DemoBase.java

package com.xxmassdeveloper.mpchartexample.notimportant;

import android.Manifest;
import android.content.pm.PackageManager;
import android.graphics.Typeface;
import android.os.Bundle;
import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import com.google.android.material.snackbar.Snackbar;

import androidx.appcompat.app.AppCompatActivity;
import androidx.core.app.ActivityCompat;
import android.view.View;
import android.widget.Toast;

import com.github.mikephil.charting.charts.Chart;
import com.xxmassdeveloper.mpchartexample.R;

/**
 * Base class of all Activities of the Demo Application.
 *
 * @author Philipp Jahoda
 */
public abstract class DemoBase extends AppCompatActivity implements ActivityCompat.OnRequestPermissionsResultCallback {

    protected final String[] months = new String[] {
            "Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Okt", "Nov", "Dec"
    };

    protected final String[] parties = new String[] {
            "Party A", "Party B", "Party C", "Party D", "Party E", "Party F", "Party G", "Party H",
            "Party I", "Party J", "Party K", "Party L", "Party M", "Party N", "Party O", "Party P",
            "Party Q", "Party R", "Party S", "Party T", "Party U", "Party V", "Party W", "Party X",
            "Party Y", "Party Z"
    };

    private static final int PERMISSION_STORAGE = 0;

    protected Typeface tfRegular;
    protected Typeface tfLight;

    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        tfRegular = Typeface.createFromAsset(getAssets(), "OpenSans-Regular.ttf");
        tfLight = Typeface.createFromAsset(getAssets(), "OpenSans-Light.ttf");
    }

    protected float getRandom(float range, float start) {
        return (float) (Math.random() * range) + start;
    }

    @Override
    public void onBackPressed() {
        super.onBackPressed();
        overridePendingTransition(R.anim.move_left_in_activity, R.anim.move_right_out_activity);
    }

    @Override
    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
        super.onRequestPermissionsResult(requestCode, permissions, grantResults);
        if (requestCode == PERMISSION_STORAGE) {
            if (grantResults.length == 1 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
                saveToGallery();
            } else {
                Toast.makeText(getApplicationContext(), "Saving FAILED!", Toast.LENGTH_SHORT)
                        .show();
            }
        }
    }

    protected void requestStoragePermission(View view) {
        if (ActivityCompat.shouldShowRequestPermissionRationale(this, Manifest.permission.WRITE_EXTERNAL_STORAGE)) {
            Snackbar.make(view, "Write permission is required to save image to gallery", Snackbar.LENGTH_INDEFINITE)
                    .setAction(android.R.string.ok, new View.OnClickListener() {
                        @Override
                        public void onClick(View v) {
                            ActivityCompat.requestPermissions(DemoBase.this, new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE}, PERMISSION_STORAGE);
                        }
                    }).show();
        } else {
            Toast.makeText(getApplicationContext(), "Permission Required!", Toast.LENGTH_SHORT)
                    .show();
            ActivityCompat.requestPermissions(DemoBase.this, new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE}, PERMISSION_STORAGE);
        }
    }

    protected void saveToGallery(Chart chart, String name) {
        if (chart.saveToGallery(name + "_" + System.currentTimeMillis(), 70))
            Toast.makeText(getApplicationContext(), "Saving SUCCESSFUL!",
                    Toast.LENGTH_SHORT).show();
        else
            Toast.makeText(getApplicationContext(), "Saving FAILED!", Toast.LENGTH_SHORT)
                    .show();
    }

    protected abstract void saveToGallery();
}