一. Window 分类
- 应用 Window（ApplicationWindow： 对应一个 Acitivity）
- 子 Window （SubWindow：不能单独存在，需要依附在特定的父 Window 中，比如常见的一些 Dialog 就是一个子 Window）
- 系统 Window （SystemWindow：需要声明权限才能创建的 Window，比如 Toast 和系统状态栏都是系统 Window）
二. Window层级
Window 是分层的，每个 Window 都有对应的 z-ordered，层级大的会覆盖在层级小的 Window 上面，这和 HTML 中的 z-index 概念是完全一致的。
在三种 Window 中，每一种Window的层级范围也是不同的，如下：
应用Window 1~99
子Window 1000~1999
系统Window 2000~2999
这些层级范围对应着 WindowManager.LayoutParams 的 type 参数，如果想要 Window 位于所有 Window 的最顶层，那么采用较大的层级即可，很显然系统 Window 的层级是最大的，当我们采用系统层级时，需要声明权限。
（1）应用程序窗口：
package android.view;
public interface WindowManager
/**
* Start of window types that represent normal application windows.
*/
public static final int FIRST_APPLICATION_WINDOW = 1;
/**
* Window type: an application window that serves as the "base" window
* of the overall application; all other application windows will
* appear on top of it.
* In multiuser systems shows only on the owning user's window.
*/
public static final int TYPE_BASE_APPLICATION = 1;
/**
* Window type: a normal application window. The {@link #token} must be
* an Activity token identifying who the window belongs to.
* In multiuser systems shows only on the owning user's window.
*/
public static final int TYPE_APPLICATION = 2;
/**
* Window type: special application window that is displayed while the
* application is starting. Not for use by applications themselves;
* this is used by the system to display something until the
* application can show its own windows.
* In multiuser systems shows on all users' windows.
*/
public static final int TYPE_APPLICATION_STARTING = 3;
/**
* Window type: a variation on TYPE_APPLICATION that ensures the window
* manager will wait for this window to be drawn before the app is shown.
* In multiuser systems shows only on the owning user's window.
*/
public static final int TYPE_DRAWN_APPLICATION = 4;
/**
* End of types of application windows.
*/
public static final int LAST_APPLICATION_WINDOW = 99;
（2）子窗口：
package android.view;
public interface WindowManager
/**
* Start of types of sub-windows. The {@link #token} of these windows
* must be set to the window they are attached to. These types of
* windows are kept next to their attached window in Z-order, and their
* coordinate space is relative to their attached window.
*/
public static final int FIRST_SUB_WINDOW = 1000;
/**
* Window type: a panel on top of an application window. These windows
* appear on top of their attached window.
*/
public static final int TYPE_APPLICATION_PANEL = FIRST_SUB_WINDOW;
/**
* Window type: window for showing media (such as video). These windows
* are displayed behind their attached window.
*/
public static final int TYPE_APPLICATION_MEDIA = FIRST_SUB_WINDOW 1;
/**
* Window type: a sub-panel on top of an application window. These
* windows are displayed on top their attached window and any
* {@link #TYPE_APPLICATION_PANEL} panels.
*/
public static final int TYPE_APPLICATION_SUB_PANEL = FIRST_SUB_WINDOW 2;
/** Window type: like {@link #TYPE_APPLICATION_PANEL}, but layout
* of the window happens as that of a top-level window, <em>not</em>
* as a child of its container.
*/
public static final int TYPE_APPLICATION_ATTACHED_DIALOG = FIRST_SUB_WINDOW 3;
/**
* Window type: window for showing overlays on top of media windows.
* These windows are displayed between TYPE_APPLICATION_MEDIA and the
* application window. They should be translucent to be useful. This
* is a big ugly hack so:
* @hide
*/
@UnsupportedAppUsage
public static final int TYPE_APPLICATION_MEDIA_OVERLAY = FIRST_SUB_WINDOW 4;
/**
* Window type: a above sub-panel on top of an application window and it's
* sub-panel windows. These windows are displayed on top of their attached window
* and any {@link #TYPE_APPLICATION_SUB_PANEL} panels.
* @hide
*/
public static final int TYPE_APPLICATION_ABOVE_SUB_PANEL = FIRST_SUB_WINDOW 5;
/**
* End of types of sub-windows.
*/
public static final int LAST_SUB_WINDOW = 1999;
（3）系统窗口：
package android.view;
public interface WindowManager
/**
* Start of system-specific window types. These are not normally
* created by applications.
*/
public static final int FIRST_SYSTEM_WINDOW = 2000;
/**
* Window type: the status bar. There can be only one status bar
* window; it is placed at the top of the screen, and all other
* windows are shifted down so they are below it.
