在java / android中更改int颜色不透明度 [英] Change int color opacity in java/android
问题描述
我正在尝试使用下一个代码更改我的主题颜色的不透明度:
I am trying to change the opacity of a color that I get of my theme with the next code:
TypedValue typedValueDrawerSelected = new TypedValue();
getTheme().resolveAttribute(R.attr.colorPrimary, typedValueDrawerSelected, true);
int colorDrawerItemSelected = typedValueDrawerSelected.data;
我希望 colorDrawerItemSelected
保持不变颜色,但它的alpha应该是25%。
I want that the colorDrawerItemSelected
keeps the same color, buth its alpha should be 25%.
我发现一些解决方案从imageView获取rgb颜色,但我还没有imageView。
I found some solutions getting the rgb color from the imageView, but I havent imageView.
感谢您的时间。
推荐答案
这还不够吗?
colorDrawerItemSelected = (colorDrawerItemSelected & 0x00FFFFFF) | 0x40000000;
它保存颜色值并将alpha设置为最大值的25%
It saves the color value and sets the alpha to 25% of max.
color int中的第一个字节负责透明度:0 - 完全透明,255(0xFF) - 不透明。在第一部分(&操作)中,我们将第一个字节设置为0并保持其他字节不变。在第二部分中,我们将第一个字节设置为0x40,即0xFF的25%(255 /4≈64)。
First byte in the color int is responsible for the transparency: 0 - completely transparent, 255 (0xFF) – opaque. In the first part ("&" operation) we set the first byte to 0 and left other bytes untouched. In the second part we set the first byte to 0x40 which is the 25% of 0xFF (255 / 4 ≈ 64).
这篇关于在java / android中更改int颜色不透明度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!