Issue
My issue: In my xml file, I define android:visibility="gone" in the linear layout labelled as assess_layout_list. Then, in the onClick() of course_adapter_layout, the whole view, I set the visibility back to View.VISIBLE, which does not work, even though the Log call just before it works, the LinearLayout object called assess_list_layout is not null, and it does work when I define the visibility="invisible" in the xml file. I want it to be gone at first though, and visible after clicking as this fits the design of the app.
Here is my course_adapter_view.xml file:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:id="@+id/course_adapter_layout"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical"
android:gravity="left"
>
<LinearLayout
android:orientation="horizontal"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginHorizontal="20dp"
android:layout_marginTop="20dp"
android:padding="15dp"
android:elevation="2dp"
android:background="@drawable/course_header_background">
<ImageView
android:layout_width="20dp"
android:layout_height="20dp"
android:src="@drawable/course_color_circle"/>
<Space
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight="0.25"/>
<TextView
android:id="@+id/course_adapter_course_code"
android:text="TextView1"
android:layout_width="wrap_content"
android:layout_height="20dp"
android:layout_weight="0.5"/>
<Space
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight="0.25"/>
<TextView
android:id="@+id/course_adapter_course_title"
android:text="TextView2"
android:layout_width="wrap_content"
android:layout_height="20dp"/>
</LinearLayout>
<LinearLayout
android:id="@+id/assess_list_layout"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical"
android:layout_marginRight="40dp"
android:layout_marginLeft="40dp"
android:background="@drawable/course_body_background"
android:padding="20dp"
android:visibility="gone"
>
<ListView
android:id="@+id/course_adapter_assess_list"
android:layout_width="match_parent"
android:layout_height="250dp"
android:layout_marginBottom="10dp"/>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal">
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="left"
android:text="More" />
<Space
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="1"/>
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="left"
android:text="New"/>
</LinearLayout>
</LinearLayout>
</LinearLayout>
Here is my CourseListAdapter.java file that I use to create each view for each course in the list of courses, minus the usual stuff:
package com.example.schoolplanner2.adapters;
public class CourseListAdapter extends ArrayAdapter<Course> {
private static final String TAG = "CourseListAdapter";
private Context context;
int mResource;
public CourseListAdapter(@NonNull Context context, int resource, @NonNull ArrayList<Course> objects) {
super(context, resource, objects);
this.context = context;
mResource = resource;
}
@NonNull
@Override
public View getView(int position, @Nullable View convertView, @NonNull ViewGroup parent) {
// get info
String course_code = getItem(position).getCourseCode();
Double course_grade = getItem(position).getCurrentGrade();
// make inflater and inflate the layout
LayoutInflater inflater = LayoutInflater.from(context);
View v = inflater.inflate(mResource, parent, false);
TextView tv_course_code = v.findViewById(R.id.course_adapter_course_code);
TextView tv_course_title = v.findViewById(R.id.course_adapter_course_title);
tv_course_code.setText(course_code);
tv_course_title.setText(String.valueOf(course_grade));
// add on click to each list view element
LinearLayout layout = v.findViewById(R.id.course_adapter_layout);
layout.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
Log.i(TAG, "List view element has been clicked " + course_code);
// expand the view to include a new fragment
LinearLayout assess_list_layout = view.findViewById(R.id.assess_list_layout);
assess_list_layout.setVisibility(View.VISIBLE);
// get the list view and add each course to the course view
ListView assessment_list_view = (ListView) view.findViewById(R.id.course_adapter_assess_list);
AssessmentListAdapter assessAdapter = new AssessmentListAdapter(getContext(), R.layout.assessment_adapter_view, getItem(position).getAssessmentList(), getItem(position));
assessment_list_view.setAdapter(assessAdapter);
}
});
return v;
}
}
Please let me know if there is any more information you need. Will also take suggestions on other ways of accomplishing the same thing. Thanks for your help. ~Seth.
Edit: when the assess_list_layout.setVisibility(View.VISIBLE) is outside of the onClick it does work.
Further Edit: Things I have tried so far to no avail:
- moving the location of where I define the LinearLayout componenent
- calling invalidate() on parent view
- using runOnUiThread()
- changing view to v in the line where I attempt to findViewById for assess_list_layout, they are the same thing so it does not help.
- calling requestLayout() on assess_list_layout
Update: I have now managed to get the assess_list_layout section to appear when the course_adapter_layout is clicked on. The only problem now is that the view does not take up anymore space on the screen, it just turns into a scrollable view that can be scrolled up and down on to see the whole view. Also, when I scroll to fast, it resets the view back to the way it was on bootup.
Solution
1.View Visibility not working
The Visibility is not working because the view is not rendered initially. Remove the visibility gone in the xml and handle the visibility fully in the adapter class. In the 'assess_list_layout' linerlayout height can be hardcode because inside this layout the listview height is already hardcoded. You can hardcode to 300 and check. This way will help the view to get the initial rendering.
2. Scroll issue
While scrolling the already visible 'assess_list_layout' view might be not visible. This is because we need to handle the visibility, this handling is similar to checkbox selection handling in listview. Hope the Course class is model class, in that add a another property named isSelected as boolean and set the default value to false. Please refer below the course class,
Course Class
public class Course {
private boolean isSelected = false;
public boolean isSelected() {
return isSelected;
}
public void setSelected(boolean selected) {
isSelected = selected;
}
}
please refer the below code changes in the adapter class.
public class CourseListAdapter extends ArrayAdapter<Course> {
private static final String TAG = "CourseListAdapter";
private Context context;
int mResource;
public CourseListAdapter(@NonNull Context context, int resource, @NonNull ArrayList<Course> objects) {
super(context, resource, objects);
this.context = context;
mResource = resource;
}
@NonNull
@Override
public View getView(int position, @Nullable View convertView, @NonNull ViewGroup parent) {
// get info
String course_code = getItem(position).getCourseCode();
Double course_grade = getItem(position).getCurrentGrade();
// make inflater and inflate the layout
LayoutInflater inflater = LayoutInflater.from(context);
View v = inflater.inflate(mResource, parent, false);
TextView tv_course_code = v.findViewById(R.id.course_adapter_course_code);
TextView tv_course_title = v.findViewById(R.id.course_adapter_course_title);
//My Change
// expand the view to include a new fragment
LinearLayout assess_list_layout = view.findViewById(R.id.assess_list_layout);
// get the list view and add each course to the course view
ListView assessment_list_view = (ListView) view.findViewById(R.id.course_adapter_assess_list);
assess_list_layout.setVisibility(View.GONE);
if (getItem().get(position).isSelected()) {
assess_list_layout.setVisibility(View.Visible);
AssessmentListAdapter assessAdapter = new AssessmentListAdapter(getContext(), R.layout.assessment_adapter_view, getItem(position).getAssessmentList(), getItem(position));
assessment_list_view.setAdapter(assessAdapter);
}
//My Change
tv_course_code.setText(course_code);
tv_course_title.setText(String.valueOf(course_grade));
// add on click to each list view element
LinearLayout layout = v.findViewById(R.id.course_adapter_layout);
layout.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
Log.i(TAG, "List view element has been clicked " + course_code);
//My Change
getItem().get(position).setSelected(true);
//My Change
assess_list_layout.setVisibility(View.VISIBLE);
AssessmentListAdapter assessAdapter = new AssessmentListAdapter(getContext(), R.layout.assessment_adapter_view, getItem(position).getAssessmentList(), getItem(position));
assessment_list_view.setAdapter(assessAdapter);
}
});
return v;
}
}
I have commented as My Change to find the difference in the code.
Answered By - Jeevanandhan