findViewById not accepting type argument even with compileSdkVersion 30

Asked By: Anonymous

I generally use kotlin for android but my college wants me to use Java. So I created a new java project in android studio.

The problem is I don’t want to cast the return value of findViewById() manually. Instead I want to pass EditText as type parameter which the function is not accepting as anticipated. I get the error :

/home/onkar/AndroidStudioProjects/MyApplication2/app/src/main/java/io/github/omkar76/myapplication/MainActivity.java:16: error: cannot find symbol
        Log.d("EDITTEXT", findViewById<EditText>(R.id.first_name).getText());
                          ^
  symbol:   variable findViewById
  location: class MainActivity

Why isn’t this working? Why is method not found? I even checked source of AppCompatActivity and it does contain required method:

 @Override
    public <T extends View> T findViewById(@IdRes int id) {
        return getDelegate().findViewById(id);
    }

My Java code is :

public class MainActivity extends AppCompatActivity {

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

        Log.d("EDITTEXT", findViewById<EditText>(R.id.first_name).getText());
    }
}

If I don’t pass type argument EditText, findViewById returns View which then I need to manually cast. According to this post starting with api 26 you don’t need to cast the returned value. I have API 30 SDK. So why this is not working. I am aware of workarounds like assigning return value to an EditText reference but my interest is in knowing why existig approach doesn’t work.

Let me know if any other details are required. Please point out what I am doing wrong. Thanks!


Solution

Answered By: Anonymous

I think you’re confused with the syntax of java.

Here public <T extends View> T findViewById(@ResId int id) means :

return value cast to T, T is resolved with the left side of the assignment declaration before the equals sign. In the following example

Edittext x = view.findViewById(R.id.abc)

So here T get assigned as Edittext as Edittext is on the left side of the assignment declaration which then returns edittext as a view. Then you can call x to getstring.
Hope this makes it clearer

techinplanet staff

techinplanet staff


Windows 10 Kaufen Windows 10 Pro Office 2019 Kaufen Office 365 Lizenz Windows 10 Home Lizenz Office 2019 Home Business Kaufen windows office 365 satın al follower kaufen instagram follower kaufen porno