我想阅读一些图书的数据，并在列表视图中显示它们并使用位图显示图书的图片。我可以显示其他信息，但我无法显示图片，我无法找到原因，因为我做了所需的位图需求，因为我使用我的照片显示的AsyncTask方法！
而且很棒的是当我点击一个项目，下载布局正确地显示书的图片时，当我再次从第一个位置打开AllBooksActivity时，它正好显示图片！@ / p>
这是我的AllBooksActivity代码：
public class AllBooksActivity extends Activity {
public ListItem adapter;
public ListView allbooklist;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_all_books);
new loadingbooks().execute();
}
private class loadingbooks extends AsyncTask<String, String, String> {
private ProgressDialog pDialog;
@Override
protected void onPreExecute() {
super.onPreExecute();
pDialog = new ProgressDialog(AllBooksActivity.this);
pDialog.setMessage("کتابها در حال بارگذاری، لطفا منتظر بمانید...");
pDialog.setIndeterminate(false);
pDialog.setCancelable(false);
pDialog.show();
}
@Override
protected String doInBackground(String... args) {
String res = JSONCommands.readData(MainActivity.params);
return res;
}
@Override
protected void onPostExecute(String res) {
if(res != null){
pDialog.dismiss();
AllBooksActivity.this.getActionBar().setTitle(MainActivity.how);
allbooklist = (ListView) findViewById(R.id.list_all);
allbooklist.setOnItemClickListener(new OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
Intent in = new Intent(getApplicationContext(), DownloadActivity.class);
in.putExtra("MyClass", MainActivity.books_array.get(position));
startActivity(in);
}
});
adapter = new ListItem(AllBooksActivity.this, MainActivity.books_array);
allbooklist.setAdapter(adapter);
}
else {
pDialog.dismiss();
AlertDialog.Builder builder = new AlertDialog.Builder(AllBooksActivity.this)
.setTitle("خطا در برقراری ارتباط با سرور")
.setMessage("نمایش کتاب ناموفق :( اتصالات را بررسی کنید.");
builder.create().show();
}
}
}
这是我的列表适配器代码：
public class ListItem extends BaseAdapter {
private int count;
private Context context;
private ArrayList<ShowBook> bookArray;
public ListItem(Context context, ArrayList<ShowBook> bookArray) {
this.count = bookArray.size();
this.context = context;
this.bookArray = bookArray;
}
@Override
public int getCount() {
// TODO Auto-generated method stub
return count;
}
@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 0;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
LayoutInflater inflater = (LayoutInflater) context.getSystemService( Context.LAYOUT_INFLATER_SERVICE );
View row = inflater.inflate(R.layout.list_item, parent, false);
TextView namketabltxt, nevisandeltxt, mozooltxt, qeymatltxt;
ImageView tasvirlimg;
namketabltxt = (TextView) row.findViewById(R.id.ltxt_namketab);
nevisandeltxt = (TextView) row.findViewById(R.id.ltxt_nevisande);
mozooltxt = (TextView) row.findViewById(R.id.ltxt_mozoo);
qeymatltxt = (TextView) row.findViewById(R.id.ltxt_qeymat);
tasvirlimg = (ImageView)row.findViewById(R.id.limg_tasvir);
namketabltxt.setText(MainActivity.books_array.get(position).namketab);
nevisandeltxt.setText(MainActivity.books_array.get(position).nevisande);
mozooltxt.setText(MainActivity.books_array.get(position).mozoo);
qeymatltxt.setText(MainActivity.books_array.get(position).qeymat);
JSONCommands.getpic(MainActivity.books_array.get(position).tasvir, tasvirlimg);
return row;
}
}
这是我的DownloadActivity代码：
@SuppressLint("ShowToast") public class DownloadActivity extends Activity {
TextView namketabdtxt, nevisandedtxt, mozoodtxt, qeymatdtxt, uplodkonandedtxt;
ImageView tasvirdimg;
Button dlbtn;
RatingBar rb;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_download);
StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder().permitAll().build();
StrictMode.setThreadPolicy(policy);
namketabdtxt = (TextView) findViewById(R.id.dtxt_namketab);
nevisandedtxt = (TextView) findViewById(R.id.dtxt_nevisande);
