void makeVisible() {
if (!mWindowAdded) {
ViewManager wm = getWindowManager();
wm.addView(mDecor, getWindow().getAttributes());
mWindowAdded = true;
}
mDecor.setVisibility(View.VISIBLE);
}
通过上面的addView方法将View添加到Window。
三、Window操作View内部机制
1.window的添加
一个window对应一个view和一个viewRootImpl,window和view通过ViewRootImpl来建立联系，它并不存在，实体是view。只能通过 windowManager来操作它。
windowManager的实现类是windowManagerImpl。它并没有直接实现三大操作，而是委托给WindowManagerGlobal。addView的实现分为以下几步：
1）.检查参数是否合法。
if (view == null) {
throw new IllegalArgumentException("view must not be null");
}
if (display == null) {
throw new IllegalArgumentException("display must not be null");
}
if (!(params instanceof WindowManager.LayoutParams)) {
throw new IllegalArgumentException("Params must be WindowManager.LayoutParams");
}
final WindowManager.LayoutParams wparams = (WindowManager.LayoutParams)params;
if (parentWindow != null) {
parentWindow.adjustLayoutParamsForSubWindow(wparams);
} else {
// If there's no parent and we're running on L or above (or in the
// system context), assume we want hardware acceleration.
final Context context = view.getContext();
if (context != null
&& context.getApplicationInfo().targetSdkVersion >= Build.VERSION_CODES.LOLLIPOP) {
wparams.flags |= WindowManager.LayoutParams.FLAG_HARDWARE_ACCELERATED;
}
}
2）.创建ViewRootImpl并将View添加到列表中。
root = new ViewRootImpl(view.getContext(), display);
view.setLayoutParams(wparams);
mViews.add(view);
mRoots.add(root);
mParams.add(wparams);
