android 11系统源码在compatibilityinfo.java判断当前返回主桌面

在Android 11系统源码中，判断当前返回主桌面的逻辑是在`CompatibilityInfo.java`文件中进行的。具体来说，可以在`getPackageCompatibilityInfo(Package pkg)`方法中找到相关的代码。

在该方法中，会首先判断当前应用是否为桌面应用，如果是，则直接返回默认的`CompatibilityInfo`对象。如果不是，则会进一步判断当前是否返回到了主桌面。这里是通过判断当前Activity的Intent是否包含`CATEGORY_HOME`来实现的。如果包含，则说明已经返回到了主桌面，此时也会返回默认的`CompatibilityInfo`对象。否则，会根据当前的系统版本和硬件设备信息，返回对应的`CompatibilityInfo`对象。

以下是相关的代码片段：

private static final int ALWAYS_NEEDS_COMPAT = (1 << 0);
private static final int NEVER_NEEDS_COMPAT = (1 << 1);
private static final int DONT_ASK_ABOUT_GL_ERRORS = (1 << 2);

public CompatibilityInfo getPackageCompatibilityInfo(Package pkg) {
    ...
    // Check if the package is a system package or a pre-installed app
    boolean isPreInstalledApp = isPreInstalledApp(pkg);
    boolean isSystemApp = (pkg.applicationInfo.flags & ApplicationInfo.FLAG_SYSTEM) != 0;
    if (!isSystemApp && !isPreInstalledApp) {
        // Check if the activity is returning to the home screen
        boolean isReturningToHomeScreen = activityIntent != null &&
                activityIntent.hasCategory(Intent.CATEGORY_HOME);
        if (isReturningToHomeScreen) {
            return DEFAULT_COMPATIBILITY_INFO;
        }

        // Check if the package has a preferred density
        int prefDensity = pkg.applicationInfo.preferredDensity;
        if (prefDensity != 0) {
            return new CompatibilityInfo(null, prefDensity);
        }

        ...
    }

    // Return the default compatibility info for system packages or pre-installed apps
    return DEFAULT_COMPATIBILITY_INFO;
}