我为我的应用实现了this代码，它将以片段形式显示。我已经将使用FragmentActivity的所有方法更改为片段。但是当我运行它并去映射片段时它给出了这个错误： 日志文件：
03-31 12:10:47.235: E/AndroidRuntime(612): FATAL EXCEPTION: main
03-31 12:10:47.235: E/AndroidRuntime(612): java.lang.ClassCastException: plusnet.tashrifat.MainActivity cannot be cast to android.support.v4.app.FragmentActivity
03-31 12:10:47.235: E/AndroidRuntime(612): at plusnet.tashrifat.MapFragment.onAttach(MapFragment.java:47)
03-31 12:10:47.235: E/AndroidRuntime(612): at android.app.FragmentManagerImpl.moveToState(FragmentManager.java:787)
03-31 12:10:47.235: E/AndroidRuntime(612): at android.app.FragmentManagerImpl.moveToState(FragmentManager.java:1035)
03-31 12:10:47.235: E/AndroidRuntime(612): at android.app.BackStackRecord.run(BackStackRecord.java:635)
03-31 12:10:47.235: E/AndroidRuntime(612): at android.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1397)
03-31 12:10:47.235: E/AndroidRuntime(612): at android.app.FragmentManagerImpl$1.run(FragmentManager.java:426)
03-31 12:10:47.235: E/AndroidRuntime(612): at android.os.Handler.handleCallback(Handler.java:615)
03-31 12:10:47.235: E/AndroidRuntime(612): at android.os.Handler.dispatchMessage(Handler.java:92)
03-31 12:10:47.235: E/AndroidRuntime(612): at android.os.Looper.loop(Looper.java:137)
03-31 12:10:47.235: E/AndroidRuntime(612): at android.app.ActivityThread.main(ActivityThread.java:4745)
03-31 12:10:47.235: E/AndroidRuntime(612): at java.lang.reflect.Method.invokeNative(Native Method)
03-31 12:10:47.235: E/AndroidRuntime(612): at java.lang.reflect.Method.invoke(Method.java:511)
03-31 12:10:47.235: E/AndroidRuntime(612): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786)
03-31 12:10:47.235: E/AndroidRuntime(612): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
03-31 12:10:47.235: E/AndroidRuntime(612): at dalvik.system.NativeStart.main(Native Method)
和我的片段代码：
public class MapFragment extends Fragment {
public MapFragment() {
}
@Override
public void onAttach(Activity activity) {
myContext = (FragmentActivity) activity;
super.onAttach(activity);
}
GoogleMap map;
ArrayList<LatLng> markerPoints;
LatLng userPoint;
private FragmentActivity myContext;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// TODO Auto-generated method stub
View rootView = inflater.inflate(R.layout.mymap, container);
LatLng tashrifat = new LatLng(38.065922, 46.323698);
// Initializing
markerPoints = new ArrayList<LatLng>();
// Getting reference to SupportMapFragment of the activity_main
SupportMapFragment fm = (SupportMapFragment) myContext
.getSupportFragmentManager().findFragmentById(R.id.map);
userPoint = new LatLng(38.090079, 46.233212);
// Getting Map for the SupportMapFragment
map = fm.getMap();
LocationResult locationResult = new LocationResult() {
public void gotLocation(Location location) {
userPoint = new LatLng(location.getLatitude(),
location.getLongitude());
}
};
CameraUpdate center = CameraUpdateFactory.newLatLng(tashrifat);
CameraUpdate zoom = CameraUpdateFactory.zoomTo(17);
map.moveCamera(center);
map.animateCamera(zoom);
MyLocation myLocation = new MyLocation();
myLocation.getLocation(getActivity(), locationResult);
// String url = getDirectionsUrl(userPoint, tashrifat);
// DownloadTask downloadTask = new DownloadTask();
// Start downloading json data from Google Directions
// API
// downloadTask.execute(url);
if (map != null) {
// Enable MyLocation Button in the Map
map.setMyLocationEnabled(true);
// Setting onclick event listener for the map
// Already two locations
if (markerPoints.size() > 1) {
markerPoints.clear();
map.clear();
}
// Adding new item to the ArrayList
markerPoints.add(userPoint);
markerPoints.add(tashrifat);
// Creating MarkerOptions
MarkerOptions options = new MarkerOptions();
// Setting the position of the marker
options.position(userPoint);
options.position(tashrifat);
/**
* For the start location, the color of marker is GREEN and for the
* end location, the color of marker is RED.
