Go Ethereum Mobile (Android) Contract ABI Error

Question

Go Ethereum Mobile (Android) Contract ABI Error

I want to interact with Smart Contract in Ethereum from a mobile device (here Android). Smart Contract works great with Javascript API from ethereum. So I want to use Go Ethereum Mobile Client (1.6.0) (included in gradle). I could connect to the blockchain, get the peer count, read the balances, but interacting with the contract is my problem.

Creating a Java class using the "abigen" command line is fine. I only need to change "bool" to "boolean" and the class should be ready to go. Whenever I try to communicate, Go Ethereum throws an exception: this.Contract.call ()

So I just want to do the following:

Contract1 electionContract = new Contract1(contractAddress,node.getEthereumClient());

//Action 1 
TransactOpts transactOpts = new TransactOpts();
transactOpts.setFrom(keyStore.getAccounts().get(0).getAddress());
                    transactOpts.setContext(gethcontext);    
Transaction transaction = contract1.sendString(transactOpts,new BigInt(0),"String");

//Action 2
contract1.Results contract1=electionContract.getString(null,new BigInt(0),new BigInt(0));

Activity 1 Declaration (generated class)

protected Transaction sendString(TransactOpts opts, BigInt identifier, String teststring) throws Exception {

Interfaces args = Geth.newInterfaces(2);
args.set(0, Geth.newInterface());
args.get(0).setBigInt(identifier);
args.set(1, Geth.newInterface());
args.get(1).setString(teststring);


return this.Contract.transact(opts, "sendString", args); //at this point the error is thrown

When trying to send data (see step 1 above)

go.Universe$proxyerror: argument count mismatch: 1 for 2

Action Declaration 2

protected Results getString(CallOpts opts, BigInt randomID, BigInt randomID2) throws Exception {
        Interfaces args = Geth.newInterfaces(2);
        args.set(0, Geth.newInterface());
        args.get(0).setBigInt(randomID);
        args.set(1, Geth.newInterface());
        args.get(1).setBigInt(randomID2);


        Interfaces results = Geth.newInterfaces(2);
        Interface result0 = Geth.newInterface();
        result0.setDefaultString();
        results.set(0, result0);
        Interface result1 = Geth.newInterface();
        result1.setDefaultBigInt();
        results.set(1, result1);


        if (opts == null) {
            opts = Geth.newCallOpts();
        }
        this.Contract.call(opts, results, "getString", args); //at this point the error is thrown

        Results result = new Results();
        result.String = results.get(0).getString();
        result.Count = results.get(1).getBigInt();

        return result;

    }

Trying to get data from a persistent function (so should be free)

go.Universe$proxyerror: `getString` abi: cannot use invalid as type ptr as argument //see action 2 below

ABI String Extract:

[ {
    "constant": false,
    "inputs": [{
        "name": "randomID",
        "type": "uint256"
    }, {
        "name": "randomString",
        "type": "string"
    }],
    "name": "sendString",
    "outputs": [],
    "payable": false,
    "type": "function"
}, {
    "constant": true,
    "inputs": [{
        "name": "randomID",
        "type": "uint256"
    }, {
        "name": "randomID2",
        "type": "uint256"
    }],
    "name": "getString",
    "outputs": [{
        "name": "randomString",
        "type": "string"
    }, {
        "name": "randomID",
        "type": "uint256"
    }],
    "payable": false,
    "type": "function"
}]