android6.0 power显示(亮度等)深入分析(二)DisplayManagerServic

android6.0 power显示(亮度等)深入分

析(二)DisplayManagerService

一、DisplayManagerService注册localDisplay的适配层 我们先来看构造函数：

[cpp] view plain copy 在CODE上查看代码片派生到我的代码片 public DisplayManagerService(Context context) { super(context);

mContext = context;

mHandler = new DisplayManagerHandler(DisplayThread.get().getLooper());//消息处理 mUiHandler = UiThread.getHandler();

mDisplayAdapterListener = new DisplayAdapterListener();//display适配层监视器

mSingleDisplayDemoMode = SystemProperties.getBoolean(\false);

PowerManager pm = (PowerManager) mContext.getSystemService(Context.POWER_SERVICE);

mGlobalDisplayBrightness = pm.getDefaultScreenBrightnessSetting();//成员变量屏幕亮度 }

我们再来看onStart函数，publish了一个BinderService和LocalService，还有发送了一个消息。

[cpp] view plain copy 在CODE上查看代码片派生到我的代码片 @Override

public void onStart() {

mHandler.sendEmptyMessage(MSG_REGISTER_DEFAULT_DISPLAY_ADAPTER);

publishBinderService(Context.DISPLAY_SERVICE, new BinderService(), true /*allowIsolated*/);

publishLocalService(DisplayManagerInternal.class, new LocalService()); }

我们看消息处理，就是调用了registerDefaultDisplayAdapter函数： [cpp] view plain copy 在CODE上查看代码片派生到我的代码片 @Override

public void handleMessage(Message msg) { switch (msg.what) {

case MSG_REGISTER_DEFAULT_DISPLAY_ADAPTER: registerDefaultDisplayAdapter(); break;

registerDefaultDisplayAdapter函数

[cpp] view plain copy 在CODE上查看代码片派生到我的代码片 private void registerDefaultDisplayAdapter() { // Register default display adapter. synchronized (mSyncRoot) {

registerDisplayAdapterLocked(new LocalDisplayAdapter(

mSyncRoot, mContext, mHandler, mDisplayAdapterListener)); } }

再来看看registerDisplayAdapterLocked

[cpp] view plain copy 在CODE上查看代码片派生到我的代码片 private void registerDisplayAdapterLocked(DisplayAdapter adapter) { mDisplayAdapters.add(adapter); adapter.registerLocked(); }

这里就是register了DefaultDisplay的适配层，就是和背光相关的。在新建LocalDisplayAdapter的时候我们把mDisplayAdapterListener传过去了。

二、LocalDisplayAdapter & LocalDisplayDevice

LocalDisplayAdapter构造函数调用了父类的，而父类也就是保存了变量 [cpp] view plain copy 在CODE上查看代码片派生到我的代码片

public LocalDisplayAdapter(DisplayManagerService.SyncRoot syncRoot, Context context, Handler handler, Listener listener) { super(syncRoot, context, handler, listener, TAG); }

上面又紧跟着调用了registerLocked函数

[cpp] view plain copy 在CODE上查看代码片派生到我的代码片 public void registerLocked() { super.registerLocked();

mHotplugReceiver = new HotplugDisplayEventReceiver(getHandler().getLooper());

for (int builtInDisplayId : BUILT_IN_DISPLAY_IDS_TO_SCAN) { tryConnectDisplayLocked(builtInDisplayId); } }

tryConnectDisplayLocked函数，先是看传入的builtInDisplayId是否支持，一个是main，一个是hdmi的。

[cpp] view plain copy 在CODE上查看代码片派生到我的代码片 private void tryConnectDisplayLocked(int builtInDisplayId) {

IBinder displayToken = SurfaceControl.getBuiltInDisplay(builtInDisplayId); if (displayToken != null) {

SurfaceControl.PhysicalDisplayInfo[] configs =

SurfaceControl.getDisplayConfigs(displayToken); if (configs == null) {

// There are no valid configs for this device, so we can't use it Slog.w(TAG, \ builtInDisplayId); return;

}

int activeConfig = SurfaceControl.getActiveConfig(displayToken); if (activeConfig < 0) {

// There is no active config, and for now we don't have the // policy to set one.

