Efficient way / right way to retrieve JSON data

Question

I am new to Android Studio, and I am trying to request API data from the Github API (e.g. https://api.github.com/users/froala) and display in my app.

I somehow made the app retrieve the JSON from the API by doing:

public class MainActivity extends AppCompatActivity {

    private TextView tvData;
    private static final String TAG = "MainActivity";

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

        Log.d(TAG, "onCreate: Starting.");


        // Set up the ViewPager with the sections adapter


        // Github tab

        Button buttonHit = (Button) findViewById(R.id.buttonHit);
        tvData = (TextView) findViewById(R.id.tvJsonItem);

        buttonHit.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

                new JSONTask().execute("https://api.github.com/users/froala");

            }
        });

    }


    public class JSONTask extends AsyncTask<String, String, String> {
        @Override
        protected String doInBackground(String... params) {

            HttpURLConnection connection = null;
            BufferedReader reader = null;

            try {
                // Pass in a String and convert to URL
                URL url = new URL(params[0]);
                connection = (HttpURLConnection) url.openConnection();
                connection.connect();

                InputStream stream = connection.getInputStream();

                // for reading data line by line
                reader = new BufferedReader(new InputStreamReader(stream));
                StringBuffer strBuffer = new StringBuffer();


                String line = "";
                while ((line = reader.readLine()) != null) {
                    strBuffer.append(line);
                }

                // If we are able to get the data

                String retreivedJson = strBuffer.toString();
                JSONObject parentObject = new JSONObject(retreivedJson);
                JsonReader jsonReader = new JsonReader(responseBody);

                return retreivedJson;

            } catch (MalformedURLException e) {
                e.printStackTrace();
            } catch (IOException e) {
                e.printStackTrace();
            } catch (JSONException e) {
                e.printStackTrace();
            } finally {
                //cant close null

                if (connection != null) {
                    // close both connection and the reader
                    connection.disconnect();
                }
                try {
                    if (reader != null) {
                        reader.close();
                    }

                } catch (IOException e) {
                    e.printStackTrace();
                }
            }

            return null;

        }

        @Override
        protected void onPostExecute(String result) {
            super.onPostExecute(result);
            tvData.setText(result);
        }
    }
}

In it looks like:

Now I just need to use this to parse the JSON. But the problem is, when I use a different URL in the JSON like https://api.github.com/users/froala/repos, retrieving the JSON data does not work and the app displays nothing when the buttons is clicked. This is weird because /users/id page and the /users/id/repos page are both JSONs and do not seem that different. I don't know why the other one does not work.

Two questions:

1. Am I using the right way to retrieve JSON from the API?
2. Why is the other link (https://api.github.com/users/froala/repos) not working with my code implementation?

Please help! I am really confused.

Answer 1

1. You can use Retrofit and get data from URL:

   You can refer to :

   https://www.androidhive.info/2016/05/android-working-with-retrofit-http-library/

2. You can use the object above

With your JSON string, i use http://www.jsonschema2pojo.org/ and create object :

-----------------------------------com.example.Example.java-----------------------------------

package com.example;

import com.google.gson.annotations.Expose;
import com.google.gson.annotations.SerializedName;

