Gmail Honeycomb App 之类的片段动画

Question

如何重新创建您在 Android 3.0+ 上的 Gmail 应用中看到的布局动画效果

我知道你可以使用 PropertyAnimators、ObjectAnimators 等，但是在我的场景中，我在屏幕上有几个可以互换的片段，所以它们都包含在自己的 FrameLayouts 中，并且所有 FrameLayouts 都在一个相对布局。

我不知道如何更改 FrameLayouts 的宽度，因为您必须通过 LayoutParams 对象对其进行编辑。

有什么想法吗？

Answer 1

我对此的看法可以查看on GitHub here

它演示了一种用动画隐藏片段的方法，就像 Gmail 所做的那样。

动画并不完美，因为左侧片段的移动速度略快于右侧片段。

隐藏的方法在代码中定义了动画，如下所示：

/**
 * Besides showing/hiding the left fragment, this method specifies that a
 * layout animation should be used. It is defined as a sliding animation.
 * The right fragment will use the default animation, which is a sliding
 * animation also.
 * 
 * If the left fragment's animation is removed from this method, the default
 * animation will be used which is a fading animation.
 * 
 * Please note that this method will only have an effect in those screen
 * configurations where the list is hideable; by default, a width between
 * 600 and 1024 dip which corresponds to a portrait view on tablets. Change
 * the boolean value in layout_constants.xml to allow for it in other screen
 * sizes.
 * 
 * @param visible
 */
protected void setLeftFragmentVisible(boolean visible) {
    if (leftFragment != null && (leftFragment.isVisible() || visible)
            && getResources().getBoolean(R.bool.leftHideable)) {
        final float listWidth = getLeftFragment().getView().getWidth();
        ViewGroup container = (ViewGroup) findViewById(R.id.dual_layout);
        // Don't clip the children, we want to draw the entire fragment even
        // if it is partially off-screen.
        container.setClipChildren(false);
        final LayoutTransition trans = container.getLayoutTransition();
        /**
         * This specifies the delay before the leftFragment will appear.
         * Change if you want the right fragment to move before.
         */
        trans.setStartDelay(LayoutTransition.APPEARING, 0);
        /**
         * This is the delay before the right fragment will start to occupy
         * the space left by the left fragment
         */
        trans.setStartDelay(LayoutTransition.CHANGE_DISAPPEARING, 100);

        /**
         * Adding, specifies that the left fragment should animate by
         * sliding into view.
         */
        ObjectAnimator animIn = ObjectAnimator.ofFloat(null, "x",
                -listWidth, 0f).setDuration(
                trans.getDuration(LayoutTransition.CHANGE_APPEARING));
        trans.setAnimator(LayoutTransition.APPEARING, animIn);

        /**
         * Removing, specifies that the left fragment should animate by
         * sliding out of view.
         */
        ObjectAnimator animOut = ObjectAnimator.ofFloat(null, "x", 0f,
                -listWidth).setDuration(
                trans.getDuration(LayoutTransition.CHANGE_DISAPPEARING));
        trans.setAnimator(LayoutTransition.DISAPPEARING, animOut);

        FragmentManager fragmentManager = getFragmentManager();
        FragmentTransaction fragmentTransaction = fragmentManager
                .beginTransaction();
        if (getLeftFragment().isVisible()) {
            fragmentTransaction.hide(getLeftFragment());
        } else {
            fragmentTransaction.show(getLeftFragment());
        }
        // The hiding/showing will automatically initiate the animations
        // since
        // we have specified that we want layout animations in the layout
        // xml
        fragmentTransaction.commit();

        /*
         * Display home as up to be able to view the list
         */
        getActionBar().setDisplayHomeAsUpEnabled(!visible);
    }
}

要完成这项工作，您需要定义您希望布局过渡具有动画效果。布局的 xml 结构顶部的一行将执行此操作：

android:animateLayoutChanges="true"

如果你不想要自定义动画，你可以删除 FragmentManager fragmentManager = getFragmentManager() 之前的所有内容。

现在在我的示例中，我使用了片段，但同样的原则应该适用于任何视图。

编辑：您应该使用布局权重来允许自动调整大小，而不是手动更改视图的宽度。