PlayerStateDesign.md

播放器状态机设计

状态机说明

• Player 状态枚举如下：

状态枚举	说明
IDLE	初始化
PREPARING	正在 prepare
PREPARED	prepare 完成
STARTED	开始播放
PAUSED	暂停播放
COMPLETED	播放完成
STOPPED	播放停止
RELEASED	播放器释放
ERROR	播放出错

• Player 状态获取 API

interface Player {
    
    @PlayerState
    int getState();

    /**
     * @see #STATE_IDLE
     */
    boolean isIDLE();

    /**
     * @see #STATE_PREPARING
     */
    boolean isPreparing();

    /**
     * @see #STATE_PREPARED
     */
    boolean isPrepared();

    /**
     * @see #STATE_STARTED
     */
    boolean isPlaying();

    /**
     * @see #STATE_PAUSED
     */
    boolean isPaused();

    /**
     * @see #STATE_COMPLETED
     */
    boolean isCompleted();

    /**
     * @see #STATE_STOPPED
     */
    boolean isStopped();

    /**
     * @see #STATE_RELEASED
     */
    boolean isReleased();

    /**
     * @see #STATE_ERROR
     */
    boolean isError();

    /**
     * @return true if {@link #getState()} is in playback state.
     * <ul>
     *   <li>{@link #STATE_PREPARED}</li>
     *   <li>{@link #STATE_STARTED}</li>
     *   <li>{@link #STATE_PAUSED}</li>
     *   <li>{@link #STATE_COMPLETED}</li>
     * </ul>
     */
    boolean isInPlaybackState();
}

状态机强检查机制

Note: 状态机强检查方法只能在特定的 state 下调用，否则会抛出 IllegalStateException 异常。

方法	有效状态
prepare	IDLE, STOPPED
setStartTime	IDLE, STOPPED
seekTo	PREPARED, STARTED, PAUSED, COMPLETED
start()	PREPARED, STARTED, PAUSED, COMPLETED
pause()	PREPARED, STARTED, PAUSED, COMPLETED
stop()	PREPARING, PREPARED, STARTED, PAUSED, COMPLETED, STOPPED
reset()	All states
release()	All states