android界面編程方面有兩大核心,一個是View代表的界面元素,一個是WindowManager代表的界面管理.前者為卒子,后者為將帥.
基礎(chǔ)
一切view,在界面最終以Window形式展現(xiàn),被WindowManager管理.
WindowManager提供有三個方法:添加View别智、更新View和刪除View.
public void addView(View view, ViewGroup.LayoutParams params);
public void updateViewLayout(View view, ViewGroup.LayoutParams params);
public void removeView(View view);
View的展現(xiàn)規(guī)則封裝在LayoutParams中,其內(nèi)部屬性見:
LayoutParams 主要的幾個屬性
flag
標識這個window怎么響應事件,怎樣的一個透明度,以及一些全屏,鎖屏顯示等等.
WindowManager.LayoutParams的各種flag含義
type
類似于前端里的z-index.值越大越在上面.
type的真正含義: 類型-->根據(jù)值的范圍將window分成三大類:
- 系統(tǒng)級窗口(System windows):
ranging from FIRST_SYSTEM_WINDOW to LAST_SYSTEM_WINDOW 2000-2999
可以在任何地方顯示 - 應用級窗口(Application windows):
ranging from FIRST_APPLICATION_WINDOW to LAST_APPLICATION_WINDOW 1-99
典型的: activity - 子窗口(Sub-windows):
ranging from FIRST_SUB_WINDOW to LAST_SUB_WINDOW 1000-1999
必須依附于某一個應用級窗口
WindowManager.LayoutParams.type的使用
WindowManager.LayoutParams.type屬性
系統(tǒng)內(nèi)置的窗口實現(xiàn)
- popupwindow
- dialog
- activity
- toast
- notification
系統(tǒng)級窗口,6.0以前的權(quán)限
一般來說,彈出系統(tǒng)級窗口需要申請android.permission.SYSTEM_ALERT_WINDOW權(quán)限,
但是,TYPE_TOAST雖然是系統(tǒng)級窗口,不用申請
然而,國產(chǎn)rom,比如MIUI,會強制要求申請此權(quán)限,更鬧心的是,還默認關(guān)閉這個權(quán)限.
所以,需要兼顧6.0以前的權(quán)限申請,以及適配:
https://github.com/hss01248/FloatWindowPermission
奇技淫巧
需求1
在屏幕上顯示一個浮動控件。需要能接收點擊事件入挣,還要能顯示在statusBar(狀態(tài)欄)之上护姆,不能被狀態(tài)欄遮住
WindowManager.LayoutParams params = new WindowManager.LayoutParams(
WindowManager.LayoutParams.MATCH_PARENT,
WindowManager.LayoutParams.WRAP_CONTENT,
WindowManager.LayoutParams.TYPE_SYSTEM_ERROR,
WindowManager.LayoutParams.FLAG_NOT_FOCUSABLE
|WindowManager.LayoutParams.FLAG_NOT_TOUCH_MODAL
| WindowManager.LayoutParams.FLAG_LAYOUT_IN_SCREEN,
PixelFormat.TRANSLUCENT);
需求2
偷偷地拍照:
- 思路1:彈出一個透明的activity,這個activity還要能夠不攔截任何事件,屏幕的所有觸摸都要能夠傳遞到下層activity.
攔路虎: 對activity的許多flag設(shè)置會無效,主要是activity無法設(shè)置不攔截事件. - 思路2: 彈出一個type = TYPE_TOAST的窗口,1平方像素.
代碼庫見此: https://github.com/hss01248/HiddenCamera
核心代碼:
final WindowManager windowManager = (WindowManager) context.getSystemService(Context.WINDOW_SERVICE);
PhotoCallback callback2 = new PhotoCallback() {
@Override
public void onFail() {
callback.onFail();
windowManager.removeView(page.getRootView());
}
@Override
public void onSuccess(String path) {
callback.onSuccess(path);
windowManager.removeView(page.getRootView());
}
};
page.setCallback(callback2);
WindowManager.LayoutParams params = new WindowManager.LayoutParams();//dialog.getWindow().getAttributes();
params.type = WindowManager.LayoutParams.TYPE_TOAST;
params.flags = WindowManager.LayoutParams.FLAG_NOT_FOCUSABLE
|WindowManager.LayoutParams.FLAG_NOT_TOUCHABLE
|WindowManager.LayoutParams.FLAG_DIM_BEHIND//后面變暗
|WindowManager.LayoutParams.FLAG_NOT_TOUCH_MODAL;
params.width = WindowManager.LayoutParams.WRAP_CONTENT;
params.height = WindowManager.LayoutParams.WRAP_CONTENT;
params.gravity = Gravity.LEFT| Gravity.TOP;
params.dimAmount = 0;//后面變暗區(qū)域透明...
windowManager.addView(page.getRootView(),params);