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如果您想要自定義Spinner的數(shù)據(jù)加載器,您可以通過擴(kuò)展AsyncTask類來實(shí)現(xiàn)。以下是一個(gè)簡單的示例,演示如何使用AsyncTask來加載數(shù)據(jù)并將其設(shè)置到Spinner中:
public class CustomLoader extends AsyncTask<Void, Void, List<String>> {
private Context mContext;
private Spinner mSpinner;
private ProgressDialog mProgressDialog;
public CustomLoader(Context context, Spinner spinner) {
mContext = context;
mSpinner = spinner;
}
@Override
protected void onPreExecute() {
super.onPreExecute();
mProgressDialog = new ProgressDialog(mContext);
mProgressDialog.setMessage("Loading data...");
mProgressDialog.show();
}
@Override
protected List<String> doInBackground(Void... voids) {
// Simulate loading data from a data source (e.g. network request, database query)
List<String> dataList = new ArrayList<>();
dataList.add("Item 1");
dataList.add("Item 2");
dataList.add("Item 3");
// Simulate a delay for demonstration purposes
try {
Thread.sleep(2000);
} catch (InterruptedException e) {
e.printStackTrace();
}
return dataList;
}
@Override
protected void onPostExecute(List<String> dataList) {
super.onPostExecute(dataList);
mProgressDialog.dismiss();
ArrayAdapter<String> adapter = new ArrayAdapter<>(mContext, android.R.layout.simple_spinner_item, dataList);
adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
mSpinner.setAdapter(adapter);
}
}
您可以在Activity或Fragment中調(diào)用CustomLoader來加載數(shù)據(jù)并設(shè)置到Spinner中:
Spinner spinner = findViewById(R.id.spinner);
CustomLoader customLoader = new CustomLoader(this, spinner);
customLoader.execute();
請注意,上述示例僅是一個(gè)簡單的演示,實(shí)際情況中您可能需要根據(jù)您的需求進(jìn)行定制和擴(kuò)展。您還可以添加錯(cuò)誤處理、數(shù)據(jù)緩存、數(shù)據(jù)過濾等功能來優(yōu)化您的自定義加載器。
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