mozoodtxt = (TextView) findViewById(R.id.dtxt_mozoo);
uplodkonandedtxt = (TextView) findViewById(R.id.dtxt_uplodkonande);
qeymatdtxt = (TextView) findViewById(R.id.dtxt_qeymat);
tasvirdimg = (ImageView) findViewById(R.id.dimg_tasvir);
dlbtn = (Button)findViewById(R.id.btn_dl);
rb = (RatingBar) findViewById(R.id.ratingBar1);
final ShowBook book = (ShowBook) getIntent().getSerializableExtra("MyClass");
this.getActionBar().setTitle(book.namketab);
namketabdtxt.setText(book.namketab);
nevisandedtxt.setText(book.nevisande);
mozoodtxt.setText(book.mozoo);
uplodkonandedtxt.setText(book.uplodkonande);
qeymatdtxt.setText(book.qeymat);
JSONCommands.getpic(book.tasvir, tasvirdimg);
dlbtn.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View arg0) {
DownloadFileFromURL downloader = new DownloadFileFromURL();
//downloader.setDownloadedFileName()
String name = book.fileketab.substring(book.fileketab.lastIndexOf("/") + 1);
downloader.setDownloadedFileName(name);
downloader.execute(JSONCommands.firstURL + book.fileketab);
}
});
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.download, menu);
return true;
}
private class DownloadFileFromURL extends AsyncTask<String, String, String> {
private String downloadedfileName;
@Override
protected void onPostExecute(String result) {
// TODO Auto-generated method stub
Toast.makeText(getApplicationContext(), "بارگذاری کتاب باموفقیت انجام شد", Toast.LENGTH_LONG).show();
Toast.makeText(getApplicationContext(), "برای دیدن آن به کتابخانه مراجعه نمایید", Toast.LENGTH_LONG).show();
}
public void setDownloadedFileName(String downloadedfileName){
this.downloadedfileName = downloadedfileName;
}
/**
* Downloading file in background thread
* */
@Override
protected String doInBackground(String... surl) {
int count;
try {
URL url = new URL(surl[0]);
URLConnection conection = url.openConnection();
conection.connect();
// this will be useful so that you can show a typical 0-100%
// progress bar
int lenghtOfFile = conection.getContentLength();
// download the file
InputStream input = new BufferedInputStream(url.openStream(),
8192);
// Output stream
//OutputStream output = new FileOutputStream(Environment
// .getExternalStorageDirectory().toString()
// + "/data/" + downloadedfileName);
OutputStream output = new FileOutputStream(getFilesDir()+File.separator +downloadedfileName);
byte data[] = new byte[1024];
long total = 0;
while ((count = input.read(data)) != -1) {
total += count;
// publishing the progress....
// After this onProgressUpdate will be called
// publishProgress("" + (int) ((total * 100) / lenghtOfFile));
// writing data to file
output.write(data, 0, count);
}
// flushing output
output.flush();
// closing streams
output.close();
input.close();
} catch (Exception e) {
Log.e("Error: ", e.getMessage());
}
return null;
}
}
/**
* After completing background task called
* **/
}
这是我使用Bitmap的getpic代码（这个函数在我的JSONCommands类中，这就是为什么我把它们称为＆＃34; JSONCommands.getpic＆＃34;）：
public static void getpic(String str, ImageView tasvir){
Bitmap bitmap;
if(str != null){
bitmap = getBitmapFromURL(firstURL+ str);
if(bitmap!=null){
tasvir.setImageBitmap(bitmap);
}
else{
tasvir.setImageResource(R.drawable.p3_books);
}
}
else{
tasvir.setImageResource(R.drawable.p3_books);
}
}
public static Bitmap getBitmapFromURL(String src) {
try {
URL url = new URL(src);
HttpURLConnection connection = (HttpURLConnection) url.openConnection();
connection.setDoInput(true);
connection.connect();
InputStream input = connection.getInputStream();
Bitmap myBitmap = BitmapFactory.decodeStream(input);
connection.disconnect();
return myBitmap;
} catch (IOException e) {
e.printStackTrace();
return null;
}
}
我无法找到解决方案而且它让我发疯了:)请帮忙，坦克你。