* In multiuser systems shows on all users' windows.
*/
public static final int TYPE_STATUS_BAR = FIRST_SYSTEM_WINDOW;
/**
* Window type: the search bar. There can be only one search bar
* window; it is placed at the top of the screen.
* In multiuser systems shows on all users' windows.
*/
public static final int TYPE_SEARCH_BAR = FIRST_SYSTEM_WINDOW 1;
/**
* Window type: phone. These are non-application windows providing
* user interaction with the phone (in particular incoming calls).
* These windows are normally placed above all applications, but behind
* the status bar.
* In multiuser systems shows on all users' windows.
* @deprecated for non-system apps. Use {@link #TYPE_APPLICATION_OVERLAY} instead.
*/
@Deprecated
public static final int TYPE_PHONE = FIRST_SYSTEM_WINDOW 2;
/**
* Window type: system window, such as low power alert. These windows
* are always on top of application windows.
* In multiuser systems shows only on the owning user's window.
* @deprecated for non-system apps. Use {@link #TYPE_APPLICATION_OVERLAY} instead.
*/
@Deprecated
public static final int TYPE_SYSTEM_ALERT = FIRST_SYSTEM_WINDOW 3;
/**
* Window type: keyguard window.
* In multiuser systems shows on all users' windows.
* @removed
*/
public static final int TYPE_KEYGUARD = FIRST_SYSTEM_WINDOW 4;
/**
* Window type: transient notifications.
* In multiuser systems shows only on the owning user's window.
* @deprecated for non-system apps. Use {@link #TYPE_APPLICATION_OVERLAY} instead.
*/
@Deprecated
public static final int TYPE_TOAST = FIRST_SYSTEM_WINDOW 5;
/**
* Window type: system overlay windows, which need to be displayed
* on top of everything else. These windows must not take input
* focus, or they will interfere with the keyguard.
* In multiuser systems shows only on the owning user's window.
* @deprecated for non-system apps. Use {@link #TYPE_APPLICATION_OVERLAY} instead.
*/
@Deprecated
public static final int TYPE_SYSTEM_OVERLAY = FIRST_SYSTEM_WINDOW 6;
/**
* Window type: priority phone UI, which needs to be displayed even if
* the keyguard is active. These windows must not take input
* focus, or they will interfere with the keyguard.
* In multiuser systems shows on all users' windows.
* @deprecated for non-system apps. Use {@link #TYPE_APPLICATION_OVERLAY} instead.
*/
@Deprecated
public static final int TYPE_PRIORITY_PHONE = FIRST_SYSTEM_WINDOW 7;
/**
* Window type: panel that slides out from the status bar
* In multiuser systems shows on all users' windows.
*/
public static final int TYPE_SYSTEM_DIALOG = FIRST_SYSTEM_WINDOW 8;
/**
* Window type: dialogs that the keyguard shows
* In multiuser systems shows on all users' windows.
*/
public static final int TYPE_KEYGUARD_DIALOG = FIRST_SYSTEM_WINDOW 9;
/**
* Window type: internal system error windows, appear on top of
* everything they can.
* In multiuser systems shows only on the owning user's window.
* @deprecated for non-system apps. Use {@link #TYPE_APPLICATION_OVERLAY} instead.
*/
@Deprecated
public static final int TYPE_SYSTEM_ERROR = FIRST_SYSTEM_WINDOW 10;
/**
* Window type: internal input methods windows, which appear above
* the normal UI. Application windows may be resized or panned to keep
* the input focus visible while this window is displayed.
* In multiuser systems shows only on the owning user's window.
*/
public static final int TYPE_INPUT_METHOD = FIRST_SYSTEM_WINDOW 11;
/**
* Window type: internal input methods dialog windows, which appear above
* the current input method window.
* In multiuser systems shows only on the owning user's window.
*/
public static final int TYPE_INPUT_METHOD_DIALOG= FIRST_SYSTEM_WINDOW 12;
/**
* Window type: wallpaper window, placed behind any window that wants
* to sit on top of the wallpaper.
* In multiuser systems shows only on the owning user's window.
*/
public static final int TYPE_WALLPAPER = FIRST_SYSTEM_WINDOW 13;
/**
* Window type: panel that slides out from over the status bar
* In multiuser systems shows on all users' windows.
*/
public static final int TYPE_STATUS_BAR_PANEL = FIRST_SYSTEM_WINDOW 14;
/**
* Window type: secure system overlay windows, which need to be displayed
* on top of everything else. These windows must not take input
* focus, or they will interfere with the keyguard.
