我有一个更新视图,在那里我需要预先选择存储在数据库中的值为一个微调器。
我有这样的想法,但适配器没有indexOf方法,所以我被卡住了。
void setSpinner(String value)
{
int pos = getSpinnerField().getAdapter().indexOf(value);
getSpinnerField().setSelection(pos);
}
我有一个更新视图,在那里我需要预先选择存储在数据库中的值为一个微调器。
我有这样的想法,但适配器没有indexOf方法,所以我被卡住了。
void setSpinner(String value)
{
int pos = getSpinnerField().getAdapter().indexOf(value);
getSpinnerField().setSelection(pos);
}
当前回答
你可以使用这种方式,只是让你的代码更简单、更清晰。
ArrayAdapter<String> adapter = (ArrayAdapter<String>) spinnerCountry.getAdapter();
int position = adapter.getPosition(obj.getCountry());
spinnerCountry.setSelection(position);
希望能有所帮助。
其他回答
基于值设置微调器的一个简单方法是
mySpinner.setSelection(getIndex(mySpinner, myValue));
//private method of your class
private int getIndex(Spinner spinner, String myString){
for (int i=0;i<spinner.getCount();i++){
if (spinner.getItemAtPosition(i).toString().equalsIgnoreCase(myString)){
return i;
}
}
return 0;
}
复杂代码的方法已经有了,这只是简单得多。
I had the same issue when trying to select the correct item in a spinner populated using a cursorLoader. I retrieved the id of the item I wanted to select first from table 1 and then used a CursorLoader to populate the spinner. In the onLoadFinished I cycled through the cursor populating the spinner's adapter until I found the item that matched the id I already had. Then assigned the row number of the cursor to the spinner's selected position. It would be nice to have a similar function to pass in the id of the value you wish to select in the spinner when populating details on a form containing saved spinner results.
@Override
public void onLoadFinished(Loader<Cursor> loader, Cursor cursor) {
adapter.swapCursor(cursor);
cursor.moveToFirst();
int row_count = 0;
int spinner_row = 0;
while (spinner_row < 0 || row_count < cursor.getCount()){ // loop until end of cursor or the
// ID is found
int cursorItemID = bCursor.getInt(cursor.getColumnIndexOrThrow(someTable.COLUMN_ID));
if (knownID==cursorItemID){
spinner_row = row_count; //set the spinner row value to the same value as the cursor row
}
cursor.moveToNext();
row_count++;
}
}
spinner.setSelection(spinner_row ); //set the selected item in the spinner
}
以下是我的完整解决方案。我有以下enum:
public enum HTTPMethod {GET, HEAD}
用于后续课程
public class WebAddressRecord {
...
public HTTPMethod AccessMethod = HTTPMethod.HEAD;
...
使用HTTPMethod enum-member设置微调器的代码:
Spinner mySpinner = (Spinner) findViewById(R.id.spinnerHttpmethod);
ArrayAdapter<HTTPMethod> adapter = new ArrayAdapter<HTTPMethod>(this, android.R.layout.simple_spinner_item, HTTPMethod.values());
mySpinner.setAdapter(adapter);
int selectionPosition= adapter.getPosition(webAddressRecord.AccessMethod);
mySpinner.setSelection(selectionPosition);
其中R.id.spinnerHttpmethod定义在布局文件中,而android.R.layout. httpmethod定义在布局文件中。Simple_spinner_item由android-studio下发。
根据Merrill的回答,我想出了这个单线解决方案……它不是很漂亮,但是你可以责怪那些维护Spinner代码的人忽略了包含一个这样做的函数。
mySpinner.setSelection(((ArrayAdapter<String>)mySpinner.getAdapter()).getPosition(myString));
你会得到一个警告,关于ArrayAdapter<String>的强制转换是如何未选中的…实际上,您可以像Merrill那样使用ArrayAdapter,但这只是将一个警告交换为另一个警告。
如果警告导致问题,只需添加
@SuppressWarnings("unchecked")
到方法签名或语句之上。
为了让应用程序记住最后选择的微调值,你可以使用下面的代码:
Below code reads the spinner value and sets the spinner position accordingly. public class MainActivity extends Activity { @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); int spinnerPosition; Spinner spinner1 = (Spinner) findViewById(R.id.spinner1); ArrayAdapter<CharSequence> adapter1 = ArrayAdapter.createFromResource( this, R.array.ccy_array, android.R.layout.simple_spinner_dropdown_item); adapter1.setDropDownViewResource(android.R.layout.simple_list_item_activated_1); // Apply the adapter to the spinner spinner1.setAdapter(adapter1); // changes to remember last spinner position spinnerPosition = 0; String strpos1 = prfs.getString("SPINNER1_VALUE", ""); if (strpos1 != null || !strpos1.equals(null) || !strpos1.equals("")) { strpos1 = prfs.getString("SPINNER1_VALUE", ""); spinnerPosition = adapter1.getPosition(strpos1); spinner1.setSelection(spinnerPosition); spinnerPosition = 0; } And put below code where you know latest spinner values are present, or somewhere else as required. This piece of code basically writes the spinner value in SharedPreferences. Spinner spinner1 = (Spinner) findViewById(R.id.spinner1); String spinlong1 = spinner1.getSelectedItem().toString(); SharedPreferences prfs = getSharedPreferences("WHATEVER", Context.MODE_PRIVATE); SharedPreferences.Editor editor = prfs.edit(); editor.putString("SPINNER1_VALUE", spinlong1); editor.commit();