BaseActivity.java

package com.door43.translationstudio.newui;

import android.Manifest;
import android.content.Intent;
import android.content.pm.PackageManager;
import android.os.Bundle;
import android.support.v4.app.ActivityCompat;
import android.support.v4.content.ContextCompat;
import android.support.v7.app.AppCompatActivity;

import com.door43.tools.reporting.GlobalExceptionHandler;
import com.door43.translationstudio.CrashReporterActivity;
import com.door43.translationstudio.ImportFileChooserActivity;
import com.door43.translationstudio.SplashScreenActivity;
import com.door43.translationstudio.AppContext;
import com.door43.translationstudio.TermsOfUseActivity;
import com.door43.translationstudio.newui.legal.LegalDocumentActivity;

import java.io.File;

/**
 * This should be extended by all activities in the app so that we can perform verification on
 * activities such as recovery from crashes.
 *
 */
public abstract class BaseActivity extends AppCompatActivity {

    private static final int PERMISSIONS_REQUEST_WRITE_EXT_STORAGE = 0;
    private static final String KEY_WAITING_FOR_PERMISSIONS = "waiting_for_permissions";
    private boolean waitingForPermissions = false;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        if(savedInstanceState != null) {
            this.waitingForPermissions = savedInstanceState.getBoolean(KEY_WAITING_FOR_PERMISSIONS);
        }
    }

    /**
     * Indicates if the activity is waiting for the user to grant manifest permissions
     * @return
     */
    public boolean waitingForPermissions() {
       return this.waitingForPermissions;
    }

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

        // request permissions
        if(!this.waitingForPermissions) {
            if (ContextCompat.checkSelfPermission(this, Manifest.permission.WRITE_EXTERNAL_STORAGE)
                    != PackageManager.PERMISSION_GRANTED) {
                ActivityCompat.requestPermissions(this,
                        new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE},
                        PERMISSIONS_REQUEST_WRITE_EXT_STORAGE);
                this.waitingForPermissions = true;
            }
        }

        // check if we crashed or if we need to reload
        if(!waitingForPermissions) {
            if (this instanceof TermsOfUseActivity == false
                    && this instanceof SplashScreenActivity == false
                    && this instanceof CrashReporterActivity == false) {
                File dir = new File(AppContext.getPublicDirectory(), AppContext.context().STACKTRACE_DIR);
                String[] crashFiles = GlobalExceptionHandler.getStacktraces(dir);
                if (crashFiles.length > 0) {
                    // restart
                    Intent intent = new Intent(this, SplashScreenActivity.class);
                    startActivity(intent);
                    finish();
                }
            }
        }
    }

    @Override
    public void onRequestPermissionsResult(int requestCode,
                                           String permissions[], int[] grantResults) {
        switch(requestCode) {
            case PERMISSIONS_REQUEST_WRITE_EXT_STORAGE: {
                if(grantResults.length > 0
                        && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
                    this.waitingForPermissions = false;
                    onResume();
                } else {
                    // The app cannot function without needed permissions
                    finish();
                }
                return;
            }
        }
    }

    @Override
    protected void onSaveInstanceState(Bundle outState) {
        outState.putBoolean(KEY_WAITING_FOR_PERMISSIONS, this.waitingForPermissions);
        super.onSaveInstanceState(outState);
    }

}