创建卡片后，如何在recyclerviewcardview中添加日期 卡创建日期

问题描述

我正在开发一个便笺应用程序，其中用户创建便笺，保存便笺后，便笺将被保存并显示在recyclerview中。我正在寻找可以显示注释创建日期的日期的东西。我已经在适配器类中实例化了日历，并设置了日期。问题是所有卡片都具有今天的日期，而与创建日期无关。如下图所示 Screenshot of emulator

以下是我的适配器类

 package com.cksapp.mvvmarchitecture;
    
    import android.util.Log;
    import android.view.LayoutInflater;
    import android.view.MenuItem;
    import android.view.View;
    import android.view.ViewGroup;
    import android.widget.ImageView;
    import android.widget.PopupMenu;
    import android.widget.TextView;
    
    import androidx.annotation.NonNull;
    import androidx.recyclerview.widget.RecyclerView;
    
    import java.text.DateFormat;
    import java.util.ArrayList;
    import java.util.Calendar;
    import java.util.List;
    
    public class NoteAdapter extends RecyclerView.Adapter<NoteAdapter.NoteHolder> {
    
        private static List<Note> notes = new ArrayList<>();
        private onItemClicklistener listener;
        private onItemClicklistener1 listener1;
        private onItemClicklistener2 listener2;
        private onItemClicklistener3 listener3;
    
        private Noteviewmodel noteviewmodel;
    
        @NonNull
        @Override
        public NoteHolder onCreateViewHolder(@NonNull ViewGroup parent,int viewType) {
            View itemView = LayoutInflater.from(parent.getContext()).inflate(R.layout.note_item,parent,false);
            return new NoteHolder(itemView);
    
        }
    
        @Override
        public void onBindViewHolder(@NonNull NoteHolder holder,final int position) {
            final Note currentNote = notes.get(position);
            holder.textViewTitle.setText(currentNote.getTitle());
            holder.textViewDescription.setText(currentNote.getDescription());
            Calendar c = Calendar.getInstance();**//calender instantiation**
            String currentDate = DateFormat.getDateInstance().format(c.getTime());
            holder.textViewdate.setText(currentDate);
    
    
        }
        private void deleteItem(int position) {
           noteviewmodel.delete(notes.get(position));
        }
    
        @Override
        public int getItemCount() {
            return notes.size();
        }
    
        public void setNotes(List<Note> notes){
            this.notes = notes;
            notifyDataSetChanged();
        }
        public Note getNoteAt(int position){
            return notes.get(position);
        }
    
        class NoteHolder extends RecyclerView.ViewHolder{
            private TextView textViewTitle,textViewdate;
            private TextView textViewDescription;
            private ImageView menupopup;
    
    
            public NoteHolder(@NonNull View itemView) {
                super(itemView);
                textViewTitle = itemView.findViewById(R.id.text_view_title);
                textViewDescription = itemView.findViewById(R.id.text_view_description);
                textViewdate = itemView.findViewById(R.id.datetext);
                menupopup = itemView.findViewById(R.id.options);
                menupopup.setonClickListener(new View.OnClickListener() {
                    @Override
                    public void onClick(View v) {
    
                        PopupMenu popupMenu = new PopupMenu(v.getContext(),v);
                        popupMenu.getMenuInflater().inflate(R.menu.popup_menu,popupMenu.getMenu());
                        popupMenu.show();
                        popupMenu.setonMenuItemClickListener(new PopupMenu.OnMenuItemClickListener() {
                            @Override
                            public boolean onMenuItemClick(MenuItem item) {
                                final int position1 = getAdapterPosition();
    
                                switch (item.getItemId()){
                                    case R.id.opennotemenu:
                                        if(position1 != RecyclerView.NO_POSITION && listener1 != null) {
                                            listener2.onItemclick2(notes.get(position1));
                                        }
                                        break;
                                    case R.id.editmenu:
                                        if(position1 != RecyclerView.NO_POSITION && listener1 != null) {
                                            listener1.onItemclick1(notes.get(position1));
                                        }
                                        break;
                                    case R.id.deletemenu:
                                        if(position1 != RecyclerView.NO_POSITION && listener != null) {
                                            listener.onItemclick(notes.get(position1));
                                        }
                                        break;
                                    case R.id.sharenote:
                                        if(position1 != RecyclerView.NO_POSITION && listener3 != null) {
                                            listener3.onItemclick3(notes.get(position1));
                                        }
                                }
                                return true;
                            }
                        });
                    }
                });
    
