检索JSON数据的有效方式/正确方法

Question

我是Android Studio新手，我正在尝试从Github API请求API数据（例如https://api.github.com/users/froala）并显示在我的应用中。

我以某种方式让应用程序通过执行以下操作从API检索JSON：

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);
        }
    }
}

看起来像：

现在我只需要使用它来解析JSON。但问题是，当我在JSON中使用不同的URL（如https://api.github.com/users/froala/repos）时，检索JSON数据不起作用，并且单击按钮时应用程序不显示任何内容。这很奇怪，因为/ users / id页面和/ users / id / repos页面都是JSON，似乎没有那么不同。我不知道为什么另一个不起作用。

两个问题：

1. 我是否使用正确的方法从API中检索JSON？
2. 为什么另一个链接（https://api.github.com/users/froala/repos）无法使用我的代码实现？

请帮忙！我真的很困惑。

Answer 1

1. 您可以使用Retrofit并从URL获取数据：

   您可以参考：

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

2. 您可以使用上面的对象

使用您的JSON字符串，我使用http://www.jsonschema2pojo.org/并创建对象：

$ ((... above with mod pasted into terminal ...)
apple-dns.net

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

-----------------------------------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;
}

}

使用Retrofit，例如：

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;
}

}

我希望它能帮到你解决问题！

Answer 2

像Retrofit这样的第三方库当然更好地工作，然后手动迭代数据，但是如果你不愿意这样做，你可以按照这个过程检索结果，如果结果数据是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());
    }
}

如果结果数据是JSONArray，那么您需要以这种方式解析它：

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){

    }
}

根据 onPostExecute（..）

中的结果数据调用该函数

    @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)
    }