Delphi XE5 Android.如何使用PowerManager.WakeLock？

发布时间：2020-12-15 03:51:47 所属栏目：大数据来源：网络整理

导读：我想保持设备开启,并避免在没有用户活动的情况下从内存中卸载我的应用程序.像服务一样的东西.我制作了像 How to check if network is available on Android and iOS ( Delphi XE5 )这样的模块,但是当我运行SetWakeLock时系统会崩溃： unit Android.PowerMana

我想保持设备开启,并避免在没有用户活动的情况下从内存中卸载我的应用程序.像服务一样的东西.我制作了像 How to check if network is available on Android and iOS ( Delphi XE5 )这样的模块,但是当我运行SetWakeLock时系统会崩溃：

unit Android.PowerManager;

interface

function SetWakeLock : boolean;
procedure ReleaseWakeLock;

implementation

uses
  System.SysUtils,Androidapi.JNI,Androidapi.JNIBridge,Androidapi.JNI.GraphicsContentViewText,Androidapi.JNI.JavaTypes,FMX.Helpers.Android;

type
  JPowerManager = interface;
  JWakeLock = interface;

  JWakeLockClass = interface(JObjectClass)
  ['{4CF7A13D-15A9-4DEE-8CA7-66600C188CB7}']
  end;

  [JavaSignature('android/os/PowerManager/WakeLock')]
  JWakeLock = interface(JObject)
  ['{55983EDC-782F-490A-BF0C-12207EB7829E}']
    {Methods}
    procedure acquire; cdecl;
    procedure release; cdecl;
    function isHeld: Boolean; cdecl;
  end;
  TJWakeLock = class(TJavaGenericImport<JWakeLockClass,JWakeLock>) end;

  JPowerManagerClass = interface(JObjectClass)
  ['{B127DD4E-1DA6-49E7-98BA-5966DC7E26FA}']
  end;

  [JavaSignature('android/os/PowerManager')]
  JPowerManager = interface(JObject)
  ['{241C3B3D-3DF0-489B-A33E-3CD7F5D26313}']
    {Methods}
    function newWakeLock(levelAndFlags: integer; tag: JString): JWakeLock; cdecl;
  end;
  TJPowerManager = class(TJavaGenericImport<JPowerManagerClass,JPowerManager>) end;

function GetPowerManager: JPowerManager;
var
  PowerServiceNative: JObject;
begin
  PowerServiceNative := SharedActivityContext.getSystemService(TJContext.JavaClass.POWER_SERVICE);
  if not Assigned(PowerServiceNative) then
    raise Exception.Create('Could not locate Power Service');
  Result := TJPowerManager.Wrap(
    (PowerServiceNative as ILocalObject).GetObjectID);
  if not Assigned(Result) then
    raise Exception.Create('Could not access Power Manager');
end;

var fWakeLock : JWakeLock = nil;

function SetWakeLock : boolean;
var
  PowerManager: JPowerManager;
begin
  result := fWakeLock<>nil;
  if result then begin
    PowerManager := GetPowerManager;
    fWakeLock := PowerManager.newWakeLock(1,StringToJString('VC'));  //PARTIAL_WAKE_LOCK =1
    Result := fWakeLock<>nil;
    if Result then begin
       fWakeLock.acquire;
       Result := fWakeLock.IsHeld;
    end;
  end else if not fWakeLock.IsHeld then
    fWakeLock.acquire;
end;

procedure ReleaseWakeLock;
begin
  if fWakeLock<>nil then begin
    fWakeLock.release;
  end;
end;

end.

解决方法

忽略我在注释中引用的错误的逻辑,你不是在接口声明中正确引用嵌套类.

这个单位适合我.注意我正在使用屏幕唤醒锁(已弃用,但仍然有效).

unit Android.JNI.PowerManager;

interface

function AcquireWakeLock : Boolean;
procedure ReleaseWakeLock;

implementation

uses
  System.SysUtils,FMX.Helpers.Android;

type
  JPowerManager = interface;
  JWakeLock = interface;

  JWakeLockClass = interface(JObjectClass)
  ['{918E171F-CDB8-4464-9507-F49272CE7636}']
  end;

  [JavaSignature('android/os/PowerManager$WakeLock')]
  JWakeLock = interface(JObject)
  ['{D17B1136-FA15-4AEB-85B1-2D490F0FD320}']
    {Methods}
    procedure acquire; cdecl;
    procedure release; cdecl;
    function isHeld: Boolean; cdecl;
  end;
  TJWakeLock = class(TJavaGenericImport<JWakeLockClass,JWakeLock>) end;

  JPowerManagerClass = interface(JObjectClass)
  ['{7D0696A2-ADEA-4158-AE1F-5E720DEDBCF9}']
    {Property methods}
    function _GetFULL_WAKE_LOCK: Integer; cdecl;
    function _GetSCREEN_BRIGHT_WAKE_LOCK: Integer; cdecl;
    function _GetSCREEN_DIM_WAKE_LOCK: Integer; cdecl;
    function _GetPARTIAL_WAKE_LOCK: Integer; cdecl;
    {Properties}
    //Keep screen on bright & keyboard on
    //Deprecated in API level 17 - Jelly Bean MR1
    property FULL_WAKE_LOCK: Integer read _GetFULL_WAKE_LOCK;
    //Keep screen on bright
    //Deprecated in API level 13 - Honeycomb MR2
    property SCREEN_BRIGHT_WAKE_LOCK: Integer read _GetSCREEN_BRIGHT_WAKE_LOCK;
    //Keep screen on dim
    //Deprecated in API level 17 - Jelly Bean MR1
    property SCREEN_DIM_WAKE_LOCK: Integer read _GetSCREEN_DIM_WAKE_LOCK;
    //Keep CPU running,screen & keyboard can go off
    property PARTIAL_WAKE_LOCK: Integer read _GetPARTIAL_WAKE_LOCK;
  end;

  [JavaSignature('android/os/PowerManager')]
  JPowerManager = interface(JObject)
  ['{DEAED658-4353-4D17-B0A3-8179E48BE87F}']
    {Methods}
    function newWakeLock(levelAndFlags: Integer; tag: JString): JWakeLock; cdecl;
  end;
  TJPowerManager = class(TJavaGenericImport<JPowerManagerClass,JPowerManager>) end;

function GetPowerManager: JPowerManager;
var
  PowerServiceNative: JObject;
begin
  PowerServiceNative := SharedActivityContext.getSystemService(
    TJContext.JavaClass.POWER_SERVICE);
  if not Assigned(PowerServiceNative) then
    raise Exception.Create('Could not locate Power Service');
  Result := TJPowerManager.Wrap(
    (PowerServiceNative as ILocalObject).GetObjectID);
  if not Assigned(Result) then
    raise Exception.Create('Could not access Power Manager');
end;

var
  WakeLock: JWakeLock = nil;

function AcquireWakeLock: Boolean;
var
  PowerManager: JPowerManager;
begin
  Result := Assigned(WakeLock);
  if not Result then
  begin
    PowerManager := GetPowerManager;
    WakeLock := PowerManager.newWakeLock(
      TJPowerManager.JavaClass.SCREEN_BRIGHT_WAKE_LOCK,StringToJString('Delphi'));
    Result := Assigned(WakeLock);
  end;
  if Result then
  begin
    if not WakeLock.IsHeld then
    begin
      WakeLock.acquire;
      Result := WakeLock.isHeld
    end;
  end;
end;

procedure ReleaseWakeLock;
begin
  if Assigned(WakeLock) then
  begin
    WakeLock.release;
    WakeLock := nil
  end;
end;

end.

（编辑：李大同）

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