Android ProgressBar Preliminary application

The download progress is instantly displayed using ProgressBar.

Problems encountered on the way:

1. The main thread cannot open URLs, use Toast, etc.

2. Child threads Cannot modify UI

3. Allow network protocols

4. Pause download and Continue download

........

Fragment_main Layout file

1 <Relativelayoutxmlns:android= "Http://schemas.android.com/apk/res/android"2 Xmlns:tools= "Http://schemas.android.com/tools"3 Android:layout_width= "Match_parent"4 Android:layout_height= "Match_parent"5 Tools:context= "Com.dragon.android.textbar.mainactivity$placeholderfragment" >6 7     <!--Prigressbar progress bar -8     <!--Progress Current Progress -9     <!--indeterminate ambiguous default false -Ten     <ProgressBar One         Android:id= "@+id/progressbar1" A style= "? Android:attr/progressbarstylehorizontal" - Android:layout_width= "Match_parent" - Android:layout_height= "Wrap_content" the android:layout_centerinparent= "true" - Android:max= "+" - android:progress= "0" - android:indeterminate= "true"/> +  -     <Button +         Android:id= "@+id/button1" A Android:layout_width= "Wrap_content" at Android:layout_height= "Wrap_content" - Android:layout_alignparenttop= "true" - Android:layout_centerhorizontal= "true" - Android:onclick= "Startload" - Android:layout_margintop= "86DP" - Android:background= "#009FEE" in Android:text= "@string/start" - Android:textcolor= "#ffffff" /> to  +     <TextView -         Android:id= "@+id/textview1" the Android:layout_width= "Wrap_content" * Android:layout_height= "Wrap_content" $ Android:layout_above= "@+id/progressbar1"Panax Notoginseng Android:background= "@null" - Android:layout_alignparentleft= "true" /> the      + </Relativelayout>

Fragment_main

Strings.xml

1 <?XML version= "1.0" encoding= "Utf-8"?>2 <Resources>3 4     <stringname= "App_name">Hwdownload</string>5     <stringname= "Hello_world">Hello world!</string>6     <stringname= "Action_settings">Settings</string>7     <stringname= "Start">Begin</string>8     <stringname= "Stop">Time out</string>9     <stringname= "Contin">Go on</string>Ten  One </Resources>

Strings

(Issue 3) configuration in the Androidmanifest file

1 <!--  -2     <uses-permission  android:name  = "Android.permission.INTERNET"/>

Mainactivity (question 1, 2)

 PackageCom.dragon.android.textbar;Importjava.io.IOException;ImportJava.io.InputStream;Importjava.net.HttpURLConnection;ImportJava.net.URL;Importandroid.app.Activity;ImportAndroid.os.Bundle;ImportAndroid.view.View;ImportAndroid.widget.Button;ImportAndroid.widget.ProgressBar;ImportAndroid.widget.TextView;ImportAndroid.widget.Toast;/*** Only the thread that creates a view can change the view's UI!!! The main thread is also called the UI thread*/ Public classMainactivityextendsActivity {PrivateProgressBar progressBar1; PrivateButton button1; PrivateTextView TextView1; @Overrideprotected voidonCreate (Bundle savedinstancestate) {Super. OnCreate (savedinstancestate);        Setcontentview (R.layout.fragment_main); ProgressBar1=(ProgressBar) Findviewbyid (R.ID.PROGRESSBAR1); Button1=(Button) Findviewbyid (R.id.button1); TextView1=(TextView) Findviewbyid (R.ID.TEXTVIEW1); }     Public voidstartload (view view) {String text=(String) button1.gettext (); //Setting the button content----is not used ...Button1.settext (Text.equals (Getresources () getString (R.string.start))?r.string.stop: (Text.equals (Getresources (). getString (r.string.stop))?r.string.contin:r.string.stop)); Progressbar1.setindeterminate (false); NewThread (NewRunnable () {Private intpercent; @Override Public voidrun () {Try {                    //The open URL must be on a child threadURL url =NewURL ("Http://b.zol-img.com.cn/sjbizhi/images/9/540x960/1472549276394.jpg"); HttpURLConnection Conn=(HttpURLConnection) url.openconnection (); //Conn.setrequestmethod ("GET"); //conn.setreadtimeout (5000); //Conn.setconnecttimeout (the);                    intContentLength =conn.getcontentlength (); if(Conn.getresponsecode () = =HTTPURLCONNECTION.HTTP_OK) {InputStream is=Conn.getinputstream (); byte[] buffer =New byte[1024]; intLen =-1; intsum = 0;  while(len = is.read (buffer))! =-1) {sum+=Len; //pay attention to the strong turn mode, prevent always 0Percent = (int) (100.0 * Sum/contentlength);
                            //Child threads running on the main threadRunonuithread (NewRunnable () {@Override Public voidrun () {progressbar1.setprogress (percent); Textview1.settext (Percent+ "%"); if(Percent = =Progressbar1.getmax ()) {Toast.maketext (mainactivity). This,                                                "Download done!", Toast.length_short). Show ();                        }                                }                            });                        } is.close ();                    Conn.disconnect (); }                } Catch(IOException e) {e.printstacktrace ();    }}). Start (); }}

However, it did not solve the problem 4, to use a breakpoint to continue, but will not be stored assets resources ... ***************

　

Android ProgressBar Preliminary application