Android ImageView 投影-移动开发问题

Android ImageView drop shadow(Android ImageView 投影)

本文介绍了Android ImageView 投影的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！

问题描述

我正在尝试向 ImageView 添加投影.Stackoverflow 的另一个答案似乎是使用画布和位图等，比它需要的复杂得多.

在 iOS 上，我会这样做:

myImageView.layer.shadowColor = [UIColor redColor].CGColor;myImageView.layer.shadowRadius = 5;myImageView.layer.shadowOffset = CGRectMake(0, 5);

它会渲染一个阴影，无论阴影是应用在视图、图像还是文本上.

我尝试在 Android 上做同样的事情，但它只是拒绝工作:

birdImageView = new ImageView(context);birdImageView.setImageResource(R.drawable.yellow_bird);油漆油漆 = 新油漆()；paint.setAntiAlias(true);birdImageView.setLayerType(LAYER_TYPE_SOFTWARE, null);paint.setShadowLayer(5, 0, 5, Color.argb(255, 255, 0, 0));birdImageView.setLayerPaint(paint);

我的鸟图像上根本看不到任何预期的红色阴影.

我做错了吗?

示例

假设我想要这样的阴影:

更新

我是否必须求助于 Android 5.0 和新的 Elevation api (http://developer.android.com/training/material/shadows-clipping.html) ?

但如果要使用新的 API，那么根据当前的人口统计数据 (http://www.droid-life.com/2016/02/02/android-distribution-february-2016/) 超过 50% 的用户将无法使用应用程序.

T_T

解决方案

在 android studio 中有 build drawable，你可以使用它来将阴影应用到任何 View.这类似于投影.

android:background=@drawable/abc_menu_dropdown_panel_holo_light"

使用这个你不能改变视图的背景颜色 &它的边框颜色.如果您想要自己的自定义可绘制对象，请使用 layer-list

<块引用>

custom_drop_shadow_drawable.xml

<块引用>

并应用到您的视图，如下所示

android:background=@drawable/custom_drop_shadow_drawable"

希望对你有帮助！感谢Android View shadow

I'm trying to add a drop shadow to an ImageView. The other Stackoverflow answer seems to be using canvas and bitmaps etc, way more complicated than it needs to be.



On iOS I would do something like this:
myImageView.layer.shadowColor = [UIColor redColor].CGColor;
myImageView.layer.shadowRadius = 5;
myImageView.layer.shadowOffset = CGRectMake(0, 5);
and it would render a drop shadow, regardless of whether the shadow is being applied on a view, an image or text.

I've tried to do the same on Android but it just refuses to work:
birdImageView = new ImageView(context);
birdImageView.setImageResource(R.drawable.yellow_bird);

Paint paint = new Paint();
paint.setAntiAlias(true);


birdImageView.setLayerType(LAYER_TYPE_SOFTWARE, null);
paint.setShadowLayer(5, 0, 5, Color.argb(255, 255, 0, 0));
birdImageView.setLayerPaint(paint);
I don't see any expected red drop shadow on my bird image at all.

Am I doing something wrong?

Example

Let's say I want the drop shadow like this:



Update

Do I have to resort to Android 5.0 and the new Elevation api (http://developer.android.com/training/material/shadows-clipping.html) ?

But if one was to use new API, then according to current demographics (http://www.droid-life.com/2016/02/02/android-distribution-february-2016/) more than 50% of users will not be able to use the app.

T_T
 解决方案 
In android studio there is in build  drawable that you can use for apply shadow to any View. That is similar like a drop shadow.
android:background="@drawable/abc_menu_dropdown_panel_holo_light"
Using this you can not change the background color of the view & its border color. If you want your own custom drawable then use layer-list

custom_drop_shadow_drawable.xml

<?xml version="1.0" encoding="utf-8"?>
<layer-list xmlns:android="http://schemas.android.com/apk/res/android">
    <!--the shadow comes from here-->
    <item
        android:bottom="0dp"
        android:drawable="@android:drawable/dialog_holo_light_frame"
        android:left="0dp"
        android:right="0dp"
        android:top="0dp">

    </item>

    <item
        android:bottom="0dp"
        android:left="0dp"
        android:right="0dp"
        android:top="0dp">
        <!--whatever you want in the background -->
        <shape android:shape="rectangle">
            <solid android:color="@android:color/red" />

        </shape>
    </item>
</layer-list>


and apply to your view like below

android:background="@drawable/custom_drop_shadow_drawable"
Hope it will help you!
Thanks Android View shadow

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问题描述

示例

更新

Example

Update

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