如何在 Android Studio 中使用 spinner 实现 SQLite Join 从表中获取 id

Question

我在 SQLite 数据库中创建了 2 个表，stok 和 sales

在 DatabaseHelper.java 中

1. 创建表stok

   String tbStok = "CREATE TABLE stok(id_stok INTEGER PRIMARY KEY AUTOINCREMENT, waktu_stok DATETIME, id_sales INTEGER, stok INTEGER, FOREIGN KEY id_sales REFERENCES sales(id_sales)";
   

2. 创建表sales

   String tbSales = "CREATE TABLE sales(id_sales INTEGER PRIMARY KEY AUTOINCREMENT, nama VARCHAR, kodesales VARCHAR, username VARCHAR, password VARCHAR, level INTEGER)";
   

3. 从 SQLite 创建列表数据

   public List<String> getSpinnerSales(){
       List<String> labels = new ArrayList<String>();
   
       // Select All Query
       String selectQuery = "SELECT  * FROM " + "sales";
   
       SQLiteDatabase db = this.getReadableDatabase();
       Cursor cursor = db.rawQuery(selectQuery, null);
   
       // looping through all rows and adding to list
       if (cursor.moveToFirst()) {
           do {
               labels.add(cursor.getString(0));
               labels.add(cursor.getString(1));
           } while (cursor.moveToNext());
       }
   
       // closing connection
       cursor.close();
       db.close();
   
       // returning lables
       return labels;
   }
   

4. 在微调器上显示

   private void loadSpinnerSales() {
       // database handler
       DatabaseHelper db = new DatabaseHelper(getApplicationContext());
   
       // Spinner Drop down elements
       List<String> lables = db.getSpinnerSales();
   
       // Creating adapter for spinner
       ArrayAdapter<String> dataAdapter = new ArrayAdapter<String>(this,
               android.R.layout.simple_spinner_item, lables);
   
       // Drop down layout style - list view with radio button
       dataAdapter
               .setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
   
       // attaching data adapter to spinner
       spsales.setAdapter(dataAdapter);
   }
   

5. 测试是否选择了微调器

       spsales.setOnItemSelectedListener(new 
           AdapterView.OnItemSelectedListener() {
           @Override
           public void onItemSelected(AdapterView<?> parent, View view, int position,long id) {
               String label = parent.getItemAtPosition(position).toString();
               Log.d("label:", label);
           }
   
           @Override
           public void onNothingSelected(AdapterView<?> adapterView) {
   
           }
       });
   

我需要id_sales 来输入值并保存到其他表 SQLite，但微调器必须显示销售名称。

Answer 1

最好的方法是使用自定义适配器 您可以将对象列表（在您的情况下是“销售 id 和名称列表”）传递给适配器，而不仅仅是字符串列表， 然后在选定的项目上，您将获得选定的对象 然后你可以得到任何你需要的 id 或 name 您可以按照此链接制作自定义适配器 https://abhiandroid.com/ui/custom-spinner-examples.html

Answer 2

我通过编辑代码解决了这个问题

// looping through all rows and adding to list
        if (cursor.moveToFirst()) {
            do {
                labels.add(cursor.getString(0)+cursor.getString(1));
            } while (cursor.moveToNext());
        }

在微调器上使用子字符串操作选定的项目

spsupir.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
            @Override
            public void onItemSelected(AdapterView<?> parent, View view, int position,long id) {
                String label = parent.getItemAtPosition(position).toString();
                String ids = String.valueOf(label).substring(0,1);
                Log.d("label:", ids);
            }

            @Override
            public void onNothingSelected(AdapterView<?> adapterView) {

            }
        });

代码编辑

String label = parent.getItemAtPosition(position).toString();
String ids = String.valueOf(label).substring(0,1);
Log.d("label:", ids);

Answer 3

另一个解决问题

第一步创建模型类

public class Sales {
    String id_sales,nama;

    public Sales(String id_sales, String nama) {
        this.id_sales = id_sales;
        this.nama = nama;
    }

    public String getId_sales() {
        return id_sales;
    }

    public void setId_sales(String id_sales) {
        this.id_sales = id_sales;
    }

    public String getNama() {
        return nama;
    }

    public void setNama(String nama) {
        this.nama = nama;
    }

    @Override
    public String toString() {
        return nama;
    }
}

第二步把SQLite表sales的所有数据放入

//Data spinner supir
    public ArrayList<Sales> getSpinnerSales(){
        ArrayList<Sales> salesList = new ArrayList<>();

        // Select All Query
        String selectQuery = "SELECT  * FROM " + "sales";

        SQLiteDatabase db = this.getReadableDatabase();
        Cursor cursor = db.rawQuery(selectQuery, null);

        // looping through all rows and adding to list
        if (cursor.moveToFirst()) {
            do {
                salesList.add(new Sales(cursor.getString(0), cursor.getString(1)));
            } while (cursor.moveToNext());
        }

        // closing connection
        cursor.close();
        db.close();

        // returning lables
        return salesList;
    }

步骤 3 生成 void 以使用来自 sqlite aa Activity 的数据

private void loadSpinnerSales() {
        // database handler
        DatabaseHelper db = new DatabaseHelper(getApplicationContext());
        ArrayList<Sales> salesList = db.getSpinnerSales();
        ArrayAdapter<Sales> adapter = new ArrayAdapter<Sales>(this, android.R.layout.simple_spinner_dropdown_item, salesList);
        spsales.setAdapter(adapter);

    }

第 4 步 OnCreate 处的加载方法

    spsales = (Spinner) findViewById(R.id.spSales);
    loadSpinnerSales();

    spsales.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
        @Override
        public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {

            Sales sales = (Sales) parent.getSelectedItem();
            Toast.makeText(getApplicationContext(),sales.getId_sales(),Toast.LENGTH_SHORT).show();
        }

        @Override
        public void onNothingSelected(AdapterView<?> parent) {
        }
    });