/*
* Copyright (C) 2010 The Android Open Source Project
*
* Licensed under the Apache License, Versi
on 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE
-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed
on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR C
ONDITI
ONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissi
ons and
* limitati
ons under the License.
*/
package android.widget;
import android.annotati
on.MenuRes;
import android.annotati
on.TestApi;
import android.compat.annotati
on.UnsupportedAppUsage;
import android.c
ontent.C
ontext;
import android.os.Build;
import android.
view.Gravity;
import android.
view.Menu;
import android.
view.MenuInflater;
import android.
view.MenuItem;
import android.
view.
View;
import android.
view.
View.
OnTouchListener;
import com.android.internal.R;
import com.android.internal.
view.menu.MenuBuilder;
import com.android.internal.
view.menu.Menu
PopupHelper;
import com.android.internal.
view.menu.ShowableListMenu;
/**
* A
PopupMenu displays a {@link Menu} in a modal
popup window anchored to a
* {@link
View}. The
popup will appear below the anchor
view if there is room,
* or above it if there is not. If the IME is visible the
popup will not
* overlap it until it is touched. Touching outside of the
popup will dismiss
* it.
*/
public class
PopupMenu {
@UnsupportedAppUsage(maxTargetSdk = Build.VERSI
ON_CODES.R, trackingBug = 170729553)
private final C
ontext mC
ontext;
private final MenuBuilder mMenu;
private final
View mAnchor;
@UnsupportedAppUsage
private final Menu
PopupHelper m
Popup;
private
OnMenuItemClickListener mMenuItemClickListener;
private
OnDismissListener m
OnDismissListener;
private
OnTouchListener mDragListener;
/**
* C
onstructor to create a new
popup menu with an anchor
view.
*
* @param c
ontext C
ontext the
popup menu is running in, through which it
* can access the
current theme, resources, etc.
* @param anchor Anchor
view for this
popup. The
popup will appear below
* the anchor if there is room, or above it if there is not.
*/
public
PopupMenu(C
ontext c
ontext,
View anchor) {
this(c
ontext, anchor, Gravity.NO_GRAVITY);
}
/**
* C
onstructor to create a new
popup menu with an anchor
view and alignment
* gravity.
*
* @param c
ontext C
ontext the
popup menu is running in, through which it
* can access the
current theme, resources, etc.
* @param anchor Anchor
view for this
popup. The
popup will appear below
* the anchor if there is room, or above it if there is not.
* @param gravity The {@link Gravity} value for aligning the
popup with its
* anchor.
*/
public
PopupMenu(C
ontext c
ontext,
View anchor, int gravity) {
this(c
ontext, anchor, gravity, R.attr.
popupMenu
Style, 0);
}
/**
* C
onstructor a create a new
popup menu with a specific
style.
*
* @param c
ontext C
ontext the
popup menu is running in, through which it
* can access the
current theme, resources, etc.
* @param anchor Anchor
view for this
popup. The
popup will appear below
* the anchor if there is room, or above it if there is not.
* @param gravity The {@link Gravity} value for aligning the
popup with its
* anchor.
* @param
popupStyleAttr An attribute in the
current theme that c
ontains a
* reference to a
style resource that supplies default values for
* the
popup window. Can be 0 to not look for defaults.
* @param
popupStyleRes A resource identifier of a
style resource that
* supplies default values for the
popup window, used
only if
*
popupStyleAttr is 0 or can not be found in the theme. Can be 0
* to not look for defaults.
*/
public
PopupMenu(C
ontext c
ontext,
View anchor, int gravity, int
popupStyleAttr,
int
popupStyleRes) {
mC
ontext = c
ontext;
mAnchor = anchor;
mMenu = new MenuBuilder(c
ontext);
mMenu.setCallback(new MenuBuilder.Callback() {
@Override
public boolean
onMenuItemSelected(MenuBuilder menu, MenuItem item) {
if (mMenuItemClickListener != null) {
return mMenuItemClickListener.
onMenuItemClick(item);
}
return false;
}
@Override
public void
onMenuModeChange(MenuBuilder menu) {
}
});
m
Popup = new Menu
PopupHelper(c
ontext, mMenu, anchor, false,
popupStyleAttr,
popupStyleRes);
m
Popup.setGravity(gravity);
m
Popup.set
OnDismissListener(new
PopupWindow.
OnDismissListener() {
@Override
public void
onDismiss() {
if (m
OnDismissListener != null) {
m
OnDismissListener.
onDismiss(
PopupMenu.this);
}
}
});
}
/**
* Sets the gravity used to align the
popup window to its anchor
view.
* <p>
* If the
popup is showing, calling this method will take effect
only
* the next time the
popup is shown.
