com.android.launcher3.taskbar.NavbarButtonsViewController.initButtons
mEnabledValue状态<T> StatePropertyHolder(T target, IntPredicate enabledCondition,Property<T, Float> property, float enabledValue, float disabledValue) {mEnableCondition = enabledCondition;mEnabledValue = enabledValue;mDisabledValue = disabledValue;mAnimator = ObjectAnimator.ofFloat(target, property, enabledValue, disabledValue);}// 初始化NavButton
private void initButtons(ViewGroup navContainer, ViewGroup endContainer,TaskbarNavButtonController navButtonController) {mBackButton = addButton(R.drawable.ic_sysbar_back, BUTTON_BACK,mNavButtonContainer, mControllers.navB
