如何从 recyclerView 中的项目获取数据并在 editTexts 上的不同活动中查看它答案

【问题标题】：How to get data from an item in a recyclerView and view it in a different activity on editTexts如何从 recyclerView 中的项目获取数据并在 editTexts 上的不同活动中查看它
【发布时间】：2022-01-16 23:29:16
【问题描述】：

当用户登录一个用户可以创建其帐户的活动时 (CreateProfileActivity)。创建配置文件后，用户将被重定向到 recyclerView 活动，其中他们的配置文件信息显示在 recyclerView 中。当用户单击 recyclerView 中的项目时，更新活动将打开。我希望他们的个人资料信息从 recyclerView 加载到更新活动中。请帮忙。

附：由于我没有只打开一次 CreateProfile_Activity，因为我不希望用户创建多个配置文件，所以现在：我运行了一次应用程序并创建了一个帐户，然后当用户更改它时登录它会打开recyclerView_Activity。

这里是recyclerView_Activity

package com.example.insert_update_activity;

import android.content.Intent;
import android.database.Cursor;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.Toast;

import androidx.annotation.Nullable;
import androidx.appcompat.app.AppCompatActivity;
import androidx.recyclerview.widget.LinearLayoutManager;
import androidx.recyclerview.widget.RecyclerView;

import java.util.ArrayList;

public class recyclerView_Activity extends AppCompatActivity {

   // Button insertBtn;
    RecyclerView recyclerView;
    DBHelper myDB;
    ArrayList<String> temp_id, temp_name, temp_age;
    myAdapter myAdapter;

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

        recyclerView = (RecyclerView) findViewById(R.id.recyclerView);
 /*       insertBtn = (Button) findViewById(R.id.insertBtn);

        insertBtn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent intent = new Intent(recyclerView_Activity.this, Insert_Activity.class);
                startActivity(intent);
            }
        });*/

        myDB = new DBHelper(recyclerView_Activity.this);

        temp_id = new ArrayList<>();
        temp_name = new ArrayList<>();
        temp_age = new ArrayList<>();

        storeDataInArrays();

        myAdapter = new myAdapter(recyclerView_Activity.this, this, temp_id, temp_name, temp_age);
        recyclerView.setAdapter(myAdapter);
        recyclerView.setLayoutManager(new LinearLayoutManager(recyclerView_Activity.this));
    }

    @Override
    protected void onActivityResult(int requestCode, int resultCode, @Nullable Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        if (requestCode == 1)
        {
            recreate();
        }
    }

    void storeDataInArrays() {
        Cursor cursor = myDB.readData();  // Cursor cursor = myDB.readAllData();

        if (cursor.getCount() == 0)
        {
            Toast.makeText(recyclerView_Activity.this, "No Data", Toast.LENGTH_SHORT).show();
        }
        else
        {
            while (cursor.moveToNext()) {

                temp_id.add(cursor.getString(0));
                temp_name.add(cursor.getString(1));
                temp_age.add(cursor.getString(2));


            }
        }
    }
}

这里是更新活动

package com.example.insert_update_activity;

import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;

import androidx.appcompat.app.AppCompatActivity;

public class Update_Activity extends AppCompatActivity {

    EditText name, age;
    Button updateBtn;
    String id;

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

        name = (EditText) findViewById(R.id.edit_name);
        age = (EditText) findViewById(R.id.edit_age);
        updateBtn = (Button) findViewById(R.id.updateBtn);

        updateBtn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

                String sName = name.getText().toString().trim();
                String sAge = age.getText().toString().trim();
                DBHelper db = new DBHelper(Update_Activity.this);

                db.updateData(id, sName, sAge);

                Intent intent = new Intent(Update_Activity.this, com.example.insert_update_activity.recyclerView_Activity.class);
                startActivity(intent);
            }
        });
        getAndSetIntentData();

    }

    void getAndSetIntentData() {
        if (getIntent().hasExtra("id") && getIntent().hasExtra("Name") && getIntent().hasExtra("Age"))
        {
            // Getting data from Intent
            id = getIntent().getStringExtra("id");
            String NAME = getIntent().getStringExtra("Name");
            String AGE = getIntent().getStringExtra("Age");

            // Setting Intent Data
            name.setText(NAME);
            age.setText(AGE);
        }
        else
        {
            Toast.makeText(Update_Activity.this, "No Data", Toast.LENGTH_SHORT).show();
        }
    }
}