Slog.w(TAG, \ builtInDisplayId); return; }

LocalDisplayDevice device = mDevices.get(builtInDisplayId); if (device == null) {

// Display was added.

device = new LocalDisplayDevice(displayToken, builtInDisplayId, configs, activeConfig);

mDevices.put(builtInDisplayId, device);

sendDisplayDeviceEventLocked(device, DISPLAY_DEVICE_EVENT_ADDED); } else if (device.updatePhysicalDisplayInfoLocked(configs, activeConfig)) { // Display properties changed.

sendDisplayDeviceEventLocked(device, DISPLAY_DEVICE_EVENT_CHANGED); } } else {

// The display is no longer available. Ignore the attempt to add it. // If it was connected but has already been disconnected, we'll get a // disconnect event that will remove it from mDevices. } }

然后再去查找这个LocalDisplayDevice，如果是找到了需要更新下configs，没找到需要新建一个LocalDisplayDevice。最后都调用了sendDisplayDeviceEventLocked函数。 我们再来看LocalDisplayDevice，如果传入的是BUILT_IN_DISPLAY_ID_MAIN就是背光的，我们获取背光的Light，保存在mBackLight变量。

[cpp] view plain copy 在CODE上查看代码片派生到我的代码片

public LocalDisplayDevice(IBinder displayToken, int builtInDisplayId,

SurfaceControl.PhysicalDisplayInfo[] physicalDisplayInfos, int activeDisplayInfo) { super(LocalDisplayAdapter.this, displayToken, UNIQUE_ID_PREFIX + builtInDisplayId); mBuiltInDisplayId = builtInDisplayId;

updatePhysicalDisplayInfoLocked(physicalDisplayInfos, activeDisplayInfo); if (mBuiltInDisplayId == SurfaceControl.BUILT_IN_DISPLAY_ID_MAIN) { LightsManager lights = LocalServices.getService(LightsManager.class); mBacklight = lights.getLight(LightsManager.LIGHT_ID_BACKLIGHT); } else {

mBacklight = null; } }

然后上面函数调用了sendDisplayDeviceEventLocked函数，就是调用了传入的参数DisplayAdapterListener

[cpp] view plain copy 在CODE上查看代码片派生到我的代码片 protected final void sendDisplayDeviceEventLocked( final DisplayDevice device, final int event) { mHandler.post(new Runnable() { @Override

public void run() {

mListener.onDisplayDeviceEvent(device, event); } }); }

如果是新建就调用了handleDisplayDeviceAdded函数，

[cpp] view plain copy 在CODE上查看代码片派生到我的代码片

private final class DisplayAdapterListener implements DisplayAdapter.Listener { @Override

public void onDisplayDeviceEvent(DisplayDevice device, int event) { switch (event) {

case DisplayAdapter.DISPLAY_DEVICE_EVENT_ADDED: handleDisplayDeviceAdded(device); break;

case DisplayAdapter.DISPLAY_DEVICE_EVENT_CHANGED: handleDisplayDeviceChanged(device); break;

case DisplayAdapter.DISPLAY_DEVICE_EVENT_REMOVED: handleDisplayDeviceRemoved(device); break; } }

@Override

public void onTraversalRequested() { synchronized (mSyncRoot) {

scheduleTraversalLocked(false); } } }

我们先来看看handleDisplayDeviceAdded，最后将device保存在了mDisplayDevices中。 [cpp] view plain copy 在CODE上查看代码片派生到我的代码片 private void handleDisplayDeviceAdded(DisplayDevice device) { synchronized (mSyncRoot) {

handleDisplayDeviceAddedLocked(device);

} }

private void handleDisplayDeviceAddedLocked(DisplayDevice device) { DisplayDeviceInfo info = device.getDisplayDeviceInfoLocked(); if (mDisplayDevices.contains(device)) {

Slog.w(TAG, \ return; }

Slog.i(TAG, \ device.mDebugLastLoggedDeviceInfo = info;

mDisplayDevices.add(device); addLogicalDisplayLocked(device);

Runnable work = updateDisplayStateLocked(device); if (work != null) { work.run(); }

scheduleTraversalLocked(false); }

三、设置背光

现在我们在上篇博客不是说背光的调制最后是在DisplayManagerService中，是在下面函数的requestGlobalDisplayStateInternal中调用的

[cpp] view plain copy 在CODE上查看代码片派生到我的代码片

public void initPowerManagement(final DisplayPowerCallbacks callbacks, Handler handler, SensorManager sensorManager) { synchronized (mSyncRoot) {

DisplayBlanker blanker = new DisplayBlanker() { @Override

public void requestDisplayState(int state, int brightness) { // The order of operations is important for legacy reasons. if (state == Display.STATE_OFF) {

requestGlobalDisplayStateInternal(state, brightness); }

callbacks.onDisplayStateChange(state);

if (state != Display.STATE_OFF) {

requestGlobalDisplayStateInternal(state, brightness); } } };

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