I am writing an application code for Android for working with a SQLite database. I repeatedly come across error warning

Non-static method 'method ()' cannot be referenced from a static context

First: what is the static context ? In my code (for the time being) there is not a single static method, not a single static variable, except that there is only one static constant for logging.

Here are a couple of examples where such a warning appears:

● addNewItem method for adding a new record to the database (belongs to a separate class for working with the database):

 public TestDB(Context context) { this.context = context; dbHelper = new testDBHelper (context); } public void addNewItem(String title, String noteText){ db = testDBHelper .getWritableDatabase(context); // здесь ContentValues cv = new ContentValues(); cv.put(testDBHelper .KEY_TITLE, title); cv.put(testDBHelper .KEY_TEXT, noteText); cv.put(testDBHelper .KEY_DATE, new Date().getTime()); db.insert(testDBHelper .TABLE_NAME, null, cv); }

● Saving to the database the values ​​entered in the fields (the code belongs to the Activity with input fields):

 String title = editTitle.getText().toString(); String text = editText.getText().toString(); TestDB testDB = new TestDB(AddItemActivity.getApplicationContext()); // здесь testDB.addNewItem(title, note);

I admit that at the moment I almost without understanding work with context , therefore I will be grateful for any explanations.

Constructor

 public TestDB(Context context) { this.context = context; testDBHelper = new TestDBHelper(context); }

in the class to work with the database is available; in Activity with input fields - no.

  • In this case, the error has nothing to do with the Context class - it says that non-static methods cannot refer to a static environment. The getWritableDatabase() method takes no parameters - getWritableDatabase() instead of getWritableDatabase(context) - pavlofff
  • getWritableDatabase () is a method of the SQLiteOpenHelper () class, inherited from TestDBHelper. - Bokov Gleb
  • Here is the code I took as a base. There is no argument. I understand that I should not stupidly repeat after the author of the code, but so far there is not enough understanding. The addNewItem() method was added by me. - Bokov Gleb
  • What getWritableDatabase() you think that you need to pass an instance of the Context class to the getWritableDatabase() method? - pavlofff
  • So, after reading your question, figured it out. In the first case, the context is not really needed. When I mistakenly addressed a class, the word context in the warning was misleading. In the second case, the wrong access to the context; correct will be AddItemActivity.this . Write then, please, in the answer some theoretical comment about the static context, so that I put a check mark on you and this question can be closed. - Bokov Hleb

1 answer 1

In this case, you encountered a compilation error while trying to call the non-static getApplicationContext() method of the getApplicationContext() class by calling static methods

Those. if the method were declared static, there would be no error.

In your case, you need to call a non-static method through a class reference, not through its name, as is done for static methods. The link to the class can be obtained through this or AddItemActivity.this . Then the method call will look like this:

 AddItemActivity.this.getApplicationContext()