示例显示如何使用v7 appcompat库中的PopupMenu显示弹出式菜单。主界面使用V4支持库的ListFragment显示数据列表，当点击列表子项时，在子项下方弹出下拉菜单，并通过设置setOnMenuItemClickListener(new PopupMenu.OnMenuItemClickListener())监听菜单点击事件，下拉菜单只有一个选项，用于移除该列表子项。
Demo下载地址：https://github.com/googlesamples/android-ActionBarCompat-ListPopupMenu/#readme
PopupMenu API：https://developer.android.google.cn/reference/android/support/v7/widget/PopupMenu
首先看看示例的运行界面：
Demo关键代码在Fragment中，主页面MainActiviy只是包含了Fragment，这里就不贴出来了：
public class PopupFragment extends ListFragment implements View.OnClickListener {
@Override
public void onActivityCreated(@Nullable Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
// 创建页面列表
ArrayList<String> items = new ArrayList<>();
for (int i = 0; i < Cheeses.CHEESES.length; i++) {
items.add(Cheeses.CHEESES[i]);
}
// 设置Adapter
setListAdapter(new PopupAdapter(items));
}
@Override
public void onListItemClick(ListView l, View v, int position, long id) {
String item = (String) l.getItemAtPosition(position);
Toast.makeText(getActivity(), "Item Clicked: " + item, Toast.LENGTH_SHORT).show();
}
@Override
public void onClick(final View v) {
// 为确保下拉菜单弹出位置的正确，需要传递一个Runnable对象。因为下拉菜单显示前，View的位置可能不一样（列表子项滚动位置会变）。
v.post(new Runnable() {
@Override
public void run() {
showPopupMenu(v);
}
});
}
private void showPopupMenu(View view) {
final PopupAdapter adapter = (PopupAdapter) getListAdapter();
// 获得发生点击事件View的Tag
final String item = (String) view.getTag();
// 创建一个PopupMenu，并把PopupMenu绑定到对应的view
PopupMenu popup = new PopupMenu(getActivity(), view);
// 为PopupMenu绑定布局文件
popup.getMenuInflater().inflate(R.menu.popup, popup.getMenu());
// 为下拉菜单设置监听
popup.setOnMenuItemClickListener(new PopupMenu.OnMenuItemClickListener() {
@Override
public boolean onMenuItemClick(MenuItem menuItem) {
switch (menuItem.getItemId()) {
case R.id.menu_remove:
// 把对应列表子项移除
adapter.remove(item);
return true;
}
return false;
}
});
// 显示下拉菜单
popup.show();
}
class PopupAdapter extends ArrayAdapter {
public PopupAdapter(ArrayList<String> items) {
super(getActivity(), R.layout.list_item, android.R.id.text1, items);
}
@NonNull
@Override
public View getView(int position, @Nullable View convertView, @NonNull ViewGroup parent) {
View view = super.getView(position, convertView, parent);
View popupButton = view.findViewById(R.id.button_popup);
popupButton.setTag(getItem(position));
popupButton.setOnClickListener(PopupFragment.this);
return view;
}
}
}
下拉菜单布局文件popup.xml
<?xml version="1.0" encoding="utf-8"?>
<menu xmlns:android="http://schemas.android.com/apk/res/android"> <item
android:id="@+id/menu_remove"
android:title="remove" /> </menu>
列表子项布局文件list_item.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="?attr/listPreferredItemHeight"
android:orientation="horizontal"> <TextView
android:id="@android:id/text1"
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight="1"
android:ellipsize="end"
android:gravity="center_vertical"
android:maxLines="1"
android:paddingLeft="8dp"
android:paddingRight="8dp"
android:textAppearance="?android:attr/textAppearanceMedium" /> <ImageView
android:id="@+id/button_popup"
android:layout_width="56dip"
android:layout_height="match_parent"
android:background="?attr/selectableItemBackground"
android:src="@mipmap/ic_action_settings" /> </LinearLayout>