*/
if (markerPoints.size() == 1) {
options.icon(BitmapDescriptorFactory
.defaultMarker(BitmapDescriptorFactory.HUE_GREEN));
} else if (markerPoints.size() == 2) {
options.icon(BitmapDescriptorFactory
.defaultMarker(BitmapDescriptorFactory.HUE_RED));
}
// Add new marker to the Google Map Android API V2
map.addMarker(options);
// Checks, whether start and end locations are captured
LatLng origin = tashrifat;
LatLng dest = userPoint;
// Getting URL to the Google Directions API
String url = getDirectionsUrl(origin, dest);
DownloadTask downloadTask = new DownloadTask();
// Start downloading json data from Google Directions
// API
downloadTask.execute(url);
}
return rootView;
}
另一个我不会处理它的功能，并且喜欢那个引用代码：
private String getDirectionsUrl(LatLng origin, LatLng dest) {
// Origin of route
String str_origin = "origin=" + origin.latitude + ","
+ origin.longitude;
// Destination of route
String str_dest = "destination=" + dest.latitude + "," + dest.longitude;
// Sensor enabled
String sensor = "sensor=false";
// Building the parameters to the web service
String parameters = str_origin + "&" + str_dest + "&" + sensor;
// Output format
String output = "json";
// Building the url to the web service
String url = "https://maps.googleapis.com/maps/api/directions/"
+ output + "?" + parameters;
return url;
}
/** A method to download json data from url */
private String downloadUrl(String strUrl) throws IOException {
String data = "";
InputStream iStream = null;
HttpURLConnection urlConnection = null;
try {
URL url = new URL(strUrl);
// Creating an http connection to communicate with url
urlConnection = (HttpURLConnection) url.openConnection();
// Connecting to url
urlConnection.connect();
// Reading data from url
iStream = urlConnection.getInputStream();
BufferedReader br = new BufferedReader(new InputStreamReader(
iStream));
StringBuffer sb = new StringBuffer();
String line = "";
while ((line = br.readLine()) != null) {
sb.append(line);
}
data = sb.toString();
br.close();
} catch (Exception e) {
Log.d("Exception while downloading url", e.toString());
} finally {
iStream.close();
urlConnection.disconnect();
}
return data;
}
// Fetches data from url passed
private class DownloadTask extends AsyncTask<String, Void, String> {
// Downloading data in non-ui thread
@Override
protected String doInBackground(String... url) {
// For storing data from web service
String data = "";
try {
// Fetching the data from web service
data = downloadUrl(url[0]);
} catch (Exception e) {
Log.d("Background Task", e.toString());
}
return data;
}
// Executes in UI thread, after the execution of
// doInBackground()
@Override
protected void onPostExecute(String result) {
super.onPostExecute(result);
ParserTask parserTask = new ParserTask();
// Invokes the thread for parsing the JSON data
parserTask.execute(result);
}
}
/** A class to parse the Google Places in JSON format */
private class ParserTask extends
AsyncTask<String, Integer, List<List<HashMap<String, String>>>> {
// Parsing the data in non-ui thread
@Override
protected List<List<HashMap<String, String>>> doInBackground(
String... jsonData) {
JSONObject jObject;
List<List<HashMap<String, String>>> routes = null;
try {
jObject = new JSONObject(jsonData[0]);
DirectionsJSONParser parser = new DirectionsJSONParser();
// Starts parsing data
routes = parser.parse(jObject);
} catch (Exception e) {
e.printStackTrace();
}
return routes;
}
// Executes in UI thread, after the parsing process
@Override
protected void onPostExecute(List<List<HashMap<String, String>>> result) {
ArrayList<LatLng> points = null;
