我有两个活动，将数组列表图像从活动sd卡传输到活动AddProductActivity。java代码是:
public class Sdcard extends Activity {
private ArrayList<String> imageUrls;
private DisplayImageOptions options;
private ImageAdapter imageAdapter;
ImageLoader imageLoader;
@SuppressWarnings("deprecation")
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_photoalbum);
getActionBar();
getActionBar().setHomeButtonEnabled(true);
getActionBar().setDisplayHomeAsUpEnabled(true);
getActionBar().setDisplayShowTitleEnabled(true);
getActionBar().setTitle("select image");
final String[] columns = { MediaStore.Images.Media.DATA,
MediaStore.Images.Media._ID };
final String orderBy = MediaStore.Images.Media.DATE_TAKEN;
Cursor imagecursor = managedQuery(
MediaStore.Images.Media.EXTERNAL_CONTENT_URI, columns, null,
null, orderBy + " DESC");
this.imageUrls = new ArrayList<String>();
for (int i = 0; i < imagecursor.getCount(); i++) {
imagecursor.moveToPosition(i);
int dataColumnIndex = imagecursor
.getColumnIndex(MediaStore.Images.Media.DATA);
imageUrls.add(imagecursor.getString(dataColumnIndex));
System.out.println("=====> Array path => " + imageUrls.get(i));
}
options = new DisplayImageOptions.Builder()
.showImageForEmptyUri(R.drawable.ic_launcher)
.showImageOnFail(R.drawable.ic_error_loadingsmall)
.cacheInMemory(true)
.cacheOnDisk(true)
.considerExifParams(true)
.bitmapConfig(Bitmap.Config.RGB_565)
.build();
imageLoader = ImageLoader.getInstance();
imageLoader.init(ImageLoaderConfiguration.createDefault(this));
imageAdapter = new ImageAdapter(this, imageUrls);
GridView gridView = (GridView) findViewById(R.id.album_gridview);
gridView.setAdapter(imageAdapter);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.select_image, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
case android.R.id.home:
Intent intent = new Intent(Sdcard.this, AddProductActivity.class);
intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
startActivity(intent);
return true;
case R.id.select_image_submit:
ArrayList<String> selectedItems = imageAdapter.getCheckedItems();
if (selectedItems.size() == 0) {
Toast.makeText(getBaseContext(), "no selected image！", Toast.LENGTH_LONG)
.show();
} else if (selectedItems.size() > 9) {
Toast.makeText(getBaseContext(), "must below 9 images", Toast.LENGTH_LONG)
.show();
} else {
Intent intent1 = new Intent(this, AddProductActivity.class);
intent1.putStringArrayListExtra("select_image", selectedItems);
intent1.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
setResult(9392,intent1);
finish();
}
default:
return super.onOptionsItemSelected(item);
}
}
@Override
protected void onStop() {
imageLoader.stop();
super.onStop();
}
public class ImageAdapter extends BaseAdapter {
ArrayList<String> mList;
LayoutInflater mInflater;
Context mContext;
SparseBooleanArray mSparseBooleanArray;
public ImageAdapter(Context context, ArrayList<String> imageList) {
// TODO Auto-generated constructor stub
mContext = context;
mInflater = LayoutInflater.from(mContext);
mSparseBooleanArray = new SparseBooleanArray();
mList = new ArrayList<String>();
this.mList = imageList;
}
public ArrayList<String> getCheckedItems() {
ArrayList<String> mTempArry = new ArrayList<String>();
for (int i = 0; i < mList.size(); i++) {
if (mSparseBooleanArray.get(i)) {
mTempArry.add(mList.get(i));
}
}
return mTempArry;
}
@Override
public int getCount() {
return imageUrls.size();
}
@Override
public Object getItem(int position) {
return null;
}
@Override
public long getItemId(int position) {
return position;
}
@Override
public View getView(final int position, View convertView,
ViewGroup parent) {
final ProgressBar spinner = (ProgressBar) findViewById(R.id.loading_image_fromsdcard);
