我想在点击事件中更新列表视图，但是因为我在oncreate（）之外的函数中添加了项目，所以点击事件中的调用不会更新列表视图。

public class MainActivity extends AppCompatActivity implements TimePickerDialog.OnTimeSetListener {
    List<String> itemlist = new ArrayList<String>();

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        // Initializing the array lists and the adapter
        Button add = findViewById(R.id.add);
        EditText editText = findViewById (R.id.editText);
        ListView listView = (ListView) findViewById (R.id.listView);
        Button delete = findViewById (R.id.delete);
        Button clear = findViewById(R.id.clear);

        ArrayAdapter adapter = new ArrayAdapter (MainActivity.this, android.
        R.layout.simple_list_item_multiple_choice, itemlist);

        add.setOnClickListener(new View.OnClickListener() {
               @Override
               public void onClick(View view) {

                   TimePickerFragment timePicker =  new TimePickerFragment();
                   timePicker.show(getSupportFragmentManager(),"time picker");
                   //If i add items like this, everyting works fine 
//                   itemlist.add(editText.getText().toString());
//                   listView.setAdapter(adapter);
//                   adapter.notifyDataSetChanged();
//                   // This is because every time when you add the item the input      space or the eidt text space will be cleared
//                   editText.getText().clear();
               }
           }
        );

        // Selecting and Deleting the items from the list when the delete button is pressed

        delete.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                SparseBooleanArray position = listView.getCheckedItemPositions();

                Integer count = listView.getCount();
                int item = count - 1;
                while (item >= 0) {
                if (position.get(item)) {
                    itemlist.remove(item);
//                    adapter.remove(itemlist.get(item));
                }
                item--;
                }
                position.clear();
                ArrayAdapter<String>  adapter = new ArrayAdapter<String>(MainActivity.this, android.R.layout.simple_list_item_multiple_choice, itemlist);
                listView.setAdapter(adapter);
                adapter.notifyDataSetChanged();
            }
        });

        // Clearing all the items in the list when the clear button is pressed
        clear.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                itemlist.clear();
                ArrayAdapter<String>  adapter = new ArrayAdapter<String>(MainActivity.this, android.R.layout.simple_list_item_multiple_choice, itemlist);
                listView.setAdapter(adapter);
                adapter.notifyDataSetChanged();
            }
        });
    }

    @Override
    public void onTimeSet(TimePicker timePicker, int i, int i1) {
        itemlist.add("The time selected is "+i+":"+i1);

        ListView listView=findViewById(R.id.listView);

        
        ArrayAdapter adapter = new ArrayAdapter<String>(MainActivity.this, android.R.layout.simple_list_item_multiple_choice, itemlist);
        listView.setAdapter(adapter);
        adapter.notifyDataSetChanged();
    }
}t.simple_list_item_multiple_choice, itemlist);
                listView.setAdapter(adapter);
                adapter.notifyDataSetChanged();
            }
        });
    }

    @Override
    public void onTimeSet(TimePicker timePicker, int i, int i1) {
        itemlist.add("The time selected is "+i+":"+i1);

        ListView listView=findViewById(R.id.listView);

        /// TODO: Make adapter accessible from here, dont create a local one
        ArrayAdapter adapter = new ArrayAdapter<String>(MainActivity.this, android.R.layout.simple_list_item_multiple_choice, itemlist);
        listView.setAdapter(adapter);
        adapter.notifyDataSetChanged();
    }
}

个字符
当我在注解部分添加类似的项目时，我不必每次都初始化适配器。我可以使用相同的适配器，但当我在ontimeset中添加项目时，我必须初始化一个新的适配器（我尝试将适配器用作类成员，但不起作用），因此我认为，oncreate中的更新不会更改UI