blocks|key|473539|text|实际上，这一行代码行不通。您可以在IDE中打开它，以查看它大致转换为|type|unstyled|depth|inlineStyleRanges|entityRanges|data|473540|val+lp+=+this.window.attributes
lp.screenBrightness+=+WindowManager.LayoutParams.BRIGHTNESS_OVERRIDE_OFF
//+this.window.attributes+=+lp+—+this+one+isn't+called,+explanation+below|code-block|syntax|javascript|473541|Kotlin不会为您执行所有嵌套的set*调用，因此它不会调用this.window.setAttributes()方法。所有对实际窗口应用更改的代码都是由这个调用触发的。|offset|length|style|CODE|473542|entityMap^0|0|0|H|4|V|R|0^^$0|@$1|2|3|4|5|6|7|O|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|Q|8|@$I|R|J|S|K|L]|$I|T|J|U|K|L]]|9|@]|A|$]]|$1|M|3|-4|5|6|7|V|8|@]|9|@]|A|$]]]|N|$]]

Actually, this one-line piece won't work. You can open it in IDE to see that it translates approximately to 

<pre><code>val lp = this.window.attributes
lp.screenBrightness = WindowManager.LayoutParams.BRIGHTNESS_OVERRIDE_OFF
// this.window.attributes = lp — this one isn't called, explanation below
</code></pre>

Kotlin won't do all nested <code>set*</code> calls for you, so it won't call <code>this.window.setAttributes()</code> method. And all the code that applies changes to actual window is triggered by this call.

blocks|key|962193|text|正如OleGG告诉我的，我试着用“一行模式”来做这件事，但是没有任何结果。我与你分享在API16(或更高版本)中唯一对我有效的事情，那就是使用SeekBar。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|962194|我在SettingsActivity中有一个伴生对象|offset|length|style|CODE|962195|companion+object+{
++++private+const+val+WRITE_SETTINGS_PERMISSION+=+100
++++private+const+val+MAX_BRIGHTNESS+=+255
++++private+const+val+MIN_BRIGHTNESS+=+20
}|code-block|syntax|javascript|962196|在SettingsActivity的onCreate()中，我调用|962197|Settings.System.putInt(this.contentResolver,+Settings.System.SCREEN_BRIGHTNESS_MODE,+Settings.System.SCREEN_BRIGHTNESS_MODE_MANUAL)
skb_brightness.max+=+MAX_BRIGHTNESS
skb_brightness.progress+=+AppPreferences.getInstance(this).brightnessKey|962198|然后我像这样创建我的监听器：|962199|object+:+SeekBar.OnSeekBarChangeListener+{
++++var+brightnessProgress+=+0

++++override+fun+onProgressChanged(seekBar:+SeekBar?,+progress:+Int,+fromUser:+Boolean)+{
++++++++brightnessProgress+=+map(progress,+0,+MAX_BRIGHTNESS,+MIN_BRIGHTNESS,+MAX_BRIGHTNESS)

++++++++if+(hasPermissionsToWriteSettings(this@SettingsActivity))+{
++++++++++++Settings.System.putInt(this@SettingsActivity.contentResolver,+Settings.System.SCREEN_BRIGHTNESS,+brightnessProgress)
++++++++++++//+Do+not+write+this+in+one-line,+won't+work
++++++++++++val+lp+=+this@SettingsActivity.window.attributes
++++++++++++lp.screenBrightness+=+brightnessProgress.toFloat()+/+255
++++++++++++this@SettingsActivity.window.attributes+=+lp
++++++++}
++++}