这里是 DBHelper

package com.example.insert_update_activity;

import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import android.widget.Toast;

import androidx.annotation.Nullable;

public class DBHelper extends SQLiteOpenHelper {

    private Context context;
    private static final String DATABASE_NAME = "Database.db";
    private static final int DATABASE_VERSION = 1;

    // Create table
    private static final String TABLE_TEMP = "TEMPP";
    private static final String COLUMN_ID = "id";
    private static final String COLUMN_NAME = "name";
    private static final String COLUMN_AGE = "age";

    public DBHelper(@Nullable Context context) {
        super(context, DATABASE_NAME, null, DATABASE_VERSION);
        this.context = context;
    }

    @Override
    public void onCreate(SQLiteDatabase db) {
        String profileQuery = "CREATE TABLE " + TABLE_TEMP +
                " (" + COLUMN_ID + " INTEGER PRIMARY KEY AUTOINCREMENT, " +
                COLUMN_NAME + " TEXT, " + COLUMN_AGE + " INTEGER " + ")";
        db.execSQL(profileQuery);

    }

    @Override
    public void onUpgrade(SQLiteDatabase db, int i, int i1) {
        db.execSQL("DROP TABLE IF EXISTS " + TABLE_TEMP);
        onCreate(db);


    }

    // Functions for TEMP TABLE ********************************************************************************************************************************************  PROFILE TEMP
    public Boolean insertData(String name, String age) {
        SQLiteDatabase db = this.getWritableDatabase();
        ContentValues cv = new ContentValues();

        cv.put(COLUMN_NAME, name);
        cv.put(COLUMN_AGE, age);

        long result = db.insert(TABLE_TEMP, null, cv);

        if (result == -1) {
            Toast.makeText(context, "Failed to Insert", Toast.LENGTH_SHORT).show();
            return  false;
        } else {
            Toast.makeText(context, "Data Inserted Successfully!", Toast.LENGTH_SHORT).show();
            return true;
        }
    }

    Cursor readData() {
        String query = "SELECT * FROM " + TABLE_TEMP;
        SQLiteDatabase db = this.getReadableDatabase();

        Cursor cursor = null;

        if (db != null) {
            cursor = db.rawQuery(query, null);
        }
        return cursor;
    }

    // Update data using where clause;
    public Boolean updateData(String row_id, String name, String age)
    {
        SQLiteDatabase db = this.getWritableDatabase(); // SQLiteDatabase db = this.getWritableDatabase();
        ContentValues cv = new ContentValues();

        cv.put(COLUMN_NAME, name);
        cv.put(COLUMN_AGE, age);

        long result = db.update(TABLE_TEMP, cv, COLUMN_ID + " =? ", new String[]{row_id});
       
        if (result == -1)
        {
            Toast.makeText(context, "Failed to Update",  Toast.LENGTH_SHORT).show();
            return false;
        }
        else
        {
            Toast.makeText(context, "Successfully Updated!",  Toast.LENGTH_SHORT).show();
            return true;
        }

    }


}

这是适配器

package com.example.insert_update_activity;

import android.app.Activity;
import android.content.Context;
import android.content.Intent;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.LinearLayout;
import android.widget.TextView;

import androidx.annotation.NonNull;
import androidx.recyclerview.widget.RecyclerView;

import java.util.ArrayList;

public class myAdapter extends RecyclerView.Adapter<myAdapter.MyViewHolder> {

    private Context context;
    Activity activity;
    private ArrayList id, name, age;

    myAdapter(Activity activity, Context context, ArrayList id, ArrayList name, ArrayList age) {

        this.activity = activity;
        this.context = context;
        this.id = id;
        this.name = name;
        this.age = age;

    }
    @NonNull
    @Override
    public MyViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
        LayoutInflater inflater = LayoutInflater.from(context);
        View view = inflater.inflate(R.layout.my_row, parent, false);
        return new MyViewHolder(view);
    }

    @Override
    public void onBindViewHolder(@NonNull MyViewHolder holder, final int position) {
        holder.id_txt.setText(String.valueOf(id.get(position)));
        holder.name_txt.setText(String.valueOf(name.get(position)));
        holder.age_txt.setText(String.valueOf(age.get(position)));
        holder.mainLayout.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent intent = new Intent(context, Update_Activity.class);
                intent.putExtra("id", String.valueOf(id.get(position)));
                intent.putExtra("name", String.valueOf(name.get(position)));
                intent.putExtra("age", String.valueOf(age.get(position)));
                activity.startActivityForResult(intent, 1);
            }
        });

