Flutter 和 Dart - 如何仅从列表中复制一个项目并将此项目添加到另一个列表中？

Question

Hi I am trying to copy only one item from a list into another list.

Example 1: listFinalDevices = listDevices.map((index) => index).toList(); works a bit, but this overwrites the listFinalDevice every time, I need to add the selected Item from the listDevice. As a kind of favorite device list.

Example 2: listFinalDevices.insertAll(listFinalDevices.length,listDevices.map((index) => index).toList()); This copy the complete list but I need only the over index referenced item.

Can someone give me a link to an example or what are the keywords for what I have to search.

UPDADTE: To make it more clearer, currently I have the following data in the list named listDevices:

[ScanResult{device: BluetoothDevice{id: 4D:55:F7:CE:03:FA, name: , type: BluetoothDeviceType.unknown, isDiscoveringServices: false, _services: [], advertisementData: AdvertisementData{localName: , txPowerLevel: null, connectable: true, manufacturerData: {}, serviceData: {0000fd6f-0000-1000-8000-00805f9b34fb: [215, 226, 39, 186, 231, 145, 9, 162, 217, 184, 33, 163, 133, 92, 23, 221, 40, 117, 217, 176]}, serviceUuids: [0000fd6f-0000-1000-8000-00805f9b34fb]}, rssi: -65}, ScanResult{device: BluetoothDevice{id: 00:80:E1:21:C4:B5, name: P2PSRV1, type: BluetoothDeviceType.le, isDiscoveringServices: false, _services: [], advertisementData: AdvertisementData{localName: P2PSRV1, txPowerLevel: null, connectable: true, manufacturerData: {33537: [0, 0, 32, 0, 0, 128, 225, 33, 196, 181]}, serviceData: {}, serviceUuids: []}, rssi: -35}, ScanResult{device: BluetoothDevice{id: 60:29:4D:9B:AC:52, name: , type: BluetoothDeviceType.unknown, isDiscoveringServices: false, _services: [], advertisementData: Adver

The target is, that I chose some Devices and put this to a kind of favorite list which should named with listFinalDevices:

[ScanResult{device: BluetoothDevice{id: 00:80:E1:21:C4:B5, name: P2PSRV1, type: BluetoothDeviceType.le, isDiscoveringServices: false, _services: [], advertisementData: AdvertisementData{localName: P2PSRV1, txPowerLevel: null, connectable: true, manufacturerData: {33537: [0, 0, 32, 0, 0, 128, 225, 33, 196, 181]}, serviceData: {}, serviceUuids: []}, rssi: -35}, ScanResult{device: BluetoothDevice{id: C5:9F:97:96:4A:A9, name: MX Anywhere 2S, type: BluetoothDeviceType.le, isDiscoveringServices: false, _services: [], advertisementData: AdvertisementData{localName: MX Anywhere 2S, txPowerLevel: 4, connectable: false, manufacturerData: {}, serviceData: {}, serviceUuids: [00001812-0000-1000-8000-00805f9b34fb]}, rssi: -50}] is not empty

Answer 1

listFinalDevices.add(listDevices[index])

Could you be clearer? You wanted to add object at index from another list to final list, right?

or maybe:

listFinalDevices.add(listDevices[listDevices.indexWhere((el) => el == index)])