A brief discussion on three methods of setting transparency and darkness on Android

This article describes three methods of setting transparency, translucency, and darkness using Android. It has certain reference value. Interested friends can learn about it.

There are roughly three types of settings for transparency effects

1. Use the transparent effect of the android system

Java code

android:background="@android:color/transparent"

For example, set the button

Java code

<button android:background=""@android:color/transparent"" android:text="@+id/Button01" android:id="@+id/Button01" android:layout_width="wrap_content" android:layout_height="wrap_content" android:textcolor="#ffffff"></button>

2. Use ARGB to control

Java code

//半透明
<Button android:background="#e0000000" />
//透明
<Button android:background="#00000000" />

Related tutorials: Java video tutorial

3. Set alpha

Java code

View v = findViewById(R.id.content);//找到你要设透明背景的layout 的id
v.getBackground().setAlpha(100);//0~255透明度值

android form transparency, darkness, etc. setting tips

Set transparency (this is the transparency of the form itself, not the background)

WindowManager.LayoutParams lp=getWindow().getAttributes();
lp.alpha=0.3f;
getWindow().setAttributes(lp);

alpha is between 0.0f and 1.0f. 1.0 is completely opaque, 0.0f is completely transparent

Set the darkness

WindowManager.LayoutParams lp=getWindow().getAttributes();
lp.dimAmount=0.5f;
getWindow().setAttributes(lp);
getWindow().addFlags(WindowManager.LayoutParams.FLAG_DIM_BEHIND);

dimAmount is between 0.0f and 1.0f, 0.0f is not dark at all, 1.0f is completely dark

Activity’s transparent and translucent effect settings transparent

res/values/styles.xml

<resources>
  <style name="Transparent">
    <item name="android:windowBackground">
       @color/transparent_background
    </item>
    <item name="android:windowNoTitle">true</item>
    <item name="android:windowIsTranslucent">true</item>
    <item name="android:windowAnimationStyle">
         @+android:style/Animation.Translucent
   </item>
  </style>
</resources>

res/values/color.xml

<?xml version="1.0" encoding="utf-8"?>
<resources>
  <color name="transparent_background">#50000000</color>
</resources>
//注意：
//color.xml的#5000000前两位是透明的效果参数从00--99（透明--不怎么透明），
//后6位是颜色的设置

manifest.xml

<activity
android:name=".TransparentActivity"
android:theme="@style/Transparent">
</activity>

java code

public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setTheme(R.style.Transparent);
        setContentView(R.layout.transparent);
}

The above configuration is completed, I hope it will be helpful to you.

Related tutorials: Android video tutorial

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