if (convertView == null) {
convertView = mInflater.inflate(
R.layout.photoalbum_gridview_item, null);
}
CheckBox mCheckBox = (CheckBox) convertView
.findViewById(R.id.select_image_cb);
final ImageView imageView = (ImageView) convertView
.findViewById(R.id.photo_img_view);
imageLoader.displayImage("file://" + imageUrls.get(position),
imageView, options, new SimpleImageLoadingListener() {
@Override
public void onLoadingStarted(String imageUri, View view) {
spinner.setVisibility(View.VISIBLE);
}
@Override
public void onLoadingFailed(String imageUri, View view,
FailReason failReason) {
String message = null;
switch (failReason.getType()) {
case IO_ERROR:
message = "Input/Output error";
break;
case DECODING_ERROR:
message = "Image can't be decoded";
break;
case NETWORK_DENIED:
message = "Downloads are denied";
break;
case OUT_OF_MEMORY:
message = "Out Of Memory error";
break;
case UNKNOWN:
message = "Unknown error";
break;
}
Toast.makeText(Sdcard.this, message,
Toast.LENGTH_SHORT).show();
spinner.setVisibility(View.GONE);
}
@Override
public void onLoadingComplete(String imageUri,
View view, Bitmap loadedImage) {
spinner.setVisibility(View.GONE);
Animation anim =AnimationUtils.loadAnimation(Sdcard.this,
R.anim.push_left_in);
imageView.setAnimation(anim);
anim.start();
}
});
imageView.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
Toast.makeText(getBaseContext(),
"selected item is " + position, Toast.LENGTH_LONG)
.show();
}
});
mCheckBox.setTag(position);
mCheckBox.setChecked(mSparseBooleanArray.get(position));
mCheckBox.setOnCheckedChangeListener(mCheckedChangeListener);
return convertView;
}
OnCheckedChangeListener mCheckedChangeListener = new OnCheckedChangeListener() {
@Override
public void onCheckedChanged(CompoundButton buttonView,
boolean isChecked) {
// TODO Auto-generated method stub
mSparseBooleanArray.put((Integer) buttonView.getTag(),
isChecked);
}
};
}
}
和活动AddProductActivity从活动sd卡接收图像并在其上显示图像，如代码
public class AddProductActivity extends Activity{
GridView gridView;
private String image;
private static final int GALLERY_REQUEST = 9390;
private DisplayImageOptions options;
ImageLoader imageLoader;
private ArrayList<String> selectImageUrls;
String[] f;
private SelectImageAdapter selectImageAdapter;
ImageView imageView;
@SuppressWarnings("deprecation")
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_add_product);
final ActionBar actionBar = getActionBar();
actionBar.setDisplayShowTitleEnabled(false);
// actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_LIST);
actionBar.setHomeButtonEnabled(true);
actionBar.setDisplayHomeAsUpEnabled(true);
actionBar.setDisplayShowTitleEnabled(true);
actionBar.setTitle("add product");
options = new DisplayImageOptions.Builder()
.showStubImage(R.drawable.ic_launcher)
.showImageOnFail(R.drawable.ic_error_loadingsmall)
.cacheInMemory().cacheOnDisc().build();
gridView = (GridView) findViewById(R.id.select_image_gridview);
this.selectImageUrls = new ArrayList<String>();
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.add_product, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
case android.R.id.home:
Intent intent = new Intent(AddProductActivity.this,
MainActivity.class);
intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
startActivity(intent);
return true;
case R.id.action_upload_picture:
return true;
default:
return super.onOptionsItemSelected(item);
}
}
public void onSelectFromSD(MenuItem item) {
Intent selectFromSdcard = new Intent(AddProductActivity.this,Sdcard.class);
startActivityForResult(selectFromSdcard, GALLERY_REQUEST);
}
@Override
public void onActivityResult(int requestCode, int resultCode, Intent data) {