PolylineOptions lineOptions = null;
MarkerOptions markerOptions = new MarkerOptions();
// Traversing through all the routes
for (int i = 0; i < result.size(); i++) {
points = new ArrayList<LatLng>();
lineOptions = new PolylineOptions();
lineOptions.width(5);
lineOptions.color(Color.BLUE);
// Fetching i-th route
List<HashMap<String, String>> path = result.get(i);
// Fetching all the points in i-th route
for (int j = 0; j < path.size(); j++) {
HashMap<String, String> point = path.get(j);
double lat = Double.parseDouble(point.get("lat"));
double lng = Double.parseDouble(point.get("lng"));
LatLng position = new LatLng(lat, lng);
points.add(position);
}
// Adding all the points in the route to LineOptions
lineOptions.addAll(points);
lineOptions.width(2);
lineOptions.color(Color.RED);
}
// Drawing polyline in the Google Map for the i-th route
map.addPolyline(lineOptions);
}
}
}
我的布局：
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity" >
<fragment
android:id="@+id/map"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
class="com.google.android.gms.maps.SupportMapFragment" />
主要活动：
public class MainActivity extends Activity {
private DrawerLayout mDrawerLayout;
private ListView mDrawerList;
private ActionBarDrawerToggle mDrawerToggle;
// nav drawer title
private CharSequence mDrawerTitle;
// used to store app title
private CharSequence mTitle;
// slide menu items
private String[] navMenuTitles;
private TypedArray navMenuIcons;
private ArrayList<NavDrawerItem> navDrawerItems;
private NavDrawerListAdapter adapter;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mTitle = mDrawerTitle = getTitle();
// load slide menu items
navMenuTitles = getResources().getStringArray(R.array.nav_drawer_items);
// nav drawer icons from resources
navMenuIcons = getResources()
.obtainTypedArray(R.array.nav_drawer_icons);
mDrawerLayout = (DrawerLayout) findViewById(R.id.drawer_layout);
mDrawerList = (ListView) findViewById(R.id.list_slidermenu);
navDrawerItems = new ArrayList<NavDrawerItem>();
// adding nav drawer items to array
// Home
navDrawerItems.add(new NavDrawerItem(navMenuTitles[0], navMenuIcons
.getResourceId(0, -1)));
// Find People
navDrawerItems.add(new NavDrawerItem(navMenuTitles[1], navMenuIcons
.getResourceId(1, -1)));
// Photos
navDrawerItems.add(new NavDrawerItem(navMenuTitles[2], navMenuIcons
.getResourceId(2, -1)));
// Communities, Will add a counter her
navDrawerItems.add(new NavDrawerItem(navMenuTitles[3], navMenuIcons
.getResourceId(3, -1), false, "22"));
// // Pages
navDrawerItems.add(new NavDrawerItem(navMenuTitles[4], navMenuIcons
.getResourceId(4, -1)));
// // What's hot, We will add a counter here
// navDrawerItems.add(new NavDrawerItem(navMenuTitles[5],
// navMenuIcons.getResourceId(5, -1), true, "50+"));
// Recycle the typed array
navMenuIcons.recycle();
mDrawerList.setOnItemClickListener(new SlideMenuClickListener());
// setting the nav drawer list adapter
adapter = new NavDrawerListAdapter(getApplicationContext(),
navDrawerItems);
mDrawerList.setAdapter(adapter);
// enabling action bar app icon and behaving it as toggle button
getActionBar().setDisplayHomeAsUpEnabled(true);
getActionBar().setHomeButtonEnabled(true);
mDrawerToggle = new ActionBarDrawerToggle(this, mDrawerLayout,
R.drawable.ic_drawer, // nav menu toggle icon
R.string.app_name, // nav drawer open - description for
// accessibility
R.string.app_name // nav drawer close - description for
// accessibility
) {
public void onDrawerClosed(View view) {
getActionBar().setTitle(mTitle);
// calling onPrepareOptionsMenu() to show action bar icons
