我在我的应用程序中使用 ViewPager 并从服务器获取数据(图像)(使用 JSON)。即使运行顺利, View 页面中也不会显示任何图像。
我读了很多关于此的教程,但没有人解决我的问题。请告诉我哪里错了...
这是我的代码:
view_pager.xml
<android.support.v4.view.ViewPager
android:id="@+id/viewpager"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_marginBottom="40dp" />
image_view.xml
<ImageView
android:id="@+id/image_adapter"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_centerInParent="true"/>
ViewPager_Adapter.java
public class ViewPager_Adapter extends PagerAdapter {
private String urls;
private LayoutInflater inflater;
private Context context;
ArrayList<String> mylist;
public ViewPager_Adapter(Context context, ArrayList<String> mylist) {
this.context = context;
this.urls = urls;
this.mylist = mylist;
inflater = LayoutInflater.from(context);
}
@Override
public void destroyItem(ViewGroup container, int position, Object object) {
container.removeView((View) object);
}
@Override
public int getCount() {
return mylist.size();
}
@Override
public Object instantiateItem(ViewGroup view, int position) {
View imageLayout = inflater.inflate(R.layout.image_view, null);
assert imageLayout != null;
final ImageView imageView = (ImageView) imageLayout.findViewById(R.id.image_adapter);
Glide.with(context)
.load(mylist.get(position))
.into(imageView);
view.addView(imageLayout,0);
return imageLayout;
}
@Override
public boolean isViewFromObject(View view, Object object) {
return view.equals(object);
}
@Override
public void restoreState(Parcelable state, ClassLoader loader) {
}
@Override
public Parcelable saveState() {
return null;
}
}
View_Pager.Java
public class View_Pager extends Fragment {
private static ViewPager mPager;
JSONArray responsearray = null;
String imageOne;
private static final String TAG_PHOTO_ONE = "Gallery_Full";
ArrayList<String> myList;
HashMap<String, String> get;
ViewPager_Adapter viewpager_adapter;
LinearLayout addimages;
int REQUEST_CODE = 100;
@Nullable
@Override
public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.view_pager, null);
mPager = view.findViewById(R.id.viewpager);
new GetImages().execute(true);
return view;
}
class GetImages extends AsyncTask<Boolean, Void, String> {
@Override
protected String doInBackground(Boolean... booleans) {
ImageApi imageApi = new ImageApi();
String result = null;
try {
result = imageApi.galleryget(sharedPreferences.getString("id", ""));
JSONObject object = new JSONObject(result);
if (object.getString("error").equalsIgnoreCase("false")) {
responsearray = object.getJSONArray("response");
return "true";
} else {
String errormsg = object.getString(result);
return errormsg;
}
} catch (ApiException e) {
e.printStackTrace();
} catch (JSONException e) {
e.printStackTrace();
}
return null;
}
@Override
protected void onPostExecute(String s) {
super.onPostExecute(s);
if (s != null) {
if (s.equalsIgnoreCase("true")) {
showList(responsearray);
}
}
}
}
public void showList(final JSONArray responsearray) {
try {
for (int i = 0; i < responsearray.length(); i++) {
JSONObject responseObject = responsearray.getJSONObject(i);
Log.e("COUNT" + i, String.valueOf(responseObject));
imageOne = responseObject.getString(TAG_PHOTO_ONE);
get = new HashMap<>();
get.put(TAG_PHOTO_ONE, imageOne);
myList = new ArrayList<>();
myList.add(String.valueOf(get));
}
viewpager_adapter = new ViewPager_Adapter(getActivity(), myList);
String test = String.valueOf(myList);
String imgpath = getString(R.string.imgpath);
String finalimgpath = imgpath + imageOne;
Log.e("FINALPATH", finalimgpath);
} catch (JSONException e) {
e.printStackTrace();
}
mPager.setAdapter(viewpager_adapter);
viewpager_adapter.notifyDataSetChanged();
}
}
最佳答案
将此代码用于 showList()
,因为您没有正确填充 arrayList,数据在一个位置被覆盖。
所以,你要做的就是在 for 循环之外初始化它。
public void showList(final JSONArray responsearray) {
try {
//here
myList = new ArrayList<>();
for (int i = 0; i < responsearray.length(); i++) {
JSONObject responseObject = responsearray.getJSONObject(i);
Log.e("COUNT" + i, String.valueOf(responseObject));
imageOne = responseObject.getString(TAG_PHOTO_ONE);
get = new HashMap<>();
get.put(TAG_PHOTO_ONE, imageOne);
myList.add(String.valueOf(get));
}
viewpager_adapter = new ViewPager_Adapter(getActivity(), myList);
String test = String.valueOf(myList);
String imgpath = getString(R.string.imgpath);
String finalimgpath = imgpath + imageOne;
Log.e("FINALPATH", finalimgpath);
} catch (JSONException e) {
e.printStackTrace();
}
mPager.setAdapter(viewpager_adapter);
viewpager_adapter.notifyDataSetChanged();
}
编辑
此外,如果您的最终图像路径如下所示,那么您必须在图像路径适配器中更新代码,如下所示。
也更新 view.addView()
中的位置。
String test = String.valueOf(mylist.get(position));
String imgpath = getString(R.string.imgpath);
String finalimgpath = imgpath + test;
Glide.with(context)
.load(finalimgpath)
.into(imageView);
view.addView(imageLayout,position);
return imageLayout;
关于java - ViewPager 未从服务器获取图像,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/55057420/