【发布时间】：2016-01-29 08:25:57
【问题描述】：
编辑：找到我的问题的解决方案。 json 字符串输出为我的本地图像返回了错误的 url。
我对 android 几乎不陌生，并且在 asyncTask 上苦苦挣扎。
我想要的是将相应的图像获取到地图上的标记。 此地图上的每个条目都有自己的图像，必须通过 json 从服务器加载。
图像加载工作正常，但我没有获得正确的工作流程来获取一个条目所需的图像。
到目前为止，我有一个解决方案可以在 for 循环中加载异步任务，但这不是正确的方法，因为应用程序在 43 个任务后拒绝继续并停止 “连接超时”
那么如何让 asynctask 脱离循环呢？
希望有人能帮忙吗？谢谢！
这是我的代码：
公共类 MapsActivity 扩展 AppCompatActivity 实现 OnMapReadyCallback {
private GoogleMap mMap;
JSONArray contentJson;
String contentId;
String imageJsonUrl;
String userId;
Bitmap bmp;
LatLng latLng;
Marker m;
HashMap<Marker, String> hashMap;
int k = 0;
// check value for Request check
final int MY_LOCATION_REQUEST_CODE = 3;
@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);
Toolbar myToolbar = (Toolbar) findViewById(R.id.my_toolbar);
setSupportActionBar(myToolbar);
getSupportActionBar().setDisplayShowTitleEnabled(false);
if(this.getIntent().getExtras() != null) {
try {
contentJson = new JSONArray(this.getIntent().getStringExtra("contentJson"));
// Log.v("TESTITEST", contentJson.toString());
} catch (JSONException e) {
Log.e("EXCEPTION", "unexpected JSON exception", e);
e.printStackTrace();
}
}
}
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.menu_maps, menu);
return true;
}
public LatLng getLatLngPosition() {
return new LatLng(0, 0);
}
/**
* Manipulates the map once available.
* This callback is triggered when the map is ready to be used.
* This is where we can add markers or lines, add listeners or move the camera. In this case,
* we just add a marker near Sydney, Australia.
* If Google Play services is not installed on the device, the user will be prompted to install
* it inside the SupportMapFragment. This method will only be triggered once the user has
* installed Google Play services and returned to the app.
*/
@Override
public void onMapReady(GoogleMap googleMap) {
mMap = googleMap;
//Ask for Permission. If granted show my Location
if (ActivityCompat.checkSelfPermission(MapsActivity.this, Manifest.permission.ACCESS_FINE_LOCATION)
!= PackageManager.PERMISSION_GRANTED) {
// Check Permissions Now
ActivityCompat.requestPermissions(MapsActivity.this,
new String[]{Manifest.permission.ACCESS_FINE_LOCATION},
MY_LOCATION_REQUEST_CODE);
} else {
// permission has been granted, continue as usual
mMap.setMyLocationEnabled(true);
}
PlaceAutocompleteFragment autocompleteFragment = (PlaceAutocompleteFragment)
getFragmentManager().findFragmentById(R.id.place_autocomplete_fragment);
autocompleteFragment.setOnPlaceSelectedListener(new PlaceSelectionListener() {
@Override
public void onPlaceSelected(Place place) {
// TODO: Get info about the selected place.
LatLng selectedLocation = place.getLatLng();
mMap.animateCamera(CameraUpdateFactory.newLatLngZoom(selectedLocation, 10f));
}
@Override
public void onError(Status status) {
// TODO: Handle the error.
Log.i("PlaceSelectorError", "An error occurred: " + status);
}
});
LatLng bonn = new LatLng(50.7323, 7.1847);
LatLng cologne = new LatLng(50.9333333, 6.95);
//mMap.addMarker(new MarkerOptions().position(bonn).title("Marker in Bonn"));
// hash map for saving content id with marker
hashMap = new HashMap<Marker, String>();
if(contentJson != null) {
if (this.getIntent().getStringExtra("contentId") == null) {
// show all contents of my friends
try {
for (int i = 0; i < contentJson.length(); i++) {
JSONObject jsonInfo = contentJson.getJSONObject(i);
JSONArray contents = jsonInfo.getJSONArray("content");
// Log.v("contentslength", String.valueOf(contents.length()));
//get all contents of one user
for (int j = 0; j < contents.length(); j++) {
JSONObject eachcontent = contents.getJSONObject(j);
//Log.v("eachcontent", eachcontent.toString());
JSONObject location = eachcontent.getJSONObject("Location");
String contentId = eachcontent.getString("id");
String contentTitle = eachcontent.getString("title");
userId = eachcontent.getString("user_id");
latLng = new LatLng(Double.valueOf(location.getString("latitude")), Double.valueOf(location.getString("longitude")));
new MapImageLoadTask("http://192.168.63.35:1234/rest_app_users/getImage/", userId, contentId, contentTitle, latLng).execute();
Log.v("contentTitle", contentTitle);
//Log.v("m", m.toString());
//m = mMap.addMarker(new MarkerOptions().title(contentTitle).position(new LatLng(Double.valueOf(location.getString("latitude")), Double.valueOf(location.getString("longitude")))).icon(BitmapDescriptorFactory.fromBitmap(bmp)));
}
}
} catch (JSONException e) {
Log.e("Exception", "unexpected JSON exception", e);
e.printStackTrace();
}
}
else {
