问题
I know that the purpose of the AsyncTask is to run asynchronously with other tasks of the app and finish in the background, but apparently I need to do this, I need to start an activity from AsyncTask and since I cant extend an activity in this class I can not use startactivityforresult, so how can I wait till my activity finishes?
Here is my code:
public class ListSpdFiles extends AsyncTask<Void, Void, String[]> {
public AsyncResponse delegate = null;
private static final String TAG = "ListSpdFiles: ";
Context applicationContext;
ContentResolver spdappliationcontext;
public final CountDownLatch setSignal= new CountDownLatch(1);
private final ReentrantLock lock = new ReentrantLock();
String username = "";
/**
* Status code returned by the SPD on operation success.
*/
private static final int SUCCESS = 4;
private boolean createbutt;
private boolean deletebutt;
private String initiator;
private String path;
private String pass;
private String url;
private SecureApp pcas;
private boolean isConnected = false; // connected to PCAS service?
private String CurrentURL = null;
private PcasConnection pcasConnection = new PcasConnection() {
@Override
public void onPcasServiceConnected() {
Log.d(TAG, "pcasServiceConnected");
latch.countDown();
}
@Override
public void onPcasServiceDisconnected() {
Log.d(TAG, "pcasServiceDisconnected");
}
};
private CountDownLatch latch = new CountDownLatch(1);
public ListSpdFiles(boolean createbutt, boolean deletebutt, String url, String pass, Context context, String initiator, String path, AsyncResponse asyncResponse) {
this.initiator = initiator;
this.path = path;
this.pass= pass;
this.url= url;
this.createbutt= createbutt;
this.deletebutt=deletebutt;
applicationContext = context.getApplicationContext();
spdappliationcontext = context.getContentResolver();
delegate = asyncResponse;
}
private void init() {
Log.d(TAG, "starting task");
pcas = new AndroidNode(applicationContext, pcasConnection);
isConnected = pcas.connect();
}
private void term() {
Log.d(TAG, "terminating task");
if (pcas != null) {
pcas.disconnect();
pcas = null;
isConnected = false;
}
}
@Override
protected void onPreExecute() {
super.onPreExecute();
init();
}
@Override
protected String[] doInBackground(Void... params) {
CurrentURL = getLastAccessedBrowserPage();
// check if connected to PCAS Service
if (!isConnected) {
Log.v(TAG, "not connected, terminating task");
return null;
}
// wait until connection with SPD is up
try {
if (!latch.await(20, TimeUnit.SECONDS)) {
Log.v(TAG, "unable to connected within allotted time, terminating task");
return null;
}
} catch (InterruptedException e) {
Log.v(TAG, "interrupted while waiting for connection in lsdir task");
return null;
}
// perform operation (this is where the actual operation is called)
try {
return lsdir();
} catch (DeadServiceException e) {
Log.i(TAG, "service boom", e);
return null;
} catch (DeadDeviceException e) {
Log.i(TAG, "device boom", e);
return null;
}
}
@Override
protected void onPostExecute(String[] listOfFiles) {
super.onPostExecute(listOfFiles);
if (listOfFiles == null) {
Log.i(TAG, "task concluded with null list of files");
} else {
Log.i(TAG, "task concluded with the following list of files: "
+ Arrays.toString(listOfFiles));
}
term();
delegate.processFinish(username);
}
@Override
protected void onCancelled(String[] listOfFiles) {
super.onCancelled(listOfFiles);
Log.i(TAG, "lsdir was canceled");
term();
}
/**
* Returns an array of strings containing the files available at the given path, or
* {@code null} on failure.
