异步任务不起作用

Question

每当我调用DownloadImage("picture_name")应用程序时，应用程序都会停止。AsyncTask在此应用程序的另一个活动中工作，但不适用于此活动。

这是我的代码：

public class ViewPostDetails extends Activity {
TextView user_nameTv2, timestamTv2,statusTv2,likeTv2,commentTv2,shareTv2,tvcomlist;
ImageView pro_picImg2, post_picImg2,privacy_picImg2,like_picImg2,comment_picImg2,share_picImg2;
ListView lvcom;
Button btnpost;
EditText etcom;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_view_post_details);
intializeAll();
int like_count = getIntent().getExtras().getInt("like");
int comment_count = getIntent().getExtras().getInt("comment");
int share_count = getIntent().getExtras().getInt("share");

String pro_pic_name = getIntent().getExtras().getString("pro_pic_name");
String post_pic_name = getIntent().getExtras().getString("post_pic_name");
String user_name = getIntent().getExtras().getString("username");
String post_time = getIntent().getExtras().getString("time");
int privacy_pic = getIntent().getExtras().getInt("privacy_pic");
String status = getIntent().getExtras().getString("status");
user_nameTv2.setText(user_name);
timestamTv2.setText(post_time);
statusTv2.setText(status);
privacy_picImg2.setImageResource(privacy_pic);
likeTv2.setText(like_count+"");
commentTv2.setText(comment_count+"");
shareTv2.setText(share_count+"");
new DownloadImage(pro_pic_name,1).execute();
new DownloadImage("post_pic_name",2).execute();
BackgroundTaskLike backgroundTaskLike = new BackgroundTaskLike(this);
backgroundTaskLike.execute(like_count+"",user_name,post_time);
}
public void intializeAll() {
pro_picImg2 = (ImageView)findViewById(R.id.image22);
user_nameTv2 = (TextView)findViewById(R.id.name22);
timestamTv2 = (TextView)findViewById(R.id.time22);
statusTv2=(TextView)findViewById(R.id.status22);
post_picImg2 = (ImageView)findViewById(R.id.postimg22);
privacy_picImg2 = (ImageView)findViewById(R.id.privacyimg22);
like_picImg2 = (ImageView) findViewById(R.id.likeimg22);
comment_picImg2 = (ImageView) findViewById(R.id.commentimg22);
share_picImg2 = (ImageView)findViewById(R.id.shareimg22);
likeTv2=(TextView) findViewById(R.id.like22);
commentTv2=(TextView) findViewById(R.id.comment22);
shareTv2=(TextView) findViewById(R.id.share22);
etcom = (EditText) findViewById(R.id.etcomment);
tvcomlist = (TextView) findViewById(R.id.tvcommentlist);
lvcom = (ListView) findViewById(R.id.lvcomment);
btnpost = (Button) findViewById(R.id.btnpost);
}
public class BackgroundTaskLike extends AsyncTask<String, Void, Void> {

Context ctx;

public BackgroundTaskLike(Context context) {
// TODO Auto-generated constructor stub
this.ctx = context;
}
@Override
protected Void doInBackground(String... arg0) {
// TODO Auto-generated method stub
String insert_post_url = "http://accsectiondemo.site11.com/updateLikeCount.php";
String Like = arg0[0];
String username = arg0[1];
String time = arg0[2];
try {
URL url = new URL(insert_post_url);
//connect to URL
HttpURLConnection httpURLConnection = (HttpURLConnection) url.openConnection();
//sending data using POST method
httpURLConnection.setRequestMethod("POST");
//for sending some data to URL 
httpURLConnection.setDoOutput(true);
//to write information in buffered writer an output stream object need to be initialized
OutputStream OS = httpURLConnection.getOutputStream();
//to write information to URL
BufferedWriter bufferedWriter = new BufferedWriter(new OutputStreamWriter(OS, "UTF-8"));
String data = URLEncoder.encode("like", "UTF-8") + "="+ URLEncoder.encode(Like,"UTF-8") + "&" + 
URLEncoder.encode("username", "UTF-8") + "="+ URLEncoder.encode(username,"UTF-8") + "&" +
URLEncoder.encode("time", "UTF-8") + "="+ URLEncoder.encode(time,"UTF-8");
bufferedWriter.write(data);
bufferedWriter.flush();
bufferedWriter.close();
OS.close();
//get response from server
InputStream is = httpURLConnection.getInputStream();
is.close();
} catch (MalformedURLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return null;
}
}

---

private class DownloadImage extends AsyncTask<Void, Void, Bitmap> {
String name;
int count;
public DownloadImage(String name,int cnt) {
this.name=name;
this.count=cnt;
}
@Override
protected Bitmap doInBackground(Void... params) {
String url = "http://accsectiondemo.site11.com/" + "pictures/" + name + ".jpg";
try {
URLConnection connection  = new URL(url).openConnection();
connection.setConnectTimeout(1000*30);
connection.setReadTimeout(1000*30);
return BitmapFactory.decodeStream((InputStream) connection.getContent(),null,null);
} catch (Exception e) {
return null;
}
}
@Override
protected void onPostExecute(Bitmap bitmap) {
if(bitmap != null ) {
if(count==1) {
pro_picImg2.setImageBitmap(bitmap);
}
else {
post_picImg2.setImageBitmap(bitmap);
}
}
}
}
}

它崩溃了.. 我还调用下载图像并手动传递参数"pp.jpg"以忽略意图数据(服务器中有一张名为"pp.jpg"的图片)。但这也行不通。

这是日志文件...

