如何在“活动”过渡上执行淡入淡出动画？

问题描述

我正在整理徽标活动和主活动之间的过渡效果，但是我遇到的问题是，在消失活动之前，该活动移至顶部：

I am codifiying a transition effect between my logo activity and my Main activity, but I have the problem that before vanish the activity move to top:

<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="http://schemas.android.com/apk/res/android"
    android:shareInterpolator="false" >

    <alpha
        android:duration="2000"
        android:fromAlpha="0.0"
        android:toAlpha="1.0" >
    </alpha>

</set>

我如何改进此代码以使效果消失？

How could I improve this code to get only a vanish effect?

推荐答案

您可以创建自己的 .xml动画文件，以淡入新的 Activity 并淡出当前的 Activity ：

You could create your own .xml animation files to fade in a new Activity and fade out the current Activity:

fade_in.xml

fade_in.xml

<?xml version="1.0" encoding="utf-8"?>
<alpha xmlns:android="http://schemas.android.com/apk/res/android"
           android:interpolator="@android:anim/accelerate_interpolator"
           android:fromAlpha="0.0" android:toAlpha="1.0"
           android:duration="500" />

fade_out.xml

fade_out.xml

<?xml version="1.0" encoding="utf-8"?>
<alpha xmlns:android="http://schemas.android.com/apk/res/android"
           android:interpolator="@android:anim/accelerate_interpolator"
           android:fromAlpha="1.0" android:toAlpha="0.0"
           android:fillAfter="true"
           android:duration="500" />

在以下代码中使用它：（在您的 Activity ）

Use it in code like that: (Inside your Activity)

Intent i = new Intent(this, NewlyStartedActivity.class);
startActivity(i);
overridePendingTransition(R.anim.fade_in, R.anim.fade_out);

上面的代码将淡化当前活动的活动并淡入新启动的活动，从而实现平稳过渡。

The above code will fade out the currently active Activity and fade in the newly started Activity resulting in a smooth transition.

更新：
@Dan J指出，使用内置的Android动画可以提高性能，经过一些测试，我确实发现确实如此。如果您希望使用内置动画，请使用：

UPDATE:@Dan J pointed out that using the built in Android animations improves performance, which I indeed found to be the case after doing some testing. If you prefer working with the built in animations, use:

overridePendingTransition(android.R.anim.fade_in, android.R.anim.fade_out);

请注意，我引用的是 android.R R 访问资源ID。

Notice me referencing android.R instead of R to access the resource id.

更新：现在，使用转换类执行转换。

UPDATE: It is now common practice to perform transitions using the Transition class introduced in API level 19.

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