++++override+fun+onStartTrackingTouch(seekBar:+SeekBar?)+{+}

++++override+fun+onStopTrackingTouch(seekBar:+SeekBar?)+{
++++++++AppPreferences.getInstance(this@SettingsActivity).brightnessKey+=+brightnessProgress
++++}
}|962200|其中，hasPermissionsToWriteSettings(this@SettingsActivity)是一个检查我是否有权限执行此操作的方法。|962201|private+fun+hasPermissionsToWriteSettings(context:+Activity):+Boolean+{
++++return+if+(Build.VERSION.SDK_INT+>=+Build.VERSION_CODES.M)+{
++++++++Settings.System.canWrite(context)
++++}+else+{
++++++++ContextCompat.checkSelfPermission(context,+Manifest.permission.WRITE_SETTINGS)+==+PackageManager.PERMISSION_GRANTED
++++}
}|962202|map函数用于映射最小值：|962203|private+fun+map(currentValue:+Int,+inputMin:+Int,+inputMax:+Int,+outputMin:+Int,+outputMax:+Int):+Int+{
++++return+(currentValue+-+inputMin)+*+(outputMax+-+outputMin)+/+(inputMax+-+inputMin)+%2B+outputMin
}|962204|AppPreferences是我的助手类，用于存储键值共享首选项中的亮度值。它就是这样做的(BRIGHTNESS_CONTROL_KEY+=+"brightnessControlValue",+DEFAULT_BRIGHTNESS+=+100)|962205|var+brightnessKey:+Int
++++get()+=+sharedPreferences.getInt(BRIGHTNESS_CONTROL_KEY,+DEFAULT_BRIGHTNESS)
++++set(value)+=+sharedPreferences.edit().putInt(BRIGHTNESS_CONTROL_KEY,+value).apply()|962206|我还在manifest.xml中添加了|962207|<uses-permission+android:name="android.permission.WRITE_SETTINGS"+/>|962208|...event如果Android+Studio告诉我，那就错了。没有这个，我就不能改变亮度。|962209|entityMap^0|0|2|G|0|0|1|G|I|A|0|0|0|0|3|1G|0|0|0|0|0|E|19|25|0|0|3|C|0|0|0^^$0|@$1|2|3|4|5|6|7|1E|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|1F|8|@$D|1G|E|1H|F|G]]|9|@]|A|$]]|$1|H|3|I|5|J|7|1I|8|@]|9|@]|A|$K|L]]|$1|M|3|N|5|6|7|1J|8|@$D|1K|E|1L|F|G]|$D|1M|E|1N|F|G]]|9|@]|A|$]]|$1|O|3|P|5|J|7|1O|8|@]|9|@]|A|$K|L]]|$1|Q|3|R|5|6|7|1P|8|@]|9|@]|A|$]]|$1|S|3|T|5|J|7|1Q|8|@]|9|@]|A|$K|L]]|$1|U|3|V|5|6|7|1R|8|@$D|1S|E|1T|F|G]]|9|@]|A|$]]|$1|W|3|X|5|J|7|1U|8|@]|9|@]|A|$K|L]]|$1|Y|3|Z|5|6|7|1V|8|@]|9|@]|A|$]]|$1|10|3|11|5|J|7|1W|8|@]|9|@]|A|$K|L]]|$1|12|3|13|5|6|7|1X|8|@$D|1Y|E|1Z|F|G]|$D|20|E|21|F|G]]|9|@]|A|$]]|$1|14|3|15|5|J|7|22|8|@]|9|@]|A|$K|L]]|$1|16|3|17|5|6|7|23|8|@$D|24|E|25|F|G]]|9|@]|A|$]]|$1|18|3|19|5|J|7|26|8|@]|9|@]|A|$K|L]]|$1|1A|3|1B|5|6|7|27|8|@]|9|@]|A|$]]|$1|1C|3|-4|5|6|7|28|8|@]|9|@]|A|$]]]|1D|$]]

As told by OleGG, I tried to do it in "one-line mode", but without any result.
I share with you the only thing that worked for me every single time in API 16 (or greater), using a SeekBar.

I have a companion object in the <code>SettingsActivity</code>

<pre><code>companion object {
 private const val WRITE_SETTINGS_PERMISSION = 100
 private const val MAX_BRIGHTNESS = 255
 private const val MIN_BRIGHTNESS = 20
}
</code></pre>

In in the <code>onCreate()</code> of <code>SettingsActivity</code>, I call

<pre><code>Settings.System.putInt(this.contentResolver, Settings.System.SCREEN_BRIGHTNESS_MODE, Settings.System.SCREEN_BRIGHTNESS_MODE_MANUAL)
skb_brightness.max = MAX_BRIGHTNESS
skb_brightness.progress = AppPreferences.getInstance(this).brightnessKey
</code></pre>

Then I create my listener like this:

<pre><code>object : SeekBar.OnSeekBarChangeListener {
 var brightnessProgress = 0

 override fun onProgressChanged(seekBar: SeekBar?, progress: Int, fromUser: Boolean) {
 brightnessProgress = map(progress, 0, MAX_BRIGHTNESS, MIN_BRIGHTNESS, MAX_BRIGHTNESS)

 if (hasPermissionsToWriteSettings(this@SettingsActivity)) {
 Settings.System.putInt(this@SettingsActivity.contentResolver, Settings.System.SCREEN_BRIGHTNESS, brightnessProgress)
 // Do not write this in one-line, won't work
 val lp = this@SettingsActivity.window.attributes
 lp.screenBrightness = brightnessProgress.toFloat() / 255
 this@SettingsActivity.window.attributes = lp
 }
 }

 override fun onStartTrackingTouch(seekBar: SeekBar?) { }

 override fun onStopTrackingTouch(seekBar: SeekBar?) {
 AppPreferences.getInstance(this@SettingsActivity).brightnessKey = brightnessProgress
 }
}
</code></pre>

Where <code>hasPermissionsToWriteSettings(this@SettingsActivity)</code> is a method that checks if I have permission to do that.