*
* This is exactly like {@link #TYPE_SYSTEM_OVERLAY} except that only the
* system itself is allowed to create these overlays. Applications cannot
* obtain permission to create secure system overlays.
*
* In multiuser systems shows only on the owning user's window.
* @hide
*/
@UnsupportedAppUsage
public static final int TYPE_SECURE_SYSTEM_OVERLAY = FIRST_SYSTEM_WINDOW 15;
/**
* Window type: the drag-and-drop pseudowindow. There is only one
* drag layer (at most), and it is placed on top of all other windows.
* In multiuser systems shows only on the owning user's window.
* @hide
*/
public static final int TYPE_DRAG = FIRST_SYSTEM_WINDOW 16;
/**
* Window type: panel that slides out from over the status bar
* In multiuser systems shows on all users' windows. These windows
* are displayed on top of the stauts bar and any {@link #TYPE_STATUS_BAR_PANEL}
* windows.
* @hide
*/
public static final int TYPE_STATUS_BAR_SUB_PANEL = FIRST_SYSTEM_WINDOW 17;
/**
* Window type: (mouse) pointer
* In multiuser systems shows on all users' windows.
* @hide
*/
public static final int TYPE_POINTER = FIRST_SYSTEM_WINDOW 18;
/**
* Window type: Navigation bar (when distinct from status bar)
* In multiuser systems shows on all users' windows.
* @hide
*/
public static final int TYPE_NAVIGATION_BAR = FIRST_SYSTEM_WINDOW 19;
/**
* Window type: The volume level overlay/dialog shown when the user
* changes the system volume.
* In multiuser systems shows on all users' windows.
* @hide
*/
public static final int TYPE_VOLUME_OVERLAY = FIRST_SYSTEM_WINDOW 20;
/**
* Window type: The boot progress dialog, goes on top of everything
* in the world.
* In multiuser systems shows on all users' windows.
* @hide
*/
public static final int TYPE_BOOT_PROGRESS = FIRST_SYSTEM_WINDOW 21;
/**
* Window type to consume input events when the systemUI bars are hidden.
* In multiuser systems shows on all users' windows.
* @hide
*/
public static final int TYPE_INPUT_CONSUMER = FIRST_SYSTEM_WINDOW 22;
/**
* Window type: Dreams (screen saver) window, just above keyguard.
* In multiuser systems shows only on the owning user's window.
* @hide
*/
public static final int TYPE_DREAM = FIRST_SYSTEM_WINDOW 23;
/**
* Window type: Navigation bar panel (when navigation bar is distinct from status bar)
* In multiuser systems shows on all users' windows.
* @hide
*/
public static final int TYPE_NAVIGATION_BAR_PANEL = FIRST_SYSTEM_WINDOW 24;
/**
* Window type: Display overlay window. Used to simulate secondary display devices.
* In multiuser systems shows on all users' windows.
* @hide
*/
@UnsupportedAppUsage
public static final int TYPE_DISPLAY_OVERLAY = FIRST_SYSTEM_WINDOW 26;
/**
* Window type: Magnification overlay window. Used to highlight the magnified
* portion of a display when accessibility magnification is enabled.
* In multiuser systems shows on all users' windows.
* @hide
*/
public static final int TYPE_MAGNIFICATION_OVERLAY = FIRST_SYSTEM_WINDOW 27;
/**
* Window type: Window for Presentation on top of private
* virtual display.
*/
public static final int TYPE_PRIVATE_PRESENTATION = FIRST_SYSTEM_WINDOW 30;
/**
* Window type: Windows in the voice interaction layer.
* @hide
*/
public static final int TYPE_VOICE_INTERACTION = FIRST_SYSTEM_WINDOW 31;
/**
* Window type: Windows that are overlaid <em>only</em> by a connected {@link
* android.accessibilityservice.AccessibilityService} for interception of
* user interactions without changing the windows an accessibility service
* can introspect. In particular, an accessibility service can introspect
* only windows that a sighted user can interact with which is they can touch
* these windows or can type into these windows. For example, if there
* is a full screen accessibility overlay that is touchable, the windows
* below it will be introspectable by an accessibility service even though
* they are covered by a touchable window.
*/
public static final int TYPE_ACCESSIBILITY_OVERLAY = FIRST_SYSTEM_WINDOW 32;
/**
* Window type: Starting window for voice interaction layer.
* @hide
*/
public static final int TYPE_VOICE_INTERACTION_STARTING = FIRST_SYSTEM_WINDOW 33;
/**
* Window for displaying a handle used for resizing docked stacks. This window is owned
* by the system process.
