使用Delphi获取音频（Android）焦点

Question

我正在尝试实施音频焦点＆＃39; delphi app：

TOnAudioFocusChange = procedure(focusChange: System.Integer) of object;
  TmyJAudioManagerListener = class(TJavaLocal, JAudioManager_OnAudioFocusChangeListener)
  private
    FOnAudioFocusChange : TOnAudioFocusChange;
  public
    Constructor Create;
    Destructor Destroy; Override;
    property myOnAudioFocusChange : TOnAudioFocusChange read FOnAudioFocusChange write FOnAudioFocusChange;
    procedure onAudioFocusChange(focusChange: System.Integer); cdecl;
  end;

我哪里错了？ 我需要这样做： http://developer.android.com/training/managing-audio/audio-focus.html