How to use Java class for GPIO control to make an application that runs on Android OS

Question

I am trying to develop an app that would allow GPIO testing, such as cat /sys/class/gpio/%s/direction, on a custom board with a touchscreen display.

I'm don't have too much experience with android development, and I'm not sure how I can implement this app.

Answer 1

If you are using the GPIO class like the one you provided you want to make a new instance for each GPIO you want to test. You don't have to create a direction class or anything like this - everything can be implemented in the MainActivity.java.

package com.pckg.gpio;


import androidx.appcompat.app.AppCompatActivity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;


public class MainActivity extends AppCompatActivity {

private final String TAG = "GpioTest";
private GPIO gpio27;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    gpio27 = new GPIO(27) // new Instance of gpio 27


final Button Direction = (Button) findViewById(R.id.ButtonDir);
    Direction.setOnClickListener(new View.OnClickListener() {
                                     public void onClick(View view) {
                                        Log.d(TAG, "direction for pin 27:" + gpio27.getInOut();
                                     }
    });
}

In this small example, you can see in the logs the directions for pin 27. I have created a new instance using the contractor in the GPIO class. You can do this for multiple gpios just create new instance.