我想在从远程服务器加载图像时在gridview中使用预加载器图像。当它从服务器加载时，我想显示这样的预加载器图像（与进度条或进度条相同）。
我想在 gridview 图像项或预加载器图像中显示小的进度条我不知道我可以使用什么，这对我来说很容易实现这一点。
任何人都可以帮助我如何在android中做这件事。
我想让它像IOS一样。此图像来自 IOS。
这是我的 android 布局 xml 文件：
activity_image_grid.xml
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="wrap_content" >
<include
android:id="@+id/title_bar"
android:layout_alignParentTop="true"
layout="@layout/activity_top_header_bar" />
<GridView
android:id="@+id/gridview"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:layout_below="@id/title_bar"
android:gravity="center"
android:horizontalSpacing="4dip"
android:numColumns="4"
android:padding="5dip"
android:stretchMode="columnWidth"
android:verticalSpacing="4dip" />
</RelativeLayout>
此 xml 文件用于 Gridview 中每个网格的项目。
item_grid_image.xml
<?xml version="1.0" encoding="utf-8"?>
<ImageView xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/image"
android:layout_width="fill_parent"
android:layout_height="75dp"
android:adjustViewBounds="true"
android:contentDescription="@string/descr_image"
android:scaleType="centerCrop" />
源代码 ：
public class ImageGridActivity extends BaseActivity {
private static final String TAG = "[ImageGridActivity]";
private DisplayImageOptions options;
private PullToRefreshGridView mPullRefreshGridView;
private GridView mGridView = null;
ArrayList<GallaryImage> mGridViewImagesList;
private ImageAdapter mImageAdapter = null;
private String mImageUrl = null;
private String mGallaryTitle = null;
// private ImageLoader imageLoader = ImageLoader.getInstance();
@Override
public void onCreate(final Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_image_grid);
options = new DisplayImageOptions.Builder()
.showStubImage(R.drawable.photo_default)
.showImageForEmptyUri(R.drawable.photo_default)
.showImageOnFail(R.drawable.ic_error).cacheInMemory()
.cacheOnDisc().bitmapConfig(Bitmap.Config.RGB_565).build();
final Bundle bundle = getIntent().getExtras();
if (bundle != null) {
mImageUrl = bundle.getString(Constants.GALLARY_FETCH_URL);
mGallaryTitle = bundle.getString(Constants.GALLARY_TYPE);
if (mGallaryTitle != null) {
Locale loc = Locale.getDefault();
TextView tvTitleText = (TextView) findViewById(R.id.tv_title_bar_text);
tvTitleText.setText(mGallaryTitle.toUpperCase(loc));
}
mPullRefreshGridView = (PullToRefreshGridView) findViewById(R.id.pull_refresh_grid);
mPullRefreshGridView.setMode(Mode.PULL_FROM_START);
mGridView = mPullRefreshGridView.getRefreshableView();
mGridViewImagesList = Utility.getImagesList(mImageUrl,
ImageGridActivity.this);
if (mGridViewImagesList != null && !mGridViewImagesList.isEmpty()) {
mImageAdapter = new ImageAdapter(mGridViewImagesList);
((GridView) mGridView).setAdapter(mImageAdapter);
} else {
// did refresh after the previous images are loaded in the
// gridview.
if (Utility.checkConnection(ImageGridActivity.this)) {
Log.i(TAG,
"Wifi/Internet Connection found , have to parse the xml");
final FetchImagesAsyncTaskFeed asyncTask = new FetchImagesAsyncTaskFeed();
asyncTask.execute(mImageUrl);
}
}
mGridView.setOnItemClickListener(new OnItemClickListener() {
@Override
public void onItemClick(final AdapterView<?> parent,
final View view, final int position, final long id) {
if (mGridViewImagesList != null
&& !mGridViewImagesList.isEmpty()) {
startImagePagerActivity(mGridViewImagesList, position);
} else {
Log.d(TAG, "There is no image about this grid image");
}
}
});
// Set a listener to be invoked when the list should be refreshed.
mPullRefreshGridView
.setOnRefreshListener(new OnRefreshListener2<GridView>() {
@Override
public void onPullDownToRefresh(
PullToRefreshBase<GridView> refreshView) {
if (mImageUrl != null) {
final FetchImagesAsyncTaskFeed asyncTask = new FetchImagesAsyncTaskFeed();
asyncTask.execute(mImageUrl);
}
}
@Override
public void onPullUpToRefresh(
PullToRefreshBase<GridView> refreshView) {
}
});
}
}
/**
* @param position
*/
private void startImagePagerActivity(
final ArrayList<GallaryImage> mImageAttributesList,
final int position) {
String[] urls = new String[mImageAttributesList.size()];
final Intent intent = new Intent(this, ImagePagerActivity.class);
intent.putExtra(Constants.GALLARY_IMAGE_POSITION_BUNDLE_KEY, position);
for (int i = 0; i < mImageAttributesList.size(); i++) {
urls[i] = mImageAttributesList.get(i).mImageUrl;
}
intent.putExtra(Constants.GALLARY_IMAGES_IMAGE_BUNDLE_KEY, urls);
startActivity(intent);
}
public class ImageAdapter extends BaseAdapter {
ArrayList<GallaryImage> imageList = null;
public ImageAdapter(final ArrayList<GallaryImage> imageAttributesList) {
this.imageList = imageAttributesList;
}
@Override
public int getCount() {
return imageList.size();
}
@Override
public Object getItem(final int position) {
return imageList.get(position);
}
@Override
public long getItemId(final int position) {
return position;
}
@Override
public View getView(final int position, final View convertView,
final ViewGroup parent) {
final ImageView imageView;
if (convertView == null) {
imageView = (ImageView) getLayoutInflater().inflate(
R.layout.item_grid_image, parent, false);
} else {
imageView = (ImageView) convertView;
}
imageLoader.displayImage(imageList.get(position).mImageUrl,
imageView, options);
return imageView;
}
/**
* @param updateData
*/
public void updatedData(ArrayList<GallaryImage> imgList) {
this.imageList = imgList;
notifyDataSetChanged();
}
}
private class FetchImagesAsyncTaskFeed extends
AsyncTask<String, Void, String> {
@Override
protected void onPreExecute() {
}
@Override
protected String doInBackground(final String... urls) {
try {
Thread.sleep(3000);
final String imageUrl = urls[0];
final GridViewImagesXMLHandler mGallaryXMLHandler = new GridViewImagesXMLHandler();
mGridViewImagesList = mGallaryXMLHandler.getImages(imageUrl);
if (mGridViewImagesList != null
&& !mGridViewImagesList.isEmpty()) {
Utility.setImagesInfromation(imageUrl, mGridViewImagesList,
ImageGridActivity.this);
}
} catch (final Exception e) {
Log.e(TAG, "Exception in fetch images from the url", e);
}
return null;
}
@Override
protected void onPostExecute(final String result) {
if (mGridViewImagesList != null && !mGridViewImagesList.isEmpty()) {
if (mImageAdapter != null) {
mImageAdapter.updatedData(mGridViewImagesList);
mPullRefreshGridView.onRefreshComplete();
} else {
mImageAdapter = new ImageAdapter(mGridViewImagesList);
((GridView) mGridView).setAdapter(mImageAdapter);
}
}
mPullRefreshGridView.onRefreshComplete();
}
}
}
