Android P ActivityManagerService（八）从Recent启动Activity

最新推荐文章于 2023-08-09 08:55:19 发布

三三不尽

最新推荐文章于 2023-08-09 08:55:19 发布

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分类专栏： Android

本文链接：https://blog.youkuaiyun.com/weixin_39821531/article/details/89848457

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本文详细探讨了在Android P中，如何从最近应用（Recent）列表启动Activity的过程。起点始于RecentView.java的startTaskActivity方法，通过ActivityManagerWrapper的startActivityFromRecentsAsync方法，进一步调用ActivityManager的startActivityFromRecents。在ActivityStackSupervisor中，关键步骤包括获取TaskRecord的anyTaskForIdLocked方法，以及判断用户是否需要凭证的UserController.shouldConfirmCredentials方法。当需要处理拦截时，会触发ActivityStartController.startActivityInPackage方法。

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startActivity之外，从Recent界面启动Activity也是应用启动的一个重要方式；

而这一切都是从RecentView.java的startTaskActivity方法开始的；

/**
 * Starts the activity for the launch task.
 *
 * @param taskView this is the {@link TaskView} that we are launching from. This can be null if
 *                 we are toggling recents and the launch-to task is now offscreen.
 */
private void startTaskActivity(TaskStack stack, Task task, @Nullable TaskView taskView,
        ActivityOptions opts, AppTransitionAnimationSpecsFuture transitionFuture,
        int windowingMode, int activityType) {
    ActivityManagerWrapper.getInstance().startActivityFromRecentsAsync(task.key, opts,
            windowingMode, activityType, succeeded -> {
        if (succeeded) {
            // Keep track of the index of the task launch
            int taskIndexFromFront = 0;
            int taskIndex = stack.indexOfTask(task);
            if (taskIndex > -1) {
                taskIndexFromFront = stack.getTaskCount() - taskIndex - 1;
            }
            EventBus.getDefault().send(new LaunchTaskSucceededEvent(taskIndexFromFront));
        } else {
            Log.e(TAG, mContext.getString(R.string.recents_launch_error_message, task.title));

            // Dismiss the task if we fail to launch it
            if (taskView != null) {
                taskView.dismissTask();
            }

            // Keep track of failed launches
            EventBus.getDefault().send(new LaunchTaskFailedEvent());
        }
    }, getHandler());
    if (transitionFuture != null) {
        mHandler.post(transitionFuture::composeSpecsSynchronous);
    }
}

ActivityManagerWrapper是SystemUI内的类；接下来看看它的startActivityFromRecentsAsync方法；

/**
 * Starts a task from Recents.
 *
 * @param resultCallback The result success callback
 * @param resultCallbackHandler The handler to receive the result callback
 */
public void startActivityFromRecentsAsync(Task.TaskKey taskKey, ActivityOptions options,
        int windowingMode, int activityType, Consumer<Boolean> resultCallback,
        Handler resultCallbackHandler) {
    if (taskKey.windowingMode == WINDOWING_MODE_SPLIT_SCREEN_PRIMARY) {
        // We show non-visible docked tasks in Recents, but we always want to launch
        // them in the fullscreen stack.
        if (options == null) {
            options = ActivityOptions.makeBasic();
        }
        options.setLaunchWindowingMode(WINDOWING_MODE_SPLIT_SCREEN_SECONDARY);
    } else if (windowingMode != WINDOWING_MODE_UNDEFINED
            || activityType != ACTIVITY_TYPE_UNDEFINED) {
        if (options == null) {
            options = ActivityOptions.makeBasic();
        }
        options.setLaunchWindowingMode(windowingMode);
        options.setLaunchActivityType(activityType);
    }
    final ActivityOptions finalOptions = options;

    // Execute this from another thread such that we can do other things (like caching the
    // bitmap for the thumbnail) while AM is busy starting our activity.
    mBackgroundExecutor.submit(new Runnable() {
        @Override
        public void run() {
            boolean result = false