[英]How to save shared preference data into an ArrayList then display on a ListView?
我試圖將鍵/值對數據從共享的首選項復制到ArrayList,然后在ListView上顯示它們,但是在使用HashMap時出現此錯誤“ Incompatible type”:
SharedPreferences sharedPref = getSharedPreferences("STData", Context.MODE_PRIVATE);
//to edit the data or add data inside my file "STData"
SharedPreferences.Editor editor = sharedPref.edit();
//create an Arraylist to store values from the sharedPref Object
ArrayList<String> STArrayList = new ArrayList<String>();
for (HashMap<String, String> map : STArrayList)
for (Map.Entry<String, String> entry : map.entrySet())
{
editor.putString(entry.getKey(), entry.getValue());
editor.commit();
String savedPref = sharedPref.getString(entry.getKey(), "");
STArrayList.add(savedPref);
Toast.makeText(getApplicationContext(),savedPref, Toast.LENGTH_LONG).show();
}
嘗試這樣的事情:
SharedPreferences sharedPref = getSharedPreferences("STData", Context.MODE_PRIVATE);
//to edit the data or add data inside my file "STData"
SharedPreferences.Editor editor = sharedPref.edit();
//create an Arraylist to store values from the sharedPref Object
ArrayList<String> STArrayList = new ArrayList<String>();
Map<String, String> map = (Map<String, String>) sharedPref.getAll();
for (Map.Entry<String, String> entry : map.entrySet()) {
editor.putString(entry.getKey(), entry.getValue());
editor.commit();
String savedPref = sharedPref.getString(entry.getKey(), "");
STArrayList.add(savedPref);
Toast.makeText(getApplicationContext(), savedPref, Toast.LENGTH_LONG).show();
}
但是我仍然不確定要實現什么目標-因為首先從共享首選項中獲取所有值,然后對其進行迭代,然后在該循環中再次將這些值放入共享首選項中: editor.putString(entry.getKey(), entry.getValue()); editor.commit();
editor.putString(entry.getKey(), entry.getValue()); editor.commit();
我認為上述行是不必要的。
最后一件事-您必須確保在共享首選項中保留的所有值都是字符串,如果您有其他不同,則Map<String, String> map = (Map<String, String>) sharedPref.getAll();
將拋出ClassCastException。
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