所以我在parse.com的网格视图中成功加载图像，但是我将图像传递给我的ImageDetail类时遇到了麻烦，而且我还试图在ViewPager中加载图像以便我可以滑动根据发送图像的位置，图库中的图像..
以下是一些供参考的代码，我将非常感谢任何帮助或建议，以帮助我更接近我想要实现的目标。
这是我的Gallery的适配器：
public class GalleryAdapter extends BaseAdapter {
Context context;
LayoutInflater inflate;
LoadImages loadImages;
public static List<MyImages> galleryImages;
private ArrayList<MyImages> imageUrls;
public GalleryAdapter(Context context, List<MyImages> galleryImages){
this.context = context;
this.galleryImages = galleryImages;
inflate = LayoutInflater.from(context);
this.imageUrls = new ArrayList<MyImages>();
this.imageUrls.addAll(galleryImages);
loadImages = new LoadImages(context);
}
public class ViewHolder {
ImageView picture;
}
@Override
public int getCount() {
return galleryImages.size();
}
@Override
public Object getItem(int position) {
return galleryImages.get(position);
}
@Override
public long getItemId(int position) {
return position;
}
@Override
public View getView(final int position, View view, ViewGroup parent) {
// TODO Auto-generated method stub
final ViewHolder holder;
if (view == null){
holder = new ViewHolder();
view = inflate.inflate(R.layout.gallery_image, null);
// find image in gallery_image
holder.picture = (ImageView) view.findViewById(R.id.picture);
view.setTag(holder);
} else {
holder = (ViewHolder) view.getTag();
}
// load into myGallery gridview
loadImages.DisplayImages(galleryImages.get(position).getImages(), holder.picture);
GalleriesFragment.myGallery.setOnItemClickListener(new OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view,
int position, long id) {
// TODO pass position of image to ImageDetail view
Intent viewPic = new Intent(context, ImageDetail.class);
// pass data
viewPic.putExtra("pic", galleryImages.get(position).getImages());
Bundle bundle = new Bundle();
bundle.putInt("position", position);
//viewPic.putExtra("position", galleryImages.get(position));
//ImageDetail.pager.setCurrentItem(galleryImages.get(position));
context.startActivity(viewPic);
}
});
return view;
}
}
这里是ImageDetail类，我试图在从图库中点击的图片中调用，然后根据所选图像的位置扫描上一张/下一张图像：
public class ImageDetail extends Activity {
private ViewPager pager;
public static String pic;
LoadImages loading = new LoadImages(this);
ImageView selectedImage;
ImageView exitToGallery;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_image_detail);
// get intent from GalleriesFragment - get selected image
Intent getPic = getIntent();
// get image
// pic = getPic.getExtras().getString("pic");
pic = getPic.getStringExtra("pic");
Bundle getBundle = getPic.getExtras();
position = getBundle.getInt("position");
// position = getPic.getExtra("position");
pager = (ViewPager) findViewById(R.id.pager);
SwipeImageAdapter swipeAdapter = new SwipeImageAdapter();
pager.setAdapter(swipeAdapter);
pager.setCurrentItem(position);
Toast.makeText(MainActivity.context,
"Simply hit the back key to return to Galleries.",
Toast.LENGTH_LONG).show();
}
// for closing the view
@Override
public void finish() {
super.finish();
}
// Class for Swipe Image Functionality using ViewPager
private class SwipeImageAdapter extends PagerAdapter {
public int getCount() {
// TODO Auto-generated method stub
return GalleryAdapter.imageUrls.size();
}
/*
* // can't seem to get correct position of image tapped public String
* getItem(int position) { // TODO Auto-generated method stub
*
* //return GalleryAdapter.getImageurls().get(position); return
* GalleriesFragment.galleryImages.get(position).toString();
*
* }
*
* public long getItemId(int position) { // TODO Auto-generated method
* stub
*
* return position;
*
* }
*/
@Override
public boolean isViewFromObject(View view, Object obj) {
// TODO Auto-generated method stub
return view == ((ImageView) obj);
}
@Override
public Object instantiateItem(ViewGroup container, int position) {
Context context = ImageDetail.this;
selectedImage = new ImageView(context);
