A boilerplate for Android Activity

BoilerplateActivity.java

// Copyright (c) 2016 boyw165
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
//    The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
//    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.

package boyw165.com.whatever;

import android.Manifest;
import android.app.AlertDialog;
import android.content.Intent;
import android.content.pm.PackageManager;
import android.net.Uri;
import android.os.Bundle;
import android.os.Environment;
import android.provider.MediaStore;
import android.support.v4.app.ActivityCompat;
import android.support.v4.content.ContextCompat;
import android.support.v7.app.AppCompatActivity;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.Button;

import java.io.File;
import java.io.IOException;

public class BoilerplateActivity extends AppCompatActivity {

    private static final String TAG = "Boilerplate";

    // Flag to indicate the request of the next task to be performed
    protected static final int REQUEST_TAKE_PHOTO = 0;
    protected static final int REQUEST_SELECT_IMAGE_IN_ALBUM = 1;

    protected static final int PERMISSIONS_REQUEST_READ_EXTERNAL_STORAGE = 0;

    private static final String SAVE_URI_PHOTO_TAKEN = "save_uri_photo_taken";

    // The URI of photo taken with camera
    private Uri mUriPhotoTaken;

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

        // Restore save-instance.
        if (savedInstanceState != null) {
            mUriPhotoTaken = savedInstanceState.getParcelable(SAVE_URI_PHOTO_TAKEN);
        }

        setContentView(R.layout.activity_main);

        if (getString(R.string.subscription_key).startsWith("Please")) {
            new AlertDialog.Builder(this)
                .setTitle(getString(R.string.add_subscription_key_tip_title))
                .setMessage(getString(R.string.add_subscription_key_tip))
                .setCancelable(false)
                .show();
        }

        Button btnTakePhoto = (Button) findViewById(R.id.button_take_a_photo);
        btnTakePhoto.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                try {
                    takePhotoFromCamera();
                } catch (IOException ex) {
                    // DO NOTHING.
                }
            }
        });

        Button btnSelectPhoto = (Button) findViewById(R.id.button_select_a_photo_in_album);
        btnSelectPhoto.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                selectPhotoFromGallery();
            }
        });
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.menu_main, menu);
        return true;
    }

    @Override
    protected void onResume() {
        super.onResume();

        if (ContextCompat.checkSelfPermission(this, Manifest.permission.READ_EXTERNAL_STORAGE)
            != PackageManager.PERMISSION_GRANTED) {

            // Should we show an explanation?
            if (ActivityCompat.shouldShowRequestPermissionRationale(
                this, Manifest.permission.READ_EXTERNAL_STORAGE)) {

                // Show an expanation to the user *asynchronously* -- don't block
                // this thread waiting for the user's response! After the user
                // sees the explanation, try again to request the permission.

            } else {

                // No explanation needed, we can request the permission.

                ActivityCompat.requestPermissions(
                    this,
                    new String[]{Manifest.permission.READ_EXTERNAL_STORAGE},
                    PERMISSIONS_REQUEST_READ_EXTERNAL_STORAGE);

                // MY_PERMISSIONS_REQUEST_READ_CONTACTS is an
                // app-defined int constant. The callback method gets the
                // result of the request.
            }
        }
    }

    @Override
    protected void onPause() {
        super.onPause();
    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
    }

    @Override
    protected void onSaveInstanceState(Bundle outState) {
        super.onSaveInstanceState(outState);

        if (mUriPhotoTaken != null) {
            outState.putParcelable(SAVE_URI_PHOTO_TAKEN, mUriPhotoTaken);
        }
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();

        //noinspection SimplifiableIfStatement
        if (id == R.id.action_settings) {
            return true;
        }

        return super.onOptionsItemSelected(item);
    }

    ///////////////////////////////////////////////////////////////////////////
    // Private ////////////////////////////////////////////////////////////////

    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        switch (requestCode) {
            case REQUEST_TAKE_PHOTO:
            case REQUEST_SELECT_IMAGE_IN_ALBUM:
                if (resultCode == RESULT_OK) {
                    Intent intent = new Intent(this, CollageEditorActivity.class);
                    intent.setData(onTakePhotoFromCameraOrGallery(resultCode, data));
                    startActivity(intent);
                }
                break;
            default:
                super.onActivityResult(requestCode, resultCode, data);
                break;
        }
    }

    protected void takePhotoFromCamera() throws IOException {
        Intent intent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);

        if (intent.resolveActivity(getPackageManager()) != null) {
            // Save the photo taken to a temporary file.
            File storageDir = getExternalFilesDir(Environment.DIRECTORY_PICTURES);
            File file = File.createTempFile("IMG_", ".jpg", storageDir);

            mUriPhotoTaken = Uri.fromFile(file);
            intent.putExtra(MediaStore.EXTRA_OUTPUT, mUriPhotoTaken);
            startActivityForResult(intent, REQUEST_TAKE_PHOTO);
        }
    }

    protected void selectPhotoFromGallery() {
        Intent intent = new Intent(Intent.ACTION_GET_CONTENT);
        intent.setType("image/*");
        if (intent.resolveActivity(getPackageManager()) != null) {
            startActivityForResult(intent, REQUEST_SELECT_IMAGE_IN_ALBUM);
        }
    }

    protected Uri onTakePhotoFromCameraOrGallery(int resultCode, Intent data) {
        if (resultCode == RESULT_OK) {
            Uri imageUri;
            if (data == null || data.getData() == null) {
                imageUri = mUriPhotoTaken;
            } else {
                imageUri = data.getData();
            }

            return imageUri;
        } else {
            return null;
        }
    }
}