Android4.4 SystemUI分析之PowerUI
阿新 • • 發佈：2019-01-30
以下分析是基於MTK Android4.4原生的SystemUI與Google 的SystemUI有微小的區別，但兩者的整體框架是差不多的。
這一篇是分析SystemUI的第一篇，先從最簡單的PowerUI著手，原始碼路徑：/frameworks/base/packages/SystemUI 程式目錄結構如下：
我匯入Eclipse編輯，報錯的原因是因為找不到Framework上的一些包和資源，這個沒有關係；修改完後在使用mmm模組編譯，再push到手機（eng版本）上進行除錯，push後需要重啟才能生效。
在AndroidManifest.xml上沒有Activity註冊
所以整個程式啟動是從外部啟動SystemUIService的。那麼是如何啟動SystemUIService的呢？看下這個檔案：/frameworks/base/services/java/com/android/server/SystemServer.java在這個檔案中可以找到<intent-filter> <action android:name="android.intent.action.MAIN" /> <category android:name="android.intent.category.LAUNCHER" /> </intent-filter>
所以SystemUI在SystemService啟動時就被呼叫了。static final void startSystemUi(Context context) { Intent intent = new Intent(); intent.setComponent(new ComponentName("com.android.systemui", "com.android.systemui.SystemUIService")); //Slog.d(TAG, "Starting service: " + intent); context.startServiceAsUser(intent, UserHandle.OWNER); }
SystemUIService的關鍵程式碼如下：
這些類package com.android.systemui; import android.app.Service; import android.content.Intent; import android.content.res.Configuration; import android.os.IBinder; import android.util.Log; import java.io.FileDescriptor; import java.io.PrintWriter; import java.util.HashMap; public class SystemUIService extends Service { private static final String TAG = "SystemUIService"; /** * The classes of the stuff to start. */ private final Class<?>[] SERVICES = new Class[] { com.android.systemui.recent.Recents.class, com.android.systemui.statusbar.SystemBars.class, com.android.systemui.usb.StorageNotification.class, com.android.systemui.power.PowerUI.class, com.android.systemui.media.RingtonePlayer.class, com.android.systemui.settings.SettingsUI.class, }; /** * Hold a reference on the stuff we start. */ private final SystemUI[] mServices = new SystemUI[SERVICES.length]; @Override public void onCreate() { HashMap<Class<?>, Object> components = new HashMap<Class<?>, Object>(); final int N = SERVICES.length; for (int i=0; i<N; i++) { Class<?> cl = SERVICES[i]; Log.d(TAG, "loading: " + cl); Log.d("dzt", "loading: " + cl); try { mServices[i] = (SystemUI)cl.newInstance(); } catch (IllegalAccessException ex) { throw new RuntimeException(ex); } catch (InstantiationException ex) { throw new RuntimeException(ex); } mServices[i].mContext = this; mServices[i].mComponents = components; Log.d(TAG, "running: " + mServices[i]); Log.d("dzt", "running: " + mServices[i]); mServices[i].start(); } } }
com.android.systemui.recent.Recents.class,
com.android.systemui.statusbar.SystemBars.class,
com.android.systemui.usb.StorageNotification.class,
com.android.systemui.power.PowerUI.class,
com.android.systemui.media.RingtonePlayer.class,
com.android.systemui.settings.SettingsUI.class,都是繼承於：SystemUI，在SystemUIService的OnCreate()函式中會建立例項，並呼叫mServices[i].start();方法。
下面就分析最簡單的com.android.systemui.power.PowerUI.class
在PowerUI的start()方法中，註冊一些監聽器
public void start() {
mLowBatteryAlertCloseLevel = mContext.getResources().getInteger(
com.android.internal.R.integer.config_lowBatteryCloseWarningLevel);
mLowBatteryReminderLevels[0] = mContext.getResources().getInteger(
com.android.internal.R.integer.config_lowBatteryWarningLevel);
mLowBatteryReminderLevels[1] = mContext.getResources().getInteger(
com.android.internal.R.integer.config_criticalBatteryWarningLevel);
final PowerManager pm = (PowerManager) mContext.getSystemService(Context.POWER_SERVICE);
mScreenOffTime = pm.isScreenOn() ? -1 : SystemClock.elapsedRealtime();
// Register for Intent broadcasts for...
