更改屏幕亮度系统设置 Android [英] Changing the Screen Brightness System Setting Android
问题描述
我正在尝试使用服务更改屏幕亮度，如下所示:
I'm attempting to change the screen brightness from withing a service, like so:
android.provider.Settings.System.putInt(getContentResolver(),
android.provider.Settings.System.SCREEN_BRIGHTNESS, bright);
问题是那是行不通的.好吧，实际上它成功地更改了亮度设置，但是直到我进入手机设置，查看新值并点击确定后，屏幕亮度才会真正改变.
Problem is that is doesn't work. Well, actually it succeeds in changing the brightness setting, but the screen brightness doesn't actually change till I go into the phones settings, look at the new value and hit Ok.
设置值后我需要做些什么才能改变亮度?
Is there something I have to do after setting the value to get the brightness to change?
推荐答案
我在从服务中更改屏幕亮度时遇到了同样的问题，几天前我成功解决了它(并更新了我的应用程序
I've had the same problem of changing screen brightness from within a service, and a couple days ago i have successfully solved it(and updated my app Phone Schedule with brightness feature ;) ). Ok, so this is the code you put into your service:
// This is important. In the next line 'brightness'
// should be a float number between 0.0 and 1.0
int brightnessInt = (int)(brightness*255);
//Check that the brightness is not 0, which would effectively
//switch off the screen, and we don't want that:
if(brightnessInt<1) {brightnessInt=1;}
// Set systemwide brightness setting.
Settings.System.putInt(getContentResolver(),
Settings.System.SCREEN_BRIGHTNESS_MODE, Settings.System.SCREEN_BRIGHTNESS_MODE_MANUAL);
Settings.System.putInt(getContentResolver(), Settings.System.SCREEN_BRIGHTNESS, brightnessInt);
// Apply brightness by creating a dummy activity
Intent intent = new Intent(getBaseContext(), DummyBrightnessActivity.class);
intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
intent.putExtra("brightness value", brightness);
getApplication().startActivity(intent);
请注意，在上面的代码片段中，我使用了两个变量来表示亮度.一个是brightness，它是一个0.0到1.0之间的浮点数，另一个是brightnessInt，它是一个0到255之间的整数.这是因为Settings.System 需要一个整数来存储系统范围的亮度值，而您将在下一个代码片段中看到的 lp.screenBrightness 需要一个浮点数.不要问我为什么不使用相同的值，这正是 Android SDK 中的方式，所以我们将不得不接受它.
Please Note that in the above code snippet I'm using two variables for brightness. One is brightness, which is a float number between 0.0 and 1.0, the other one is brightnessInt, which is an integer between 0 and 255. The reason for this is that Settings.System requires an integer to store system wide brightness value, while the lp.screenBrightness which you will see in the next code snippet requires a float. Don't ask me why not use the same value, this is just the way it is in Android SDK, so we're just going to have to live with it.
这是 DummyBrightnessActivity 的代码:
This is the code for DummyBrightnessActivity:
public class DummyBrightnessActivity extends Activity{
private static final int DELAYED_MESSAGE = 1;
private Handler handler;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
handler = new Handler() {
@Override
public void handleMessage(Message msg) {
if(msg.what == DELAYED_MESSAGE) {
DummyBrightnessActivity.this.finish();
}
super.handleMessage(msg);
}
};
Intent brightnessIntent = this.getIntent();
float brightness = brightnessIntent.getFloatExtra("brightness value", 0);
WindowManager.LayoutParams lp = getWindow().getAttributes();
lp.screenBrightness = brightness;
getWindow().setAttributes(lp);
Message message = handler.obtainMessage(DELAYED_MESSAGE);
//this next line is very important, you need to finish your activity with slight delay
handler.sendMessageDelayed(message,1000);
}
}
这是您将活动添加到 AndroidManifest.xml 的方式，这可能是最重要的部分:
This is how you add your activity to the AndroidManifest.xml, probably the most important part:
<activity android:name="com.antonc.phone_schedule.DummyBrightnessActivity"
android:taskAffinity="com.antonc.phone_schedule.Dummy"
android:excludeFromRecents="true"
android:theme="@style/EmptyActivity"></activity>
关于什么是什么的一点解释.
A little explanation about what's what.
android:taskAffinity 必须与你的包名不同！它使 DummyBrightnessActivity 不在您的主要活动堆栈中启动，而是在一个单独的活动中启动，这意味着当 DummyBrightnessActivity 关闭时，您将看不到下一个活动，无论它是什么.在我加入这一行之前，关闭 DummyBrightnessActivity 会显示我的主要活动.
android:taskAffinity must be different, than your package name! It makes DummyBrightnessActivity be started not in your main stack of activities, but in a separate, which means that when DummyBrightnessActivity is closed, you won't see the next activity, whatever that may be. Until i included this line, closing DummyBrightnessActivity would bring up my main activity.
android:excludeFromRecents="true" 使此活动在您绝对想要的最近启动的应用程序列表中不可用.
android:excludeFromRecents="true" makes this activity not available in the list of recently launched apps, which you definetely want.
android:theme="@style/EmptyActivity" 定义了 DummyBrightnessActivity 对用户的显示方式，这就是你让它不可见的地方.这是在styles.xml 文件中定义此样式的方式:
android:theme="@style/EmptyActivity" defines the way DummyBrightnessActivity looks like to the user, and this is where you make it invisible. This is how you define this style in the styles.xml file:
<style name="EmptyActivity" parent="android:Theme.Dialog">
<item name="android:windowIsTranslucent">true</item>
<item name="android:windowAnimationStyle">@android:style/Animation.Toast</item>
<item name="android:background">#00000000</item>
<item name="android:windowBackground">#00000000</item>
<item name="android:windowNoTitle">true</item>
<item name="android:colorForeground">#000</item>
</style>
这样你的 DummyBrightnessActivity 对用户是不可见的.我不确定所有这些样式参数是否真的有必要，但这种方式对我有用.
This way your DummyBrightnessActivity will be invisible to the user. I'm not shure if all of those style parameters are really necessary, but it works for me this way.
我希望能解释清楚，但如果您有任何问题，请告诉我.
I hope that explains it, but if you have any questions, just let me know.
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