System.out.println("[requestCode=" + requestCode + "]" + "[resultCode="
+ resultCode + "]");
if (requestCode == GALLERY_REQUEST && resultCode == 9392
&& data != null) {
// image = data.getData().toString();
selectImageUrls = data.getStringArrayListExtra("select_image");
if (selectImageUrls != null) {
// System.out.println("recieve =" + selectImageUrls.size());
f = (String[]) selectImageUrls
.toArray(new String[selectImageUrls.size()]);
if (selectImageAdapter == null) {
selectImageAdapter = new SelectImageAdapter(this,
selectImageUrls);
imageLoader.init(ImageLoaderConfiguration
.createDefault(this));
gridView.setAdapter(selectImageAdapter);
selectImageAdapter.notifyDataSetChanged();
gridView.setOnItemClickListener(new OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent,
View view, int position, long id) {
startFullImagePagerActivity(position);
}
});
} else {
selectImageAdapter.notifyDataSetChanged();
}
} else {
return;
}
} else {
super.onActivityResult(requestCode, resultCode, data);
}
}
protected void startFullImagePagerActivity(int position) {
// TODO Auto-generated method stub
Intent i = new Intent(AddProductActivity.this,
FullScreenViewActivity.class);
i.putStringArrayListExtra("position_url", selectImageUrls);
i.putExtra("position", position);
startActivity(i);
}
public class SelectImageAdapter extends BaseAdapter {
LayoutInflater mInflater;
Context mContext;
public SelectImageAdapter(Context context, ArrayList<String> imageList) {
// TODO Auto-generated constructor stub
mContext = context;
mInflater = LayoutInflater.from(mContext);
imageLoader = ImageLoader.getInstance();
}
@Override
public int getCount() {
// TODO Auto-generated method stub
return selectImageUrls.size();
}
@Override
public Object getItem(int position) {
// TODO Auto-generated method stub
return null;
}
@Override
public long getItemId(int position) {
// TODO Auto-generated method stub
return position;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
// TODO Auto-generated method stub
if (convertView == null) {
convertView = mInflater.inflate(R.layout.select_image, null);
}
final ImageView imageView = (ImageView) convertView.findViewById(R.id.select_images);
final ProgressBar spinner = (ProgressBar)convertView.findViewById(R.id.select_image_loading);
//final ViewAnimator animator = (ViewAnimator)convertView.findViewById(R.id.animator);
imageLoader.displayImage("file://" + selectImageUrls.get(position), imageView,
options, new SimpleImageLoadingListener() {
@Override
public void onLoadingStarted(String imageUri, View view) {
spinner.setVisibility(View.VISIBLE);
//animator.setDisplayedChild(1);
}
@Override
public void onLoadingFailed(String imageUri, View view,
FailReason failReason) {
String message = null;
switch (failReason.getType()) {
case IO_ERROR:
message = "Input/Output error";
break;
case DECODING_ERROR:
message = "Image can't be decoded";
break;
case NETWORK_DENIED:
message = "Downloads are denied";
break;
case OUT_OF_MEMORY:
message = "Out Of Memory error";
break;
case UNKNOWN:
message = "Unknown error";
break;
}Toast.makeText(AddProductActivity.this, message,Toast.LENGTH_SHORT).show();
spinner.setVisibility(View.GONE);
//animator.setDisplayedChild(0);
}
@Override
public void onLoadingComplete(String imageUri,
View view, Bitmap loadedImage) {
// Animation anim =
// AnimationUtils.loadAnimation(Sdcard.this,
// R.anim.push_left_in);
// imageView.setAnimation(anim);
// anim.start();
spinner.setVisibility(View.GONE);
notifyDataSetChanged();//followed with Armin's suggestion
}
});
return convertView;
}
}
但是当它返回活动AddProductActivity时，图像没有出现在gridview中，如果我单击editorText来激活键盘，则图像出现在gridview中。所以我很困惑，等待一些建议，谢谢!
