Switch findViewById returns null

Question

I am trying 2 days to solve this problem. I made a fragment in which I made a switch to enable and disable bluetooth. Well in my main activity i wrote:

bluetoothSwitch = (Switch) findViewById(R.id.bluetooth_switch);
bluetoothSwitch.setOnClickListener(clicked);

where clicked:

clicked = new ButtonClicked();

and:

class ButtonClicked implements AdapterView.OnClickListener
{
    @Override
    public void onClick(View view) {
        switch (view.getId()) {
            case R.id.bluetooth_switch:
                if (bluetoothAdapter.isEnabled()){
                    bluetoothAdapter.disable();
                    Log.d("Log", "Bluetooth is disabled");
                }
                else{
                    bluetoothAdapter.enable();
                    Log.d("Log", "Bluetooth is enabled");
                }
                break;
            case R.id.buttonSearch:
                arrayListBluetoothDevices.clear();
                startSearching();
                break;
            case R.id.discoverable_switch:
                makeDiscoverable();
                break;
            default:
                break;
        }
    }
}

when I run it the findViewById return null...Do you have any idea???

Where exactly is `R.id.bluetooth_switch` located? In your Activity or Fragment. Because right now you are searching in Activity. — Murat Karagöz, Jul 25 '16 at 15:42
Show your xml file for both your fragment and the activity hat contains it — user3793589, Jul 25 '16 at 15:43

score 2 · Accepted Answer · edited May 23 '17 at 10:28

2

What you're trying to do won't work - your findViewByID looks for the view inside your activity xml but the view (R.id.bluetooth_switch) is inside the fragment's xml.
Look on this SO answer for code implementation.

edited May 23 '17 at 10:28

Community

1
1

answered Jul 25 '16 at 15:45

Nir Duan

6,164
4
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score 0 · Answer 2 · answered Jul 25 '16 at 15:46

0

"findViewById" returns null when the provided id (in your example, it's called "bluetooth_switch") doesn't exist in the "resource tree" of the current container

answered Jul 25 '16 at 15:46

hello404

22
2

score 0 · Answer 3 · answered Jul 25 '16 at 16:30

0

I solved it moving these lines of code to my fragment java file. Thanks.

answered Jul 25 '16 at 16:30

Χρήστος Γεωργακίδης

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score 0 · Answer 4 · answered Dec 01 '21 at 07:07

0

In my case, had called setId() on the view for tracking, and so findViewById returns null. Maybe might help someone

answered Dec 01 '21 at 07:07

N. Kyalo

47
3

Switch findViewById returns null

4 Answers4