public class Example {

@SerializedName("id")
@Expose
private Integer id;
@SerializedName("name")
@Expose
private String name;
@SerializedName("full_name")
@Expose
private String fullName;
@SerializedName("owner")
@Expose
private Owner owner;
@SerializedName("private")
@Expose
private Boolean _private;
@SerializedName("html_url")
@Expose
private String htmlUrl;
@SerializedName("description")
@Expose
private String description;
@SerializedName("fork")
@Expose
private Boolean fork;
@SerializedName("url")
@Expose
private String url;
@SerializedName("forks_url")
@Expose
private String forksUrl;
@SerializedName("keys_url")
@Expose
private String keysUrl;
@SerializedName("collaborators_url")
@Expose
private String collaboratorsUrl;
@SerializedName("teams_url")
@Expose
private String teamsUrl;
@SerializedName("hooks_url")
@Expose
private String hooksUrl;
@SerializedName("issue_events_url")
@Expose
private String issueEventsUrl;
@SerializedName("events_url")
@Expose
private String eventsUrl;
@SerializedName("assignees_url")
@Expose
private String assigneesUrl;
@SerializedName("branches_url")
@Expose
private String branchesUrl;
@SerializedName("tags_url")
@Expose
private String tagsUrl;
@SerializedName("blobs_url")
@Expose
private String blobsUrl;
@SerializedName("git_tags_url")
@Expose
private String gitTagsUrl;
@SerializedName("git_refs_url")
@Expose
private String gitRefsUrl;
@SerializedName("trees_url")
@Expose
private String treesUrl;
@SerializedName("statuses_url")
@Expose
private String statusesUrl;
@SerializedName("languages_url")
@Expose
private String languagesUrl;
@SerializedName("stargazers_url")
@Expose
private String stargazersUrl;
@SerializedName("contributors_url")
@Expose
private String contributorsUrl;
@SerializedName("subscribers_url")
@Expose
private String subscribersUrl;
@SerializedName("subscription_url")
@Expose
private String subscriptionUrl;
@SerializedName("commits_url")
@Expose
private String commitsUrl;
@SerializedName("git_commits_url")
@Expose
private String gitCommitsUrl;
@SerializedName("comments_url")
@Expose
private String commentsUrl;
@SerializedName("issue_comment_url")
@Expose
private String issueCommentUrl;
@SerializedName("contents_url")
@Expose
private String contentsUrl;
@SerializedName("compare_url")
@Expose
private String compareUrl;
@SerializedName("merges_url")
@Expose
private String mergesUrl;
@SerializedName("archive_url")
@Expose
private String archiveUrl;
@SerializedName("downloads_url")
@Expose
private String downloadsUrl;
@SerializedName("issues_url")
@Expose
private String issuesUrl;
@SerializedName("pulls_url")
@Expose
private String pullsUrl;
@SerializedName("milestones_url")
@Expose
private String milestonesUrl;
@SerializedName("notifications_url")
@Expose
private String notificationsUrl;
@SerializedName("labels_url")
@Expose
private String labelsUrl;
@SerializedName("releases_url")
@Expose
private String releasesUrl;
@SerializedName("deployments_url")
@Expose
private String deploymentsUrl;
@SerializedName("created_at")
@Expose
private String createdAt;
@SerializedName("updated_at")
@Expose
private String updatedAt;
@SerializedName("pushed_at")
@Expose
private String pushedAt;
@SerializedName("git_url")
@Expose
private String gitUrl;
@SerializedName("ssh_url")
@Expose
private String sshUrl;
@SerializedName("clone_url")
@Expose
private String cloneUrl;
@SerializedName("svn_url")
@Expose
private String svnUrl;
@SerializedName("homepage")
@Expose
private String homepage;
@SerializedName("size")
@Expose
private Integer size;
@SerializedName("stargazers_count")
@Expose
private Integer stargazersCount;
@SerializedName("watchers_count")
@Expose
private Integer watchersCount;
@SerializedName("language")
@Expose
private String language;
@SerializedName("has_issues")
@Expose
private Boolean hasIssues;
@SerializedName("has_projects")
@Expose
private Boolean hasProjects;
@SerializedName("has_downloads")
@Expose
private Boolean hasDownloads;
@SerializedName("has_wiki")
@Expose
private Boolean hasWiki;
@SerializedName("has_pages")
@Expose
private Boolean hasPages;
@SerializedName("forks_count")
@Expose
private Integer forksCount;
@SerializedName("mirror_url")
@Expose
private Object mirrorUrl;
@SerializedName("archived")
@Expose
private Boolean archived;
@SerializedName("open_issues_count")
@Expose
private Integer openIssuesCount;
@SerializedName("forks")
@Expose
private Integer forks;
@SerializedName("open_issues")
@Expose
private Integer openIssues;
@SerializedName("watchers")
@Expose
private Integer watchers;
@SerializedName("default_branch")
@Expose
private String defaultBranch;