* @hide
*/
public static final int TYPE_DOCK_DIVIDER = FIRST_SYSTEM_WINDOW 34;
/**
* Window type: like {@link #TYPE_APPLICATION_ATTACHED_DIALOG}, but used
* by Quick Settings Tiles.
* @hide
*/
public static final int TYPE_QS_DIALOG = FIRST_SYSTEM_WINDOW 35;
/**
* Window type: shares similar characteristics with {@link #TYPE_DREAM}. The layer is
* reserved for screenshot region selection. These windows must not take input focus.
* @hide
*/
public static final int TYPE_SCREENSHOT = FIRST_SYSTEM_WINDOW 36;
/**
* Window type: Window for Presentation on an external display.
* @see android.app.Presentation
* @hide
*/
public static final int TYPE_PRESENTATION = FIRST_SYSTEM_WINDOW 37;
/**
* Window type: Application overlay windows are displayed above all activity windows
* (types between {@link #FIRST_APPLICATION_WINDOW} and {@link #LAST_APPLICATION_WINDOW})
* but below critical system windows like the status bar or IME.
* <p>
* The system may change the position, size, or visibility of these windows at anytime
* to reduce visual clutter to the user and also manage resources.
* <p>
* Requires {@link android.Manifest.permission#SYSTEM_ALERT_WINDOW} permission.
* <p>
* The system will adjust the importance of processes with this window type to reduce the
* chance of the low-memory-killer killing them.
* <p>
* In multi-user systems shows only on the owning user's screen.
*/
public static final int TYPE_APPLICATION_OVERLAY = FIRST_SYSTEM_WINDOW 38;
/**
* End of types of system windows.
*/
public static final int LAST_SYSTEM_WINDOW = 2999;
窗口显示顺序：
Type 值越大层级越高，Type 值大的覆盖 Type 值小的，这只是一般规律。
（三）如何真正查看 Window 的优先级
/frameworks/base/services/core/java/com/android/server/policy/WindowManagerPolicy.java
default int getWindowLayerFromTypeLw(int type, boolean canAddInternalSystemWindow) {
if (type >= FIRST_APPLICATION_WINDOW && type <= LAST_APPLICATION_WINDOW) {
return APPLICATION_LAYER;
}
switch (type) {
case TYPE_WALLPAPER:
// wallpaper is at the bottom, though the window manager may move it.
return 1;
case TYPE_PRESENTATION:
case TYPE_PRIVATE_PRESENTATION:
return APPLICATION_LAYER;
case TYPE_DOCK_DIVIDER:
return APPLICATION_LAYER;
case TYPE_QS_DIALOG:
return APPLICATION_LAYER;
case TYPE_PHONE:
return 3;
case TYPE_SEARCH_BAR:
case TYPE_VOICE_INTERACTION_STARTING:
return 4;
case TYPE_VOICE_INTERACTION:
// voice interaction layer is almost immediately above apps.
return 5;
case TYPE_INPUT_CONSUMER:
return 6;
case TYPE_SYSTEM_DIALOG:
return 7;
case TYPE_TOAST:
// toasts and the plugged-in battery thing
return 8;
case TYPE_PRIORITY_PHONE:
// SIM errors and unlock. Not sure if this really should be in a high layer.
return 9;
case TYPE_SYSTEM_ALERT:
// like the ANR / app crashed dialogs
return canAddInternalSystemWindow ? 11 : 10;
case TYPE_APPLICATION_OVERLAY:
return 12;
case TYPE_DREAM:
// used for Dreams (screensavers with TYPE_DREAM windows)
return 13;
case TYPE_INPUT_METHOD:
// on-screen keyboards and other such input method user interfaces go here.
return 14;
case TYPE_INPUT_METHOD_DIALOG:
// on-screen keyboards and other such input method user interfaces go here.
return 15;
case TYPE_STATUS_BAR:
return 17;
case TYPE_STATUS_BAR_PANEL:
return 18;
case TYPE_STATUS_BAR_SUB_PANEL:
return 19;
case TYPE_KEYGUARD_DIALOG:
return 20;
case TYPE_VOLUME_OVERLAY:
// the on-screen volume indicator and controller shown when the user
// changes the device volume
return 21;
case TYPE_SYSTEM_OVERLAY:
// the on-screen volume indicator and controller shown when the user
// changes the device volume
return canAddInternalSystemWindow ? 22 : 11;
case TYPE_NAVIGATION_BAR:
// the navigation bar, if available, shows atop most things
return 23;
case TYPE_NAVIGATION_BAR_PANEL:
// some panels (e.g. search) need to show on top of the navigation bar
return 24;
case TYPE_SCREENSHOT:
// screenshot selection layer shouldn't go above system error, but it should cover
// navigation bars at the very least.