IntentFilter filter = new IntentFilter();
filter.addAction(Intent.ACTION_BATTERY_CHANGED);
filter.addAction(Intent.ACTION_SCREEN_OFF);
filter.addAction(Intent.ACTION_SCREEN_ON);
/// M: Support show battery level when configuration changed. @{
filter.addAction(Intent.ACTION_CONFIGURATION_CHANGED);
/// M: Support show battery level when configuration changed. @}
/// M: Hide low battery dialog when PowerOffAlarm ring. @{
filter.addAction("android.intent.action.normal.boot");
filter.addAction("android.intent.action.ACTION_SHUTDOWN_IPO");
/// M: Hide low battery dialog when PowerOffAlarm ring. @}
mContext.registerReceiver(mIntentReceiver, filter, null, mHandler);
}SystemUI上的電池是如何畫上去的呢？看下圖
在status_bar.xml這個佈局檔案中可以找到
<com.android.systemui.BatteryMeterView
android:id="@+id/battery"
android:layout_height="16dp"
android:layout_width="10.5dp"
android:layout_marginBottom="0.33dp"
android:layout_marginStart="4dip"
/>
我在這裡把BatteryMeterView.java拿出來寫了一個Demo就是上圖在Activity上顯示的電池小圖示
在BatteryMeterView類中有兩個重要的函式來註冊廣播和登出廣播
@Override
public void onAttachedToWindow() {
super.onAttachedToWindow();
IntentFilter filter = new IntentFilter();
filter.addAction(Intent.ACTION_BATTERY_CHANGED);
filter.addAction(ACTION_LEVEL_TEST);
final Intent sticky = getContext().registerReceiver(mTracker, filter);
if (sticky != null) {
// preload the battery level
mTracker.onReceive(getContext(), sticky);
}
}
@Override
public void onDetachedFromWindow() {
super.onDetachedFromWindow();
getContext().unregisterReceiver(mTracker);
}private class BatteryTracker extends BroadcastReceiver {
@Override
public void onReceive(Context context, Intent intent) {
final String action = intent.getAction();
if (action.equals(Intent.ACTION_BATTERY_CHANGED)) {
if (testmode && !intent.getBooleanExtra("testmode", false))
return;
level = (int) (100f * intent.getIntExtra(
BatteryManager.EXTRA_LEVEL, 0) / intent.getIntExtra(
BatteryManager.EXTRA_SCALE, 100));
plugType = intent.getIntExtra(BatteryManager.EXTRA_PLUGGED, 0);
plugged = plugType != 0;
health = intent.getIntExtra(BatteryManager.EXTRA_HEALTH,
BatteryManager.BATTERY_HEALTH_UNKNOWN);
status = intent.getIntExtra(BatteryManager.EXTRA_STATUS,
BatteryManager.BATTERY_STATUS_UNKNOWN);
technology = intent
.getStringExtra(BatteryManager.EXTRA_TECHNOLOGY);
voltage = intent.getIntExtra(BatteryManager.EXTRA_VOLTAGE, 0);
temperature = intent.getIntExtra(
BatteryManager.EXTRA_TEMPERATURE, 0);
Log.i(TAG, "onReceive ----- level = " + level + " plugType = "
+ plugType + " health = " + health + " status = "
+ status + " technology = " + technology
+ " voltage = " + voltage + " temperature = "
+ temperature);
setContentDescription(context.getString(
R.string.accessibility_battery_level, level));
postInvalidate();
}
}
}
BatteryTracker mTracker = new BatteryTracker();整個小圖示的繪製都是在public void draw(Canvas c)中完成的，沒有用到圖片，詳細的細節就需要好好分析原始碼
log的TAG
private static final String TAG = TestSystemUI.class.getSimpleName();
得到的TAG就是TestSystemUI