android 适配器ArrayAdapter下拉框的值怎么存进缓冲里面

您可以使用SharedPreferences来存储下拉框的值。以下是一个示例代码：

在onItemSelected方法中，将所选值存储到SharedPreferences中：

@Override
public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
    String selectedItem = parent.getItemAtPosition(position).toString();
    SharedPreferences.Editor editor = getSharedPreferences("MyPrefs", MODE_PRIVATE).edit();
    editor.putString("selectedItem", selectedItem);
    editor.apply();
}

在onCreate方法中，读取SharedPreferences中存储的值，并将其设置为下拉框的默认选择：

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

    // Get the SharedPreferences instance
    SharedPreferences prefs = getSharedPreferences("MyPrefs", MODE_PRIVATE);

    // Get the selected item from SharedPreferences
    String selectedItem = prefs.getString("selectedItem", null);

    // Get the array of items for the ArrayAdapter
    String[] items = {"Item 1", "Item 2", "Item 3"};

    // Create the ArrayAdapter
    ArrayAdapter<String> adapter = new ArrayAdapter<>(this, android.R.layout.simple_spinner_dropdown_item, items);

    // Set the adapter for the Spinner
    Spinner spinner = findViewById(R.id.spinner);
    spinner.setAdapter(adapter);

    // Set the default selection for the Spinner
    if (selectedItem != null) {
        int position = adapter.getPosition(selectedItem);
        spinner.setSelection(position);
    }
}

注意：在此示例中，我们将SharedPreferences的名称设置为"MyPrefs"。您可以根据自己的需要更改此名称