将 Spinner 选择保存到 SQLite 数据库中

Question

我查看了所有与将微调器保存到数据库相关的问题，但似乎没有任何效果。

我已经开始努力添加ItemSelectedListener，但它抛出了一个错误，

这是我的代码

OnItemSelectedListener 是我为表格其余部分插入的地方

public class OnClickListenerCreateMenuItem implements View.OnClickListener {
@Override
public void onClick(View view) {


    final Context context = view.getContext();
    LayoutInflater inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
    final View formElementsView = inflater.inflate(R.layout.menuitem_input_form, null, false);

    final EditText editTextItemName = (EditText) formElementsView.findViewById(R.id.editTextItemName);
    final EditText editTextItemDesc = (EditText) formElementsView.findViewById(R.id.editTextItemDesc);
    final EditText editTextItemPrice = (EditText) formElementsView.findViewById(R.id.editTextItemPrice);
    final EditText editTextItemCost = (EditText) formElementsView.findViewById(R.id.editTextItemCost);
    final Spinner itemCategory = (Spinner) formElementsView.findViewById(R.id.spinnerCategory);

    itemCategory.setAdapter(
            ((SettingsMenuItem) context).loadSpinnerData()
    );

    itemCategory.setOnItemSelectedListener(
            ((SettingsMenuItem) context).loadSpinnerData()
    );


    new AlertDialog.Builder(context)
            .setView(formElementsView)
            .setTitle("Create Item")
            .setPositiveButton("Add",
                    new DialogInterface.OnClickListener() {
                        public void onClick(DialogInterface dialog, int id) {


                            String itemName = editTextItemName.getText().toString();
                            String itemDescription = editTextItemDesc.getText().toString();
                            String itemPrice = editTextItemPrice.getText().toString();
                            String itemCost = editTextItemCost.getText().toString();
                            String valueOfSelectedCat= itemCategory.getSelectedItem().toString();


                            ObjectMenuItem objectMenuItem = new ObjectMenuItem();
                            objectMenuItem.name = itemName;
                            objectMenuItem.description = itemDescription;
                            objectMenuItem.price = Float.parseFloat(itemPrice);
                            objectMenuItem.cost = Float.parseFloat(itemCost);
                            objectMenuItem.cat = valueOfSelectedCat;

                            boolean createSuccessful = new TableControllerMenuItem(context).create(objectMenuItem);


                            if(createSuccessful){
                                Toast.makeText(context, "Item was saved.", Toast.LENGTH_SHORT).show();
                            }else{
                                Toast.makeText(context, "Unable to save item.", Toast.LENGTH_SHORT).show();
                            }
                            ((SettingsMenuItem) context).readRecords();
                            ((SettingsMenuItem) context).countRecords();



                            dialog.cancel();

                        }

                    }).show();




}

我的实际微调器在这里设置并填充在这里

public class SettingsMenuItem extends AppCompatActivity {

Spinner spinner;
Context context;
String id;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_settings_menu_item);
    Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
    setSupportActionBar(toolbar);

    countRecords();
    readRecords();

    FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
    fab.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
                    .setAction("Action", null).show();
        }
    });

    Button buttonCreateLocation = (Button) findViewById(R.id.btnAdd);
    buttonCreateLocation.setOnClickListener(new OnClickListenerCreateMenuItem());
}

public void countRecords() {

    int recordCount = new TableControllerMenuItem(this).count();
    TextView textViewRecordCount = (TextView) findViewById(R.id.textViewRecordCount);
    textViewRecordCount.setText(recordCount + " records found.");

}

public void readRecords() {

    LinearLayout linearLayoutRecords = (LinearLayout) findViewById(R.id.linearLayoutRecords);
    linearLayoutRecords.removeAllViews();

    List<ObjectMenuItem> menuitem = new TableControllerMenuItem(this).read();

    if (menuitem.size() > 0) {

        for (ObjectMenuItem obj : menuitem) {

            int id = obj.id;
            String menuitemName = obj.name;
            String menuitemDescription = obj.description;
            Float menuitemPrice = obj.price;
            Float menuitemCost = obj.cost;
            String itemCategory = obj.cat;

            String textViewContents = menuitemName;

            TextView textViewMenuItem = new TextView(this);
            textViewMenuItem.setPadding(0, 10, 0, 10);
            textViewMenuItem.setText(textViewContents);
            textViewMenuItem.setTag(Integer.toString(id));
            textViewMenuItem.setTextSize(20.0f);

            textViewMenuItem.setOnLongClickListener(new OnLongClickListenerMenuItem());


            linearLayoutRecords.addView(textViewMenuItem);
        }

    } else {

        TextView locationItem = new TextView(this);
        locationItem.setPadding(8, 8, 8, 8);
        locationItem.setText("No records yet.");

        linearLayoutRecords.addView(locationItem);
    }

}

public ArrayAdapter loadSpinnerData() {

    Log.d("CON", "setting spinner data");

    Spinner s = (Spinner) findViewById(R.id.spinnerCategory);
    DatabaseHandler h = new DatabaseHandler(getApplicationContext());

    List<String> names = h.getAllNames();

    ArrayAdapter<String> dataAdapter = new ArrayAdapter<String>(this, android.R.layout.simple_spinner_item, names);

    dataAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);




    return dataAdapter;


}





    }

这是我的崩溃日志

--------- 崩溃开始 02-14 08:29:07.627 14332-14332/com.jenovaprojects.restaurant E/AndroidRuntime: 致命例外: main 进程：com.jenovaprojects.restaurant，PID：14332 java.lang.ClassCastException: android.widget.ArrayAdapter 不能转换为 android.widget.AdapterView$OnItemSelectedListener 在 com.jenovaprojects.restaurant.OnClickListenerCreate.OnClickListenerCreateMenuItem.onClick(OnClickListenerCreateMenuItem.java:41) 在 android.view.View.performClick(View.java:5204) 在 android.view.View$PerformClick.run(View.java:21156) 在 android.os.Handler.handleCallback(Handler.java:739) 在 android.os.Handler.dispatchMessage(Handler.java:95) 在 android.os.Looper.loop(Looper.java:148) 在 android.app.ActivityThread.main(ActivityThread.java:5466) 在 java.lang.reflect.Method.invoke（本机方法） 在 com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726) 在 com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)

Answer 1

请让您的 LogCat 查看这些错误，并在可能的情况下显示您想要插入所选数据的数据库查询和表结构。

简单的过程是在你的情况下将 onItemSelected 的一个侦听器放在微调器上

itemCategory.setOnItemSelectedListener(replce your context here);

然后做必要的spinner接口实现

实现 OnItemSelectedListener

当您从微调器中选择任何项目时，将调用此方法 onItemSelected。它将返回您单击的项目的位置，您可以从中轻松找出单击的项目。

adapter.getItemAtPosition(pos).toString()

通过这个你会得到项目的文本。

第二部分 - 向sqlite db插入数据

创建一个 db 对象并对其进行初始化，然后调用适当的方法来插入您选择的选择数据。

Answer 2

使用 Android 指南中的这段代码，您应该能够实现 OnItemSelectedListener

public class SpinnerActivity extends Activity implements OnItemSelectedListener {
...

    public void onItemSelected(AdapterView<?> parent, View view, int pos, long id) {
        // An item was selected. You can retrieve the selected item using
        parent.getItemAtPosition(pos)
    }
}

我不确定为什么它不起作用，但如果没有更多代码，就很难说清楚。如果这没有帮助，请发布您用于保存选择的代码，以便我们尝试找出发生了什么。