Android 启动时不会显示RecyclerView中的图像
我有一个Android 启动时不会显示RecyclerView中的图像,android,android-recyclerview,android-volley,adapter,android-viewholder,Android,Android Recyclerview,Android Volley,Adapter,Android Viewholder,我有一个RecyclerView，里面有一张卡片列表，每张卡片上都有一张图片。当我开始向下滚动时，屏幕外开始的卡在屏幕上出现时会加载图像，但屏幕上开始的卡只有在移离屏幕并返回屏幕时才会加载图像 它似乎也有点随机性。用于上下文的Gif： gif中的最后一个示例（前3个餐厅图像不加载）是最常见的 视图持有者： public class LocationsViewHolder extends RecyclerView.ViewHolder{ private ImageView locationIma
RecyclerViewpublic class LocationsViewHolder extends RecyclerView.ViewHolder{
private ImageView locationImage;
private TextView locationName;
private TextView locationAddress;
public LocationsViewHolder(View itemView) {
super(itemView);
locationName = (TextView)itemView.findViewById(R.id.location_name);
locationAddress = (TextView)itemView.findViewById(R.id.location_address);
locationImage = (ImageView) itemView.findViewById(R.id.location_image);
}
public void updateUI(Place place){
locationName.setText(place.getName());
if(place.getPhotoID() != null){
// Log.v("IMAGE", "photoID for " + place.getName() + ": " + place.getPhotoID());
locationImage.setImageBitmap(place.getImage());
} else {
locationImage.setImageResource(R.drawable.no_image);
}
}
}
public class LocationsAdapter extends RecyclerView.Adapter<LocationsViewHolder>{
ArrayList<Place> locations;
Context context;
GetNearbyPlacesData data;
public LocationsAdapter(ArrayList<Place> locations, Context context) {
this.locations = locations;
this.context = context;
data = GetNearbyPlacesData.getInstance(context);
}
@Override
public LocationsViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View card = LayoutInflater.from(parent.getContext()).inflate(R.layout.card_location, parent, false);
return new LocationsViewHolder(card);
}
@Override
public void onBindViewHolder(LocationsViewHolder holder, int position) {
Place location = locations.get(position);
holder.updateUI(location);
}
@Override
public int getItemCount() {
return locations.size();
}
}
Bitmap bitmap;
public void downloadPlaceImage(String imageKey, final Place place){
String url = buildImgURL(imageKey);
ImageRequest imageRequest = new ImageRequest(url, new Response.Listener<Bitmap>() {
@Override
public void onResponse(Bitmap response) {
bitmap = response;
place.setImage(bitmap);
Log.v("IMG", "downloaded image");
}
}, 0, 0, null, new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
}
});
requestQueue.add(imageRequest);
}
}
ArrayList<Place> placesList;
public ArrayList<Place> downloadPlacesData(Bundle bundle){
String url = buildPlaceURL(bundle);
placesList = new ArrayList<>();
//TODO make more requests for the next pages of results since each page is limited to 20 places
JsonObjectRequest jsonObjectRequest = new JsonObjectRequest(url, null, new Response.Listener<JSONObject>() {
@Override
public void onResponse(JSONObject response) {
try {
JSONArray results = response.getJSONArray("results");
for(int i = 0; i < results.length(); i++){
JSONObject main = results.getJSONObject(i);
JSONObject geo = main.getJSONObject("geometry");
JSONObject loc = geo.getJSONObject("location");
String placeID = main.getString("place_id");
String name = main.getString("name");
String lat = loc.getString("lat");
String lng = loc.getString("lng");
String photoID = null;
try {
if (main.getJSONArray("photos") != null) {
JSONArray photos = main.getJSONArray("photos");
photoID = photos.getJSONObject(0).getString("photo_reference");
}
}catch (JSONException e){
Log.v("JSON4", e.getLocalizedMessage());
}
Place place = new Place(photoID, name, placeID, Double.parseDouble(lat), Double.parseDouble(lng), context);
Log.v("NAME", name);
placesList.add(place);
}
onPlacesLoadedListener.placesLoaded(placesList);
}catch (JSONException e){
Log.v("JSON", e.getLocalizedMessage());
}
}
}, new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
}
});
requestQueue.add(jsonObjectRequest);
return placesList;
}
@Override
public void placesLoaded(ArrayList<Place> list) {
Log.v("PLACES", "adding places");
MarkerOptions markerOptions = new MarkerOptions();
// build a resource path using the type of place
String type = URLInfo.getString("type");
String resourcePath = "drawable/pin_" + type;
// create a resource path out of the String created
int resource = getResources().getIdentifier(resourcePath, null, this.getPackageName());
// set the marker icon according to the place type
markerOptions.icon(BitmapDescriptorFactory.fromResource(resource));
for(int i = 0; i < list.size(); i++){
// get the latitude and longitude
double lat = list.get(i).getLat();
double lng = list.get(i).getLng();
// set the marker position and title
markerOptions.position(new LatLng(lat, lng));
markerOptions.title(list.get(i).getName());
mMap.addMarker(markerOptions);
}
createLocationsListFragment();
}
private void createLocationsListFragment() {
