Android 读取QR二维码方法《转》

{
   Google ZXing Call demo

   Delphi Version: Delphi XE5 Version 19.0.13476.4176

   By: flcop(zylove619@hotmail.com) 
}

unit UMain;

interface

uses
  System.SysUtils, System.Types, System.UITypes, System.Classes, System.Variants,
  FMX.Types, FMX.Controls, FMX.Forms, FMX.Graphics, FMX.Dialogs, FMX.StdCtrls,
  FMX.Layouts, FMX.Memo,

  System.Rtti, 
  FMX.Helpers.Android,
  Androidapi.JNI.Net,
  Androidapi.JNI.GraphicsContentViewText,
  Androidapi.JNI.JavaTypes,
  FMX.platform,
  FMX.Platform.Android;

type
  TFrmMain = class(TForm)
    Memo1: TMemo;
    Button1: TButton;
    Button2: TButton;
    Button3: TButton;
    PanelOpt: TPanel;
    Panel2: TPanel;
    SBTitle: TSpeedButton;
    procedure Button1Click(Sender: TObject);
    procedure FormCreate(Sender: TObject);
    procedure SBTitleClick(Sender: TObject);
  private
    { Private declarations }
    FClipboardService: IFMXClipboardService;
    FClipboardValue: TValue;
    FZXingCalled: Boolean;
    procedure CallZXing(const ACodeMode: string);
    function IsIntentCallable(const AIntent: JIntent): Boolean;
    function GetZXingIntent: JIntent;
    procedure ClipboardSave;
    procedure ClipboardBack;
    procedure ShowInfo(const AInfo: string);
    function HandleAppEvent(AAppEvent: TApplicationEvent; AContext: TObject): Boolean;
    procedure CheckEnvironment;
    procedure OpenURL(const AURL: string);
  public
    { Public declarations }
  end;

var
  FrmMain: TFrmMain;

implementation

{$R *.fmx}

const
  CodeModes: array[0..2] of string = ('PRODUCT_MODE', 'QR_CODE_MODE', 'SCAN_MODE');

procedure TFrmMain.Button1Click(Sender: TObject);
begin
  // 0, 1, 2
  CallZXing(CodeModes[TButton(Sender).Tag]);
end;

procedure TFrmMain.CallZXing(const ACodeMode: string);
var
  LIntent: JIntent;
begin
  ClipboardSave;
  FClipboardService.SetClipboard('');
  LIntent := GetZXingIntent();
  LIntent.putExtra(StringToJString('SCAN_MODE'), StringToJString(ACodeMode));
  SharedActivity.startActivityForResult(LIntent, 0);
  FZXingCalled := True;
end;

procedure TFrmMain.CheckEnvironment;
var
  LFMXApplicationEventService: IFMXApplicationEventService;
  LIsZXingCallable: Boolean;
  LStr: string;
begin
  if TPlatformServices.Current.SupportsPlatformService(IFMXApplicationEventService,
       IInterface(LFMXApplicationEventService)) then
    LFMXApplicationEventService.SetApplicationEventHandler(HandleAppEvent)
  else
    LStr := '调用失败,不支持IFMXApplicationEventService!';

  if not TPlatformServices.Current.SupportsPlatformService(IFMXClipboardService,
       IInterface(FClipboardService)) then
    LStr := LStr + sLineBreak + '调用失败, 不支持IFMXClipboardService!';

  LIsZXingCallable := IsIntentCallable(GetZXingIntent);
  if not LIsZXingCallable then
  begin
    SBTitle.Text := '点我去ZXing下载页...';
    SBTitle.OnClick := SBTitleClick;
    LStr := LStr + sLineBreak + '未发现ZXing, 请安装ZXing后重新启动本程序';
  end else
    SBTitle.Text := 'Google ZXing Call';

  ShowInfo(LStr.Trim);

  PanelOpt.Enabled := Assigned(LFMXApplicationEventService) and
          Assigned(FClipboardService) and LIsZXingCallable;
end;

procedure TFrmMain.ClipboardBack;
begin
  FClipboardService.SetClipboard(FClipboardValue);
end;

procedure TFrmMain.ClipboardSave;
begin
  FClipboardValue := FClipboardService.GetClipboard;
end;

procedure TFrmMain.FormCreate(Sender: TObject);
begin
  CheckEnvironment;
end;

function TFrmMain.GetZXingIntent: JIntent;
const
  GOOGLE_ZXING = 'com.google.zxing.client.android.SCAN';
  GOOGLE_ZXING_PACKAGE = 'com.google.zxing.client.android';
begin
  Result := TJIntent.JavaClass.init(StringToJString(GOOGLE_ZXING));
  Result.setPackage(StringToJString(GOOGLE_ZXING_PACKAGE));
end;

function TFrmMain.HandleAppEvent(AAppEvent: TApplicationEvent;
  AContext: TObject): Boolean;
var
  LResult: string;
begin
  if FZXingCalled and (AAppEvent = TApplicationEvent.aeBecameActive) then
  begin
    LResult := FClipboardService.GetClipboard.ToString;
    if LResult.IsEmpty then
      ShowInfo('扫描取消')
    else
      ShowInfo(LResult);
    ClipboardBack;
    FZXingCalled := False;
  end;
  Result := True;
end;

function TFrmMain.IsIntentCallable(const AIntent: JIntent): Boolean;
var
  LJPackageManager: JPackageManager;
begin
  Result := False;
  if Assigned(AIntent) then
  begin
    LJPackageManager := SharedActivityContext.getPackageManager;
    Result := LJPackageManager.queryIntentActivities(AIntent,
      TJPackageManager.JavaClass.MATCH_DEFAULT_ONLY).size <> 0;
  end;
end;

procedure TFrmMain.OpenURL(const AURL: string);
var
  LIntent: JIntent;
begin
  LIntent := TJIntent.JavaClass.init(TJIntent.JavaClass.ACTION_VIEW, 
    TJnet_Uri.JavaClass.parse(StringToJString(AURL)));
  SharedActivity.startActivity(LIntent);
end;

procedure TFrmMain.SBTitleClick(Sender: TObject);
begin
  OpenURL('http://code.google.com/p/zxing/downloads/list&#39;);
end;

procedure TFrmMain.ShowInfo(const AInfo: string);
begin
  Memo1.Text := AInfo;
end;

end.