MainActivity?AppCompatActivity?{ ????(Bundle?savedInstanceState)?{ ????????.onCreate(savedInstanceState)setContentView(R.layout.)Image?a=Image()Image.MyAsyncTask?task=a.MyAsyncTask()task.execute()} ????(View?view)?{ ????????startActivity(Intent(Image.))} }<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" ? ?android:layout_width="match_parent" ? ?android:layout_height="match_parent" ? ?android:orientation="vertical"><Button ? ?android:onClick="loadimage" ? ?android:layout_width="match_parent" ? ?android:layout_height="wrap_content" ? ?android:text="loading image" ? ?/></LinearLayout>Image?Activity?{ ????ImageView?ProgressBar?String?=?(Bundle?savedInstanceState)?{ ????????.onCreate(savedInstanceState)setContentView(R.layout.)=?(ImageView)?findViewById(R.id.)=?(ProgressBar)?findViewById(R.id.)MyAsyncTask().execute()} ????MyAsyncTask?AsyncTask<StringVoidBitmap>?{ ????????()?{ ????????????.onPreExecute().setVisibility(View.)} ????????(Bitmap?bitmap)?{ ????????????.onPostExecute(bitmap).setVisibility(View.).setImageBitmap(bitmap)} ????????Bitmap?(String...?params)?{???String?url?=?params[]Bitmap?bitmap?=?URLConnection?connectionInputStream?is{ ????????????????connection?=?URL(url).openConnection()is?=?connection.getInputStream()BufferedInputStream?bis?=?BufferedInputStream(is)bitmap?=?BitmapFactory.(bis)is.close()bis.close()}?(IOException?e)?{ ????????????????e.printStackTrace()} ????????????bitmap} ????} }<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" ? ?android:layout_width="match_parent" ? ?android:layout_height="match_parent"> ? ?<ImageView ? ? ? ?android:id="@+id/image" ? ? ? ?android:layout_width="match_parent" ? ? ? ?android:layout_height="match_parent" /> ? ?<ProgressBar ? ? ? ?android:id="@+id/progressBar" ? ? ? ?android:layout_width="wrap_content" ? ? ? ?android:layout_height="wrap_content" ? ? ? ?android:layout_centerInParent="true" ? ? ? ?android:visibility="gone" /></RelativeLayout>activity都定義了