FragmentManager fm = getSupportFragmentManager();
LocationsListFragment fragment = LocationsListFragment.newInstance();
fm.beginTransaction().add(R.id.container_locations, fragment).commit();
}
public class LocationsViewHolder extends RecyclerView.ViewHolder{
private ImageView locationImage;
private TextView locationName;
private TextView locationAddress;
public LocationsViewHolder(View itemView) {
super(itemView);
locationName = (TextView)itemView.findViewById(R.id.location_name);
locationAddress = (TextView)itemView.findViewById(R.id.location_address);
locationImage = (ImageView) itemView.findViewById(R.id.location_image);
}
public void updateUI(Place place){
locationName.setText(place.getName());
if(place.getPhotoID() != null){
// Log.v("IMAGE", "photoID for " + place.getName() + ": " + place.getPhotoID());
locationImage.setImageBitmap(place.getImage());
} else {
locationImage.setImageResource(R.drawable.no_image);
}
}
}
public class LocationsAdapter extends RecyclerView.Adapter<LocationsViewHolder>{
ArrayList<Place> locations;
Context context;
GetNearbyPlacesData data;
public LocationsAdapter(ArrayList<Place> locations, Context context) {
this.locations = locations;
this.context = context;
data = GetNearbyPlacesData.getInstance(context);
}
@Override
public LocationsViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View card = LayoutInflater.from(parent.getContext()).inflate(R.layout.card_location, parent, false);
return new LocationsViewHolder(card);
}
@Override
public void onBindViewHolder(LocationsViewHolder holder, int position) {
Place location = locations.get(position);
holder.updateUI(location);
}
@Override
public int getItemCount() {
return locations.size();
}
}
Bitmap bitmap;
public void downloadPlaceImage(String imageKey, final Place place){
String url = buildImgURL(imageKey);
ImageRequest imageRequest = new ImageRequest(url, new Response.Listener<Bitmap>() {
@Override
public void onResponse(Bitmap response) {
bitmap = response;
place.setImage(bitmap);
Log.v("IMG", "downloaded image");
}
}, 0, 0, null, new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
}
});
requestQueue.add(imageRequest);
}
}
ArrayList<Place> placesList;
public ArrayList<Place> downloadPlacesData(Bundle bundle){
String url = buildPlaceURL(bundle);
placesList = new ArrayList<>();
//TODO make more requests for the next pages of results since each page is limited to 20 places
JsonObjectRequest jsonObjectRequest = new JsonObjectRequest(url, null, new Response.Listener<JSONObject>() {
@Override
public void onResponse(JSONObject response) {
try {
JSONArray results = response.getJSONArray("results");
for(int i = 0; i < results.length(); i++){
JSONObject main = results.getJSONObject(i);
JSONObject geo = main.getJSONObject("geometry");
JSONObject loc = geo.getJSONObject("location");
String placeID = main.getString("place_id");
String name = main.getString("name");
String lat = loc.getString("lat");
String lng = loc.getString("lng");
String photoID = null;
try {
if (main.getJSONArray("photos") != null) {
JSONArray photos = main.getJSONArray("photos");
photoID = photos.getJSONObject(0).getString("photo_reference");
}
}catch (JSONException e){
Log.v("JSON4", e.getLocalizedMessage());
}
Place place = new Place(photoID, name, placeID, Double.parseDouble(lat), Double.parseDouble(lng), context);
Log.v("NAME", name);
placesList.add(place);
}
onPlacesLoadedListener.placesLoaded(placesList);
}catch (JSONException e){
Log.v("JSON", e.getLocalizedMessage());
}
}
}, new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
}
});
requestQueue.add(jsonObjectRequest);
return placesList;
}
@Override
public void placesLoaded(ArrayList<Place> list) {
Log.v("PLACES", "adding places");
MarkerOptions markerOptions = new MarkerOptions();
// build a resource path using the type of place
String type = URLInfo.getString("type");
String resourcePath = "drawable/pin_" + type;
// create a resource path out of the String created
int resource = getResources().getIdentifier(resourcePath, null, this.getPackageName());
// set the marker icon according to the place type
markerOptions.icon(BitmapDescriptorFactory.fromResource(resource));
for(int i = 0; i < list.size(); i++){
// get the latitude and longitude
double lat = list.get(i).getLat();
double lng = list.get(i).getLng();
// set the marker position and title
markerOptions.position(new LatLng(lat, lng));
markerOptions.title(list.get(i).getName());
mMap.addMarker(markerOptions);
}
createLocationsListFragment();
}
private void createLocationsListFragment() {
FragmentManager fm = getSupportFragmentManager();
LocationsListFragment fragment = LocationsListFragment.newInstance();
fm.beginTransaction().add(R.id.container_locations, fragment).commit();
}
public class LocationsViewHolder extends RecyclerView.ViewHolder{
