Unable to modify ArrayAdapter in ListView: UnsupportedOperationException
I'm trying to make a list containing names. This list should be modifiable (add, delete, sort, etc). However, whenever I tried to change the items in the ArrayAdapter, the program crashed, with java.lang.UnsupportedOperationException
error. Here is my code:
ListView panel = (ListVie开发者_运维百科w) findViewById(R.id.panel);
String[] array = {"a","b","c","d","e","f","g"};
final ArrayAdapter<String> adapter = new ArrayAdapter<String>(this,
android.R.layout.simple_list_item_1, array);
adapter.setNotifyOnChange(true);
panel.setAdapter(adapter);
Button button = (Button) findViewById(R.id.button);
button.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
adapter.insert("h", 7);
}
});
I tried insert, remove and clear methods, and none of them worked. Would someone tell me what I did wrong?
I tried it out myself and found it didn't work, so I checked out the source code of ArrayAdapter and found out the problem: The ArrayAdapter
, on being initialized by an array, converts the array into an AbstractList
(List<String>
) which cannot be modified.
Solution
Use an ArrayList<String>
instead using an array while initializing the ArrayAdapter.
String[] array = {"a","b","c","d","e","f","g"};
ArrayList<String> lst = new ArrayList<String>(Arrays.asList(array));
final ArrayAdapter<String> adapter = new ArrayAdapter<String>(this,
android.R.layout.simple_list_item_1, lst);
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