コンストラクタで目的のテキスト用のStringを使用してカスタムArrayAdapterを作成する必要があります。次に、配列の最初の要素をデフォルトのテキストに切り替える必要があります。ユーザーがスピナーをクリックすると、元の配列に戻ります。
例:
Activityクラス:
public class SpinnerActivity extends Activity {
Spinner spinner;
String defaultTextForSpinner = "Your deafult text here";
String[] arrayForSpinner = {"One", "Two", "Three"};
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_spinner);
spinner = (Spinner) findViewById(R.id.your_spinner);
spinner.setAdapter(new CustomSpinnerAdapter(this, R.layout.spinner_row, arrayForSpinner, defaultTextForSpinner));
}
}
CustomSpinnerAdapterクラス:
public class CustomSpinnerAdapter extends ArrayAdapter<String>{
Context context;
String[] objects;
String firstElement;
boolean isFirstTime;
public CustomSpinnerAdapter(Context context, int textViewResourceId, String[] objects, String defaultText) {
super(context, textViewResourceId, objects);
this.context = context;
this.objects = objects;
this.isFirstTime = true;
setDefaultText(defaultText);
}
@Override
public View getDropDownView(int position, View convertView, ViewGroup parent) {
if(isFirstTime) {
objects[0] = firstElement;
isFirstTime = false;
}
return getCustomView(position, convertView, parent);
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
notifyDataSetChanged();
return getCustomView(position, convertView, parent);
}
public void setDefaultText(String defaultText) {
this.firstElement = objects[0];
objects[0] = defaultText;
}
public View getCustomView(int position, View convertView, ViewGroup parent) {
LayoutInflater inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
View row = inflater.inflate(R.layout.spinner_row, parent, false);
TextView label = (TextView) row.findViewById(R.id.spinner_text);
label.setText(objects[position]);
return row;
}
}
おかげで私のために働きました。 –