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我發佈之前已經研究過,但無法真正得到明確的答案,所以我來到這裏。在這些代碼行中,我想了解他們究竟做了什麼。我來自cpp背景,這裏的東西真的不一樣。AsyncTask幫助需要了解
new DisplayImageFromURL((ImageView) findViewById(R.id.my_image))
.execute("http://www.tmonews.com/wp-content/uploads/2012/10/androidfigure.jpg");
這段代碼究竟幹什麼?在我的代碼中有一個私有類聲明在下面,但我不知道它傳遞給下一個類的信息。
private class DisplayImageFromURL extends AsyncTask<String, Void, Bitmap> {
ImageView bmImage;
@Override
protected void onPreExecute() {
// TODO Auto-generated method stub
super.onPreExecute();
pd = new ProgressDialog(MainActivity.this);
pd.setMessage("Loading...");
pd.show();
}
public DisplayImageFromURL(ImageView bmImage) {
this.bmImage = bmImage;
}
protected Bitmap doInBackground(String... urls) {
String urldisplay = urls[0];
Bitmap mIcon11 = null;
try {
InputStream in = new java.net.URL(urldisplay).openStream();
mIcon11 = BitmapFactory.decodeStream(in);
} catch (Exception e) {
Log.e("Error", e.getMessage());
e.printStackTrace();
}
return mIcon11;
}
protected void onPostExecute(Bitmap result) {
bmImage.setImageBitmap(result);
pd.dismiss();
}
}
}
這段代碼做了什麼?這個花括號是什麼意思?
public DisplayImageFromURL(ImageView bmImage) {
this.bmImage = bmImage;
}
而這最後一個..從哪裏得到URL?
protected Bitmap doInBackground(String... urls) {
String urldisplay = urls[0];
閱讀文檔http://developer.android.com/reference/android/os/AsyncTask.html – Raghunandan
'那有什麼大括號的意思是在這裏嗎?'也許閱讀關於Java:http://ocw.mit.edu/courses/electrical-engineering-and-computer-science/6-092-introduction-to-programming-in-java-january-iap-2010/index .htm – verybadalloc
先生,我已閱讀官方安卓文檔 – user2479697