android - 如何连接删除按钮以删除 ListView 中的一个项目？

Question

我知道有很多主题或多或少相同的话题，但没有一个能涵盖我的情况:

我试图让我的删除按钮删除 ListView 中的一行，并且删除按钮出现在每一行中我让这部分工作但我无法让它在我的主要 Activity 中工作。每次我将此部分放入我的代码时，代码都会中断:

ImageButton removeButton = (ImageButton) findViewById(R.id.btnDel);
removeButton.setOnClickListener(new View.OnClickListener() {
    @Override
    public void onClick(View view) {
        onRemoveButtonClick();
    }
    private void  onRemoveButtonClick() {
        ToDoItem item = (ToDoItem) v.getTag();
        notifyDataSetChanged();
}

我的 MainActivity 没有这段代码也能正常工作。我不知道这是代码还是我将它放在我的 MainActivity 中的位置，如果有人能告诉我，我将不胜感激。

MainActivity.java

public class MainActivity extends AppCompatActivity {
    private static final String LOG_TAG = "ToDoApp";
    private ToDoListManager listManager;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        ListView todoList = (ListView) findViewById(R.id.todo_list);
        listManager = new ToDoListManager(getApplicationContext());
        ToDoItemAdapter adapter = new ToDoItemAdapter(this, listManager.getList());


        todoList.setAdapter(adapter);
        ImageButton addButton = (ImageButton) findViewById(R.id.add_item);
        addButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                onAddButtonClick();
            }
        });
    }

    @Override
    protected void onPause() {
        super.onPause();
        listManager.saveList();
    }

    private void onAddButtonClick() {
        AlertDialog.Builder builder = new AlertDialog.Builder(this);
        builder.setTitle(R.string.add_item);

        final EditText input = new EditText(this);
        input.setInputType(InputType.TYPE_CLASS_TEXT);
        builder.setView(input);

        builder.setPositiveButton(
            R.string.ok,
            new DialogInterface.OnClickListener() {
                @Override
                public void onClick(DialogInterface dialogInterface, int i) {
                    //Add item to list
                    ToDoItem item = new ToDoItem(
                            input.getText().toString(),
                            false
                    );
                    listManager.addItem(item);
                    Log.i(LOG_TAG, input.getText().toString());
                }
            });
        builder.setNegativeButton(
            R.string.cancel,
            new DialogInterface.OnClickListener(){
                @Override
                public void onClick(DialogInterface dialog, int Which) {
                    dialog.cancel();
                }
            });

        builder.show();
    }

    private class ToDoItemAdapter extends ArrayAdapter<ToDoItem> {

        private  Context context;
        private List<ToDoItem> items;
        public ToDoItemAdapter(Context context, List<ToDoItem> items){
            super(context,-1,  items);

            this.context = context;
            this.items = items;
        }

        @Override
        public View getView(int position, View convertView, ViewGroup parent) {
            if(convertView == null) {
                LayoutInflater inflater = (LayoutInflater) context.
                    getSystemService(Context.LAYOUT_INFLATER_SERVICE);
                convertView = inflater.inflate(R.layout.to_do_item_layout, parent, false);
            }

            TextView textView = (TextView) convertView.findViewById(R.id.item);
            CheckBox checkBox = (CheckBox) convertView.findViewById(R.id.checkBox);

            textView.setText(items.get(position).getDescription());
            checkBox.setChecked(items.get(position).isComplete());

            convertView.setTag(items.get(position));
            convertView.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    ToDoItem item = (ToDoItem) v.getTag();
                    item.toggleComplete();
                    notifyDataSetChanged();
                }
            });
            return convertView;
        }
    }
}

ToDoListManager.java

public class ToDoListManager {


private static final String APP_PREFERENCES = "todoapp";
private static final String TODO_ITEMS = "itemslist";

private List<ToDoItem> items;
private SharedPreferences savedData;

public  ToDoListManager(Context context) {

     savedData = context.getSharedPreferences (
        APP_PREFERENCES,
        Context.MODE_PRIVATE
    );

    String json = savedData.getString(TODO_ITEMS, null);
    if (json == null) {
    items = new ArrayList<>();
  } else {

 Type type = new TypeToken<List<ToDoItem>>() {}.getType();
 items = new Gson().fromJson(json, type);
}


}
 public List<ToDoItem> getList() {
 return items;
 }
 public void  addItem(ToDoItem item) {
    items.add(item);
    saveList();

 }
 public  void saveList() {
    SharedPreferences.Editor edit =savedData.edit();
    edit.clear();
    String json = new Gson().toJson(items);

    edit.putString(TODO_ITEMS, json);
    edit.apply();
 }

}

ToDoItem.java

public class ToDoItem {
private String description;
private boolean isComplete;

public ToDoItem (String description,boolean isComplete) {
    this.description = description;
    this.isComplete = isComplete;
}

public String getDescription() {
    return  description;
}
public boolean isComplete() {
    return isComplete;
}
public void toggleComplete() {
    isComplete = !isComplete;
}
@Override
public String toString() {
    return description;
}
}

enter image description here

Answer 1

1.) 首先向您的 to_do_item_layout 添加一个按钮

2.) 现在添加此代码以向每个项目添加一个按钮

Button btn = (Button) convertView.findViewById(R.id.my_btn);

3.) 给它添加一个监听器

btn.setOnClickListener(new View.OnClickListener() {
      @Override
      public void onClick(View v) {
         items.remove(items.get(position));         
      }
});