exitToGallery = new ImageView(context);
exitToGallery.setImageResource(R.drawable.close);
LinearLayout.LayoutParams layout = new LinearLayout.LayoutParams(
300, 500);
selectedImage.setLayoutParams(layout);
// pager.getCurrentItem();
// loading.DisplayImages(GalleryAdapter.imageUrls.indexOf(position),
// selectedImage);
loading.DisplayImages(pic, selectedImage);
// selectedImage.setImageResource(GalleryAdapter.imageUrls.indexOf(getBundle));
// using below stretches images, but otherwise they show up tiny on the image detail page =(
selectedImage.setScaleType(ImageView.ScaleType.FIT_XY);
// selectedImage.setScaleType(ImageView.ScaleType.CENTER_INSIDE);
exitToGallery.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
// TODO return to Galleries
finish();
}
});
((ViewPager) container).addView(selectedImage, 0);
((ViewPager) container).addView(exitToGallery, 0);
return selectedImage;
}
@Override
public void destroyItem(ViewGroup container, int position, Object obj) {
((ViewPager) container).removeView((ImageView) obj);
}
}
}
- 我也试过将从意图传递的图像加载到ImageDetail活动的图像视图中，但我无法显示图像。
我有更多的类/代码可供参考，与parse.com调用我的图片有关，但我认为我现在所分享的内容可能足以支持上下文。
已修改为包含加载图片的课程
public class LoadImages {
CacheMemory cacheMem = new CacheMemory();
CacheFile cacheFile;
private Map<ImageView, String> myPictures = Collections.synchronizedMap(new WeakHashMap<ImageView, String>());
ExecutorService executeService;
// this will display images to UI
Handler handleImages = new Handler();
public LoadImages(Context context){
cacheFile = new CacheFile(context);
executeService = Executors.newFixedThreadPool(5);
}
final int placeholder = R.drawable.famous;
public void DisplayImages(String url, ImageView pic){
myPictures.put(pic, url);
Bitmap bitmap = cacheMem.get(url);
if (bitmap != null){
pic.setImageBitmap(bitmap);
} else {
queuePic(url, pic);
pic.setImageResource(placeholder);
}
}
private void queuePic(String url, ImageView pic){
PicToLoad loadPic = new PicToLoad(url, pic);
executeService.submit(new PicLoader(loadPic));
}
private Bitmap getBitmap(String url){
File file = cacheFile.getFile(url);
Bitmap newBitmap = decode(file);
if (newBitmap != null){
return newBitmap;
}
// download my gallery images from parse.com
try {
Bitmap bitmap = null;
URL imgUrl = new URL(url);
HttpURLConnection connect = (HttpURLConnection) imgUrl.openConnection();
connect.setConnectTimeout(20000);
connect.setReadTimeout(20000);
connect.setInstanceFollowRedirects(true);
InputStream input = connect.getInputStream();
OutputStream output = new FileOutputStream(file);
Utilities.copy(input, output);
output.close();
connect.disconnect();
bitmap = decode(file);
return bitmap;
} catch (Throwable exception){
exception.printStackTrace();
if (exception instanceof OutOfMemoryError)
cacheMem.clear();
return null;
}
}
// decode image, scale to reduce memory usage
private Bitmap decode(File file) {
try{
BitmapFactory.Options options = new BitmapFactory.Options();
options.inJustDecodeBounds = true;
FileInputStream stream = new FileInputStream(file);
BitmapFactory.decodeStream(stream, null, options);
stream.close();
final int desiredImgSize = 150;
int width = options.outWidth, height = options.outHeight;
int scale = 1;
while (true){
if (width / 2 < desiredImgSize || height / 2 < desiredImgSize)
break;
width /= 2;
height /= 2;
scale *= 2;
}
BitmapFactory.Options options2 = new BitmapFactory.Options();
options2.inSampleSize = scale;
FileInputStream stream2 = new FileInputStream(file);
Bitmap bitmap = BitmapFactory.decodeStream(stream2, null, options2);
stream2.close();
return bitmap;
} catch (FileNotFoundException e){
} catch (IOException e){
e.printStackTrace();
}
return null;
}
// for queue
private class PicToLoad {
public String url;
public ImageView pic;
public PicToLoad(String url2, ImageView pic2){
url = url2;
pic = pic2;
}
}
class PicLoader implements Runnable {
PicToLoad picToLoad;
PicLoader(PicToLoad picToLoad) {