public Integer getId() {
return id;
}

public void setId(Integer id) {
this.id = id;
}

public String getName() {
return name;
}

public void setName(String name) {
this.name = name;
}

public String getFullName() {
return fullName;
}

public void setFullName(String fullName) {
this.fullName = fullName;
}

public Owner getOwner() {
return owner;
}

public void setOwner(Owner owner) {
this.owner = owner;
}

public Boolean getPrivate() {
return _private;
}

public void setPrivate(Boolean _private) {
this._private = _private;
}

public String getHtmlUrl() {
return htmlUrl;
}

public void setHtmlUrl(String htmlUrl) {
this.htmlUrl = htmlUrl;
}

public String getDescription() {
return description;
}

public void setDescription(String description) {
this.description = description;
}

public Boolean getFork() {
return fork;
}

public void setFork(Boolean fork) {
this.fork = fork;
}

public String getUrl() {
return url;
}

public void setUrl(String url) {
this.url = url;
}

public String getForksUrl() {
return forksUrl;
}

public void setForksUrl(String forksUrl) {
this.forksUrl = forksUrl;
}

public String getKeysUrl() {
return keysUrl;
}

public void setKeysUrl(String keysUrl) {
this.keysUrl = keysUrl;
}

public String getCollaboratorsUrl() {
return collaboratorsUrl;
}

public void setCollaboratorsUrl(String collaboratorsUrl) {
this.collaboratorsUrl = collaboratorsUrl;
}

public String getTeamsUrl() {
return teamsUrl;
}

public void setTeamsUrl(String teamsUrl) {
this.teamsUrl = teamsUrl;
}

public String getHooksUrl() {
return hooksUrl;
}

public void setHooksUrl(String hooksUrl) {
this.hooksUrl = hooksUrl;
}

public String getIssueEventsUrl() {
return issueEventsUrl;
}

public void setIssueEventsUrl(String issueEventsUrl) {
this.issueEventsUrl = issueEventsUrl;
}

public String getEventsUrl() {
return eventsUrl;
}

public void setEventsUrl(String eventsUrl) {
this.eventsUrl = eventsUrl;
}

public String getAssigneesUrl() {
return assigneesUrl;
}

public void setAssigneesUrl(String assigneesUrl) {
this.assigneesUrl = assigneesUrl;
}

public String getBranchesUrl() {
return branchesUrl;
}

public void setBranchesUrl(String branchesUrl) {
this.branchesUrl = branchesUrl;
}

public String getTagsUrl() {
return tagsUrl;
}

public void setTagsUrl(String tagsUrl) {
this.tagsUrl = tagsUrl;
}

public String getBlobsUrl() {
return blobsUrl;
}

public void setBlobsUrl(String blobsUrl) {
this.blobsUrl = blobsUrl;
}

public String getGitTagsUrl() {
return gitTagsUrl;
}

public void setGitTagsUrl(String gitTagsUrl) {
this.gitTagsUrl = gitTagsUrl;
}

public String getGitRefsUrl() {
return gitRefsUrl;
}

public void setGitRefsUrl(String gitRefsUrl) {
this.gitRefsUrl = gitRefsUrl;
}

public String getTreesUrl() {
return treesUrl;
}

public void setTreesUrl(String treesUrl) {
this.treesUrl = treesUrl;
}

public String getStatusesUrl() {
return statusesUrl;
}

public void setStatusesUrl(String statusesUrl) {
this.statusesUrl = statusesUrl;
}

public String getLanguagesUrl() {
return languagesUrl;
}

public void setLanguagesUrl(String languagesUrl) {
this.languagesUrl = languagesUrl;
}

public String getStargazersUrl() {
return stargazersUrl;
}

public void setStargazersUrl(String stargazersUrl) {
this.stargazersUrl = stargazersUrl;
}

public String getContributorsUrl() {
return contributorsUrl;
}

public void setContributorsUrl(String contributorsUrl) {
this.contributorsUrl = contributorsUrl;
}

public String getSubscribersUrl() {
return subscribersUrl;
}

public void setSubscribersUrl(String subscribersUrl) {
this.subscribersUrl = subscribersUrl;
}

public String getSubscriptionUrl() {
return subscriptionUrl;
}

public void setSubscriptionUrl(String subscriptionUrl) {
this.subscriptionUrl = subscriptionUrl;
}

public String getCommitsUrl() {
return commitsUrl;
}

public void setCommitsUrl(String commitsUrl) {
this.commitsUrl = commitsUrl;
}

public String getGitCommitsUrl() {
return gitCommitsUrl;
}

public void setGitCommitsUrl(String gitCommitsUrl) {
this.gitCommitsUrl = gitCommitsUrl;
}