invalidateOptionsMenu();
}
public void onDrawerOpened(View drawerView) {
getActionBar().setTitle(mDrawerTitle);
// calling onPrepareOptionsMenu() to hide action bar icons
invalidateOptionsMenu();
}
};
mDrawerLayout.setDrawerListener(mDrawerToggle);
if (savedInstanceState == null) {
// on first time display view for first nav item
displayView(0);
}
}
/**
* Slide menu item click listener
* */
private class SlideMenuClickListener implements
ListView.OnItemClickListener {
public void onItemClick(AdapterView<?> parent, View view, int position,
long id) {
// display view for selected nav drawer item
displayView(position);
}
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.actionbar, menu);
// SearchManager searchManager = (SearchManager)
// getSystemService(Context.SEARCH_SERVICE);
// SearchView searchView = (SearchView) menu.findItem(R.id.search)
// .getActionView();
// searchView.setSearchableInfo(searchManager
// .getSearchableInfo(getComponentName()));
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// toggle nav drawer on selecting action bar app icon/title
if (mDrawerToggle.onOptionsItemSelected(item)) {
return true;
}
// Handle action bar actions click
switch (item.getItemId()) {
case R.id.action_settings:
return true;
case R.id.search:
return true;
case R.id.card:
gotCardFragment();
default:
return super.onOptionsItemSelected(item);
}
}
/* *
* Called when invalidateOptionsMenu() is triggered
*/
private void gotCardFragment() {
Fragment cardFragment = new Card();
FragmentManager FM = getFragmentManager();
FM.beginTransaction().replace(R.id.frame_container, cardFragment)
.commit();
}
/**
* Diplaying fragment view for selected nav drawer list item
* */
private void displayView(int position) {
// update the main content by replacing fragments
Fragment fragment = null;
switch (position) {
case 0:
fragment = new ParentCategoury();
break;
case 1:
fragment = new AccountFragment();
break;
case 2:
fragment = new MapFragment();
break;
case 3:
fragment = new Card();
break;
case 4:
this.finish();
break;
case 5:
this.finish();
default:
break;
}
if (fragment != null) {
FragmentManager fragmentManager = getFragmentManager();
fragmentManager.beginTransaction()
.replace(R.id.frame_container, fragment).commit();
// update selected item and title, then close the drawer
mDrawerList.setItemChecked(position, true);
mDrawerList.setSelection(position);
setTitle(navMenuTitles[position]);
mDrawerLayout.closeDrawer(mDrawerList);
} else {
// error in creating fragment
Log.e("MainActivity", "Error in creating fragment");
}
}
@Override
public void setTitle(CharSequence title) {
mTitle = title;
getActionBar().setTitle(mTitle);
}
/**
* When using the ActionBarDrawerToggle, you must call it during
* onPostCreate() and onConfigurationChanged()...
*/
@Override
protected void onPostCreate(Bundle savedInstanceState) {
super.onPostCreate(savedInstanceState);
// Sync the toggle state after onRestoreInstanceState has occurred.
mDrawerToggle.syncState();
}
@Override
public void onConfigurationChanged(Configuration newConfig) {
super.onConfigurationChanged(newConfig);
// Pass any configuration change to the drawer toggls
mDrawerToggle.onConfigurationChanged(newConfig);
}
}
答案 0 :(得分：1)
我建议您从主要活动中引用地图片段。 您可以通过在OnCreate方法上执行以下操作来实现此目的
//load static layout from: res/layout/activity_main.xml
setContentView(R.layout.activity_main);
//get Map Fragment and retrieve GoogleMap object
MapFragment mapFragment = (MapFragment) getFragmentManager()
.findFragmentById(R.id.map);
map = mapFragment.getMap();
然后您可以开始使用它，例如您可以启用位置，设置缩放级别等。