    }

    @Override
    public int getItemCount() {

        return id.size();
    }

    public class MyViewHolder extends RecyclerView.ViewHolder {

        TextView id_txt, name_txt, age_txt;
        LinearLayout mainLayout;

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

            id_txt = itemView.findViewById(R.id.id_txt);
            name_txt = itemView.findViewById(R.id.name_txt);
            age_txt = itemView.findViewById(R.id.age_txt);
            mainLayout = itemView.findViewById(R.id.mainLayout);

        }
    }
}

这里是 recyclerView 的 xml 文件 my_row

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:orientation="vertical"
    android:id="@+id/mainLayout">

    <androidx.cardview.widget.CardView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:outlineSpotShadowColor="#000000"
        app:cardElevation="3dp">

        <androidx.constraintlayout.widget.ConstraintLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:padding="12dp">

            <TextView
                android:id="@+id/id_txt"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_marginRight="10dp"
                android:text="1"
                android:textColor="#9A9797"
                android:textSize="35dp"
                android:textStyle="bold"
                app:layout_constraintEnd_toEndOf="parent"
                app:layout_constraintTop_toTopOf="parent" />

            <TextView
                android:id="@+id/nameTitle"
                android:layout_width="90dp"
                android:layout_height="wrap_content"
                android:layout_marginLeft="10dp"
                android:layout_marginTop="10dp"
                android:text="NAME:"
                android:textColor="#000"
                android:textSize="16sp"
                android:textStyle="bold"
                app:layout_constraintStart_toStartOf="parent"
                app:layout_constraintTop_toTopOf="parent" />

            <TextView
                android:id="@+id/ageTitle"
                android:layout_width="90dp"
                android:layout_height="wrap_content"
                android:text="AGE:"
                android:textColor="#000"
                android:textSize="16sp"
                android:textStyle="bold"
                app:layout_constraintStart_toStartOf="@+id/nameTitle"
                app:layout_constraintTop_toBottomOf="@+id/nameTitle" />

            <TextView
                android:id="@+id/name_txt"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="Name"
                android:textSize="15sp"
                app:layout_constraintStart_toEndOf="@+id/nameTitle"
                app:layout_constraintTop_toTopOf="@+id/nameTitle" />

            <TextView
                android:id="@+id/age_txt"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="Age"
                android:textSize="15sp"
                app:layout_constraintStart_toEndOf="@+id/ageTitle"
                app:layout_constraintTop_toBottomOf="@+id/nameTitle" />


        </androidx.constraintlayout.widget.ConstraintLayout>
    </androidx.cardview.widget.CardView>

</LinearLayout>

登录活动非常简单。如果用户名==“User1”和密码==“123456”，它只允许用户登录。 CreateProfile_Activity 只使用一次 insertData

【问题讨论】：

标签： java android sqlite

【解决方案1】：

好的，现在它可以工作了。我不确定这是为什么，但我会发布我所做的更改。

所以一个问题出在 myAdapter 中。在 mainLayout OnClick 中，“姓名”和“年龄”与 UpdateActivity 中的“姓名”和“年龄”不同，我从 Intent 获取数据。 “年龄”和“姓名”的第一个字母都不是大写字母。我更改的另一件事是 onBindHolder 中的 get(position)。

现在 onBindHolder 看起来像这样：

public void onBindViewHolder(@NonNull MyViewHolder holder, final int position) {
    holder.id_txt.setText(String.valueOf(id.get(holder.getAdapterPosition())));
    holder.name_txt.setText(String.valueOf(name.get(holder.getAdapterPosition())));
    holder.age_txt.setText(String.valueOf(age.get(holder.getAdapterPosition())));


    holder.mainLayout.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            Intent intent = new Intent(v.getContext(), Update_Activity.class);
            intent.putExtra("id", String.valueOf(id.get(holder.getAdapterPosition())));
            intent.putExtra("Name", String.valueOf(name.get(holder.getAdapterPosition())));
            intent.putExtra("Age", String.valueOf(age.get(holder.getAdapterPosition())));
            v.getContext().startActivity(intent);
            //activity.startActivityForResult(intent, 1);
        }
    });

}

希望对大家有所帮助

【讨论】：