版本5上带有getBackground（）。setAlpha的按钮-棒棒糖无法正常工作 [英] Button with getBackground().setAlpha on version 5 - lollipop isn't working correctly

问题描述

我有这段代码，并且适用于API 14之后的每个版本，但是在Android 5.0（Lollipop）上无法正常工作。

I have this code and works for every version since API 14 but on Android 5.0 (Lollipop) isn't working correctly.

下面是我想要的方式出现的按钮。

Below is the way how I want the buttons to appear.

单击button1

click of button1

buttonArrivals.getBackground().setAlpha(180);
buttonDepartures.getBackground().setAlpha(255);

单击按钮2

click of button2

buttonArrivals.getBackground().setAlpha(255);
buttonDepartures.getBackground().setAlpha(180);

在棒棒糖版本中，按钮显示相同的Alpha，但我从未设置相同的Alpha。我只是使用上面的代码。

On the Lollipop version, the buttons appear with the same Alpha but I never set the same alpha. I just use the code above.

更新2014年11月24日

这是按钮的XML（AutoResizeButton扩展按钮）

Here is the XML of the buttons (AutoResizeButton extends Button)

br.com.timo.gru.util.AutoResizeButton
            android:id="@+id/buttonArrivals"
            android:layout_width="0dp"
            android:layout_height="match_parent"
            android:layout_weight="2"
            android:background="#00abbd"
            android:drawableLeft="@drawable/icon_aviao_desemb"
            android:drawablePadding="-5dp"
            android:drawableStart="@drawable/icon_aviao_desemb"
            android:gravity="center"
            android:paddingEnd="0dp"
            android:paddingLeft="2dp"
            android:paddingRight="0dp"
            android:text="@string/chegadas"
            android:textColor="@android:color/white"

br.com.timo.gru.util.AutoResizeButton
            android:id="@+id/buttonPartidas"
            android:layout_width="0dp"
            android:layout_height="match_parent"
            android:layout_weight="2"
            android:background="#00abbd"
            android:drawableLeft="@drawable/icon_aviao_partida"
            android:drawablePadding="-5dp"
            android:drawableStart="@drawable/icon_aviao_partida"
            android:ellipsize="end"
            android:gravity="center"
            android:text="@string/partidas"
            android:textColor="@android:color/white"

推荐答案

内部ColorState（由ColorDrawable使用）在这两个按钮之间共享（优化），因此只要您在一个按钮的背景上更改Alpha，其他按钮也将获得此更改。
您可以尝试在更改背景可绘制对象的alpha之前对其进行突变：

Internally ColorState (used by ColorDrawable) is shared between these 2 buttons (optimization), so whenever you change alpha on one button's background - other button will get this change as well. You can try to to mutate background drawable before changing its alpha:

buttonArrivals.getBackground().mutate().setAlpha(180);
buttonDepartures.getBackground().mutate().setAlpha(255);

您也可以阅读Romain Guy关于发生这种情况的很好解释： http://curious-creature.org/2009/05/02/drawable-mutations

You can also read good explanation from Romain Guy on why this is happening: http://curious-creature.org/2009/05/02/drawable-mutations

但是，您似乎尝试实现一些可以使用Android选择器轻松实现的功能。您可以为每种按钮状态（在您选择的情况下/未选择的情况下）指定不同的颜色，因此在代码中，您只需要更新状态：

However, it looks like you try to implement something which is easily achievable with Android selectors. You can specify different color for each button state (in your case selected/not selected), so in your code you just need to update state:

buttonArrivals.setSelected(true);
buttonDepartures.setSelected(false);

选择器如下所示：

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

    <item android:color="#ff00abbd"
        android:state_selected="true" >
    </item>

    <item android:color="#b400abbd"
        android:state_selected="false">
    </item>

</selector>

这篇关于版本5上带有getBackground（）。setAlpha的按钮-棒棒糖无法正常工作的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！