如何将字符串迭代器值添加到 ArrayAdapter?
How to add String Iterator values to an ArrayAdapter?
我正在尝试将字符串迭代器的值添加到 ArrayAdapter,但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);
微调器仅显示我的 pref 文件中的值,而不显示来自 readCitiesFromPref() 方法的额外字符串值;
我已经验证了 Iterator String returned 有值。在调试模式下,我能够看到这没有添加到适配器从首选项中获得的现有 mObjects
谢谢
编辑:根据请求添加 readCitiesFromPref() 方法,尽管我认为它是无关紧要的,因为 return 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;
}
问题出在 readCitiesFromPref
中,因为当您创建迭代器时,您也在迭代所有元素,只有在那之后您才 returning 迭代器,它将具有值对于 hasNext() = null
,因此此代码 while(userCities.hasNext()){
将永远不会执行。要解决此问题,只需 return 加载所有值后的迭代器。
我正在尝试将字符串迭代器的值添加到 ArrayAdapter,但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);
微调器仅显示我的 pref 文件中的值,而不显示来自 readCitiesFromPref() 方法的额外字符串值;
我已经验证了 Iterator String returned 有值。在调试模式下,我能够看到这没有添加到适配器从首选项中获得的现有 mObjects
谢谢
编辑:根据请求添加 readCitiesFromPref() 方法,尽管我认为它是无关紧要的,因为 return 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;
}
问题出在 readCitiesFromPref
中,因为当您创建迭代器时,您也在迭代所有元素,只有在那之后您才 returning 迭代器,它将具有值对于 hasNext() = null
,因此此代码 while(userCities.hasNext()){
将永远不会执行。要解决此问题,只需 return 加载所有值后的迭代器。