*/
private String[] lsdir() throws DeadDeviceException, DeadServiceException {
Result<List<String>> result = pcas.lsdir(initiator, path); // the lsdir call to the
boolean crtbut = createbutt;
boolean dlbut= deletebutt;
ArrayList<String> mylist = new ArrayList<String>();
final Global globalVariable = (Global) applicationContext;
if (crtbut==false && dlbut == false){
if ( globalVariable.getPasswordButt()==false ) {
final boolean isusername = globalVariable.getIsUsername();
if (isusername == true) {
Log.i(TAG, "current url: " + CurrentURL);
if (Arrays.toString(result.getValue().toArray(new String[0])).contains(CurrentURL)) {
String sharareh = Arrays.toString(result.getValue().toArray(new String[0]));
String[] items = sharareh.split(", ");
for (String item : items) {
String trimmed;
if (item.startsWith("[" + CurrentURL + ".")) {
trimmed = item.replace("[" + CurrentURL + ".", "");
if (trimmed.endsWith(".txt]")) {
trimmed = trimmed.replace(".txt]", "");
mylist.add(trimmed.replace(".txt]", ""));
} else if (trimmed.endsWith(".txt")) {
trimmed = trimmed.replace(".txt", "");
mylist.add(trimmed.replace(".txt", ""));
}
Log.i(TAG, "list of files sharareh: " + trimmed);
} else if (item.startsWith(CurrentURL + ".")) {
trimmed = item.replace(CurrentURL + ".", "");
if (trimmed.endsWith(".txt]")) {
trimmed = trimmed.replace(".txt]", "");
mylist.add(trimmed.replace(".txt]", ""));
} else if (trimmed.endsWith(".txt")) {
trimmed = trimmed.replace(".txt", "");
mylist.add(trimmed.replace(".txt", ""));
}
Log.i(TAG, "list of files sharareh: " + trimmed);
}
}
}
globalVariable.setPopupdone(false);
Intent i = new Intent(applicationContext, PopUp.class);
i.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
i.putExtra("EXTRA_SESSION_ID", mylist);
applicationContext.startActivity(i);
username = globalVariable.getUsername();
}
else if (isusername == false)
Log.i(TAG, "Wrong Input Type For Username.");
}
if (result.getState() != SUCCESS) {
Log.v(TAG, "operation failed");
return null;
}
if (result.getValue() == null) {
Log.v(TAG, "operation succeeded but operation returned null list");
return null;
}
return result.getValue().toArray(new String[0]);
}
//}
if (result.getState() != SUCCESS) {
Log.v(TAG, "operation failed");
return null;
}
if (result.getValue() == null) {
Log.v(TAG, "operation succeeded but operation returned null list");
return null;
}
return result.getValue().toArray(new String[0]);
}
public String getLastAccessedBrowserPage() {
String Domain = null;
Cursor webLinksCursor = spdappliationcontext.query(Browser.BOOKMARKS_URI, Browser.HISTORY_PROJECTION, null, null, Browser.BookmarkColumns.DATE + " DESC");
int row_count = webLinksCursor.getCount();
int title_column_index = webLinksCursor.getColumnIndexOrThrow(Browser.BookmarkColumns.TITLE);
int url_column_index = webLinksCursor.getColumnIndexOrThrow(Browser.BookmarkColumns.URL);
if ((title_column_index > -1) && (url_column_index > -1) && (row_count > 0)) {
webLinksCursor.moveToFirst();
while (webLinksCursor.isAfterLast() == false) {
if (webLinksCursor.getInt(Browser.HISTORY_PROJECTION_BOOKMARK_INDEX) != 1) {
if (!webLinksCursor.isNull(url_column_index)) {
Log.i("History", "Last page browsed " + webLinksCursor.getString(url_column_index));
try {
Domain = getDomainName(webLinksCursor.getString(url_column_index));
Log.i("Domain", "Last page browsed " + Domain);
return Domain;
} catch (URISyntaxException e) {
e.printStackTrace();
}
break;
}
}
webLinksCursor.moveToNext();
}
}
webLinksCursor.close();
return null;
}
public String getDomainName(String url) throws URISyntaxException {
URI uri = new URI(url);
String domain = uri.getHost();
return domain.startsWith("www.") ? domain.substring(4) : domain;
}}
My Activity class:
public class PopUp extends Activity {
private static final String TAG = "PopUp";
ArrayList<String> value = null;
ArrayList<String> usernames;
@Override
protected void onCreate(Bundle savedInstanceState) {
final Global globalVariable = (Global) getApplicationContext();
globalVariable.setUsername("");
Bundle extras = getIntent().getExtras();
if (extras != null) {
value = extras.getStringArrayList("EXTRA_SESSION_ID");
}
usernames = value;
super.onCreate(savedInstanceState);
setContentView(R.layout.popupactivity);
final Button btnOpenPopup = (Button) findViewById(R.id.openpopup);
btnOpenPopup.setOnClickListener(new Button.OnClickListener() {
@Override
public void onClick(View arg0) {
LayoutInflater layoutInflater = (LayoutInflater) getBaseContext().getSystemService(LAYOUT_INFLATER_SERVICE);
View popupView = layoutInflater.inflate(R.layout.popup, null);
final PopupWindow popupWindow = new PopupWindow(popupView, LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT);
Button btnSelect = (Button) popupView.findViewById(R.id.select);
Spinner popupSpinner = (Spinner) popupView.findViewById(R.id.popupspinner);
ArrayAdapter<String> adapter = new ArrayAdapter<String>(PopUp.this, android.R.layout.simple_spinner_item, usernames);
adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
popupSpinner.setAdapter(adapter);
popupSpinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
@Override
public void onItemSelected(AdapterView<?> arg0, View arg1, int arg2, long arg3) {
globalVariable.setUsername(usernames.get(arg2));
}
@Override
public void onNothingSelected(AdapterView<?> arg0) {
}
});
btnSelect.setOnClickListener(new Button.OnClickListener() {
@Override
public void onClick(View v) {
globalVariable.setPopupdone(true);
popupWindow.dismiss();
finish();
}
}
);
popupWindow.showAsDropDown(btnOpenPopup, 50, -30);
}
});
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.poupup_menu, menu);
return true;
}}
来源：https://stackoverflow.com/questions/35579932/how-to-wait-for-an-activity-to-finish-in-asynctask