Android 13 亮度调节代码分析

frameworks\base\packages\SystemUI\res\layout\quick_settings_brightness_dialog.xml

进度条控件

<com.android.systemui.settings.brightness.BrightnessSliderViewxmlns:android="http://schemas.android.com/apk/res/android"android:id="@+id/brightness_slider"android:layout_width="match_parent"android:layout_height="@dimen/brightness_mirror_height"android:layout_gravity="center"android:contentDescription="@string/accessibility_brightness"android:importantForAccessibility="no" ><com.android.systemui.settings.brightness.ToggleSeekBarandroid:id="@+id/slider"android:layout_width="match_parent"android:layout_height="wrap_content"android:layout_gravity="center_vertical"android:minHeight="48dp"android:thumb="@null"android:background="@null"android:paddingStart="0dp"android:paddingEnd="0dp"android:progressDrawable="@drawable/brightness_progress_drawable"android:splitTrack="false"/></com.android.systemui.settings.brightness.BrightnessSliderView>

frameworks\base\packages\SystemUI\src\com\android\systemui\settings\brightness\BrightnessSliderView.java

// Inflated from quick_settings_brightness_dialog@Overrideprotected void onFinishInflate() {super.onFinishInflate();setLayerType(LAYER_TYPE_HARDWARE, null);mSlider = requireViewById(R.id.slider);mSlider.setAccessibilityLabel(getContentDescription().toString());// Finds the progress drawable. Assumes brightness_progress_drawable.xmltry {LayerDrawable progress = (LayerDrawable) mSlider.getProgressDrawable();DrawableWrapper progressSlider = (DrawableWrapper) progress.findDrawableByLayerId(android.R.id.progress);LayerDrawable actualProgressSlider = (LayerDrawable) progressSlider.getDrawable();mProgressDrawable = actualProgressSlider.findDrawableByLayerId(R.id.slider_foreground);} catch (Exception e) {// Nothing to do, mProgressDrawable will be null.}}

frameworks\base\packages\SystemUI\src\com\android\systemui\settings\brightness\BrightnessController.java

private volatile boolean mAutomatic;  // Brightness adjusted automatically using ambient light.private volatile boolean mIsVrModeEnabled;private boolean mListening;private boolean mExternalChange;private boolean mControlValueInitialized;private float mBrightnessMin = PowerManager.BRIGHTNESS_MIN;private float mBrightnessMax = PowerManager.BRIGHTNESS_MAX;

    private void updateSlider(float brightnessValue, boolean inVrMode) {final float min;final float max;if (inVrMode) {min = mMinimumBacklightForVr;max = mMaximumBacklightForVr;} else {min = mBrightnessMin;max = mBrightnessMax;}// Ensure the slider is in a fixed position first, then check if we should animate.if (mSliderAnimator != null && mSliderAnimator.isStarted()) {mSliderAnimator.cancel();}// convertGammaToLinearFloat returns 0-1if (BrightnessSynchronizer.floatEquals(brightnessValue,convertGammaToLinearFloat(mControl.getValue(), min, max))) {// If the value in the slider is equal to the value on the current brightness// then the slider does not need to animate, since the brightness will not change.return;}// Returns GAMMA_SPACE_MIN - GAMMA_SPACE_MAXfinal int sliderVal = convertLinearToGammaFloat(brightnessValue, min, max);animateSliderTo(sliderVal);}

亮度最小值由PowerManager.BRIGHTNESS_MIN控制

frameworks\base\core\java\android\os\PowerManager.java 修改即可

    //Brightness values for new float implementation:/*** Brightness value for fully on as float.* @hide*/public static final float BRIGHTNESS_MAX = 1.0f;/*** Brightness value for minimum valid brightness as float.* @hide*/public static final float BRIGHTNESS_MIN = 0.5f;/*** Brightness value for fully off in float.* @hide*/public static final float BRIGHTNESS_OFF_FLOAT = -1.0f;