我在第29行(private ListView lv = (ListView) findViewById(R.id.ScanList);)获得了NPE ,但我想这是因为以下行:
this.adapter = new SimpleAdapter(ScannerActivity.this, arraylist, R.layout.row, new String[] { ITEM_KEY }, new int[] { R.id.list_value });
什么属于"R.id.list_value"和"R.layout.row"它是一个row.xml？我不知道我在那里写的东西!
要知道代码是如何工作的,我粘贴一个relvant部分:
public class ScannerActivity extends Activity implements OnClickListener {
private WifiManager wifi;
private ListView lv = (ListView) findViewById(R.id.ScanList);
private Button buttonScan = (Button) findViewById(R.id.scannow_button);
private Switch enable;
private int size = 0;
private List<ScanResult> results;
private final String ITEM_KEY = "key";
private final ArrayList<HashMap<String, String>> arraylist = new ArrayList<HashMap<String, String>>();
private SimpleAdapter adapter;
/* …