如何创建部分不可见的视图

问题描述

我想要实现的效果是图片中的效果:

What I'd like to achieve is effect like the one in the picture:

所以基本上有一个 TextView 慢慢消失了.我不希望整个 View 都做成例如50％透明，而例如让它的左部分变成0％透明，而在右边平滑地变成100％透明.

So basically there's a TextView which slowly disappears. I don't want whole View to be made for example 50% transparent, but rather for example left part of it to be 0% transparent, and it smoothly goes into 100% transparency at the right side.

我知道某些组件(例如 ListView )使用了此功能，但是是否可以以非常简单的方式手动进行操作?

I know that some components (e.g. ListView) uses this, but is it possible to do it manually in quite easy way?

预先感谢答案

推荐答案

首先，创建一个具有alpha渐变的形状.将XML放入您的可绘制目录.我们称它为gradient_view.xml

First, create a shape with an alpha gradient. Place the XML into your drawable directory. Let's call it gradient_view.xml

<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android"
    android:shape="rectangle">
    <gradient
        android:angle="90"
        android:startColor="#FFFFFFFF"
        android:endColor="#00FFFFFF"
        android:type="linear"/>
</shape>

现在，在您的TextView右侧的布局中创建一个视图.您需要适当地设置宽度和高度，并根据需要在视图中定位(带有layout_toTheRightOf的RelativeLayout可以很好地工作).

Now create a view in your layout to the right of your TextView. You'll need to set width and height appropriately and position in your view as required (RelativeLayout with layout_toTheRightOf would work well).

<View android:layout_width="100dp"
    android:layout_height="50dp"
    android:background="@drawable/gradient_view"/>

在代码的正确位置进行动画处理.将-200更改为所需的值(甚至更好，找到渐变视图的左X并减去TextView的左边缘以找到要移动的量).

In the right place in your code, animate it. Change the -200 to whatever you need (or even better, find the left X of your gradient view and subtract the left edge of your TextView to find the amount to move).

TranslationAnimation anim = new TranslateAnimation(0, -200, 0, 0);
anim.setDuration(1000);
myTextView.startAnimation(anim);

http://developer.android.com/reference/android/view/animation/TranslateAnimation.html

还有很多工作要做，但这是您所需要的大部分.

There's a bit more work to do but this is most of what you need.

祝你好运

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