c++ - How to avoid waitForStarted with QProcess to stop GUI from freezing? -


i running wscript qprocess run vb script converts excel files tab delimited text files. script runs fine , everything, gui freezes , user unable interact significant amount of time. here code:

/* create txt files , store paths */ (int = 0; < excelfilepaths.size(); ++i) {         wscript->start("wscript.exe", qstringlist() << vbs.filename() << excelfilepaths.at(i) << newdir.absolutepath() + "/" + qstring::number(i + 1));     wscript->waitforfinished();     payloadpaths.push_back(newdir.absolutepath() + "/" + qstring::number(i + 1)); }

so whats going on have multiple excel file paths , qprocess allocated on heap. qprocess runs vb script converts excel files text files , stores path of new text file. takes long time (about 20 seconds 4 excel files). during time gui frozen. user able use parts of gui don't interfere process.

now suspect cause of issue is

qprocess::waitforfinished()

and i've read online connecting finished() , error() signals of qprocess remove problem. i've been having difficulty doing so. i'm running code method of class inherits qobject , containst q_object macro, should set. need putting rest of pieces together. how can make gui not freeze while qprocess running? please help.

to quote documentation @ section called synchronous process api:

  • waitforstarted() blocks until process has started.
  • waitforreadyread() blocks until new data available reading on current read channel.
  • waitforbyteswritten() blocks until 1 payload of data has been written process.
  • waitforfinished() blocks until process has finished.

calling these functions main thread (the thread calls qapplication::exec()) may cause user interface freeze.

keep in mind. may overcome issue using that:

connect(process, static_cast<void(qprocess::*)(int, qprocess::exitstatus)>(&qprocess::finished), [=](int exitcode, qprocess::exitstatus exitstatus){ /* ... */ });

note there more signals may suite desired purpose.


Comments

Post a Comment

Popular posts from this blog

jOOQ update returning clause with Oracle -

according http://www.jooq.org/doc/3.8/manual/sql-building/sql-statements/update-statement/ jooq doesn't support returning clause in update statements databases except firebird , postgres. does know, still correct oracle jooq? according oracle's documentation, oracle db supports returning clase delete, insert, or update statements. incorrect manual you're right - manual wrong , should fixed: https://github.com/jooq/jooq/issues/5470 single row update returning jooq 3.8 added support single row update .. returning statements. internally, uses callablestatement , pl/sql block of form: begin update "my_table" set "my_table"."column" = 'xyz' "my_table"."id" = 1 returning "my_table"."id", "my_table"."column" ?, ?; ? := sql%rowcount; end; the relevant issue is: https://github.com/jooq/jooq/issues/5190 multi row update returning a...
Read more

java - Warning equals/hashCode on @Data annotation lombok with inheritance -

i have entity inherits other. on other hand, i'm using lombok project reduce boilerplate code, put @data annotation. annotation @data inheritance produces next warning: generating equals/hashcode implementation without call superclass, though class not extend java.lang.object. if intentional, add '@equalsandhashcode(callsuper=false)' type. is advisable add annotation @equalsandhashcode (callsuper = true) or @equalsandhashcode (callsuper = false) ? if not added, 1 callsuper=false or callsuper=true ? the default value false . 1 if don't specify , ignore warning. yes, recommended add @equalsandhashcode annotation on @data annotated classes extend else object. cannot tell if need true or false , depends on class hierarchy, , need examined on case-by-case basis. however, project or package, can configure in lombok.config call super methods if not direct subclass of object. lombok.equalsandhashcode.callsuper = call for configuration system ...
Read more

java - BasicPathUsageException: Cannot join to attribute of basic type -

i using java 8 jpa (hibernate 5.2.1). have clause works perfectly, until introduce clause make use foreign key table values too. i getting following error: basicpathusageexception: cannot join attribute of basic type i think problem related fact have join table, , not sure how create join using join table. employee - employee_category - category model (employee.java): @manytomany(cascade = cascadetype.all, fetch=fetchtype.eager) @jointable ( name="employee_category", joincolumns={ @joincolumn(name="emp_id", referencedcolumnname="id") }, inversejoincolumns={ @joincolumn(name="cat_id", referencedcolumnname="id") } ) private set<category> categories; model (category.java): @id private string id; jpa when introduce following code, fails error above (i think problem new piece of code): join<t, category> category = from.join("id"); predicates.add(criteriabuilder.like(category....
Read more