<pre><code>private fun hasPermissionsToWriteSettings(context: Activity): Boolean {
 return if (Build.VERSION.SDK_INT &gt;= Build.VERSION_CODES.M) {
 Settings.System.canWrite(context)
 } else {
 ContextCompat.checkSelfPermission(context, Manifest.permission.WRITE_SETTINGS) == PackageManager.PERMISSION_GRANTED
 }
}
</code></pre>

The map function is for mapping the min value:

<pre><code>private fun map(currentValue: Int, inputMin: Int, inputMax: Int, outputMin: Int, outputMax: Int): Int {
 return (currentValue - inputMin) * (outputMax - outputMin) / (inputMax - inputMin) + outputMin
}
</code></pre>

And the <code>AppPreferences</code> is my helper class to store the value of the brightness in the key-value shared-preferences. It does just this <code>(BRIGHTNESS_CONTROL_KEY = "brightnessControlValue", DEFAULT_BRIGHTNESS = 100)</code>:

<pre><code>var brightnessKey: Int
 get() = sharedPreferences.getInt(BRIGHTNESS_CONTROL_KEY, DEFAULT_BRIGHTNESS)
 set(value) = sharedPreferences.edit().putInt(BRIGHTNESS_CONTROL_KEY, value).apply()
</code></pre>

I added also in the <code>manifest.xml</code>:

<pre><code>&lt;uses-permission android:name="android.permission.WRITE_SETTINGS" /&gt;
</code></pre>

...event if Android Studio tolds me that's wrong. Without this, I cannot change brightness.

blocks|key|962220|text|在Kotlin中，更新活动中单个参数的最短方法如下所示：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|962221|++++window.attributes+=+window.attributes.apply+{
++++++++screenBrightness+=+WindowManager.LayoutParams.BRIGHTNESS_OVERRIDE_OFF
++++}|code-block|syntax|javascript|962222|这是因为您需要从android.view.getAttributes()获取当前的LayoutParams，更新screenBrightness值，然后使用更新后的LayoutParams调用android.view.setAttributes()。|offset|length|style|CODE|962223|entityMap^0|0|0|8|S|2O|S|0^^$0|@$1|2|3|4|5|6|7|O|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|Q|8|@$I|R|J|S|K|L]|$I|T|J|U|K|L]]|9|@]|A|$]]|$1|M|3|-4|5|6|7|V|8|@]|9|@]|A|$]]]|N|$]]

The shortest way to update a single parameter from an Activity would be something like this in Kotlin:
<pre><code> window.attributes = window.attributes.apply {
 screenBrightness = WindowManager.LayoutParams.BRIGHTNESS_OVERRIDE_OFF
 }
</code></pre>
This is because you'll need to get the current LayoutParams from <code>android.view.getAttributes()</code>, update the screenBrightness value, and then call <code>android.view.setAttributes()</code> with the updated LayoutParams.

To set a minimum screen brightness in Android Java:

<pre><code>final WindowManager.LayoutParams lp = getWindow().getAttributes();
lp.screenBrightness = WindowManager.LayoutParams.BRIGHTNESS_OVERRIDE_OFF;
getWindow().setAttributes(lp);
</code></pre>

To change screen brightness in Android Kotlin:

<pre><code>val lp = this.window.attributes
lp.screenBrightness = WindowManager.LayoutParams.BRIGHTNESS_OVERRIDE_OFF
this.window.attributes = lp
</code></pre>

However (as a beginner in Kotlin), I was surprised to see that this one line also works:

<pre><code>window.attributes.screenBrightness = WindowManager.LayoutParams.BRIGHTNESS_OVERRIDE_OFF
</code></pre>

Why does this work? Are there any unwanted side effects with this code?

Set Android screen brightness in Kotlin in one line (versus Java)

翻译质量差，导致语言生硬或混乱。

没有提供实际的解决方法或示例。

解答不清晰，无法理解或解决问题。

页面排版不美观，阅读体验差。

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在Android Java中设置最小屏幕亮度：final WindowManager.LayoutParams lp = getWindow().getAttributes();lp.screenBrightness = WindowManager.LayoutParams.BRIGHTNESS_OVERRIDE_OF...

问在一行中设置Android屏幕亮度(以Kotlin为单位)(对比Java)
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问在一行中设置Android屏幕亮度(以Kotlin为单位)(对比Java)EN