this.picToLoad = picToLoad;
}
@Override
public void run() {
// TODO Auto-generated method stub
try {
if (recycleImageView(picToLoad))
return;
Bitmap bit = getBitmap(picToLoad.url);
cacheMem.put(picToLoad.url, bit);
if (recycleImageView(picToLoad))
return;
DisplayBitmap display = new DisplayBitmap(bit, picToLoad);
handleImages.post(display);
} catch (Throwable e){
e.printStackTrace();
}
}
}
boolean recycleImageView(PicToLoad picToLoad) {
String tag = myPictures.get(picToLoad.pic);
if (tag == null || !tag.equals(picToLoad.url))
return true;
return false;
}
// display Bitmap on UI
class DisplayBitmap implements Runnable {
Bitmap bitmap;
PicToLoad picToLoad;
public DisplayBitmap(Bitmap bm, PicToLoad pl){
bitmap = bm;
picToLoad = pl;
}
@Override
public void run() {
// TODO Auto-generated method stub
if (recycleImageView(picToLoad))
return;
if (bitmap != null){
picToLoad.pic.setImageBitmap(bitmap);
} else {
picToLoad.pic.setImageResource(placeholder);
}
}
}
public void clearCache(){
cacheMem.clear();
cacheFile.clear();
}
}
答案 0 :(得分：0)
ViewPager的getCount方法返回零，它应该返回arraylist中的条目数，即arraylist.size（）
答案 1 :(得分：0)
因此，对于任何可能遇到与我相同问题的人，我都能让它发挥作用！
当我传递图像时：
GalleriesFragment.myGallery.setOnItemClickListener(new OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view,
int position, long id) {
// TODO pass position of image to ImageDetail view
Intent viewPic = new Intent(context, ImageDetail.class);
// pass data
viewPic.putExtra("pic", galleryImages.get(position).getImages());
// pass position
viewPic.putExtra("id", position);
context.startActivity(viewPic);
}
});
如何接收它：
public class ImageDetail extends Activity {
// changed from private to public static
public static ViewPager pager;
public static String pic;
public static int position;
LoadImages loading = new LoadImages(this);
ImageView selectedImage;
ImageView exitToGallery;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_image_detail);
// get intent from GalleriesFragment - get selected image
Intent getPic = getIntent();
// get image
pic = getPic.getStringExtra("pic");
// get position to open image tapped and display in the pager
position = getPic.getExtras().getInt("id");
Log.d("position = ", +position+"");
pager = (ViewPager) findViewById(R.id.pager);
SwipeImageAdapter swipeAdapter = new SwipeImageAdapter();
pager.setAdapter(swipeAdapter);
pager.setCurrentItem(position);
Toast.makeText(MainActivity.context,
"Simply hit the back key to return to Galleries.",
Toast.LENGTH_LONG).show();
}
// for closing the view
@Override
public void finish() {
super.finish();
}
// Class for Swipe Image Functionality using ViewPager
private class SwipeImageAdapter extends PagerAdapter {
public int getCount() {
// TODO Auto-generated method stub
return GalleryAdapter.imageUrls.size();
}
Object getItem(int position){
return position;
}
@Override
public boolean isViewFromObject(View view, Object obj) {
// TODO Auto-generated method stub
return view == ((ImageView) obj);
}
@Override
public Object instantiateItem(ViewGroup container, int position) {
Context context = ImageDetail.this;
selectedImage = new ImageView(context);
exitToGallery = new ImageView(context);
exitToGallery.setImageResource(R.drawable.close);
LinearLayout.LayoutParams layout = new LinearLayout.LayoutParams(
300, 500);
selectedImage.setLayoutParams(layout);
String img = GalleryAdapter.galleryImages.get(position).getImages();
loading.DisplayImages(img, selectedImage);
selectedImage.setScaleType(ImageView.ScaleType.CENTER_INSIDE);
exitToGallery.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
// TODO return to Galleries
finish();
}
});
((ViewPager) container).addView(selectedImage, 0);
((ViewPager) container).addView(exitToGallery, 0);
return selectedImage;
}
@Override
public void destroyItem(ViewGroup container, int position, Object obj) {
((ViewPager) container).removeView((ImageView) obj);
}
}
}