            }
        }
        public interface onItemClicklistener{
            void onItemclick(Note note);
        }
        public void setonItemClicklistener(onItemClicklistener listener){
            this.listener = listener;
    
        }
        public interface onItemClicklistener1{
            void onItemclick1(Note note);
        }
        public void setonItemClicklistener1(onItemClicklistener1 listener1){
            this.listener1 = listener1;
    
        }
        public interface onItemClicklistener2{
            void onItemclick2(Note note);
        }
        public void setonItemClicklistener2(onItemClicklistener2 listener2){
            this.listener2 =  listener2;
        }
        public interface onItemClicklistener3{
            void onItemclick3(Note note);
        }
        public void setonItemClicklistener3(onItemClicklistener3 listener3){
            this.listener3 = listener3;
        }
    }




**My add note activity**

package com.cksapp.mvvmarchitecture;

import androidx.annotation.NonNull;
import androidx.appcompat.app.AppCompatActivity;

import android.content.Intent;
import android.os.Bundle;
import android.provider.ContactsContract;
import android.util.Log;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.view.View;
import android.widget.EditText;
import android.widget.NumberPicker;
import android.widget.Toast;

import java.text.DateFormat;
import java.util.Calendar;
import java.util.Date;

public class NewActivityNote extends AppCompatActivity {
    EditText title,description;

    public static final String EXTRA_TITLE = "com.cksapp.mvvmarchitecture.EXTRA_TITLE";
    public static final String EXTRA_ID = "com.cksapp.mvvmarchitecture.EXTRA_ID";
    public static final String EXTRA_DESCRIPTION = "com.cksapp.mvvmarchitecture.EXTRA_DESCRIPTION";
    String currentDate;


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_new_note);
        title = findViewById(R.id.title1);
        description = findViewById(R.id.description1);
        getSupportActionBar().setHomeAsUpIndicator(R.drawable.ic_close);

        Intent intent = getIntent();
        if(intent.hasExtra(EXTRA_ID)){
            setTitle("Edit Note");
            title.setText(intent.getStringExtra(EXTRA_TITLE));
            description.setText(intent.getStringExtra(EXTRA_DESCRIPTION));
        }

        setTitle("Add Note");
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        MenuInflater menuInflater = getMenuInflater();
        menuInflater.inflate(R.menu.new_note,menu);
        return true;
    }

    @Override
    public boolean onoptionsItemSelected(@NonNull MenuItem item) {
        switch (item.getItemId()){
            case R.id.save:
                savenote();
                return true;
            default:
                return super.onoptionsItemSelected(item);
        }
       
    }

    private void savenote() {
        String title1 = title.getText().toString();
        String description1 = description.getText().toString();


        if(title1.trim().isEmpty() || description1.trim().isEmpty()){
            Toast.makeText(NewActivityNote.this,"Enter title and description",Toast.LENGTH_SHORT).show();
            return;
        }

        Intent data = new Intent();
        data.putExtra(EXTRA_TITLE,title1);
        data.putExtra(EXTRA_DESCRIPTION,description1);


        int id = getIntent().getIntExtra(EXTRA_ID,-1);
        if(id != -1){
            data.putExtra(EXTRA_ID,id);
        }


        setResult(RESULT_OK,data);
        finish();
    }

    public void doSave(View view) {
        savenote();
    }
}

就像您建议的那样，我在项目中所做的更改是，这是我添加的转换器类

    import androidx.room.TypeConverter;

import java.sql.Date;


public class Converters {
    @TypeConverter
    public static Date fromTimestamp(Long value) {
        return value == null ? null : new Date(value);
    }

    @TypeConverter
    public static Long datetoTimestamp(Date date) {
        return date == null ? null : date.getTime();
    }
}

我在实体类中添加了日期对象

import androidx.room.Entity;
import androidx.room.PrimaryKey;

import java.sql.Date;


@Entity(tableName = "note_table")
public class Note {
    @PrimaryKey(autoGenerate = true)
    private int id;
    private String title;
    private String description;
    private Date date;



    public Note(String title,String description) {
        this.title = title;
        this.description = description;

    }
   public void setDate(Date date){
        this.date = date;
   }

   public Date getDate(){
        return date;
   }

    public void setId(int id) {
        this.id = id;
    }

    public int getId() {
        return id;
    }

    public String getTitle() {
        return title;
    }


    public String getDescription() {
        return description;
    }

}

下面是我的NewNoteActivity savenote方法，我想在其中记录日期

private void savenote() {
        String title1 = title.getText().toString();
        String description1 = description.getText().toString();
        Date date = Calendar.getInstance().getTime();
        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-mm-dd hh:mm:ss");
        currentDate = sdf.format(date);

