如何添加“长点击侦听器"偏好? [英] How to add a "long click listener" to a Preference?
问题描述
我有一个 PreferenceActivity
,我想在其中动态添加首选项.
I have an PreferenceActivity
where I would like to add Preferences dynamically.
长按时,这些操作会起作用,但是 OnPreferenceClickListener
仅支持常规点击,不支持长按.
On a long click, these shall do something, however OnPreferenceClickListener
only supports normal clicks, no long clicks.
有没有实现此功能的方法,我错过了什么吗?
Is there a way to implement this feature, did I miss something?
谢谢
推荐答案
如果链接消失,以下是该链接上帖子的主体.注意:我在下方未编写任何内容.
内置的Preference类具有一种用于接收点击的方法onClick,但是没有一种用于接收长时间点击的方法.在我当前的项目中,我实际上对此有需求,并找到了实现它的方法.
The built-in Preference class has a method to receive clicks, onClick, but no method to receive long clicks. In my current project, I actually have a need for this, and found a way to implement it.
PreferenceActivity实际上是一个ListActivity,在幕后有一个特殊的适配器.使用常规ListView机制setOnItemClickListener处理常规(不长)单击.设置此代码的代码在PreferenceScreen中:
PreferenceActivity is actually a ListActivity, with a special adapter behind the scenes. The usual (not long) clicks are processed by using the usual ListView mechanism, setOnItemClickListener. The code to set this up is in PreferenceScreen:
public final class PreferenceScreen extends PreferenceGroup implements AdapterView.OnItemClickListener.... {
public void bind(ListView listView) {
listView.setOnItemClickListener(this);
listView.setAdapter(getRootAdapter());
onAttachedToActivity();
}
public void onItemClick(AdapterView parent, View view, int position, long id) {
Object item = getRootAdapter().getItem(position);
if (!(item instanceof Preference)) return;
final Preference preference = (Preference) item;
preference.performClick(this);
}
}
将PreferenceScreen子类化并覆盖绑定以向列表视图添加长按侦听器是很容易的,除非该类是最终类.因此,我最终将以下代码添加到我的PreferenceActivity子类中:
It would be really easy to subclass PreferenceScreen and override bind to add a long-item-click listener to the list view, except this class is final. Because of this, I ended up adding the following code into my PreferenceActivity subclass:
public class BlahBlahActivity extends PreferenceActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
addPreferencesFromResource(R.xml.account_options_prefs);
ListView listView = getListView();
listView.setOnItemLongClickListener(new OnItemLongClickListener() {
@Override
public boolean onItemLongClick(AdapterView<?> parent, View view, int position, long id) {
ListView listView = (ListView) parent;
ListAdapter listAdapter = listView.getAdapter();
Object obj = listAdapter.getItem(position);
if (obj != null && obj instanceof View.OnLongClickListener) {
View.OnLongClickListener longListener = (View.OnLongClickListener) obj;
return longListener.onLongClick(view);
}
return false;
}
});
}
}
现在,我可以拥有一个实现View.OnLongClickListener的Preference子类,该类会自动被长按:
Now I can have a Preference subclass that implements View.OnLongClickListener, which is automatically invoked for long clicks:
public class BlahBlahPreference extends CheckBoxPreference implements View.OnLongClickListener {
@Override
public boolean onLongClick(View v) {
// Do something for long click
return true;
}
}
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