Using Reflection to access Dtmf functionalties in Android

Question

everyone. I'm trying to access the sendDtmf method in android.internal.telephony.CallManager using Reflection to send these tones to an IVR Voice.

The code is the following:

import java.lang.reflect.Method;

import android.content.Context;
import android.util.Log;


public class RefelectionFactory {

public boolean sendDtmf(char c, Context context) throws IllegalArgumentException {

    try{
      @SuppressWarnings("rawtypes")
      //Class Phone = cl.loadClass("com.android.internal.telephony.Phone");

        ClassLoader classLoader = context.getClassLoader();
        final Class<?> classCallManager = classLoader.loadClass("com.android.internal.telephony.CallManager");

      //Parameters Types
      @SuppressWarnings("rawtypes")
      Class[] paramTypes= new Class[1];
      paramTypes[0]= Context.class;

      //Method get = Phone.getMethod("sendDtmf",  paramTypes);
      Method get = classCallManager.getMethod("sendDtmf",  paramTypes);
      get.setAccessible(true);

      //Parameters
      Object[] params= new Object[1];
      params[0]= context;

      get.invoke(null, params);

    }catch( IllegalArgumentException iAE ){
        throw iAE;
    }catch( Exception e ){
        Log.e("ERRORE", "sendDtmf", e);
    }
    return true;
}


}

When I'm compiling the code, in LogCat this Exception is thrown:

java.lang.NoSuchMethodException: sendDtmf [class android.content.Context]
java.lang.Class.getConstructorOrMethod(Class.java:460)
java.lang.Class.getMethod(Class.java:915)
it.digitalnatives.*****.ricarica.RefelectionFactory.sendDtmf(RefelectionFactory.java:39)
it.digitalnatives.*****.ricarica.MainRicarica$2.onClick(MainRicarica.java:541)
android.view.View.performClick(View.java:3511)
android.view.View$PerformClick.run(View.java:14105)
android.os.Handler.handleCallback(Handler.java:605)
android.os.Handler.dispatchMessage(Handler.java:92)
android.os.Looper.loop(Looper.java:137)
android.app.ActivityThread.main(ActivityThread.java:4424)
java.lang.reflect.Method.invokeNative(Native Method)
java.lang.reflect.Method.invoke(Method.java:511)
com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784)
com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551)
dalvik.system.NativeStart.main(Native Method)

I'm stuck with this stuff and i've some requests. 1) Is this code correct? 2) The sendDtmf() method really exist in ClassManager class and if so can I access to that?

Any suggestion will be strong appreciated.

Answer 1

Try a different set of parameter types, I can't remember sendDtmf ever taking a Context - the ICS and 2.3 versions all take a char, i.e. CallManager#sendDtmf(char c)

I'd recommend:

Class<?>[] paramTypes = new Class<?>[]{char.class};
Method get = classCallManager.getMethod("sendDtmf",  paramTypes);

Edit: Now with an example.

class Dtmf {
    private static final String CALL_MANAGER = "com.android.internal.telephony.CallManager";
    private static final String SEND_DTMF = "sendDtmf";
    private static final String GET_INSTANCE = "getInstance";
    private Method mSendDtmfMethod;
    private Object mCallManager;
    public Dtmf() {
        try {
            Class<?> callManagerClass = Class.forName(CALL_MANAGER);
            // Obtain an instance of CallManager
            Method getInstanceMethod = callManagerClass.getMethod(GET_INSTANCE);
            mCallManager = getInstanceMethod.invoke(null);
            // Get sendDtmf(char)
            Class<?>[] sendDtmfParamTypes = new Class<?>[]{char.class};
            mSendDtmfMethod = callManagerClass.getMethod(SEND_DTMF, sendDtmfParamTypes);
        } catch (ClassNotFoundException e) {
        } catch (NoSuchMethodException e) {
        } catch (IllegalArgumentException e) {
        } catch (IllegalAccessException e) {
        } catch (InvocationTargetException e) {
        }
    }

    public boolean sendDtmf(char ch) {
        boolean result = false;
        if (mCallManager != null && mSendDtmfMethod != null) {
            try {
                Object res = mSendDtmfMethod.invoke(mCallManager, 
                        new Object[]{Character.valueOf(ch)});

                if (res instanceof Boolean) {
                    result = ((Boolean) res).booleanValue(); 
                }
            } catch (IllegalArgumentException e) {
            } catch (IllegalAccessException e) {
            } catch (InvocationTargetException e) {
            }
        }
        return result;
    }
}

Dunno what protections they've placed inside the call manager - or if you, as a user application, is even able to invoke this method successfully - but this example will at least let you try.