Asynchronous tasks for Android

/** * Three generic parameters for an asynchronous task: * 1, the parameter type passed in when the Execute method is called, input parameter * 2, progressupdate method into parameter * 3, return type of the return result type of the asynchronous task Doinbackground, Dopostexecute of the method of use * * * Some Considerations for using asynchronous Tasks * 1, an asynchronous task can only be executed once, more than once, will run out of exception * 2, must be created in the UI thread example of an asynchronous task * 3, you must call the Execute method in the UI thread * *    public class Asynctasktest extends Activity {private TextView tv_show;        @Override protected void OnCreate (Bundle savedinstancestate) {super.oncreate (savedinstancestate);        Setcontentview (r.layout.activity_async_task_test);    Initialize View Control Tv_show = (TextView) Findviewbyid (r.id.tv_show); }/** * Start asynchronous Task * @param view */public void StartAsyncTask (view view) throws Exception {Download        Asynctask asynctask = new Downloadasynctask (this);    Asynctask.execute (New URL ("http://baidu.com"));        } public class Downloadasynctask extends asynctask<url,integer,void>{private Context mcontext;        Private ProgressDialog progressdialog = null;           Public Downloadasynctask (Context context) { This.mcontext = context; }/** * Start the background task before execution, * generally do some initialization work, such as: Initialization dialog box */@Override protected void Onpre            Execute () {progressdialog = new ProgressDialog (mcontext);            Progressdialog.settitle ("In-mission execution");            Progressdialog.setmessage ("The task is executing, please wait patiently ...");            Sets the user cannot cancel the progress bar dialog box progressdialog.setcancelable (false);            Progressdialog.setmax (100);            Progressdialog.setprogressstyle (progressdialog.style_horizontal);        Progressdialog.show (); /** * Perform background tasks * @param params * @return */@Override protected Void            Doinbackground (URL ... params) {int i = 1;                for (; i < i++) {try {thread.sleep (300);                } catch (Interruptedexception e) {e.printstacktrace ();            } publishprogress (i);            }return null; }/** * Update progress information * @param values */@Override protected void Onprogressupdate (I            Nteger. Values) {super.onprogressupdate (values);            Tv_show.settext (Values[0] + "");        Progressdialog.setprogress (Values[0]); }/** * Do something after the background operation * @param aVoid */@Override protected void Onpostexecut            E (Void aVoid) {super.onpostexecute (aVoid);            Progressdialog.dismiss ();        ProgressDialog = null; }    }}

　　

Asynchronous tasks for Android