public String getCommentsUrl() {
return commentsUrl;
}

public void setCommentsUrl(String commentsUrl) {
this.commentsUrl = commentsUrl;
}

public String getIssueCommentUrl() {
return issueCommentUrl;
}

public void setIssueCommentUrl(String issueCommentUrl) {
this.issueCommentUrl = issueCommentUrl;
}

public String getContentsUrl() {
return contentsUrl;
}

public void setContentsUrl(String contentsUrl) {
this.contentsUrl = contentsUrl;
}

public String getCompareUrl() {
return compareUrl;
}

public void setCompareUrl(String compareUrl) {
this.compareUrl = compareUrl;
}

public String getMergesUrl() {
return mergesUrl;
}

public void setMergesUrl(String mergesUrl) {
this.mergesUrl = mergesUrl;
}

public String getArchiveUrl() {
return archiveUrl;
}

public void setArchiveUrl(String archiveUrl) {
this.archiveUrl = archiveUrl;
}

public String getDownloadsUrl() {
return downloadsUrl;
}

public void setDownloadsUrl(String downloadsUrl) {
this.downloadsUrl = downloadsUrl;
}

public String getIssuesUrl() {
return issuesUrl;
}

public void setIssuesUrl(String issuesUrl) {
this.issuesUrl = issuesUrl;
}

public String getPullsUrl() {
return pullsUrl;
}

public void setPullsUrl(String pullsUrl) {
this.pullsUrl = pullsUrl;
}

public String getMilestonesUrl() {
return milestonesUrl;
}

public void setMilestonesUrl(String milestonesUrl) {
this.milestonesUrl = milestonesUrl;
}

public String getNotificationsUrl() {
return notificationsUrl;
}

public void setNotificationsUrl(String notificationsUrl) {
this.notificationsUrl = notificationsUrl;
}

public String getLabelsUrl() {
return labelsUrl;
}

public void setLabelsUrl(String labelsUrl) {
this.labelsUrl = labelsUrl;
}

public String getReleasesUrl() {
return releasesUrl;
}

public void setReleasesUrl(String releasesUrl) {
this.releasesUrl = releasesUrl;
}

public String getDeploymentsUrl() {
return deploymentsUrl;
}

public void setDeploymentsUrl(String deploymentsUrl) {
this.deploymentsUrl = deploymentsUrl;
}

public String getCreatedAt() {
return createdAt;
}

public void setCreatedAt(String createdAt) {
this.createdAt = createdAt;
}

public String getUpdatedAt() {
return updatedAt;
}

public void setUpdatedAt(String updatedAt) {
this.updatedAt = updatedAt;
}

public String getPushedAt() {
return pushedAt;
}

public void setPushedAt(String pushedAt) {
this.pushedAt = pushedAt;
}

public String getGitUrl() {
return gitUrl;
}

public void setGitUrl(String gitUrl) {
this.gitUrl = gitUrl;
}

public String getSshUrl() {
return sshUrl;
}

public void setSshUrl(String sshUrl) {
this.sshUrl = sshUrl;
}

public String getCloneUrl() {
return cloneUrl;
}

public void setCloneUrl(String cloneUrl) {
this.cloneUrl = cloneUrl;
}

public String getSvnUrl() {
return svnUrl;
}

public void setSvnUrl(String svnUrl) {
this.svnUrl = svnUrl;
}

public String getHomepage() {
return homepage;
}

public void setHomepage(String homepage) {
this.homepage = homepage;
}

public Integer getSize() {
return size;
}

public void setSize(Integer size) {
this.size = size;
}

public Integer getStargazersCount() {
return stargazersCount;
}

public void setStargazersCount(Integer stargazersCount) {
this.stargazersCount = stargazersCount;
}

public Integer getWatchersCount() {
return watchersCount;
}

public void setWatchersCount(Integer watchersCount) {
this.watchersCount = watchersCount;
}

