我试图纠正下面的代码，但没有成功.Matlab说：
public class MapsActivity extends FragmentActivity implements OnMapReadyCallback {
public GoogleMap mMap;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_maps);
// Obtain the SupportMapFragment and get notified when the map is ready to be used.
SupportMapFragment mapFragment = (SupportMapFragment) getSupportFragmentManager()
.findFragmentById(R.id.map);
mapFragment.getMapAsync(this);
}
public void onMapSearch (View view) throws IOException {
//hide button when button is pressed
InputMethodManager inputManager = (InputMethodManager) getSystemService(this.INPUT_METHOD_SERVICE);
inputManager.hideSoftInputFromWindow(getCurrentFocus().getWindowToken(), InputMethodManager.HIDE_NOT_ALWAYS);
//preview the entered address as an Tost in bar
EditText locationSearch = (EditText) findViewById(R.id.editText);
String location = locationSearch.getText().toString();
//this will animate camera and zoom 12.0f
mMap.animateCamera(CameraUpdateFactory.zoomTo(12.0f));
//further address search codes
List<Address> addressList = null;
//if nothing will be entered in the edit-text will not show a toast rather than crashing of thekha app
if (locationSearch.getText().toString().equals("")){
Toast.makeText(this,"Bitch please enter A Value",Toast.LENGTH_LONG).show();
}
else {
//process of exception handling and finding location
if (location != null || !location.equals("")) {
Geocoder geocoder = new Geocoder(this);
try {
addressList = geocoder.getFromLocationName(location, 1);
} catch (IOException e) {
e.printStackTrace();
}
//if address is greater than one then these processes will happen
if(addressList.size()>0) {
Address address = addressList.get(0);
LatLng latLng = new LatLng(address.getLatitude(), address.getLongitude());
mMap.addMarker(new MarkerOptions()
.position(latLng)
.title(location + " is Here- ")
.icon(BitmapDescriptorFactory.defaultMarker(BitmapDescriptorFactory.HUE_BLUE)));
mMap.animateCamera(CameraUpdateFactory.newLatLng(latLng));
Toast.makeText(this, location+" is here, Zoom In or Zoom Out to make your Thekha Visible ", Toast.LENGTH_LONG)
.show(); //popup type to show entered data
}
else {
//process where entered entry will not gonna find , this will gonna a toast to show popup
Toast.makeText(this,"Entered Address Not Found", Toast.LENGTH_LONG).show();
}
}
}
}
private class RetriveMarkerTask extends AsyncTask<String,Void,String> {
private Context context;
private GoogleMap gMap;
public RetriveMarkerTask(Context context, GoogleMap mMap) {
this.context = context;
this.gMap = mMap;
}
protected void onPreExecute(){
Toast.makeText(context, "pre execute", Toast.LENGTH_LONG).show();
}
protected String doInBackground(String... markerGetUrl) {
android.os.Debug.waitForDebugger();
HttpURLConnection conn = null;
final StringBuilder json = new StringBuilder();
int read;
char[] buff = new char[1024];
try {
//connect to the web service
URL url = new URL(markerGetUrl[0]);
conn = (HttpURLConnection) url.openConnection();
//This will read the json data into string builder
InputStreamReader in = new InputStreamReader(conn.getInputStream());
while ((read = in.read(buff)) != -1) {
json.append(buff, 0, read);
}
} catch (IOException e) {
return null;
} catch (Exception ex) {
return null;
} finally {
if (conn != null) {
conn.disconnect();
}
}
String markersJson = new String(buff).trim();
return markersJson;
}
protected void onPostExecute(String markers) {
Toast.makeText(context, "Post Execute", Toast.LENGTH_LONG).show();
LatLng dwarka = new LatLng(28.570317,77.32182);
gMap.moveCamera(CameraUpdateFactory.newLatLngZoom(dwarka, 13));
gMap.addMarker(
new MarkerOptions()
.title("Wine Beer Liquor Shop, Sector 18, Noida")
.snippet("Sector 18, Near Centre Stage Mall, Noida")
.position(dwarka));
/*
try {
JSONArray jsonArray = new JSONArray(markers);
for (int i =0; i<jsonArray.length(); i++){
//create marker of each place in the json data
JSONObject jsonObject = jsonArray.getJSONObject(i);
String placeName = jsonObject.getString("name");
String placeAddress = jsonObject.getString("address");
double latitude = jsonObject.getJSONArray("latlang").getDouble(0);
double longitude = jsonObject.getJSONArray("latlang").getDouble(1);
LatLng loc = new LatLng(latitude, longitude);
gMap.moveCamera(CameraUpdateFactory.newLatLngZoom(loc, 13));
gMap.addMarker(new MarkerOptions()
.title(placeName)
.snippet(placeAddress)
.position(loc)
);
}
}catch (JSONException e){
e.printStackTrace();
}
*/
}
}
//OnReady map starts here when we can enter or add Marker to the map
@Override
public void onMapReady(GoogleMap googleMap) {
Toast.makeText(this, "On Map ready", Toast.LENGTH_LONG).show();
mMap = googleMap;
try {
String url = new String("http://www.loofre.com/api-for-webservice/?debug=true&action=getLocations");
RetriveMarkerTask markerTask = new RetriveMarkerTask(this, mMap);
markerTask.execute(url);
}catch (Exception e){
Toast.makeText(this,"Can not fetch data",Toast.LENGTH_LONG).show();
}
if (ActivityCompat.checkSelfPermission(this, android.Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission
(this, android.Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
// TODO: Consider calling
// ActivityCompat#requestPermissions
// here to request the missing permissions, and then overriding
// public void onRequestPermissionsResult(int requestCode, String[] permissions,
// int[] grantResults)
// to handle the case where the user grants the permission. See the documentation
// for ActivityCompat#requestPermissions for more details.
return;
}
//tool bar and other tool related on map uiSettings
mMap.setMyLocationEnabled(true);
mMap.getUiSettings().setZoomControlsEnabled(true);
mMap.getUiSettings().setMapToolbarEnabled(true);
mMap.getUiSettings().setMyLocationButtonEnabled(true);
}
}
这是代码
Error using *
Inner matrix dimensions must agree.
Error in
Atten = a*l*f;
我甚至尝试使用a=[0.6 1.89 4.1 0.9 0.8 3];
l=[0.5 0.5 0.5 0.5 0.5 0.5];
f=[1000000:4000000:21000000];
Atten = a*l*f;
plot(f,Atten)
，但它没有用
如何更正代码？
由于
答案 0 :(得分：1)
这是一个数学问题，而不是编程错误。
你试图乘以3 [1x6]矩阵，当然这是不可能的。
也许你想要这个操作
[1x6]*[6x1]*[1x6] = [1x6]
而不是
[1x6]*[1x6]*[1x6] = Impossible
在这种情况下，您可以使用此运算符.'来转置矩阵：
Atten = a*l.'*f;
result:
5.6450e+06 2.8225e+07 5.0805e+07 7.3385e+07 9.5965e+07 1.1855e+08
在这种情况下，l.'将是[6x1]矩阵，现在可以进行操作
有关此运算符的详细信息：Tranpose vectore or matrix
答案 1 :(得分：0)
您的矩阵维度存在不匹配。 确保将矩阵与正确的维度相乘。
您可以使用.'运算符转置矩阵。
答案 2 :(得分：0)
如果您想要按元素相乘，可以在.
*