*
* @param gravity the gravity used to align the
popup window
* @see #getGravity()
*/
public void setGravity(int gravity) {
m
Popup.setGravity(gravity);
}
/**
* @return the gravity used to align the
popup window to its anchor
view
* @see #setGravity(int)
*/
public int getGravity() {
return m
Popup.getGravity();
}
/**
* Returns an {@link
OnTouchListener} that can be added to the anchor
view
* to implement drag
-to
-open behavior.
* <p>
* When the listener is set
on a
view, touching that
view and dragging
* outside of its bounds will open the
popup window. Lifting will select
* the
currently touched list item.
* <p>
* Example usage:
* <pre>
*
PopupMenu my
Popup = new
PopupMenu(c
ontext, myAnchor);
* myAnchor.set
OnTouchListener(my
Popup.getDragToOpenListener());
* </pre>
*
* @return a touch listener that c
ontrols drag
-to
-open behavior
*/
public
OnTouchListener getDragToOpenListener() {
if (mDragListener == null) {
mDragListener = new ForwardingListener(mAnchor) {
@Override
protected boolean
onForwardingStarted() {
show();
return true;
}
@Override
protected boolean
onForwardingStopped() {
dismiss();
return true;
}
@Override
public ShowableListMenu get
Popup() {
// This will be null until show() is called.
return m
Popup.get
Popup();
}
};
}
return mDragListener;
}
/**
* Returns the {@link Menu} associated with this
popup. Populate the
* returned Menu with items before calling {@link #show()}.
*
* @return the {@link Menu} associated with this
popup
* @see #show()
* @see #getMenuInflater()
*/
public Menu getMenu() {
return mMenu;
}
/**
* @return a {@link MenuInflater} that can be used to inflate menu items
* from XML into the menu returned by {@link #getMenu()}
* @see #getMenu()
*/
public MenuInflater getMenuInflater() {
return new MenuInflater(mC
ontext);
}
/**
* Inflate a menu resource into this
PopupMenu. This is equivalent to
* calling {@code
popupMenu.getMenuInflater().inflate(menuRes,
popupMenu.getMenu())}.
*
* @param menuRes Menu resource to inflate
*/
public void inflate(@MenuRes int menuRes) {
getMenuInflater().inflate(menuRes, mMenu);
}
/**
* Show the menu
popup anchored to the
view specified during c
onstructi
on.
*
* @see #dismiss()
*/
public void show() {
m
Popup.show();
}
/**
* Dismiss the menu
popup.
*
* @see #show()
*/
public void dismiss() {
m
Popup.dismiss();
}
/**
* Sets a listener that will be notified when the user selects an item from
* the menu.
*
* @param listener the listener to notify
*/
public void set
OnMenuItemClickListener(
OnMenuItemClickListener listener) {
mMenuItemClickListener = listener;
}
/**
* Sets a listener that will be notified when this menu is dismissed.
*
* @param listener the listener to notify
*/
public void set
OnDismissListener(
OnDismissListener listener) {
m
OnDismissListener = listener;
}
/**
* Sets whether the
popup menu's adapter is forced to show ic
ons in the
* menu item
views.
* <p>
* Changes take effect
on the next call to show().
*
* @param forceShowIc
on {@code true} to force ic
ons to be shown, or
* {@code false} for ic
ons to be opti
onally shown
*/
public void setForceShowIc
on(boolean forceShowIc
on) {
m
Popup.setForceShowIc
on(forceShowIc
on);
}
/**
* Interface resp
onsible for receiving menu item click events if the items
* themselves do not have individual item click listeners.
*/
public interface
OnMenuItemClickListener {
/**
* This method will be invoked when a menu item is clicked if the item
* itself did not already handle the event.
*
* @param item the menu item that was clicked
* @return {@code true} if the event was handled, {@code false}
* otherwise
*/
boolean
onMenuItemClick(MenuItem item);
}
/**
* Callback interface used to notify the applicati
on that the menu has closed.
*/
public interface
OnDismissListener {
/**
* Called when the associated menu has been dismissed.
*
* @param menu the
popup menu that was dismissed
*/
void
onDismiss(
PopupMenu menu);
}
/**
* Returns the {@link List
View} representing the list of menu items in the
currently showing
* menu.
*
* @return The
view representing the list of menu items.
* @hide
*/
@TestApi
public List
View getMenuList
View() {
if (!m
Popup.isShowing()) {
return null;
}
return m
Popup.get
Popup().getList
View();
}
}
本文介绍了一种在iOS应用中创建自定义对话框的方法，利用UIViewController实现覆盖当前上下文的透明背景视图，并展示了如何调整视图控制器的过渡样式以平滑地呈现对话框。
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