// if we only want to see a specific content
try {
for (int i = 0; i < contentJson.length(); i++) {
JSONObject jsonInfo = contentJson.getJSONObject(i);
JSONArray contents = jsonInfo.getJSONArray("content");
//get all contents of one user
for (int j = 0; j < contents.length(); j++) {
JSONObject eachcontent = contents.getJSONObject(j);
JSONObject location = eachcontent.getJSONObject("Location");
if(eachcontent.getString("id").equals(this.getIntent().getStringExtra("contentId"))) {
String contentId = eachcontent.getString("id");
String contentTitle = eachcontent.getString("title");
userId = eachcontent.getString("user_id");
latLng = new LatLng(Double.valueOf(location.getString("latitude")), Double.valueOf(location.getString("longitude")));
// Log.v("LATLNG", contentId);
new MapImageLoadTask("http://192.168.63.35:1234/rest_app_users/getImage/", userId, contentId, contentTitle, latLng).execute();
continue;
}
}
}
} catch (JSONException e) {
Log.e("LOGEDILOG", "unexpected JSON exception", e);
e.printStackTrace();
}
}
}
mMap.setOnMyLocationChangeListener(new GoogleMap.OnMyLocationChangeListener() {
@Override
public void onMyLocationChange(Location location) {
mMap.animateCamera(CameraUpdateFactory.newLatLngZoom(
new LatLng(location.getLatitude(), location.getLongitude()), 10f));
mMap.setOnMyLocationChangeListener(null);
}
});
mMap.setOnInfoWindowClickListener(new GoogleMap.OnInfoWindowClickListener() {
@Override
public void onInfoWindowClick(Marker marker) {
String id = hashMap.get(marker);
Log.v("BITMAP", bmp.toString());
try {
Context context = getApplicationContext();
Intent mapIntent = new Intent(getApplicationContext(), contentDetailActivity.class);
mapIntent.putExtra("contentId", id);
mapIntent.putExtra("contentJson", contentJson.toString());
mapIntent.putExtra("userId", userId);
String filename = "profileImage.png";
FileOutputStream stream = context.openFileOutput(filename, Context.MODE_PRIVATE);
bmp.compress(Bitmap.CompressFormat.PNG, 100, stream);
//Cleanup
stream.close();
mapIntent.putExtra("image", filename);
startActivity(mapIntent);
} catch (Exception e) {
e.printStackTrace();
}
}
});
}
public Marker[] addMarkers() {
return null;
}
/**
* lets you load Image from external source via url
*/
public class MapImageLoadTask extends AsyncTask<Void, Void, Bitmap> {
private final String LOG_TAG = MapImageLoadTask.class.getSimpleName();
String url, userId, contentId, title;
LatLng location;
BufferedReader reader = null;
public MapImageLoadTask(String url, String userId, String contentId, String title, LatLng location) {
this.url = url;
this.userId = userId;
this.contentId = contentId;
this.title = title;
this.location = location;
}
private String getImageUrlFromJson(String imageJson) throws JSONException {
JSONObject imageJsonOutput = new JSONObject(imageJson);
imageJsonUrl = imageJsonOutput.getString("imageUrl");
//Log.v(LOG_TAG, imageJsonUrl);
return imageJsonUrl;
}
@Override
protected Bitmap doInBackground(Void... params) {
String imageJson = null;
try {
URL urlConnection = new URL(url + userId);
HttpURLConnection connection = (HttpURLConnection) urlConnection
.openConnection();
connection.setDoInput(true);
connection.connect();
InputStream input = connection.getInputStream();
StringBuffer buffer = new StringBuffer();
if (input == null) {
// Nothing to do.
//forecastJsonStr = null;
return null;
}
reader = new BufferedReader(new InputStreamReader(input));
String line;
while ((line = reader.readLine()) != null) {
// Since it's JSON, adding a newline isn't necessary (it won't affect parsing)
// But it does make debugging a *lot* easier if you print out the completed
// buffer for debugging.
buffer.append(line + "\n");
}
if (buffer.length() == 0) {
return null;
}
imageJson = buffer.toString();
} catch (Exception e) {
e.printStackTrace();
}
try {
String jsonUrl = getImageUrlFromJson(imageJson);
URL url = new URL(jsonUrl);
bmp = BitmapFactory.decodeStream(url.openConnection().getInputStream());
return bmp;
}
catch(Exception e) {
e.printStackTrace();
}
return null;
}
@Override
protected void onPostExecute(Bitmap result) {
super.onPostExecute(result);
k +=1;
Log.v("COUNTER", String.valueOf(k));
m = mMap.addMarker(new MarkerOptions().title(title).position(location).icon(BitmapDescriptorFactory.fromBitmap(bmp)));
hashMap.put(m, contentId);
}
}
}
【问题讨论】：
-
朋友好，新建AsyncTask时，可以把Id放到构造函数中。 public ImageLoadTask(String id, String url, String userId) { this.url = url;这个.id = id; this.userId = userId; }
标签： java android google-maps android-asynctask