When to call findViewById in an Activity

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我在风中等你
我在风中等你 2021-01-28 12:54

I am encountering the following issue. I have the following lines of code :

Spinner domainSpinner = (Spinner) findViewById(R.id.domain);
domainSpinner.setVisibi         


        
2条回答
  •  陌清茗
    陌清茗 (楼主)
    2021-01-28 13:16

    You should always initialise your views on the OnCreate method in an activity to make sure the view exists when you want to reference it. Like below:

    private Spinner domainSpinner;
    
    @Override
        protected void onCreate(final Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_main);
            domainSpinner = (Spinner) findViewById(R.id.domain);
        }
    

    Let me know if this helps!

    UPDATE: If you need to use the variable outside of the on create method, then declare a global variable and still initialise it on create, then use it where needed.

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