JSONObject 的 java.lang.NullPointerException 错误

Question

我在这一行遇到了 java.lang.NullPointerException pdao.majPost(c);当我尝试从 API 获取帖子并尝试将帖子插入我的 SQLite 数据库时。

我的 JSON 解析器类:

private PostsDAO pdao;

public void data() {

    AsyncHttpClient client = new AsyncHttpClient();
    client.get("http://twitter.192.168.1.38.xip.io/api/v1/posts", new AsyncHttpResponseHandler() {
        @Override
        public void onSuccess(String response) {

            JSONObject data;
            JSONArray posts;
            try {
                data = new JSONObject(response);

                // Traitement des posts
                posts = data.getJSONArray("posts");
                for (int i = 0; i < posts.length(); i++) {
                    JSONObject c = posts.getJSONObject(i);
                    pdao.majPost(c);
                }

            } catch (JSONException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }

        }
    });

}

我的 PostDAO 文件

public void majPost(JSONObject c) throws JSONException {
    ContentValues values = new ContentValues();
    values.put("id_post", c.getInt("id_post"));
    values.put("id_user", c.getInt("id_user"));
    values.put("content", c.getString("content"));
    values.put("photo", c.getString("photo"));
    values.put("masked", c.getInt("masked"));
    values.put("deleted", c.getInt("deleted"));
    values.put("created_at", c.getString("created_at"));
    values.put("updated_at", c.getString("updated_at"));
    db.insert("posts", null, values);
}

Answer 1

与以下人员合作

PostsDAO pdao = new PostsDAO();

因为你从未初始化过pdao

 PostsDAO pdao=null;

比初始化

pdao = new PostsDAO();