image url:http://i61.tinypic.com/2ch9onq.png激活键盘图像出现:http://i61.tinypic.com/2l8uumc.png
如果我在AddProductActivity中使用这个getView()方法，它工作得很好。
@Override
public View getView(final int position, View convertView, ViewGroup
parent)
{
if (convertView == null){
imageView = new ImageView(mContext);
imageView.setLayoutParams(new GridView.LayoutParams(245, 150));
imageView.setScaleType(ImageView.ScaleType.CENTER_CROP);
}
else {
imageView = (ImageView) convertView;
}
BitmapFactory.Options bmOptions = new BitmapFactory.Options();
bmOptions.inJustDecodeBounds = false ;
bmOptions.inSampleSize = 4;
bmOptions.inPurgeable = true ;
Bitmap bitmap = BitmapFactory.decodeFile(selectImageUrls.get(position), bmOptions);
imageView.setImageBitmap(bitmap);
return imageView;
}
但是当它将图像转换回AddProductActivity时，它不平滑
尝试替换适配器代码
public class SelectImageAdapter extends BaseAdapter {
Context mContext;
ViewHolder holder;
public SelectImageAdapter(Context context, ArrayList<String> imageList) {
// TODO Auto-generated constructor stub
mContext = context;
imageLoader = ImageLoader.getInstance();
}
@Override
public int getCount() {
// TODO Auto-generated method stub
return selectImageUrls.size();
}
@Override
public Object getItem(int position) {
// TODO Auto-generated method stub
return null;
}
@Override
public long getItemId(int position) {
// TODO Auto-generated method stub
return position;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
if (convertView == null) {
holder = new ViewHolder();
convertView = LayoutInflater.from(mContext).inflate(R.layout.select_image, null);
holder.imageView = (ImageView) convertView.findViewById(R.id.select_images);
holder.spinner = (ProgressBar)convertView.findViewById(R.id.select_image_loading);
convertView.setTag(holder);
}else{
holder = (ViewHolder) convertView.getTag();
}
//final ViewAnimator animator = (ViewAnimator)convertView.findViewById(R.id.animator);
imageLoader.displayImage("file://" + selectImageUrls.get(position),holder.imageView,
options, new SimpleImageLoadingListener() {
@Override
public void onLoadingStarted(String imageUri, View view) {
holder.spinner.setVisibility(View.VISIBLE);
//animator.setDisplayedChild(1);
}
@Override
public void onLoadingFailed(String imageUri, View view,
FailReason failReason) {
String message = null;
switch (failReason.getType()) {
case IO_ERROR:
message = "Input/Output error";
break;
case DECODING_ERROR:
message = "Image can't be decoded";
break;
case NETWORK_DENIED:
message = "Downloads are denied";
break;
case OUT_OF_MEMORY:
message = "Out Of Memory error";
break;
case UNKNOWN:
message = "Unknown error";
break;
}
Toast.makeText(AddProductActivity.this, message,Toast.LENGTH_SHORT).show();
holder.spinner.setVisibility(View.GONE);
//animator.setDisplayedChild(0);
}
@Override
public void onLoadingComplete(String imageUri,
View view, Bitmap loadedImage) {
// Animation anim =
// AnimationUtils.loadAnimation(Sdcard.this,
// R.anim.push_left_in);
// imageView.setAnimation(anim);
// anim.start();
holder.spinner.setVisibility(View.GONE);
}
});
return convertView;
}
class ViewHolder {
ImageView imageView;
ProgressBar spinner;
}
}
我认为代码中缺少的是在加载图像后对notifyDataSetChanged() 的调用(在 onLoadingComplete() 侦听器的回调中)。
以上代码的编写方式，如果在onLoadingComplete()中调用notifyDataSetChanged()，它将解决您的问题。
但是，在该回调方法中每次调用notifyDataSetChanged()可能会显著降低性能。图片越多，性能越差。
如果通过上述操作观察到性能下降，我建议使用图像刷新辅助机制来解决这个问题。这样你可以调用notifyDataSetChanged():
- 加载n张图片后
- 或每过t秒
希望以上信息对你有所帮助。