Implement Custom Android SDK Callback Events With Delphi XE5 Firemonkey On Android

//This is called from the Java activity's onBarCodeComplete() method
procedure onBarCodeCompleteNative(PEnv: PJNIEnv; This: JNIObject; BarCode: JNIString); cdecl;
begin
  Log.d('+onBarCodeCompleteNative');
  Log.d('Thread (Main: %.8x, Current: %.8x, Java:%.8d (%2:.8x), POSIX:%.8x)',
    [MainThreadID, TThread.CurrentThread.ThreadID, TJThread.JavaClass.currentThread.getId, GetCurrentThreadID]);
  ARNBarCode := JNIStringToString(PEnv, BarCode);
  Log.d('Calling Synchronize');
  TThread.Synchronize(nil, onBarCodeCompleteThreadSwitcher);
  Log.d('Synchronize is over');
  Log.d('-onBarCodeCompleteNative');
end;
 
//This is called from the Java activity's onBarCodeComplete() method
procedure onBarCodeFailNative(PEnv: PJNIEnv; This: JNIObject); cdecl;
begin
  Log.d('+onBarCodeFailNative');
  Log.d('Thread (Main: %.8x, Current: %.8x, Java:%.8d (%2:.8x), POSIX:%.8x)',
    [MainThreadID, TThread.CurrentThread.ThreadID, TJThread.JavaClass.currentThread.getId, GetCurrentThreadID]);
  Log.d('Calling Synchronize');
  TThread.Synchronize(nil, onBarCodeFailThreadSwitcher);
  Log.d('Synchronize is over');
  Log.d('-onBarCodeFailNative');
end;
 
procedure TFormMain.RegisterDelphiNativeMethods;
var
  PEnv: PJNIEnv;
  ActivityClass: JNIClass;
  NativeMethods: array[0..1] of JNINativeMethod;
begin
  Log.d('Starting the registration JNI stuff');
 
  PEnv := TJNIResolver.GetJNIEnv;
 
  Log.d('Registering interop methods');
 
  NativeMethods[0].Name := 'onBarCodeCompleteNative';
  NativeMethods[0].Signature := '(Ljava/lang/String;)V';
  NativeMethods[0].FnPtr := @onBarCodeCompleteNative;
 
  NativeMethods[1].Name := 'onBarCodeFailNative';
  NativeMethods[1].Signature := '()V';
  NativeMethods[1].FnPtr := @onBarCodeFailNative;
 
  ActivityClass := PEnv^.GetObjectClass(
    PEnv, PANativeActivity(System.DelphiActivity).clazz);
 
  PEnv^.RegisterNatives(PEnv, ActivityClass, @NativeMethods[0], 2);
 
  PEnv^.DeleteLocalRef(PEnv, ActivityClass);
end;

package com.winarhi.nativeactivitysubclass;
 
import android.os.Build;
import android.os.Handler;
import android.os.Message;
import android.os.RemoteException;
 
import java.io.IOException;
 
import com.honeywell.decodemanager.DecodeManager;
import com.honeywell.decodemanager.barcode.DecodeResult;
 
public class NativeActivitySubclass extends com.embarcadero.firemonkey.FMXNativeActivity{
 
    //private final int ID_SCANSETTING = 0x12;
    //private final int ID_CLEAR_SCREEN = 0x13;
 
    private DecodeManager mDecodeManager = null;
    public String strDecodeResult = "";
    private final int WA_SCANTIMEOUT = 5000;
    long WA_mScanAccount = 0;
 
    private void WA_CreateDecodeManager() {
        if (mDecodeManager == null)
            mDecodeManager = new DecodeManager(this, ScanResultHandler);
    }
 
    private void WA_DestroyDecodeManager() {
        if (mDecodeManager != null) {
            try {
                mDecodeManager.release();
                mDecodeManager = null;
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }
    }
 
    private void WA_DoScan() throws Exception {
        if (mDecodeManager != null) {
            try {
                strDecodeResult = "";
                mDecodeManager.doDecode(WA_SCANTIMEOUT);
            } catch (RemoteException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }
    }
 
    public native void onBarCodeCompleteNative(String BarCode);
    public native void onBarCodeFailNative();
 
    private Handler ScanResultHandler = new Handler() {
        public void handleMessage(Message msg) {
            switch (msg.what) {
                case DecodeManager.MESSAGE_DECODER_COMPLETE:
                    WA_mScanAccount++;
                    DecodeResult decodeResult = (DecodeResult) msg.obj;
 
                    //byte codeid = decodeResult.codeId;
                    //byte aimid = decodeResult.aimId;
                    //int iLength = decodeResult.length;
 
                    strDecodeResult = decodeResult.barcodeData;
                    onBarCodeCompleteNative(strDecodeResult);
                    break;
 
                case DecodeManager.MESSAGE_DECODER_FAIL: {
                    strDecodeResult = "";
                    onBarCodeFailNative();
                }
                break;
                case DecodeManager.MESSAGE_DECODER_READY:
                {
                }
                break;
                default:
                    super.handleMessage(msg);
                    break;
            }
        }
    };
    private void WA_cancelScan() throws Exception {
        mDecodeManager.cancelDecode();
    }
}

uses
  Androidapi.JNIBridge,
  Androidapi.JNI.App;
 
type
  JNativeActivitySubclassClass = interface(JNativeActivityClass)
  ['{829C77FB-08F1-4D19-9782-3C58EECAAAAA}']
    {Methods}
    //function init: JFMXNativeActivity; cdecl;
  end;
 
  [JavaSignature('com/winarhi/nativeactivitysubclass/NativeActivitySubclass')]
  JNativeActivitySubclass = interface(JNativeActivity)
  ['{2FA559EC-D1D7-46AA-9C52-FEFC6B3AAAAA}']
    {Methods}
    procedure WA_DoScan;
    procedure WA_CreateDecodeManager;
    procedure WA_DestroyDecodeManager;
  end;
  TJNativeActivitySubclass = class(TJavaGenericImport<JNativeActivitySubclassClass, JNativeActivitySubclass>) end;