我在API 8中遇到了AsyncTask的问题...
这是我的代码......
try{
new loadPhotos().execute(""+USER._id,"date","DESC");
}catch(Exception e){
e.printStackTrace();
}
在你问之前......是的，我很绝望，所以我用try {} catch
包围了一切public class loadPhotos extends AsyncTask<String,Object,Void>{
ProgressBar pb;
ImageView img;
TableRow.LayoutParams paramsImage;
List<String> urlsOfImages;
TableLayout tl;
TableRow tr;
LayoutParams lp;
int numberOfPhotos=0;
@Override
protected void onPreExecute(){
urlsOfImages = new ArrayList<String>(); //There is stored urls of all images ( www.example.com/image1.jpg ... etc)
try {
allUserPhotoBitmaps.clear(); //allUserPhotoBitmaps is List<Bitmap>
pb = (ProgressBar) findViewById(R.id.profile_photos_progress_bar);
pb.setVisibility(View.VISIBLE);
tl = (TableLayout) findViewById(R.id.profile_photos_table_layout);
tl.removeAllViews();
tr = new TableRow(Profile.this);
lp = new LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT);
tr.setLayoutParams(lp);
}catch(Exception e){
Toast.makeText(Profile.this, "Error in onPreExecute", Toast.LENGTH_LONG).show();
}
}
@Override
protected Void doInBackground(String... arg) {
try{
// This function basicaly returns List<HashMap<String,String>> with informations about photos ( web_path, latitude, longitude, city, etc...)
allUserPhotoInformations = myDb.getUrlsOfUserImages(arg[0],arg[1],arg[2]);
}catch(Exception e){
Toast.makeText(Profile.this, "Error downloading images", Toast.LENGTH_SHORT).show();
}
if ( allUserPhotoInformations != null ) {
for (int i=0 ; i < allUserPhotoInformations.size() ; i++){
try{
Bitmap bm = getBitmapFromURL(allUserPhotoInformations.get(i).get("file_path"));
allUserPhotoBitmaps.add(bm);
publishProgress(bm,i);
}
catch(Exception e){
return null;
}
}
}
return null;
}
@Override
protected void onProgressUpdate(Object... arg){
img = new ImageView(getBaseContext());
paramsImage = new TableRow.LayoutParams( (((int)screenWidth)/2)-16 , (((((int)screenWidth)/2)-15)/16)*11 );
paramsImage.setMargins(10,10,0,0);
img.setLayoutParams(paramsImage);
img.setBackgroundColor(Color.parseColor("#FF000000"));
try{
img.setImageBitmap((Bitmap) arg[0]);
}catch(Exception e){
Toast.makeText(Profile.this,"Cannot put Bitmap into ImageView",Toast.LENGTH_LONG).show();
}
img.setVisibility(View.VISIBLE);
img.setOnClickListener(new ImageListener((Integer)arg[1])); //here I passing index to onClickListener
tr.addView(img);
if ( numberOfPhotos==1 ){
try{
tl.addView(tr, new TableLayout.LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.WRAP_CONTENT));
}catch(Exception e){
e.printStackTrace();
Toast.makeText(Profile.this,"Cannot inflate tableLayout",Toast.LENGTH_LONG).show();
}
tr = new TableRow(Profile.this);
tr.setLayoutParams(lp);
numberOfPhotos--;
}
else {
numberOfPhotos++;
}
}
@Override
protected void onPostExecute(Void arg){
pb.setVisibility(View.GONE);
userPhotos.setText("uploaded: "+allUserPhotoBitmaps.size()+" photos");
if ( numberOfPhotos==1 ){
try{
tl.addView(tr, new TableLayout.LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.WRAP_CONTENT));
}catch(Exception e){
e.printStackTrace();
Toast.makeText(Profile.this,"Cannot inflate tableLayout",Toast.LENGTH_LONG).show();
}
tr = new TableRow(Profile.this);
tr.setLayoutParams(lp);
}
}
在我的设备（API＆gt; 15）中，一切都运行良好，但在API 10中它会崩溃应用程序...我想要的，我也可以提供OnClickListener或其他一些方法......
是的，这里...... 我如何下载图片：
public Bitmap getBitmapFromURL(String src) {
try {
java.net.URL url = new java.net.URL(src);
HttpURLConnection connection = (HttpURLConnection) url.openConnection();
connection.setDoInput(true);
connection.connect();
InputStream input = connection.getInputStream();
Bitmap myBitmap = BitmapFactory.decodeStream(input);
double width;
double height;
width = (screenWidth)/myBitmap.getRowBytes();
if ( myBitmap.getWidth() > myBitmap.getHeight() ){
Log.w("size","landscape");
height = ((myBitmap.getRowBytes()*width)/16)*11;
width = (height/11)*16;
}
else {
Log.w("size","protrait");
height = ((myBitmap.getRowBytes()*width)/11)*16;
width = (height/16)*11;
}
Bitmap bitmap = Bitmap.createScaledBitmap(myBitmap, (int)width, (int)height, true);
return bitmap;
} catch (Exception e) {
e.printStackTrace();
Toast.makeText(Profile.this, "Error parsing image to bitmap", Toast.LENGTH_LONG).show();
return null;
}
}
任何帮助？
答案 0 :(得分：1)
在new loadPhotos().execute(""+USER._id,"date","DESC");中呼叫onCreate并使用Asynctask并尝试避免main thread中的加载。您的应用程序崩溃的主要原因之一可能是您在main thread.中调用了方法
例如：
String zoomouturl = "your url";
new ImageDownload().execute(zoomouturl);
尝试
public class ImageDownload extends AsyncTask<String, Void, String> {
protected String doInBackground(String... params) {
// TODO Auto-generated method stub
bmOptions = new BitmapFactory.Options();
bmOptions.inSampleSize = 1;
loadBitmap(zoomouturl, bmOptions);
return zoomouturl;
}
protected void onPostExecute(String imageUrl) {
if (!imageUrl.equals("")) {
Constants._image.setImageBitmap(bm);
} else {
Toast.makeText(this,
"not found proper bitmap.. ", Toast.LENGTH_LONG)
.show();
}
}
}
和
public static Bitmap loadBitmap(String URL, BitmapFactory.Options options) {
InputStream in = null;
try {
in = OpenHttpConnection(URL);
bm = BitmapFactory.decodeStream(in, null, options);
in.close();
} catch (IOException e1) {
}
return bm;
}
private static InputStream OpenHttpConnection(String strURL)
throws IOException {
InputStream inputStream = null;
URL url = new URL(strURL);
URLConnection conn = url.openConnection();
try {
HttpURLConnection httpConn = (HttpURLConnection) conn;
httpConn.setRequestMethod("GET");
httpConn.connect();
if (httpConn.getResponseCode() == HttpURLConnection.HTTP_OK) {
inputStream = httpConn.getInputStream();
}
} catch (Exception ex) {
}
return inputStream;
}