG_ENABLED) {
Log.i(TAG, "Response code = " + code);
}
if (code == HttpURLConnection.HTTP_OK) {
String data = helper.getResponseData();
if (Constants.LOG_ENABLED) {
Log.v(TAG, "Response Data - " + data);
}
ARParser par = new ARParser();
String data_ = par.ParseAR(data);
Log.i(TAG, "RETURN DATA IS " + data_);
// Get Object
BufferedReader br = new BufferedReader(new StringReader(
data_));
InputSource is = new InputSource(br);
// Create XML Parser
ARXMLFormatter parser = new ARXMLFormatter();
SAXParserFactory factory = SAXParserFactory.newInstance();
SAXParser sp = factory.newSAXParser();
XMLReader reader = sp.getXMLReader();
reader.setContentHandler(parser);
reader.parse(is);
myData = parser.itemList;
if (myData != null) {
String OutputData = "";
Location itemLocation = null;
for (Item item : myData) {
if (item != null) {
itemLocation = new Location("");
itemLocation.setLatitude(Double
.parseDouble(item.getLat()));
itemLocation.setLongitude(Double
.parseDouble(item.getLg()));
if (location != null) {
float distanceInMeters = itemLocation
.distanceTo(location);
Log.d(TAG, "distanceInMeters is "
+ distanceInMeters);
if (distanceInMeters <= Double
.parseDouble(item.getR())) {
// Must have to clean the directory
// before
// writing data
File savefilepath1 = new File(
COURSE_ZIP_FILE_PATH);
cleanDirectory(savefilepath1);
Image realData = null;
String imageName = "";
for (int k = 0; k < 8; k++) {
realData = null;
imageName = "";
switch (k) {
case 0: {
realData = item.getN();
imageName = "n.png";
break;
}
case 1: {
realData = item.getE();
imageName = "e.png";
break;
}
case 2: {
realData = item.getS();
imageName = "s.png";
break;
}
case 3: {
realData = item.getW();
imageName = "w.png";
break;
}
case 4: {
realData = item.getNe();
imageName = "ne.png";
break;
}
case 5: {
realData = item.getNw();
imageName = "nw.png";
break;
}
case 6: {
realData = item.getSe();
imageName = "se.png";
break;
}
case 7: {
realData = item.getSw();
imageName = "sw.png";
break;
}
}
url_[k] = realData.getL();
boolean status = false;
if (realData.getU() != ""
&& realData.getU() != null)
status = DownloadFile(
realData.getU()
.replace(
"http",
"https"),
imageName);
Log.d(TAG, "Download status is "
+ status);
}
Log.d(TAG,
"This is the item to processed");
return "SUCCESS";
}
OutputData = OutputData + item.toString();
} else
return "GPSISSUE";
} else
Log.e("Items", "No details");
}
Log.d(TAG, "OutputData data is " + OutputData);
}
return "NODATA";
}
} catch (Exception ex) {
ex.printStackTrace();
return "ERROR";
}
return "NODATA";
}
XML文件位于
之下 <FrameLayout
android:id="@+id/laucnh_layout"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerInParent="true" >
<ImageView
android:id="@+id/btnSubmit"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:adjustViewBounds="true"
android:background="@drawable/launch"
android:onClick="@string/onClick"
android:scaleType="center" />
</FrameLayout>
即使我试图将活动指标放在onPreExecute()中，onPostExecute()也不起作用。
我不确定可能是什么原因。
请帮忙。
答案 0 :(得分：0)
您必须将asyncTask中的更新发布到UI。这是一个例子。因此，在onProgressUpdate函数中，您可以更新UI。我希望这会有所帮助。
private class DownloadFilesTask extends AsyncTask<URL, Integer, Long> {
protected Long doInBackground(URL... urls) {
int count = urls.length;
long totalSize = 0;
for (int i = 0; i < count; i++) {
totalSize += Downloader.downloadFile(urls[i]);
publishProgress((int) ((i / (float) count) * 100));
// Escape early if cancel() is called
if (isCancelled()) break;
}
return totalSize;
}
protected void onProgressUpdate(Integer... progress) {
setProgressPercent(progress[0]);
}
protected void onPostExecute(Long result) {
showDialog("Downloaded " + result + " bytes");
}
}