public String getLanguage() {
return language;
}

public void setLanguage(String language) {
this.language = language;
}

public Boolean getHasIssues() {
return hasIssues;
}

public void setHasIssues(Boolean hasIssues) {
this.hasIssues = hasIssues;
}

public Boolean getHasProjects() {
return hasProjects;
}

public void setHasProjects(Boolean hasProjects) {
this.hasProjects = hasProjects;
}

public Boolean getHasDownloads() {
return hasDownloads;
}

public void setHasDownloads(Boolean hasDownloads) {
this.hasDownloads = hasDownloads;
}

public Boolean getHasWiki() {
return hasWiki;
}

public void setHasWiki(Boolean hasWiki) {
this.hasWiki = hasWiki;
}

public Boolean getHasPages() {
return hasPages;
}

public void setHasPages(Boolean hasPages) {
this.hasPages = hasPages;
}

public Integer getForksCount() {
return forksCount;
}

public void setForksCount(Integer forksCount) {
this.forksCount = forksCount;
}

public Object getMirrorUrl() {
return mirrorUrl;
}

public void setMirrorUrl(Object mirrorUrl) {
this.mirrorUrl = mirrorUrl;
}

public Boolean getArchived() {
return archived;
}

public void setArchived(Boolean archived) {
this.archived = archived;
}

public Integer getOpenIssuesCount() {
return openIssuesCount;
}

public void setOpenIssuesCount(Integer openIssuesCount) {
this.openIssuesCount = openIssuesCount;
}

public Integer getForks() {
return forks;
}

public void setForks(Integer forks) {
this.forks = forks;
}

public Integer getOpenIssues() {
return openIssues;
}

public void setOpenIssues(Integer openIssues) {
this.openIssues = openIssues;
}

public Integer getWatchers() {
return watchers;
}

public void setWatchers(Integer watchers) {
this.watchers = watchers;
}

public String getDefaultBranch() {
return defaultBranch;
}

public void setDefaultBranch(String defaultBranch) {
this.defaultBranch = defaultBranch;
}

}

-----------------------------------com.example.Owner.java-----------------------------------

package com.example;

import com.google.gson.annotations.Expose;
import com.google.gson.annotations.SerializedName;

public class Owner {

@SerializedName("login")
@Expose
private String login;
@SerializedName("id")
@Expose
private Integer id;
@SerializedName("avatar_url")
@Expose
private String avatarUrl;
@SerializedName("gravatar_id")
@Expose
private String gravatarId;
@SerializedName("url")
@Expose
private String url;
@SerializedName("html_url")
@Expose
private String htmlUrl;
@SerializedName("followers_url")
@Expose
private String followersUrl;
@SerializedName("following_url")
@Expose
private String followingUrl;
@SerializedName("gists_url")
@Expose
private String gistsUrl;
@SerializedName("starred_url")
@Expose
private String starredUrl;
@SerializedName("subscriptions_url")
@Expose
private String subscriptionsUrl;
@SerializedName("organizations_url")
@Expose
private String organizationsUrl;
@SerializedName("repos_url")
@Expose
private String reposUrl;
@SerializedName("events_url")
@Expose
private String eventsUrl;
@SerializedName("received_events_url")
@Expose
private String receivedEventsUrl;
@SerializedName("type")
@Expose
private String type;
@SerializedName("site_admin")
@Expose
private Boolean siteAdmin;

public String getLogin() {
return login;
}

public void setLogin(String login) {
this.login = login;
}

public Integer getId() {
return id;
}

public void setId(Integer id) {
this.id = id;
}

public String getAvatarUrl() {
return avatarUrl;
}

public void setAvatarUrl(String avatarUrl) {
this.avatarUrl = avatarUrl;
}

public String getGravatarId() {
return gravatarId;
}

public void setGravatarId(String gravatarId) {
this.gravatarId = gravatarId;
}

public String getUrl() {
return url;
}

public void setUrl(String url) {
this.url = url;
}

public String getHtmlUrl() {
return htmlUrl;
}

public void setHtmlUrl(String htmlUrl) {
this.htmlUrl = htmlUrl;
}

public String getFollowersUrl() {
return followersUrl;
}

public void setFollowersUrl(String followersUrl) {
this.followersUrl = followersUrl;
}

public String getFollowingUrl() {
return followingUrl;
}

public void setFollowingUrl(String followingUrl) {
this.followingUrl = followingUrl;
}

