android 如何在 TextView 上设置 Recyclerview 项目

Question

这是我的主屏幕，我希望当我单击 Select 所有复选框，然后选中所有复选框并在下面的 textView（仅文本）上设置所有复选框的文本。我成功地 select 所有复选框，但无法在带有单独逗号的文本框上设置文本，在适配器的帮助下，我获得了整个数据列表，但无法在主 activity 文本视图布局上设置它。请给我建议任何有用的方法来完成这项工作。 Thnakyou.

public class MainActivity extends AppCompatActivity {
CheckBox checkboxAll;
EditText editSearch;
RecyclerView recyclerView;
TextView dataList;
MainAdapter mainAdapter;
DataAdapter dataAdapter;
List<MainModel> list;
List<String> showList = new ArrayList<>();
SharedPreferences sharedPreferences;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    sharedPreferences = this.getSharedPreferences("prefs", Context.MODE_PRIVATE);
    recyclerView = findViewById(R.id.recyclerView);
    checkboxAll = findViewById(R.id.checkboxAll);
    dataList = findViewById(R.id.dataList);
    editSearch = findViewById(R.id.editSearch);

    editSearch.addTextChangedListener(new TextWatcher() {
        @Override
        public void beforeTextChanged(CharSequence charSequence, int i, int i1, int i2) {

        }

        @Override
        public void onTextChanged(CharSequence charSequence, int i, int i1, int i2) {
            String editValue = String.valueOf(charSequence);
            filter(editValue);

        }

        @Override
        public void afterTextChanged(Editable editable) {

        }
    });

    checkboxAll.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            if (checkboxAll.isChecked()) {
                mainAdapter.selectAll();
            } else {
                mainAdapter.unselectAll();
            }
        }
    });

    list = new ArrayList<>();
    String[] cityname = getResources().getStringArray(R.array.cityList);

    for (int i = 0; i < cityname.length; i++) {
        MainModel mainModel = new MainModel(false, cityname[i]);
        list.add(mainModel);
    }
    RecyclerView.LayoutManager layoutManager = new LinearLayoutManager(this);
    recyclerView.setLayoutManager(layoutManager);
    mainAdapter = new MainAdapter(MainActivity.this, list);
    recyclerView.setAdapter(mainAdapter);
}



private void filter(String searchValue) {
    ArrayList<MainModel> filteredList = new ArrayList<>();
    for (MainModel item : list) {
        if (item.getCityName().toLowerCase().contains(searchValue.toLowerCase())) {
            filteredList.add(item);
        }
    }
    mainAdapter.filterList(filteredList);
}

}

适配器是：-

public class MainAdapter extends RecyclerView.Adapter<MainAdapter.ViewHolder> {

Context context;
List<MainModel> cityList = new ArrayList<>();
int checkValue = 0;
List<String> allValues;
SharedPreferences sharedPreferences;

public MainAdapter(Context context, List<MainModel> list) {

    sharedPreferences = context.getSharedPreferences("prefs", Context.MODE_PRIVATE);
    this.context = context;
    this.cityList = list;
}

public void selectAll() {
    checkValue = 1;
    notifyDataSetChanged();
}

public void unselectAll() {
    checkValue = 2;
    notifyDataSetChanged();
}

@NonNull
@Override
public MainAdapter.ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {

    View view = LayoutInflater.from(context).inflate(R.layout.list_items, parent, false);
    return new ViewHolder(view);
}

@Override
public void onBindViewHolder(@NonNull MainAdapter.ViewHolder holder, int position) {

    holder.itemName.setText(cityList.get(position).getCityName());

    if (checkValue == 1) {
        holder.itemCheckBox.setChecked(true);

    } else if (checkValue == 2) {
        holder.itemCheckBox.setChecked(false);
    }
}


@Override
public int getItemCount() {
    return cityList.size();
}

public class ViewHolder extends RecyclerView.ViewHolder {
    CheckBox itemCheckBox;
    TextView itemName;

    public ViewHolder(@NonNull View itemView) {
        super(itemView);

        itemCheckBox = itemView.findViewById(R.id.itemCheckBox);
        itemName = itemView.findViewById(R.id.itemName);
    }
}

public void filterList(ArrayList<MainModel> filteredList) {
    cityList = filteredList;
    notifyDataSetChanged();
}

}

Answer 1

在选中所有复选框的事件中，您更新绑定到文本视图的可观察字段。您 post 更新后的字符串到该可观察对象，您应该会在文本视图中看到它们。

Answer 2

您可以使用界面实现它，我在下面添加代码片段

class MainActivity extends AppCompatActivity implements MainAdapter.MyRecyclerClickListener {


@Override
protected void onCreate(@Nullable Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    ...

    RecyclerView.LayoutManager layoutManager = new LinearLayoutManager(this);
    recyclerView.setLayoutManager(layoutManager);
    MainAdapter mainAdapter = new MainAdapter(MainActivity.this, list);
    recyclerView.setAdapter(mainAdapter);

    mainAdapter.setClickListener(this);


}

@Override
public void onAllItemSelected(String text) {
    // set on TextView
}

@Override
public void onAllItemUnSelected(String text) {
    // set on TextView toi clear all previous value
}

}

public class MainAdapter extends RecyclerView.Adapter<MainAdapter.ViewHolder> {

    private MyRecyclerClickListener myRecyclerClickListener;
    
    public void selectAll() {
        checkValue = 1;
        StringBuilder stringBuilder = new StringBuilder();
        for (MainModel cityModel : cityList) {
            stringBuilder.append(cityModel.getCityName()).append(",");

        }
        myRecyclerClickListener.onAllItemSelected(stringBuilder.toString());
        notifyDataSetChanged();
    }

    public void unselectAll() {
        checkValue = 2;
        myRecyclerClickListener.onAllItemUnSelected("");
        notifyDataSetChanged();
    }
    
    public void  setClickListener(MyRecyclerClickListener myRecyclerClickListener){
        this.myRecyclerClickListener = myRecyclerClickListener
    }


    public  interface MyRecyclerClickListener{
        void onAllItemSelected(String text);
        void onAllItemUnSelected(String text);
    }

}

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