ViewUtilsLollipop.java 文件源码

/** Creates and sets a {@link StateListAnimator} with a custom elevation value */
static void setDefaultAppBarLayoutStateListAnimator(final View view, final float elevation) {
  final int dur = view.getResources().getInteger(R.integer.app_bar_elevation_anim_duration);

  final StateListAnimator sla = new StateListAnimator();

  // Enabled and collapsible, but not collapsed means not elevated
  sla.addState(
      new int[] {android.R.attr.enabled, R.attr.state_collapsible, -R.attr.state_collapsed},
      ObjectAnimator.ofFloat(view, "elevation", 0f).setDuration(dur));

  // Default enabled state
  sla.addState(
      new int[] {android.R.attr.enabled},
      ObjectAnimator.ofFloat(view, "elevation", elevation).setDuration(dur));

  // Disabled state
  sla.addState(new int[0], ObjectAnimator.ofFloat(view, "elevation", 0).setDuration(0));

  view.setStateListAnimator(sla);
}