干货答疑分享记录：as导入问题，LSP含义，分屏进入SplashScreen

背景：

vip学员群经常会有学员遇到一些常见的android framework开发问题，近期收集整理一些疑问，主要有以下3个：

1、android studio对源码进行导入时候，老是无法跳转到系统source code

2、学员在群里询问dumpOtherProcessesInfoLSP中末尾的LSP含义是啥

3、学员询问分屏过程中请问到底有没有Splash Screen的画面展示，看到有图层，但是没有看到有Icon

下面针对上面3个学员的疑问进行分别解答记录。

问题1：

android studio对源码进行导入时候，老是无法跳转到系统source code
这个问题学员已经按照我之前分享的blog
aosp源码导入android studio常见问题汇总-学员答疑
对相关的android.iml进行了相关的修改，把sourceFolder放到最顶部了

但是发现

最后原因发现是

问题2：

有学员提问ams代码中的dumpOtherProcessesInfoLSP方法尾部的LSP是啥含义

正确解答其实在ActivityManagerService类中本身有对这个LSP等进行解释，其实指的是锁的范围。

frameworks/base/services/core/java/com/android/server/am/ActivityManagerService.java

   /**
     * The lock for process management.
     *
     * <p>
     * This lock is widely used in conjunction with the {@link #mGlobalLock} at present,
     * where it'll require any of the locks to read from a data class, and both of the locks
     * to write into that data class.
     *
     * For the naming convention of function suffixes:
     * <ul>
     *    <li>-LOSP:    Locked with any Of global am Service or Process lock</li>
     *    <li>-LSP:     Locked with both of global am Service and Process lock</li>
     *    <li>-Locked:  Locked with global am service lock alone</li>
     *    <li>-LPr:     Locked with Process lock alone</li>
     * </ul>
     * For the simplicity, the getters/setters of the fields in data classes usually don't end with
     * the above suffixes even if they're guarded by the locks here.
     * </p>
     *
     * <p>
     * In terms of locking order, it should be right below to the {@link #mGlobalLock},
     * and above everything else which used to be underneath the {@link #mGlobalLock}.
     * As of today, the core components(services/providers/broadcasts) are still guarded by
     * the {@link #mGlobalLock} alone, so be cautious, avoid from acquiring the {@link #mGlobalLock}
     * while holding this lock.
     * </p>
     *
     */
    final ActivityManagerGlobalLock mProcLock = ENABLE_PROC_LOCK
            ? new ActivityManagerProcLock() : mGlobalLock;

问题3：

学员在学习新版本aosp15的分屏功能时候，使用Winscope分析分屏启动发现有如下不理解的画面：

学员疑问在正常情况下Splash窗口都是有Icon的，这里明显没有看到有Icon，只看到一个背景图，这个是为啥？

这里其实可以通过SplashScreenView相关日志对比看出相关的线索：
正常打开App时候，展示的SplashScreenView的相关打印

01-15 13:43:58.920   816   947 D SplashScreenView: Icon: view: android.widget.ImageView{90f9ece V.ED..... ......I. 0,0-0,0 #1020504 android:id/splashscreen_icon_view} drawable: com.android.wm.shell.startingsurface.SplashscreenIconDrawableFactory$ImmobileIconDrawable@f5d91ef size: 560

可以看出这里有相关的Icon信息，大小是560

分屏情况下的打印：
可以看到size大小是0

01-15 13:44:25.555   816   947 D SplashScreenView: Icon: view: null drawable: null size: 0

调试发现其实在SplashScreenView创建时候会根据mSuggestType来设置icon相关的情况：
调试发现分屏情况下mSuggestType是STARTING_WINDOW_TYPE_SOLID_COLOR_SPLASH_SCREEN类型。

  /**
     * Prefer solid color splash screen starting window.
     * @hide
     */
    public static final int STARTING_WINDOW_TYPE_SOLID_COLOR_SPLASH_SCREEN = 3;

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