06-16 14：36：01.045：E/Android运行时(1101)：致命异常：主要 06-16 14：36：01.045： E/AndroidRuntime(1101)： 进程： com.example.finderror， PID： 1101 06-16 14：36：01.045： E/AndroidRuntime(1101)： java.lang.NullPointerException 06-16 14：36：01.045： E/AndroidRuntime(1101)： at com.example.finderror.ViewAdapter$1.onClick(ViewAdapter.java：191) 06-16 14：36：01.045： E/AndroidRuntime(1101)： at android.view.View.performClick(View.java：4438) 06-16 14：36：01.045： E/AndroidRuntime(1101)： at android.view.View$PerformClick.run(View.java：18422) 06-16 14：36：01.045： E/AndroidRuntime(1101)： at android.os.Handler.handleCallback(Handler.java：733) 06-16 14：36：01.045： E/AndroidRuntime(1101)： at android.os.Handler.dispatchMessage(Handler.java：95) 06-16 14：36：01.045： E/AndroidRuntime(1101)： at android.os.Looper.loop(Looper.java：136) 06-16 14：36：01.045： E/AndroidRuntime(1101)： at android.app.ActivityThread.main(ActivityThread.java：5017) 06-16 14：36：01.045： E/AndroidRuntime(1101)： at java.lang.reflect.Method.invokeNative(Native Method) 06-16 14：36：01.045： E/AndroidRuntime(1101)： at java.lang.reflect.Method.invoke(Method.java：515) 06-16 14：36：01.045： E/AndroidRuntime(1101)： at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java：779) 06-16 14：36：01.045： E/AndroidRuntime(1101)： at com.android.internal.os.ZygoteInit.main(ZygoteInit.java：595) 06-16 14：36：01.045： E/AndroidRuntime(1101)： at dalvik.system.NativeStart.main(Native Method)

视图适配器代码在这里...

当我不调用Asynctask DownloadImage时，代码可以正常工作，但我无法在imageView中设置所需的图片。但是当我调用此应用程序时崩溃。

public class ViewAdapter extends ArrayAdapter {
private Context context;
List list = new ArrayList();
public ViewAdapter(Context context, int resource) {
super(context, resource);
this.context = context;
// TODO Auto-generated constructor stub
}

public void add(ClassDorkar ob) {
// TODO Auto-generated method stub
super.add(ob);
list.add(ob);
}

@Override
public int getCount() {
// TODO Auto-generated method stub
return this.list.size();
}
@Override
public Object getItem(int position) {
// TODO Auto-generated method stub
return this.list.get(position);
}
@Override
public View getView(final int position, View convertView, ViewGroup parent) {
View row;
final View intentView;
row = convertView;
intentView = row;
if(row==null) {
LayoutInflater layoutInflater = (LayoutInflater) this.getContext().getSystemService(Context.LAYOUT_INFLATER_SERVICE);
row = layoutInflater.inflate(R.layout.testlayout2,parent,false);
ImageView pro_picImg2 = (ImageView) row.findViewById(R.id.image2);
TextView user_nameTv2 = (TextView) row.findViewById(R.id.name2);
TextView timestamTv2 = (TextView) row.findViewById(R.id.time2);
TextView statusTv2=(TextView) row.findViewById(R.id.status2);
ImageView post_picImg2 = (ImageView) row.findViewById(R.id.postimg2);
ImageView privacy_picImg2 = (ImageView) row.findViewById(R.id.privacyimg2);
ImageView like_picImg2 = (ImageView) row.findViewById(R.id.likeimg2);
ImageView comment_picImg2 = (ImageView) row.findViewById(R.id.commentimg2);
ImageView share_picImg2 = (ImageView) row.findViewById(R.id.shareimg2);
final TextView likeTv2=(TextView) row.findViewById(R.id.like2);
TextView commentTv2=(TextView) row.findViewById(R.id.comment2);
TextView shareTv2=(TextView) row.findViewById(R.id.share2);
final ClassDorkar cd = (ClassDorkar) getItem(position);
pro_picImg2.setImageBitmap(cd.getPro_pic());
user_nameTv2.setText(cd.getUsername());
timestamTv2.setText(cd.getTime());
statusTv2.setText(cd.getStatus());
post_picImg2.setImageBitmap(cd.getPost_pic());
privacy_picImg2.setImageResource(cd.getPrivacy());
String s = cd.getLike() + "";
likeTv2.setText(s);
s = cd.getComment() + "";
commentTv2.setText(s);
s = cd.getShare() + "";
shareTv2.setText(s);
like_picImg2.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View arg0) {
// TODO Auto-generated method stub
int like = cd.getLike();
String user_name = cd.getUsername();
String post_time = cd.getTime();
like++;
cd.setLike(like);
String s = like + "";
likeTv2.setText(s);
Intent intent = new Intent(intentView.getContext(), ViewPostDetails.class);
//intent.putExtra("pro_pic_name", cd.getPro_pic_name());
//intent.putExtra("post_pic_name", cd.getPost_pic_name());
intent.putExtra("like", like);
intent.putExtra("comment", cd.getComment());
intent.putExtra("share", cd.getShare());
intent.putExtra("username", user_name);
intent.putExtra("time", post_time);
intent.putExtra("privacy_pic",cd.getPrivacy());
intent.putExtra("status", cd.getStatus());
context.startActivity(intent);
}
});
return row;
}

}

Answer 1

我找到了一个解决方案。虽然这是偶然的，但它有效。

我更改了异步任务名称，应用程序正在工作。