Unexpected-Keyboard/srcs/juloo.keyboard2/ListGroupPreference.java

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package juloo.keyboard2;
import android.content.Context;
import android.content.SharedPreferences;
import android.preference.Preference;
import android.preference.PreferenceGroup;
import android.util.AttributeSet;
import android.view.View;
import android.view.ViewGroup;
import java.util.ArrayList;
import java.util.List;
import org.json.JSONArray;
import org.json.JSONException;
/** A list of preferences where the users can add items to the end and modify
and remove items. Backed by a string list. Implement user selection in
[select()]. */
public abstract class ListGroupPreference<E> extends PreferenceGroup
{
boolean _attached = false;
List<E> _values;
/** The "add" button currently displayed. */
AddButton _add_button = null;
public ListGroupPreference(Context context, AttributeSet attrs)
{
super(context, attrs);
setOrderingAsAdded(true);
setLayoutResource(R.layout.pref_listgroup_group);
_values = new ArrayList<E>();
}
/** Overrideable */
/** The label to display on the item for a given value. */
abstract String label_of_value(E value, int i);
/** Called every time the list changes and allows to change the "Add" button
appearance.
[prev_btn] is the previously attached button, might be null. */
AddButton on_attach_add_button(AddButton prev_btn)
{
if (prev_btn == null)
return new AddButton(getContext());
return prev_btn;
}
/** Called every time the list changes and allows to disable the "Remove"
buttons on every items. Might be used to enforce a minimum number of
items. */
boolean should_allow_remove_item()
{
return true;
}
/** Called when an item is added or modified. */
abstract void select(SelectionCallback<E> callback);
/** Called when an item is modified. */
void select(SelectionCallback<E> callback, E _old_value)
{
select(callback);
}
/** A separate class is used as the same serializer must be used in the
static context. See [Serializer] below. */
abstract Serializer<E> get_serializer();
/** Load/save utils */
/** Read a value saved by preference from a [SharedPreferences] object.
[serializer] must be the same that is returned by [get_serializer()].
Returns [null] on error. */
static <E> List<E> load_from_preferences(String key,
SharedPreferences prefs, List<E> def, Serializer<E> serializer)
{
String s = prefs.getString(key, null);
return (s != null) ? load_from_string(s, serializer) : def;
}
/** Decode a list of string previously encoded with [save_to_string]. Returns
[null] on error. */
static <E> List<E> load_from_string(String inp, Serializer<E> serializer)
{
try
{
List<E> l = new ArrayList<E>();
JSONArray arr = new JSONArray(inp);
for (int i = 0; i < arr.length(); i++)
l.add(serializer.load_item(arr.get(i)));
return l;
}
catch (JSONException e)
{
return null;
}
}
/** Encode a list of string so it can be passed to
[Preference.persistString()]. Decode with [load_from_string]. */
static <E> String save_to_string(List<E> items, Serializer<E> serializer)
{
List<Object> serialized_items = new ArrayList<Object>();
for (E it : items)
{
try
{
serialized_items.add(serializer.save_item(it));
}
catch (JSONException e) {}
}
return (new JSONArray(serialized_items)).toString();
}
/** Protected API */
/** Set the values. If [persist] is [true], persist into the store. */
void set_values(List<E> vs, boolean persist)
{
_values = vs;
reattach();
if (persist)
persistString(save_to_string(vs, get_serializer()));
}
void add_item(E v)
{
_values.add(v);
set_values(_values, true);
}
void change_item(int i, E v)
{
_values.set(i, v);
set_values(_values, true);
}
void remove_item(int i)
{
_values.remove(i);
set_values(_values, true);
}
/** Internal */
@Override
protected void onSetInitialValue(boolean restoreValue, Object defaultValue)
{
String input = (restoreValue) ? getPersistedString(null) : (String)defaultValue;
if (input != null)
{
List<E> values = load_from_string(input, get_serializer());
if (values != null)
set_values(values, false);
}
}
@Override
protected void onAttachedToActivity()
{
super.onAttachedToActivity();
if (_attached)
return;
_attached = true;
reattach();
}
void reattach()
{
if (!_attached)
return;
removeAll();
boolean allow_remove_item = should_allow_remove_item();
int i = 0;
for (E v : _values)
{
addPreference(this.new Item(getContext(), i, v, allow_remove_item));
i++;
}
_add_button = on_attach_add_button(_add_button);
_add_button.setOrder(Preference.DEFAULT_ORDER);
addPreference(_add_button);
}
class Item extends Preference
{
final E _value;
final int _index;
public Item(Context ctx, int index, E value, boolean allow_remove)
{
super(ctx);
_value = value;
_index = index;
setPersistent(false);
setTitle(label_of_value(value, index));
if (allow_remove)
setWidgetLayoutResource(R.layout.pref_listgroup_item_widget);
}
@Override
protected View onCreateView(ViewGroup parent)
{
View v = super.onCreateView(parent);
View remove_btn = v.findViewById(R.id.pref_listgroup_remove_btn);
if (remove_btn != null)
remove_btn.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View _v)
{
remove_item(_index);
}
});
v.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View _v)
{
select(new SelectionCallback<E>() {
public void select(E value)
{
change_item(_index, value);
}
});
}
});
return v;
}
}
class AddButton extends Preference
{
public AddButton(Context ctx)
{
super(ctx);
setPersistent(false);
setLayoutResource(R.layout.pref_listgroup_add_btn);
}
@Override
protected void onClick()
{
select(new SelectionCallback<E>() {
public void select(E value)
{
add_item(value);
}
});
}
}
public interface SelectionCallback<E>
{
public void select(E value);
}
/** Methods for serializing and deserializing abstract items.
[StringSerializer] is an implementation. */
public interface Serializer<E>
{
/** [obj] is an object returned by [save_item()]. */
E load_item(Object obj) throws JSONException;
/** Serialize an item into JSON. Might return an object that can be inserted
in a [JSONArray]. */
Object save_item(E v) throws JSONException;
}
public static class StringSerializer implements Serializer<String>
{
public String load_item(Object obj) { return (String)obj; }
public Object save_item(String v) { return v; }
}
}