如何删除ListView中的特定项目？

Question

In Android Studio, I have a listview on the main page where multiple courses can keep being added. When I click on a list view course it takes me to a second page. On the second page there is a delete button that will delete that specific course I clicked on and take me back to the main page.

Can someone please help me with the on click listener for the delete button in order for the above procedure to work?

Answer 1

A ListView takes a list of items and uses that list to show what you see on the screen. What you need to do is on the second page, just remove that item from the list and call notifyDataSetChanged() method on the adapter of the ListView. This will cause the adapter to create all the items again and you won't see that deleted item anymore.

EDIT

Just something to get you started. If you have a class which contains the list of all the courses that are being added, you can simply remove that course on your delete button click.

class Courses {
    List<Course> courseList;

    //Your other members and functions

    void removeCourse(Course course) {
        courseList.remove(course);
    }
}

class Course {
    //Some details
}

button.setOnClickListener(new View.OnClickListener() {
         public void onClick(View v) {
             //Call that remvoeCourse method here
             courses.removeCourse(selectedCourse);
         }
});    

Answer 2

How do you delete a specific item in a ListView?

You can achieve your problem by Share Preference or startActivityForResult .

Using startActivityForResult

Start your second activity with startActivityForResult() in your first Activity;

Intent i = new Intent(this, SecondActivity.class);
startActivityForResult(i, 1);

and get the result back when you click delete function

Intent intent = new Intent();
intent.putExtra("result",position);
setResult(Activity.RESULT_OK,returnIntent);
finish();

add this in your OnBackButton

Intent intent = new Intent();
setResult(Activity.RESULT_CANCELED, intent);
finish();

and finally get the result in onActivityResult() in First Activity

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {

    if (requestCode == 1) {
        if(resultCode == Activity.RESULT_OK){
            String result=data.getIntExtra("position");
           // Do your operation here 
           // delete position you getting here from intent
        }
        if (resultCode == Activity.RESULT_CANCELED) {
            //Write your code if there's no result
        }
    }
}

Using Share Preference

Save your position or Id for Listview Item in share preference and call onBackPressed() method in your delete function. Do these operation in 2 activity.

PreferenceManager.getDefaultSharedPreferences(this).edit().putInt("position", position).commit();
onBackPressed();

In your first Activity do operation in your onRestart method

  @Override
    protected void onRestart() {
        super.onRestart();
        int position = PreferenceManager.getDefaultSharedPreferences(this).getInt("position", 0);
        // delete item from arraylist 
        // notify your adapter
    }