private ImageView locationImage;
private TextView locationName;
private TextView locationAddress;
public LocationsViewHolder(View itemView) {
super(itemView);
locationName = (TextView)itemView.findViewById(R.id.location_name);
locationAddress = (TextView)itemView.findViewById(R.id.location_address);
locationImage = (ImageView) itemView.findViewById(R.id.location_image);
}
public void updateUI(Place place){
locationName.setText(place.getName());
if(place.getPhotoID() != null){
// Log.v("IMAGE", "photoID for " + place.getName() + ": " + place.getPhotoID());
locationImage.setImageBitmap(place.getImage());
} else {
locationImage.setImageResource(R.drawable.no_image);
}
}
}
public class LocationsAdapter extends RecyclerView.Adapter<LocationsViewHolder>{
ArrayList<Place> locations;
Context context;
GetNearbyPlacesData data;
public LocationsAdapter(ArrayList<Place> locations, Context context) {
this.locations = locations;
this.context = context;
data = GetNearbyPlacesData.getInstance(context);
}
@Override
public LocationsViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View card = LayoutInflater.from(parent.getContext()).inflate(R.layout.card_location, parent, false);
return new LocationsViewHolder(card);
}
@Override
public void onBindViewHolder(LocationsViewHolder holder, int position) {
Place location = locations.get(position);
holder.updateUI(location);
}
@Override
public int getItemCount() {
return locations.size();
}
}
Bitmap bitmap;
public void downloadPlaceImage(String imageKey, final Place place){
String url = buildImgURL(imageKey);
ImageRequest imageRequest = new ImageRequest(url, new Response.Listener<Bitmap>() {
@Override
public void onResponse(Bitmap response) {
bitmap = response;
place.setImage(bitmap);
Log.v("IMG", "downloaded image");
}
}, 0, 0, null, new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
}
});
requestQueue.add(imageRequest);
}
}
ArrayList<Place> placesList;
public ArrayList<Place> downloadPlacesData(Bundle bundle){
String url = buildPlaceURL(bundle);
placesList = new ArrayList<>();
//TODO make more requests for the next pages of results since each page is limited to 20 places
JsonObjectRequest jsonObjectRequest = new JsonObjectRequest(url, null, new Response.Listener<JSONObject>() {
@Override
public void onResponse(JSONObject response) {
try {
JSONArray results = response.getJSONArray("results");
for(int i = 0; i < results.length(); i++){
JSONObject main = results.getJSONObject(i);
JSONObject geo = main.getJSONObject("geometry");
JSONObject loc = geo.getJSONObject("location");
String placeID = main.getString("place_id");
String name = main.getString("name");
String lat = loc.getString("lat");
String lng = loc.getString("lng");
String photoID = null;
try {
if (main.getJSONArray("photos") != null) {
JSONArray photos = main.getJSONArray("photos");
photoID = photos.getJSONObject(0).getString("photo_reference");
}
}catch (JSONException e){
Log.v("JSON4", e.getLocalizedMessage());
}
Place place = new Place(photoID, name, placeID, Double.parseDouble(lat), Double.parseDouble(lng), context);
Log.v("NAME", name);
placesList.add(place);
}
onPlacesLoadedListener.placesLoaded(placesList);
}catch (JSONException e){
Log.v("JSON", e.getLocalizedMessage());
}
}
}, new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
}
});
requestQueue.add(jsonObjectRequest);
return placesList;
}
@Override
public void placesLoaded(ArrayList<Place> list) {
Log.v("PLACES", "adding places");
MarkerOptions markerOptions = new MarkerOptions();
// build a resource path using the type of place
String type = URLInfo.getString("type");
String resourcePath = "drawable/pin_" + type;
// create a resource path out of the String created
int resource = getResources().getIdentifier(resourcePath, null, this.getPackageName());
// set the marker icon according to the place type
markerOptions.icon(BitmapDescriptorFactory.fromResource(resource));
for(int i = 0; i < list.size(); i++){
// get the latitude and longitude
double lat = list.get(i).getLat();
double lng = list.get(i).getLng();
// set the marker position and title
markerOptions.position(new LatLng(lat, lng));
markerOptions.title(list.get(i).getName());
mMap.addMarker(markerOptions);
}
createLocationsListFragment();
}
private void createLocationsListFragment() {
FragmentManager fm = getSupportFragmentManager();
LocationsListFragment fragment = LocationsListFragment.newInstance();
fm.beginTransaction().add(R.id.container_locations, fragment).commit();
}
如果您有图像的url或位图，则使用glide，因为它将缓存您的图像。如果您发送url并加载它，则进行网络调用
在RecyclerView中，您必须确保为每个项目返回唯一的Id，或者如果没有稳定的Id，则应返回RecyclerView.no_Id（-1）。请避免返回不稳定的值。（稳定值是唯一的值，即使数据集的位置发生变化也不会改变） 在RecyclerView适配器中添加getItemId回调 例如：
（在您的示例视频中）在餐厅和药店之间切换时执行什么代码？例如，适配器的数据是如何更新的？当选择其中一个项目时，它会下载附近的位置数据，类似于图像下载（JSON和截图）编辑：我会将此添加到主帖子中