6 June 2024 Leave a comment Tech-Help
Making a background partially transparent in Android can add a sleek, modern look to your UI. This article will guide you through the steps necessary to achieve a 20% transparent background for a TextView in Android.
Using Hexadecimal Color Codes
To make the background of a TextView 20% transparent, you can manipulate the alpha channel of a color in its hexadecimal representation. The format for a color with an alpha channel is #AARRGGBB, where AA represents the alpha value, and RR, GG, and BB represent the red, green, and blue channels, respectively.
Example for Red Color
For instance, to make a red background 20% transparent, you would use:
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:background="#33FF0000" />
In this example, 33 is the hexadecimal value for 20% transparency (since 255 * 0.2 = 51, which is 33 in hexadecimal).
Calculating Alpha Values
To calculate the alpha value for any percentage of transparency, follow these steps:
- Subtract the desired transparency percentage from 100 to get the opacity percentage. (e.g., 20% transparency means 80% opacity).
- Multiply the opacity percentage by 255 (the maximum value for an 8-bit channel).
- Convert the resulting value to hexadecimal.
- Prepend this hexadecimal value to the RGB color code.
General Hex Opacity Values
Here are some common opacity values:
- 100% —
FF - 95% —
F2 - 90% —
E6 - 85% —
D9 - 80% —
CC - 75% —
BF - 70% —
B3 - 65% —
A6 - 60% —
99 - 55% —
8C - 50% —
80 - 45% —
73 - 40% —
66 - 35% —
59 - 30% —
4D - 25% —
40 - 20% —
33 - 15% —
26 - 10% —
1A - 5% —
0D - 0% —
00
Practical Example
Let’s say you want to set a background color to 20% transparent black. You would use the following XML code:
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:background="#33000000" />
Here, 33 represents 20% transparency, and 000000 represents black.
Conclusion
Understanding how to manipulate the alpha channel in hexadecimal color codes allows you to create visually appealing designs with partial transparency. This technique can be applied to various UI elements to enhance the user experience.
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