android - Progress Bar is not showing up when visibility is changed to visible in java code -

i'm making progress bar visible , invisible in async task. i'm doing db operations in async task while doing operations want show progressdialog. finishes operation. want make invisible. code below. problem progresssbar not show up.

activity_xml code:

<?xml version="1.0" encoding="utf-8"?> <relativelayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" android:id="@+id/activity_course_list" android:layout_width="match_parent" android:layout_height="match_parent" tools:context="info.lms.courselist">  <!-- actionbar displayed @ top --> <linearlayout     android:layout_width="match_parent"     android:layout_height="wrap_content"     android:orientation="vertical"> <include     layout="@layout/tool_bar"     android:layout_width="match_parent"     android:layout_height="wrap_content" />  <listview     android:layout_width="match_parent"     android:layout_height="wrap_content"     android:id="@+id/course_list"></listview>  </linearlayout>  <progressbar     android:id="@+id/progressbar"     style="?android:attr/progressbarstyle"     android:layout_width="wrap_content"     android:layout_height="wrap_content"     android:visibility="invisible"     android:layout_centerhorizontal="true"     android:layout_centervertical="true" /> </relativelayout> 

i'm using async task want make progress bar visible , invisible

    private class tmpcourseofferingtask extends asynctask<string,void,jsonobject> {      public tmpcourseofferingtask(){         super();     }     @override     protected void onpreexecute(){      super.onpreexecute();      progressbar.setvisibility(view.visible);      }     @override     protected jsonobject doinbackground(string...params){          return null;     }      @override     protected void onpostexecute(jsonobject json) {       thread.sleep(5000);       } catch (jsonexception e) {             e.printstacktrace();    } catch (interruptedexception e) {             e.printstacktrace();    }     progressbar.setvisibility(view.gone);  } 

first, remove thread.sleep(millis) onpostexecute , put in doinbackground. onpostexecute, onpreexecute, runs on main thread sleep should put in background process.

your flow (at moment) this:

• asynctask created
• pre-execute = progressbar visible
• onbackground = nothing
• post-execute = thread sleep. --> stopping ui thread , view has no time update visibility because it's stopped
• progressbar = view.gone.

this not showing progress because thread being stopped immediatly , view changes applied once after return. use code below , works me.

another thing catch without try (?) code missing or not working. 2 fixes work. like:

 private class tmpcourseofferingtask extends asynctask<string,void,jsonobject> {      public tmpcourseofferingtask(){         super();     }     @override     protected void onpreexecute(){      super.onpreexecute();      progressbar.setvisibility(view.visible);      }     @override     protected jsonobject doinbackground(string...params){        try{       systemclock.sleep(timeinmills);       }catch(exception ignored){       }finally{         return null;       }    }      @override     protected void onpostexecute(jsonobject json) {        progressbar.setvisibility(view.gone);     }  } 

another fix:

you have relativelayout linearlayout , progressbar.. progressbar should visibility "gone" view space not kept used. can remove useless linearlayout , this:

<?xml version="1.0" encoding="utf-8"?> <relativelayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" android:id="@+id/activity_course_list" android:layout_width="match_parent" android:layout_height="match_parent" tools:context="info.lms.courselist">  <include     amdrpod:id="@+id/includeid"     layout="@layout/tool_bar"     android:layout_width="match_parent"     android:layout_height="wrap_content" />  <listview     android:layout_below="@+id/includeid"     android:layout_width="match_parent"     android:layout_height="wrap_content"     android:id="@+id/course_list"/>  <progressbar     android:id="@+id/progressbar"     style="?android:attr/progressbarstyle"     android:layout_width="wrap_content"     android:layout_height="wrap_content"     android:visibility="gone"     android:layout_centerinparent="true" /> </relativelayout> 

(wrote hand, might not perfect)