return 25;
case TYPE_SYSTEM_ERROR:
// system-level error dialogs
return canAddInternalSystemWindow ? 26 : 10;
case TYPE_MAGNIFICATION_OVERLAY:
// used to highlight the magnified portion of a display
return 27;
case TYPE_DISPLAY_OVERLAY:
// used to simulate secondary display devices
return 28;
case TYPE_DRAG:
// the drag layer: input for drag-and-drop is associated with this window,
// which sits above all other focusable windows
return 29;
case TYPE_ACCESSIBILITY_OVERLAY:
// overlay put by accessibility services to intercept user interaction
return 30;
case TYPE_SECURE_SYSTEM_OVERLAY:
return 31;
case TYPE_BOOT_PROGRESS:
return 32;
case TYPE_POINTER:
// the (mouse) pointer layer
return 33;
default:
Slog.e("WindowManager", "Unknown window type: " type);
return APPLICATION_LAYER;
}
}
以上返回的是除 Application 外的 Window 的层级，在开发系统应用时可以选择一种开发自己的 Window.
（四） 层级高低具体分析（对比Toast以及软键盘）
低于toast--->盖不住toast
低于软键盘--->盖不住软键盘
依附Activity使用--->is your activity running?
public static int getWindowType(int num) {
switch (num) {
case 1:
return WindowManager.LayoutParams.TYPE_PHONE;//低于toast 低于软键盘
case 2:
return WindowManager.LayoutParams.TYPE_SEARCH_BAR;//低于toast 低于软键盘
case 3:
return WindowManager.LayoutParams.TYPE_SYSTEM_DIALOG;//低于toast 低于软键盘
case 4:
return WindowManager.LayoutParams.TYPE_PRIORITY_PHONE;//高于toast 低于软键盘
case 5:
return WindowManager.LayoutParams.TYPE_APPLICATION_OVERLAY;//高于toast 低于软键盘
case 6:
return WindowManager.LayoutParams.TYPE_INPUT_METHOD_DIALOG;//高于toast 盖住键盘
case 7:
return WindowManager.LayoutParams.TYPE_SYSTEM_ERROR;//高于toast 低于软键盘
case 8:
return WindowManager.LayoutParams.TYPE_KEYGUARD_DIALOG;//高于toast 低于软键盘
case 9:
return WindowManager.LayoutParams.TYPE_SYSTEM_ALERT;//高于toast 高于软键盘
case 10:
return WindowManager.LayoutParams.TYPE_STATUS_BAR;//高于toast 高于软键盘（键盘会把透明view顶起）
case 11:
return WindowManager.LayoutParams.TYPE_STATUS_BAR_PANEL;//高于toast 高于软键盘（键盘会把透明view顶起）
case 12:
return WindowManager.LayoutParams.TYPE_SYSTEM_OVERLAY;//低于下级页面
case 13:
return WindowManager.LayoutParams.TYPE_ACCESSIBILITY_OVERLAY;//is your activity running?
case 14:
return WindowManager.LayoutParams.TYPE_BASE_APPLICATION;// is your activity running?
case 15:
return WindowManager.LayoutParams.TYPE_APPLICATION;// is your activity running?
case 16:
return WindowManager.LayoutParams.TYPE_APPLICATION_STARTING;// is your activity running?
case 17:
return WindowManager.LayoutParams.TYPE_DRAWN_APPLICATION;// is your activity running?
case 18:
return WindowManager.LayoutParams.TYPE_APPLICATION_PANEL;// is your activity running?
case 19:
return WindowManager.LayoutParams.TYPE_APPLICATION_MEDIA;// is your activity running?
case 20:
return WindowManager.LayoutParams.TYPE_APPLICATION_SUB_PANEL;// is your activity running?
case 21:
return WindowManager.LayoutParams.TYPE_APPLICATION_ATTACHED_DIALOG;// is your activity running?
case 22:
return WindowManager.LayoutParams.TYPE_WALLPAPER;// is your activity running?
case 23:
return WindowManager.LayoutParams.TYPE_TOAST;// is your activity running?
case 24:
return WindowManager.LayoutParams.TYPE_INPUT_METHOD;//is your activity running?
case 25:
return WindowManager.LayoutParams.TYPE_PRIVATE_PRESENTATION;//permission denied for window type 2030
default:
return 0;
}
}
（五）如何定制系统层级
改变层级关系需要改写 getWindowLayerFromTypeLw 的 switch 顺序结构和返回值
如果需要更改一些 Window 的行为，需要修改
/frameworks/base/services/core/java/com/android/server/policy/PhoneWindowManager.java
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