第20讲 icameraservicelistener.aidl详解|极客笔记-凯发k8旗舰厅

本讲是android camera native framework专题的第20讲，我们介绍icameraservicelistener.aidl详解。

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icameraservicelistener类图

android aidl oneway修饰符

在 android aidl中，oneway 是一种修饰符，用于声明一个方法是单向的（one-way）。

使用 oneway 修饰符声明的方法不会阻塞调用线程，而是立即返回并在后台运行，因此不需要等待方法执行完成。

这种方式适用于客户端和服务端之间不需要进行同步通信的情况，例如通知服务端某项任务已经完成。

需要注意的是，在客户端调用带有 oneway 修饰符的方法时，无法得知方法是否返回成功或失败，因为该方法会立即返回，而不会等待服务端响应。因此，建议将 oneway 修饰符仅用于不需要接收服务端响应的方法。

icameraservicelistener.aidl接口详解

android 13 icameraservicelistener.aidl代码

/** @hide */
interface icameraservicelistener
{
    /**
     * initial status will be transmitted with onstatuschange immediately
     * after this listener is added to the service listener list.
     *
     * allowed transitions:
     *
     *     (any)               -> not_present
     *     not_present         -> present
     *     not_present         -> enumerating
     *     enumerating         -> present
     *     present             -> not_available
     *     not_available       -> present
     *
     * a state will never immediately transition back to itself.
     *
     * the enums must match the values in
     * include/hardware/camera_common.h when applicable
     */
    // device physically unplugged
    const int status_not_present      = 0;
    // device physically has been plugged in and the camera can be used exclusively
    const int status_present          = 1;
    // device physically has been plugged in but it will not be connect-able until enumeration is
    // complete
    const int status_enumerating      = 2;
    // camera is in use by another app and cannot be used exclusively
    const int status_not_available    = -2;
    // use to initialize variables only
    const int status_unknown          = -1;
    oneway void onstatuschanged(int status, string cameraid);
    /**
     * notify registered client about status changes for a physical camera backing
     * a logical camera.
     */
    oneway void onphysicalcamerastatuschanged(int status, string cameraid, string physicalcameraid);
    /**
     * the torch mode status of a camera.
     *
     * initial status will be transmitted with ontorchstatuschanged immediately
     * after this listener is added to the service listener list.
     *
     * the enums must match the values in
     * include/hardware/camera_common.h
     */
    // the camera's torch mode has become not available to use via
    // settorchmode().
    const int torch_status_not_available = 0;
    // the camera's torch mode is off and available to be turned on via
    // settorchmode().
    const int torch_status_available_off = 1;
    // the camera's torch mode is on and available to be turned off via
    // settorchmode().
    const int torch_status_available_on  = 2;
    // use to initialize variables only
    const int torch_status_unknown = -1;
    oneway void ontorchstatuschanged(int status, string cameraid);
    oneway void ontorchstrengthlevelchanged(string cameraid, int newtorchstrength);
    /**
     * notify registered clients about camera access priority changes.
     * clients which were previously unable to open a certain camera device
     * can retry after receiving this callback.
     */
    oneway void oncameraaccessprioritieschanged();
    /**
     * notify registered clients about cameras being opened/closed.
     * only clients with android.permission.camera_open_close_listener permission
     * will receive such callbacks.
     */
    oneway void oncameraopened(string cameraid, string clientpackageid);
    oneway void oncameraclosed(string cameraid);
}