How do I begin to use this Java library?

Question

Teaching myself Java, still very new. Last night I learned how to import this library into my project in Android Studio. But now I'm confused as to how to actually start using it.

I know that Java works with classes and that supposedly a library is just a collection of classes (and probably others things too...) that you can begin using once you import it. But the author of this library told me to just use this:

BackgroundMail bm = new BackgroundMail(context);
bm.setGmailUserName("sendername@gmail.com");
bm.setGmailPassword("sender_email_password");
bm.setMailTo("receiver@gmail.com");
bm.setFormSubject("Subject");
bm.setFormBody("Body");
bm.send();

But when I try to put that into another one of my classes, I get red errors all over the place. So then I tried to create a Java class within my app's files and I still got red errors. Could someone kindly help me, a total beginner, get started here? I'd like to use this library to send an email in the background of my app.

To import the library:

I followed this answer: https://stackoverflow.com/a/35369267/5241266 and used Approach 2.

MainActivity.Java: this is where I put the import code.

package moviehelper.moviesfree;


import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import com.creativityapps.gmailbackgroundlibrary.BackgroundMail;

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
    }
}

For now, I have not added the block of code that the author told me to use (see above).

The Gradle Console error:

I get the following error when doing Build -> Make Project:

error: package com.creativityapps.gmailbackgroundlibrary does not exist

import com.creativityapps.gmailbackgroundlibrary.BackgroundMail;

My project tree: I think there might be some problem with this structure. It looks like the library was added as its own project? Although I'm not sure.

Did you import the classes? Show your code, and say what the errors are. — Carcigenicate, May 25 '17 at 23:13
Can tell us where exactly you inserted that code? how did you include the library? what errors are you getting? — Ahmad, May 25 '17 at 23:15
@Ahmad I believe the approach I used put the library in as a module — loltospoon, May 26 '17 at 00:33
Did you add the dependencies in the build.gradle? Are you getting any errors in the Gradle Console? — David Rawson, May 26 '17 at 00:39
@DavidRawson The dependencies seems to have been added in by itself through the method I linked in the question. It resulted in this line in the `build.gradle` file: `dependencies {compile project(':emailbackgroundlib') }` (there are other dependencies here as well). The error I put in the question is from the Gradle Console. — loltospoon, May 26 '17 at 00:47
@cricket_007 because I'm new and did not know that method exists. — loltospoon, May 26 '17 at 01:06
@cricket_007 so did I not need to import as a module? All I need to do is put the library in through those few lines of code? — loltospoon, May 26 '17 at 01:15
You did not need to manually download the project yourself and follow that other post you found, no. About 6 lines of gradle code, and violà, you've compiled the library and it'll import fine — OneCricketeer, May 26 '17 at 03:09
@cricket_007 I wanna try out the simple method that you've described above. I added the lines of code into my gradle file. Now I just build and thats it? — loltospoon, May 26 '17 at 22:00
@cricket_007 I don't think so because my app crashed when I ran it on my Galaxy S3 phone. — loltospoon, May 26 '17 at 22:25

score 1 · Answer 1 · answered May 26 '17 at 03:12

If you don't want to use the JitPack approach as documented in the instructions, then look at the settings.gradle file in the Github example.

It includes both modules (app and the library).

Then, once that is setup, you can compile project(:libraryName) in the app/build.gradle file's dependencies section. Again, see the Github sample for the syntax.

With those two steps (plus one to download the library), it should be importable within the app code.

score 0 · Answer 2 · answered May 25 '17 at 23:26

0

Assuming you followed along with the other steps on the readme, at the top of your code you need to tell the source file to import the classes:

import com.creativityapps.gmailbackgroundlibrary.BackgroundMail;

public class MainActivity extends AppCompatActivity {
    [your code]
}

I would also recommend looking through the sample code included in the github project

answered May 25 '17 at 23:26

apoteet

742
5
21

This is giving me an error: `error: package com.creativityapps.gmailbackgroundlibrary does not exist` – loltospoon May 26 '17 at 00:23
You need to compile the project first – OneCricketeer May 26 '17 at 01:03
@cricket_007 I did Build -> Make Project – loltospoon May 26 '17 at 01:10

score 0 · Answer 3 · answered May 26 '17 at 03:59

You are doing some wrong steps friend. You can follow this

Find your gradle file with name buid.gradle (Project: [ YOUR_PROJECT_NAME ] ) Then find and add this line

allprojects {
    repositories {
        jcenter()
        maven { url "https://jitpack.io" }
    }
}

You are done 50% now. Now press SHIFT+CTRL+ALT+S and wait for a window.

On the Window, select DEPENDENCY TAB on top.

Click on + BUTTON at top right. Click on Library Dependency.

Now paste com.github.yesidlazaro:GmailBackground:1.2.0 there.

Click on OK and exit the window. Gradle recompiles.

Now simply put your code, If RED syntax error showing, Click at the code where error is showing and when a BLUE pop comes, Press ALT+ENTER.

Everything done..!

How do I begin to use this Java library?

3 Answers3