接下来，我尝试将currentDate字符串访问适配器类以设置日期

 @Override
    public void onBindViewHolder(@NonNull NoteHolder holder,final int position) {
        final Note currentNote = notes.get(position);
        holder.textViewTitle.setText(currentNote.getTitle());
        holder.textViewDescription.setText(currentNote.getDescription());
        NewActivityNote n = new NewActivityNote();
        String date = n.currentDate;
        holder.textViewdate.setText(date);

最后，它给了我null代替日期textview。文本视图最终设置为无（空）

执行上述任务后，我的模拟器的屏幕截图 result

下面是我完整的NewNoteActivity

import androidx.annotation.NonNull;
import androidx.appcompat.app.AppCompatActivity;

import android.content.Intent;
import android.os.Bundle;
import android.provider.ContactsContract;
import android.util.Log;
import android.view.Gravity;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.widget.EditText;
import android.widget.ImageView;
import android.widget.NumberPicker;
import android.widget.TextView;
import android.widget.Toast;

import java.text.DateFormat;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;
import java.util.Locale;

public class NewActivityNote extends AppCompatActivity {
    EditText title,menu);
        return true;
    }

    @Override
    public boolean onoptionsItemSelected(@NonNull MenuItem item) {
        switch (item.getItemId()){
            case R.id.save:
                savenote();
                return true;
            default:
                return super.onoptionsItemSelected(item);
        }
       
    }

    private void savenote() {
        String title1 = title.getText().toString();
        String description1 = description.getText().toString();
        Date date = Calendar.getInstance().getTime();
        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-mm-dd hh:mm:ss");
        currentDate = sdf.format(date);



        if(title1.trim().isEmpty() || description1.trim().isEmpty()){
            LayoutInflater inflater = getLayoutInflater();
            View layout = inflater.inflate(R.layout.toast_custom,(ViewGroup) findViewById(R.id.toastlayout));
            TextView t1 = layout.findViewById(R.id.toasttext);
            ImageView i1 = layout.findViewById(R.id.toastimage);
            t1.setText("Enter title and description");
            i1.setimageResource(R.drawable.ic_error);
            Toast toast = new Toast(getApplicationContext());
            toast.setGravity(Gravity.CENTER,0);
            toast.setDuration(Toast.LENGTH_LONG);
            toast.setView(layout);
            toast.show();
            return;
        }

        Intent data = new Intent();
        data.putExtra(EXTRA_TITLE,id);
        }
        LayoutInflater inflater = getLayoutInflater();
        View layout = inflater.inflate(R.layout.toast_custom,(ViewGroup) findViewById(R.id.toastlayout));
        TextView t1 = layout.findViewById(R.id.toasttext);
        ImageView i1 = layout.findViewById(R.id.toastimage);
        t1.setText("Enjoy,Note saved to your collections!");
        i1.setimageResource(R.drawable.ic_check);
        Toast toast = new Toast(getApplicationContext());
        toast.setGravity(Gravity.CENTER,0);
        toast.setDuration(Toast.LENGTH_LONG);
        toast.setView(layout);
        toast.show();


        setResult(RESULT_OK,data);
        finish();
    }

    public void doSave(View view) {
        savenote();
    }
}

我的班上班

package com.cksapp.mvvmarchitecture;

import androidx.lifecycle.LiveData;

import androidx.room.Dao;
import androidx.room.Delete;
import androidx.room.Insert;
import androidx.room.Query;

import androidx.room.Update;

import java.util.List;

@Dao
public interface NoteDao {

    @Insert
    void insert(Note note);

    @Update
    void update(Note note);

    @Delete
    void delete(Note note);

    @Query("DELETE FROM note_table")
    void deleteallNotes();



    @Query("Select * from note_table order by id desc")
    LiveData<List<Note>> getAllNotes();
}

解决方法

如前所述，您需要将日期保存在笔记实体中。

如果您对建议的时间获取方式感兴趣，请阅读this answer。

然后，您应该将时间转换为Long并将其保存（在您的note类中）到数据库中。 然后，在显示日期时，您必须将数字转换回格式化的日期。

还可以让Room处理携带有关时间信息的复杂对象，例如Date类（由您的c.getTime()调用返回）。 作为将Date对象保存到数据库的示例，您可以根据文档中的this example定义一个简单的转换器类。