Detailed Explanation of Android WindowManger Hierarchy Analysis
- 2021-12-19 06:44:55
- OfStack
Catalog 1. Window Categorization 2. Window Hierarchy (1) Application Window: (2) Child Window: (3) System Window: (3) How to Really View the Priority of Window (4) Level Analysis (Compare Toast with Soft Keyboard) (5) How to Customize System Hierarchy
1. Window classification
Apply Window (ApplicationWindow: corresponding to 1 Acitivity)
Child Window (SubWindow: It cannot exist alone and needs to be attached to a specific parent Window, for example, one common Dialog is one child Window)
System Window (SystemWindow: Window that requires declaring permissions to create, such as Toast and System Status Bar are both System Window)
2. Window level
Window is layered, and each Window has a corresponding z-ordered. The large level will cover the small level Window, which is completely consistent with the concept of z-index in HTML.
Among the three Window, the hierarchical range of each Window is also different, as follows:
Application of Window 1 ~ 99
Sub Window 1000 ~ 1999
System Window 2000 ~ 2999
These level ranges correspond to type parameters of WindowManager. LayoutParams. If you want Window to be at the top level of all Window, you can adopt a larger level. Obviously, the level of system Window is the largest. When we adopt system level, we need to declare permissions.
(1) Application window:
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) Sub-windows:
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) System window:
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;Window display order:
The larger the Type value, the higher the level, and the larger the Type value, the smaller the Type value, which is just a general rule.
(3) How to really view the priority of Window
/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;
}
}What is returned above is the level of Window except Application. When developing system applications, you can choose one to develop your own Window.
(4) Specific analysis of level (compared with Toast and soft keyboard)
Below toast---> Can't be covered toast
Lower than soft keyboard ---> Can't cover the soft keyboard
Attachment Activity Use --->is your activity running?
public static int getWindowType(int num) {
switch (num) {
case 1:
return WindowManager.LayoutParams.TYPE_PHONE;// Below toast Lower than soft keyboard
case 2:
return WindowManager.LayoutParams.TYPE_SEARCH_BAR;// Below toast Lower than soft keyboard
case 3:
return WindowManager.LayoutParams.TYPE_SYSTEM_DIALOG;// Below toast Lower than soft keyboard
case 4:
return WindowManager.LayoutParams.TYPE_PRIORITY_PHONE;// Above toast Lower than soft keyboard
case 5:
return WindowManager.LayoutParams.TYPE_APPLICATION_OVERLAY;// Above toast Lower than soft keyboard
case 6:
return WindowManager.LayoutParams.TYPE_INPUT_METHOD_DIALOG;// Above toast Cover the keyboard
case 7:
return WindowManager.LayoutParams.TYPE_SYSTEM_ERROR;// Above toast Lower than soft keyboard
case 8:
return WindowManager.LayoutParams.TYPE_KEYGUARD_DIALOG;// Above toast Lower than soft keyboard
case 9:
return WindowManager.LayoutParams.TYPE_SYSTEM_ALERT;// Above toast Higher than soft keyboard
case 10:
return WindowManager.LayoutParams.TYPE_STATUS_BAR;// Above toast Higher than the soft keyboard (the keyboard will be transparent view Jacking up)
case 11:
return WindowManager.LayoutParams.TYPE_STATUS_BAR_PANEL;// Above toast Higher than the soft keyboard (the keyboard will be transparent view Jacking up)
case 12:
return WindowManager.LayoutParams.TYPE_SYSTEM_OVERLAY;// Below the lower page
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;
}
}
(5) How to customize the system hierarchy
Changing the hierarchical relationship requires overwriting the switch order structure and return value of getWindowLayerFromTypeLw
If you need to change the behavior of Window, you need to modify it
/frameworks/base/services/core/java/com/android/server/policy/PhoneWindowManager.java