Android10 源码状态栏蓝牙电量图标相关类

BatteryMeterDrawableBase：电量图标基类

BluetoothDeviceLayerDrawable： LayerDrawable 包含蓝牙设备图标和电池电量图标

        BatteryMeterDrawable：内部类，继承自BatteryMeterDrawableBase

        BluetoothDeviceLayerDrawableState：内部类，继承自ConstantState

电量图标

电量图标由BatteryMeterDrawableBase绘制，虽然BluetoothDeviceLayerDrawable的内部类BatteryMeterDrawable继承自BatteryMeterDrawableBase，但并没有重写太多东西

    public BatteryMeterDrawableBase(Context context, int frameColor) {mContext = context;final Resources res = context.getResources();TypedArray levels = res.obtainTypedArray(R.array.batterymeter_color_levels); //15、100TypedArray colors = res.obtainTypedArray(R.array.batterymeter_color_values); //红色、白色final int N = levels.length();mColors = new int[2 * N];for (int i = 0; i < N; i++) {mColors[2 * i] = levels.getInt(i, 0);if (colors.getType(i) == TypedValue.TYPE_ATTRIBUTE) {mColors[2 * i + 1] = Utils.getColorAttrDefaultColor(context,colors.getThemeAttributeId(i, 0));} else {mColors[2 * i + 1] = colors.getColor(i, 0);}}levels.recycle();  //回收资源colors.recycle();mWarningString = context.getString(R.string.battery_meter_very_low_overlay_symbol);mCriticalLevel = mContext.getResources().getInteger(com.android.internal.R.integer.config_criticalBatteryWarningLevel); //=5：临界电量值mButtonHeightFraction = context.getResources().getFraction(R.fraction.battery_button_height_fraction, 1, 1); //高度百分比mSubpixelSmoothingLeft = context.getResources().getFraction( //不知道是什么，也没被调用R.fraction.battery_subpixel_smoothing_left, 1, 1);mSubpixelSmoothingRight = context.getResources().getFraction( //不知道是什么，也没被调用R.fraction.battery_subpixel_smoothing_right, 1, 1);......}

 想要修改什么，修改对应的资源值就好。

整合

由BluetoothDeviceLayerDrawable将蓝牙图标放在左边，电量图标放在右边。

BluetoothDeviceLayerDrawable的构造函数是私有的，通过createLayerDrawable方法获取实例对象。

    public static BluetoothDeviceLayerDrawable createLayerDrawable(Context context, int resId,int batteryLevel, float iconScale) {final Drawable deviceDrawable = context.getDrawable(resId);final BatteryMeterDrawable batteryDrawable = new BatteryMeterDrawable(context,context.getColor(R.color.meter_background_color), batteryLevel);final int pad = context.getResources().getDimensionPixelSize(R.dimen.bt_battery_padding);batteryDrawable.setPadding(pad, pad, pad, pad);//创建final BluetoothDeviceLayerDrawable drawable = new BluetoothDeviceLayerDrawable(new Drawable[]{deviceDrawable, batteryDrawable});  //图层// Set the bluetooth icon at the leftdrawable.setLayerGravity(0 /* index of deviceDrawable */, Gravity.START); //蓝牙图标// Set battery icon to the right of the bluetooth icon//下面两句确认电量图标绘制的其实像素点（x,y）=(deviceDrawable.getIntrinsicWidth(),deviceDrawable.getIntrinsicHeight() * (1 - iconScale))drawable.setLayerInsetStart(1 /* index of batteryDrawable */,deviceDrawable.getIntrinsicWidth());  //电量图标drawable.setLayerInsetTop(1 /* index of batteryDrawable */,(int) (deviceDrawable.getIntrinsicHeight() * (1 - iconScale)));drawable.setConstantState(context, resId, batteryLevel, iconScale);return drawable;}