its a very simple code yet it cant run
ArrayAdapter<CharSequence> adapter = ArrayAdapter.createFromResource(this,R.array.Categories, android.R.layout.simple_spinner_item);
adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
itemCat.setAdapter(adapter);
Ive named my spinner itemCat, array as Categories and adapter as adapter.
Process: com.example.myapplication, PID: 3716 java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.myapplication/com.example.myapplication.item_register}: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.Spinner.setAdapter(android.widget.SpinnerAdapter)' on a null object reference
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.Spinner.setAdapter(android.widget.SpinnerAdapter)' on a null object reference
You have to first create the view then call the methods.
Secondly, the spinner should be created under the onCreate()
.
某些东西是空的,导致这次崩溃。我猜你的 itemCat 是空的,你没有创建它。
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