我怎麼能發送從數據庫中的所有字段在java文件到另一個Java文件？

Question

我有一個簡單的汽車數據庫是這樣的：

db.addCar(new Car("Alfa Romeo","Giulietta","1.4 TB Distinctive","Benzine","1.4","120","2012","5","1465","4351","54000")); 
     db.addCar(new Car("Audi","A6","2.0 TDi","Diesel","2.0","170","2012","6","1455","4915","183600")); 
     db.addCar(new Car("BMW","7 Series","7.30 ID Comfort","Benzine","3.0","245","2012","6","1450","4835","528000")); 
     db.addCar(new Car("Chevrolet","Captiva","2.0 LT AT","Diesel","2.0","163","2012","6","1756","4673","79950")); 
     db.addCar(new Car("Citroen","C5","1.6 HDi Comfort","Diesel","1.6","112","2012","5","1458","4779","67430")); 

我'使用3個紡紗廠選擇前三個欄（製造商，型號，類型），還我可以送他們到我的結果XML頁面用這種方法

b3.setOnTouchListener(new View.OnTouchListener(){ 
      @Override 
       public boolean onTouch(View comparePage2, MotionEvent event) { 

       Intent intent = new Intent(getApplicationContext(), Compare2.class); 
        //Create a bundle object 
        Bundle car = new Bundle(); 

        //Inserts a String value into the mapping of this Bundle 
        car.putString("make", spinner_make.getSelectedItem().toString()); 
        car.putString("model", spinner_model.getSelectedItem().toString()); 
        car.putString("type", spinner_type.getSelectedItem().toString()); 
        car.putString("make2", spinner_make2.getSelectedItem().toString()); 
        car.putString("model2", spinner_model2.getSelectedItem().toString()); 
        car.putString("type2", spinner_type2.getSelectedItem().toString()); 


        //Add the bundle to the intent. 
        intent.putExtras(car); 


        //start the DisplayActivity 
        startActivity(intent); 

       return false; 
       } 

private void loadSpinnerData() { 
     DatabaseHandler db = new DatabaseHandler(getApplicationContext()); 

     List <String> makers = db.getAllMakers(); 
     ArrayAdapter<String> dataAdapter = new ArrayAdapter<String>(this, 
       android.R.layout.simple_spinner_item, makers); 

     List <String> models = db.getAllModels(); 
     ArrayAdapter<String> dataAdapter2 = new ArrayAdapter<String>(this, 
       android.R.layout.simple_spinner_item, models); 

     List <String> types = db.getAllTypes(); 
     ArrayAdapter<String> dataAdapter3 = new ArrayAdapter<String>(this, 
       android.R.layout.simple_spinner_item, types); 

     List <String> makers2 = db.getAllMakers(); 
     ArrayAdapter<String> dataAdapter4 = new ArrayAdapter<String>(this, 
       android.R.layout.simple_spinner_item, makers2); 

     List <String> models2 = db.getAllModels(); 
     ArrayAdapter<String> dataAdapter5 = new ArrayAdapter<String>(this, 
       android.R.layout.simple_spinner_item, models2); 

     List <String> types2 = db.getAllTypes(); 
     ArrayAdapter<String> dataAdapter6 = new ArrayAdapter<String>(this, 
       android.R.layout.simple_spinner_item, types2); 


     spinner_make.getContext(); 

// Drop down layout style - list view with radio button 
     dataAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item); 
     dataAdapter2.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item); 

// attaching data adapter to spinner 
     spinner_make.setAdapter(dataAdapter); 
     spinner_model.setAdapter(dataAdapter2); 
     spinner_type.setAdapter(dataAdapter3); 
     spinner_make2.setAdapter(dataAdapter4); 
     spinner_model2.setAdapter(dataAdapter5); 
     spinner_type2.setAdapter(dataAdapter6); 


} 

但我怎麼能發送其他領域到XML頁面用同樣的方法？

Answer 1

簡短的回答是：你需要找回所有你想通過從數據庫發送到下一個Activity數據。話雖這麼說，我可能會做以下修改來實現這一目標：

1.從數據庫中的所有（必需的）數據

在你DatabaseHandler類，創建一個返回所有汽車的方法，由做你的第一個代碼片段的反面。或者至少返回下一個Activity所需的全部數據。我會假設你會在這裏返回的所有數據：

Cursor c = // TODO: implement: query database for car data 
List<Car> cars = new ArrayList<Car>(); 
for (c.moveToFirst(); !c.isAfterLast(); c.moveToNext()) { 
    cars.add(new Car(...)); // add every car 
} 

2.有Car實施Serializable。

將您的Car類的定義更改爲Serializable。這應該是沒有問題的，假定類只是一個簡單的字段集合：

public class Car implements Serializable { 
    private static final long serialVersionUID = 1234567890L; 

    // constructor(s), fields, getters, setters below 
} 

3.獲取選中的車從微調

對於這個例子的目的，我只是要通過使用所選的位置從原來的收集得到步驟1中的汽車和它放入Intent（無需創建一個單獨的Bundle）：

Intent intent = new Intent(getApplicationContext(), Compare2.class); 
Car selectedCar = cars.get(spinner.getSelectedItemPosition()); 
intent.putSerializableExtra("selected_car", selectedCar); 

可以多單車，甚至是整個集合（前提是集也實現Serializable做到這一點;即ArrayList）。在接收端，就可以檢索數據做上述相反：

Car selectedCar = (Car) getIntent().getSerializableExtra("selected_car"); 

---

現在，您的代碼片段建議你要去不同的車的規格比較，在未來Activity。如果是這樣的話，那麼你可能不需要改變很多。我會考慮更改適配器從cars收集得到他們的數據，而不是再次查詢數據庫中的數據的一列，你已經有了 - 這應該是一個簡單的變化。

如果你有某種過濾回事，根據不同的紡紗廠的選擇，那麼你要確保你的方法返回的所有數據的汽車藉此選擇考慮。我會留給你自己弄清楚這些細節。