public String getGistsUrl() {
return gistsUrl;
}

public void setGistsUrl(String gistsUrl) {
this.gistsUrl = gistsUrl;
}

public String getStarredUrl() {
return starredUrl;
}

public void setStarredUrl(String starredUrl) {
this.starredUrl = starredUrl;
}

public String getSubscriptionsUrl() {
return subscriptionsUrl;
}

public void setSubscriptionsUrl(String subscriptionsUrl) {
this.subscriptionsUrl = subscriptionsUrl;
}

public String getOrganizationsUrl() {
return organizationsUrl;
}

public void setOrganizationsUrl(String organizationsUrl) {
this.organizationsUrl = organizationsUrl;
}

public String getReposUrl() {
return reposUrl;
}

public void setReposUrl(String reposUrl) {
this.reposUrl = reposUrl;
}

public String getEventsUrl() {
return eventsUrl;
}

public void setEventsUrl(String eventsUrl) {
this.eventsUrl = eventsUrl;
}

public String getReceivedEventsUrl() {
return receivedEventsUrl;
}

public void setReceivedEventsUrl(String receivedEventsUrl) {
this.receivedEventsUrl = receivedEventsUrl;
}

public String getType() {
return type;
}

public void setType(String type) {
this.type = type;
}

public Boolean getSiteAdmin() {
return siteAdmin;
}

public void setSiteAdmin(Boolean siteAdmin) {
this.siteAdmin = siteAdmin;
}

}

And using Retrofit, ex:

 Call<Example> call = apiService.getData(URL);


    call.enqueue(new Callback<Example>() {
        @Override
        public void onResponse(Call<Example> call, Response<Example> response) {

            Log.d(TAG, "response.body(): " + response.body().getExample());


        }

        @Override
        public void onFailure(Call<Example> call, Throwable t) {
            // Log error here since request failed

            Log.e(TAG, t.toString());
        }
    });

I hope it will help your problem!

Answer 2

Third party libraries like Retrofit of course work better then iterating through the data manually, but in case you're not willing to go through that way you could follow this procedure to retrieve results if the resulting data is an JSONObject:

public void formatJSONObjectData(String results){
    try {
        JSONObject jsonObject = new JSONObject(results);
        if(jsonObject.optString("login")!=null)
            tvData.append(jsonObject.getString("login"));
        if (jsonObject.optInt("id")!=null)
            tvData.append(jsonObject.getString("id"));
        if(jsonObject.optString("avatar_url")!=null)
            tvData.append(jsonObject.getString("avatar_url"));

        //you could accordingly retrieve the results from the jsonObject for a specfic key and append it to the TextView
    }catch (JSONException jsonException){
        Log.e("Error",jsonException.getMessage());
    }
}

If the resulting data is JSONArray then you need to parse it in this way:

public void formatJSONArray(String results){
    try {
        JSONArray jsonArray = new JSONArray(results);
        for(int i=0;i<jsonArray.length();i++){
            JSONObject jsonObject=jsonArray.getJSONObject(i);
            if(jsonObject.optString("name")!=null)
                tvData.append(jsonObject.getString("name"));
            if (jsonObject.optInt("id")!=null)
                tvData.append(jsonObject.getString("id"));
            if(jsonObject.optString("full_name")!=null)
                tvData.append(jsonObject.getString("full_name"));

            if(jsonObject.optJSONObject("owner")!=null){
                JSONObject ownerObject=jsonObject.getJSONObject("owner");
                if(ownerObject.optString("login")!=null)
                    tvData.append(ownerObject.getString("login"));
                if (ownerObject.optInt("id")!=null)
                    tvData.append(ownerObject.getString("id"));
                if(jsonObject.optString("avatar_url")!=null)
                    tvData.append(ownerObject.getString("avatar_url"));
            }
        }
    }catch (JSONException jsonException){

    }
}

Call the function as per your resulting data from your onPostExecute(..)

    @Override
    protected void onPostExecute(String result) {
        super.onPostExecute(result);
       /* for JSONObject data*/
       if(result!=null && !result.isEmpty()) 
            formatJSONData(result)


       /* for JSONArray data*/
       if(result!=null && !result.isEmpty()) 
            formatJSONArray(result)
    }