我正在尝试添加字符串迭代器和ArrayAdapter的值,但是没有得到正确的结果。这是我的代码:
Spinner copyFromCity = (Spinner) findViewById(R.id.spinner);
// Create an ArrayAdapter using the string array and a default spinner layout
ArrayAdapter<CharSequence> adapter = ArrayAdapter.createFromResource(this,
R.array.predefined_cities, android.R.layout.simple_spinner_item);
// Add values from our custom cities onto the Adapter via SharedPreferences
prefs = getSharedPreferences(MY_PREFS_NAME, Context.MODE_PRIVATE);
Iterator<String> userCities = readCitiesFromPref();
while(userCities.hasNext()){
adapter.add(userCities.next());
}
// Specify the layout to use when the list of choices appears
adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
// Apply the adapter to the spinner
copyFromCity.setAdapter(adapter);
微调器只显示来自我的pref文件的值,而不是来自方法readCitiesFromPref()的额外String值;
我已经验证返回的Iterator字符串有值。在调试模式下,我能够看到这不会添加到适配器从首选项中的现有mObject中
由于
编辑:根据请求添加readCitiesFromPref()方法虽然我认为它是无关紧要的,因为返回值是准确的并且具有预期的字符串迭代器:
protected Iterator<String> readCitiesFromPref() {
// See if preferences store this
JSONObject citiesList = null;
Iterator<String> userCities = null;
try {
// Yes, so get the values out
citiesList = new JSONObject(prefs.getAll());
userCities = citiesList.keys();
while (userCities.hasNext()) {
Log.i("Ram = ", userCities.next());
}
} catch (NullPointerException e1) {
//
}
return userCities;
}
答案 0 :(得分:2)
问题出现在readCitiesFromPref
中,因为当你创建迭代器时,你也在迭代所有的元素,只有在你返回迭代器后才会有hasNext() = null
的值,因此,此代码while(userCities.hasNext()){
永远不会被执行。要解决此问题,只需在加载所有值后返回迭代器。