我正在尝试在片段内的网格视图中显示图像，并且图像是在异步任务加载器中的运行时下载的，并且我在同一片段中使用基本适配器。
现在，除了加载图像但没有显示加载器动画外，一切正常。我的 Fragment 类如下，其中包含 BaseAdapter 和 AsyncLoader
package friends.appModules.mainClasses;
import java.io.IOException;
import java.io.InputStream;
import java.net.URL;
import java.util.ArrayList;
import java.util.List;
import friends.appModules.commonClasses.Cheeses;
import android.content.Context;
import android.graphics.drawable.Drawable;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v4.app.LoaderManager;
import android.support.v4.content.AsyncTaskLoader;
import android.support.v4.content.Loader;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.BaseAdapter;
import android.widget.GridView;
import android.widget.ImageView;
import android.widget.Toast;
public class PeopleNearYou extends Fragment implements LoaderManager.LoaderCallbacks<List<Images>>{
private GridView pnuGridView;
ImageAdapter myImageAdapter;
boolean isLoadFinished = false;
@Override
public void onActivityCreated(Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
Log.d("Where am I?", "in onActivityCreated PeopleNearYou");
getLoaderManager().initLoader(1, null, this);
}
/* First Method call after onActivityCreated*/
@Override
public Loader<List<Images>> onCreateLoader(int id, Bundle args) {
Log.d("Where am I?", "in onCreateLoader PeopleNearYou");
return new PeopleNearYouLoader(getActivity());
}
@Override
/*Fourth Method Called*/
public void onLoadFinished(Loader<List<Images>> loader,
List<Images> data) {
Log.d("Where am I?", "in onLoadFinished PeopleNearYou");
final Context c = this.getActivity().getApplicationContext();
myImageAdapter = new ImageAdapter(c);
myImageAdapter.setData(data);
pnuGridView.setAdapter(myImageAdapter);
}
@Override
public void onLoaderReset(Loader<List<Images>> loader) {
Log.d("Where am I?", "in onLoaderReset PeopleNearYou");
myImageAdapter.setData(null);
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
Log.d("Where am I?", "in onCreateView PeopleNearYou");
View view = inflater.inflate(R.layout.people_near_you, container, false);
pnuGridView = (GridView) view.findViewById(R.id.gridview);
//pnuGridView.setBackgroundColor(R.color.dark_gry_txt);
return view;
}
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
}
public class ImageAdapter extends BaseAdapter{
private Context mContext;
private List<Images> finallyListCreated;
public ImageAdapter(Context c) {
Log.d("Where am I?", "in ImageAdapter Constructor PeopleNearYou");
mContext = c;
pnuGridView.setOnItemClickListener(new OnItemClickListener() {
public void onItemClick(AdapterView<?> parent, View v, int position, long id) {
Toast.makeText(mContext, "" + position, Toast.LENGTH_SHORT).show();
}
});
}
public int getCount() {
Log.d("Where am I?", "in getCount PeopleNearYou");
return 20;
}
public Object getItem(int position) {
Log.d("Where am I?", "in getItem PeopleNearYou");
return null;
}
public long getItemId(int position) {
Log.d("Where am I?", "in getItemId PeopleNearYou");
return 0;
}
public void setData(List<Images> data) {
Log.d("Where am I ??", "in onSetData() PeopleNearYou");
if (data != null) {
finallyListCreated = data;
}
}
public View getView(int position, View convertView, ViewGroup parent) {
Log.d("Where am I?", "in getView PeopleNearYou");
ImageView imageView;
if (convertView == null) { // if it's not recycled, initialize some attributes
imageView = new ImageView(mContext);
imageView.setLayoutParams(new GridView.LayoutParams(85, 85));
imageView.setScaleType(ImageView.ScaleType.CENTER_CROP);
imageView.setPadding(8, 8, 8, 8);
imageView.setBackgroundColor(R.color.dark_gry_txt);
} else {
imageView = (ImageView) convertView;
}
Images item = finallyListCreated.get(position);
imageView.setImageDrawable(item.getImageUrl());
return imageView;
}
}
public static class PeopleNearYouLoader extends AsyncTaskLoader<List<Images>>{
Context loaderContext;
List<Images> loaderImageList;
public PeopleNearYouLoader(Context context) {
super(context);
Log.d("Where am I?", "in PeopleNearYouLoader Constructor PeopleNearYou");
loaderContext = context;
}
@Override
/*Third method called if there are no images in the list else Deliver Result method will be called*/
public List<Images> loadInBackground()
{
Log.d("Where am I ??", "in loadInBackground() PeopleNearYou");
List<Images> peopleNearYouImagesList = new ArrayList<Images>(20);
for (int i=0; i<20; i++) {
Log.d("Where am I ??", "For loop to set Image objects PeopleNearYou");
Images peopleNearYouImages = new Images(loadImageFromUrl(Cheeses.imageUrls[i]));
peopleNearYouImagesList.add(peopleNearYouImages);
}
return peopleNearYouImagesList;
}
@Override
public void onCanceled(List<Images> data) {
super.onCanceled(data);
onReleaseResources(data);
}
@Override
public void deliverResult(List<Images> images) {
if (isReset()) {
if (images != null) {
onReleaseResources(images);
}
}
List<Images> oldImages = images;
loaderImageList = images;
if (isStarted()) {
super.deliverResult(images);
Log.d("Where am I ??", "in isStarted = true PeopleNearYou");
}
if (oldImages != null) {
onReleaseResources(oldImages);
Log.d("Where am I ??", "in oldImages != null PeopleNearYou");
}
}
@Override
/* Second method called*/
protected void onStartLoading() {
if (loaderImageList != null) {
deliverResult(loaderImageList);
Log.d("Where am I ??", "in onStartLoading() and list is not null");
}
else {
Log.d("Where am I ??", "in onStartLoading() and list is null");
forceLoad();
}
}
@Override
protected void onStopLoading() {
cancelLoad();
Log.d("Where am I ??", "in onStopLoading() PeopleNearYou");
}
@Override
protected void onReset() {
super.onReset();
onStopLoading();
if (loaderImageList != null) {
onReleaseResources(loaderImageList);
loaderImageList = null;
}
}
protected void onReleaseResources(List<Images> data) {
Log.d("Where am I ??", "in onReleaseResources() PeopleNearYou");
}
public Drawable loadImageFromUrl(String url) {
InputStream inputStream;
try {
inputStream = new URL(url).openStream();
} catch (IOException e) {
throw new RuntimeException(e);
}
return Drawable.createFromStream(inputStream, "src");
}
}
}
我的gridview布局是：
<?xml version="1.0" encoding="utf-8"?>
<GridView xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/gridview"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:numColumns="auto_fit"
android:verticalSpacing="10dp"
android:horizontalSpacing="10dp"
android:columnWidth="90dp"
android:stretchMode="columnWidth"
android:gravity="center"
/>
我的代码中使用的图像类也是：
package friends.appModules.mainClasses;
import android.app.Application;
import android.graphics.drawable.Drawable;
public class Images extends Application{
private Drawable imageUrl;
public Images(Drawable imageUrl) {
this.imageUrl = imageUrl;
}
public Drawable getImageUrl() {
return imageUrl;
}
}
提前致谢。