[英]how to get an array outside of an if statement and for loop
我正在開發應用程序,但遇到了問題……我無法在if語句之外訪問數組……這是我的代碼:
public class MainActivity extends Activity {
TextView textLat;
TextView textLong;
TextView textChange;
TextView testid;
float gpsSpeed = 0;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
textLat = (TextView)findViewById(R.id.textLat);
textLong = (TextView)findViewById(R.id.textLong);
textChange = (TextView)findViewById(R.id.textChange);
testid = (TextView)findViewById(R.id.testid);
LocationManager lm = (LocationManager)getSystemService(Context.LOCATION_SERVICE);
LocationListener ll = new mylocationlistener();
lm.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0, 0, ll);
}
@SuppressWarnings("unchecked")
public static void main(String argv[]) {
try {
File fXmlFile = new File("/Users/mkyong/staff.xml");
DocumentBuilderFactory dbFactory = DocumentBuilderFactory.newInstance();
DocumentBuilder dBuilder = dbFactory.newDocumentBuilder();
Document doc = dBuilder.parse(fXmlFile);
//optional, but recommended
//read this - http://stackoverflow.com/questions/13786607/normalization-in-dom-parsing-with-java-how-does-it-work
doc.getDocumentElement().normalize();
NodeList nList = doc.getElementsByTagName("station");
int rows = nList.getLength();
int cols = 9;
for (int temp = 0; temp < nList.getLength(); temp++) {
Node nNode = nList.item(temp);
if (nNode.getNodeType() == Node.ELEMENT_NODE) {
Element eElement = (Element) nNode;
String[][]options = new String[cols][rows];
options[0][0] = eElement.getElementsByTagName("name").item(0).getTextContent();
options[1][0] = eElement.getElementsByTagName("code").item(0).getTextContent();
options[2][0] = eElement.getElementsByTagName("lat").item(0).getTextContent();
options[3][0] = eElement.getElementsByTagName("long").item(0).getTextContent();
options[4][0] = eElement.getElementsByTagName("longlat").item(0).getTextContent();
options[5][0] = eElement.getElementsByTagName("uziadvies").item(0).getTextContent();
options[6][0] = eElement.getElementsByTagName("bijzonderheden").item(0).getTextContent();
options[7][0] = eElement.getElementsByTagName("ref").item(0).getTextContent();
options[8][0] = eElement.getElementsByTagName("groterkleiner").item(0).getTextContent();
}
}
} catch (Exception e) {
e.printStackTrace();
}
}
class mylocationlistener implements LocationListener {
@Override
public void onLocationChanged(Location location) {
if(location != null)
{
double pLong = location.getLongitude();
double pLat = location.getLatitude();
gpsSpeed = ((location.getSpeed()*3600)/1000);
textLat.setText(Double.toString(pLat));
textLong.setText("jo");
double compareLatCoords = 51.704704;
double compareLongCoords = 4.854369;
testid.setText(Float.toString(gpsSpeed));
if (pLat <= compareLatCoords)
{
textChange.setText("Je bent net de bedaulxstraat doorgereden");
}
if (pLong >= compareLongCoords)
{
textChange.setText("U bent door een andere straat gereden dan daarnet.");
}
}
}
@Override
public void onProviderDisabled(String provider) {
// TODO Auto-generated method stub
}
@Override
public void onProviderEnabled(String provider) {
// TODO Auto-generated method stub
}
@Override
public void onStatusChanged(String arg0, int arg1, Bundle arg2) {
// TODO Auto-generated method stub
}
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
}
它是關於數組的:options [i] [j],在if語句之外無法訪問...我已經進行了兩天的工作,但找不到解決方案...
編輯:感謝所有的答案,但是當我嘗試在public void onLocationChanged(Location location) {...}
訪問變量(例如: options[1][0]
)時。 我收到錯誤消息:選項無法解析為變量。
肯尼思,問候
在for-loop
之外聲明數組String[][]options
,並在必要時進行定義。
String[][]options = null;
for (int temp = 0; temp < nList.getLength(); temp++) {
Node nNode = nList.item(temp);
if (nNode.getNodeType() == Node.ELEMENT_NODE) {
Element eElement = (Element) nNode;
options = new String[cols][rows];
...
如果您在if語句內定義任何變量,它將是local variable
->“,並且local variable
的范圍是括起來的括號,您只能在if
塊內部訪問它”,因此在if
語句外部定義options
String[][]options = new String[cols][rows];
if (nNode.getNodeType() == Node.ELEMENT_NODE) {
...
}
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