How do I add In-App-Purchase to a Button?

Question

I want to add buttons in my App which start an In-App Purchase and after succesfully paid it should perform an action.

What i did already...

I added buttons to the layout ,which got IDs like "doc_link1" to "doc_link11".

Question: Each button should cause an In - App Purchase and after paid should before an action. I already set up my In-App-Purchase Account and IDs in the Google Play Console.

How can I add those In-App-Purchase IDs to the buttons successfully, that when a user presses the button it performs the In-App-Purchase?

package com.test.keyboard;

import android.content.Intent;
import android.net.Uri;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageView;


public class LinksFragment extends Fragment implements View.OnClickListener {
    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        View view = inflater.inflate(R.layout.roko_mojis_p2, null);
        view.findViewById(R.id.doc_link_1).setOnClickListener(this);
        view.findViewById(R.id.doc_link_2).setOnClickListener(this);
        view.findViewById(R.id.doc_link_4).setOnClickListener(this);
        view.findViewById(R.id.doc_link_5).setOnClickListener(this);
        view.findViewById(R.id.doc_link_6).setOnClickListener(this);
        view.findViewById(R.id.doc_link_7).setOnClickListener(this);
        view.findViewById(R.id.doc_link_8).setOnClickListener(this);
        view.findViewById(R.id.doc_link_9).setOnClickListener(this);
        view.findViewById(R.id.doc_link_10).setOnClickListener(this);
        view.findViewById(R.id.doc_link_11).setOnClickListener(this);
        return view;
    }

    private void sendMail() {
        String mailto = "mailto:" + getResources().getString(R.string.email_mailto) +
                "?subject=" + Uri.encode(getResources().getString(R.string.email_subject)) +
                "&body=" + Uri.encode("");

        Intent emailIntent = new Intent(Intent.ACTION_SENDTO);
        emailIntent.setData(Uri.parse(mailto));
        startActivity(Intent.createChooser(emailIntent, "Send Email"));
    }


    @Override
    public void onClick(View view) {
        switch (view.getId()) {
            case R.id.doc_link_1:
                // About Me
                startActivity(new Intent(Intent.ACTION_VIEW, Uri.parse("http://www.google.com")));
                break;
            case R.id.doc_link_2:
                // How to install
                startActivity(new Intent(Intent.ACTION_VIEW, Uri.parse("http://www.google.com")));
                break;
            case R.id.doc_link_4:
                // Purchase Pack 1
                sendMail();
                break;
            case R.id.doc_link_5:
                // Purchase Pack 2
                startActivity(new Intent(Intent.ACTION_VIEW, Uri.parse("http://www.google.com")));
                break;
            case R.id.doc_link_6:
                // Purchase Pack 3
                startActivity(new Intent(Intent.ACTION_VIEW, Uri.parse("http://www.google.com")));
                break;
            case R.id.doc_link_7:
                // Purchase Pack 4
                startActivity(new Intent(Intent.ACTION_VIEW, Uri.parse("http://www.google.com")));
                break;
            case R.id.doc_link_8:
                // Purchase Pack 5
                startActivity(new Intent(Intent.ACTION_VIEW, Uri.parse("http://www.google.com")));
                break;
            case R.id.doc_link_9:
                // Purchase Pack 6
                startActivity(new Intent(Intent.ACTION_VIEW, Uri.parse("http://www.google.com")));
                break;
            case R.id.doc_link_10:
                // Purchase Pack 7
                startActivity(new Intent(Intent.ACTION_VIEW, Uri.parse("http://www.google.com")));
                break;
            case R.id.doc_link_11:
                // Purchase Pack 8
                startActivity(new Intent(Intent.ACTION_VIEW, Uri.parse("http://www.google.com")));
                break;
            default:
                startActivity(new Intent(Intent.ACTION_VIEW, Uri.parse("http://www.google.com")));
                break;
        }
    }
}

Answer 1

If you're using googles in-app billing library, you can do it like this:

case R.id.doc_link_1:
    BillingFlowParams flowParams = BillingFlowParams.newBuilder()
             .setSku(skuId)
             .setType(SkuType.INAPP) // SkuType.SUB for subscription
             .build();
    int responseCode = mBillingClient.launchBillingFlow(flowParams);

See https://developer.android.com/google/play/billing/billing_library_overview#Enable