Question

我想保存最后一次在微调器中单击的项目号，当我打开应用程序时，我希望微调器在此项目号中打开。但是，即使我现在保存项目位置，打开应用程序时它也不会在该位置打开。打开应用程序时，我希望选择打开的最后一个项目。

 @Override
    public void onItemSelected(AdapterView<?> parent, View v, int position, long id) {
 SharedPreferences prefs = getSharedPreferences("..",Context.MODE_PRIVATE);

Integer indexValue =spinner.getSelectedItemPosition();

        sharedPreferences = getSharedPreferences(MyPREFERENCES, MODE_PRIVATE);
        SharedPreferences.Editor editor = getSharedPreferences(MyPREFERENCES, MODE_PRIVATE).edit();
        editor.putInt("Spinner", indexValue);
        editor.apply();
}

 protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
refRoomsNew.addValueEventListener(new ValueEventListener() {
                @Override
  public void onDataChange(@NonNull DataSnapshot dataSnapshot) {

for (DataSnapshot snapshot : dataSnapshot.getChildren()){
        spinner = (Spinner)findViewById(R.id.spinnerMain);
         ArrayAdapter<String> dataAdapter = new ArrayAdapter<String(MainActivity.this,android.R.layout.simple_spinner_item, RoomsNew);
                        dataAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
           spinner.setAdapter(dataAdapter);
           String data = snapshot.getValue(String.class);
           RoomsNew.add(data);
           Integer spinnerNew = prefs.getInt("Spinner", 0);

if(spinnerNew != null ) {
                   spinner.setSelection(spinnerNew);
                        }
                        addListenerOnSpinnerItemSelection();
                        }
 }

   refRooms.addValueEventListener(new ValueEventListener() {
                        @Override
       public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
         for (DataSnapshot snapshot : dataSnapshot.getChildren()){
          spinner = (Spinner)findViewById(R.id.spinnerMain);
          ArrayAdapter<String> dataAdapter = new ArrayAdapter<String>           (MainActivity.this,android.R.layout.simple_spinner_item, Rooms);
                                dataAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
            spinner.setAdapter(dataAdapter);
            String data = snapshot.getValue(String.class);
            Rooms.add(data);
            Integer spinnerNew = prefs.getInt("Spinner", 0);

                                if(spinnerNew != null ) {
      spinner.setSelection(spinnerNew);
                                }
                                addListenerOnSpinnerItemSelection();

                            }
                    }

    public void addListenerOnSpinnerItemSelection() {
            spinner.setOnItemSelectedListener(this);
        }

Answer 1

很抱歉用Kotlin编写解决方案。下面是工作代码。

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
        xmlns:android="http://schemas.android.com/apk/res/android"
        xmlns:tools="http://schemas.android.com/tools"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        tools:context=".MainActivity">

    <TextView
            android:id="@+id/txt_select"
            android:layout_margin="8dp"
            android:text="Select Month"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"/>

    <Spinner
            android:layout_below="@id/txt_select"
            android:id="@+id/spinner"
            android:layout_margin="16dp"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"/>

</RelativeLayout>

MainActivity.kt

class MainActivity : AppCompatActivity(), AdapterView.OnItemSelectedListener {

    private val monthList = arrayOf("Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Noc", "Dec")
    private var preferenceManger = PreferenceManager(this)

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)


        val adapter: ArrayAdapter<String> =
            ArrayAdapter(this, android.R.layout.simple_spinner_item, monthList)
        adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item)
        spinner.adapter = adapter
        spinner.onItemSelectedListener = this
    }

    override fun onResume() {
        super.onResume()
        spinner.setSelection(preferenceManger.getSelection())
    }


    override fun onNothingSelected(parent: AdapterView<*>?) {
        spinner.setSelection(preferenceManger.getSelection())
    }

    override fun onItemSelected(parent: AdapterView<*>?, view: View?, position: Int, id: Long) {
        preferenceManger.setSelection(position)
    }
}

PreferenceManager.kt

const val PREFERENCE_NAME = "test"
const val KEY_SELECTION = "key_selection"

class PreferenceManager(val context: Context) {

    fun setSelection(pos: Int) {
        val sharedPref = context.getSharedPreferences(PREFERENCE_NAME, MODE_PRIVATE)
        sharedPref.edit().putInt(KEY_SELECTION, pos).commit()
    }

    fun getSelection(): Int {
        val sharedPref = context.getSharedPreferences(PREFERENCE_NAME, MODE_PRIVATE)
        return sharedPref.getInt(KEY_SELECTION, 0)
    }

}

让我知道更多帮助：）

Answer 2

在Java中具有相同的答案

注意：以下是示例代码，您可以在其中存储微调框选择。

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <TextView
        android:id="@+id/txt_select"
        android:layout_margin="8dp"
        android:text="Select Month"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"/>

    <Spinner
        android:layout_below="@id/txt_select"
        android:id="@+id/spinner"
        android:layout_margin="16dp"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"/>

</RelativeLayout>

MainActivity.java

public class MainActivity extends AppCompatActivity implements AdapterView.OnItemSelectedListener {

    private String[] monthList = {"Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Noc", "Dec"};
    private PreferenceManager preferenceManger;
    Spinner spinner;


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

        preferenceManger = new PreferenceManager(this);


        spinner = findViewById(R.id.spinner);
        ArrayAdapter<String> adapter = new ArrayAdapter(this, android.R.layout.simple_spinner_item, monthList);
        adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
        spinner.setAdapter(adapter);
        spinner.setOnItemSelectedListener(this);

    }

    @Override
    protected void onResume() {
        super.onResume();
        spinner.setSelection(preferenceManger.getSelection());
    }

    @Override
    public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
        preferenceManger.setSelection(position);
    }

    @Override
    public void onNothingSelected(AdapterView<?> parent) {
        spinner.setSelection(preferenceManger.getSelection());

    }
}

PreferenceManager.java

public class PreferenceManager {
    private static final String PREFERENCE_NAME = "test";
    private static final String KEY_SELECTION = "key_selection";

    Context mContext;

    public PreferenceManager(Context context) {
        mContext = context;
    }

    public void setSelection(int pos) {
        SharedPreferences sharedPref = mContext.getSharedPreferences(PREFERENCE_NAME, MODE_PRIVATE);
        sharedPref.edit().putInt(KEY_SELECTION, pos).commit();
    }

    public int getSelection() {
        SharedPreferences sharedPref = mContext.getSharedPreferences(PREFERENCE_NAME, MODE_PRIVATE);
        return sharedPref.getInt(KEY_SELECTION, 0);
    }
}

检索并保存选定的微调位置

2 个答案: