单击按钮后如何下载文件(Android Studio) [英] How to download a file after clicking a button (Android Studio)
问题描述
我最近在我的应用中创建了一个活动.现在，我希望用户在要查看指南时下载.pdf文件.我想在一个按钮上实现它.知道如何正确执行此操作吗?
I recently created an activity in my app. Now I wanted the user to download a .pdf file when he/she wants to view the guidelines. I wanted to implement this on a button. Any idea how to do this properly?
在下面提供我的代码:
public class Exhibitor_Registration_Activity extends AppCompatActivity {
Button buttonDownload;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_exhibitor_registration_);
this.setTitle("Buyer Registration");
Toolbar myToolbar = (Toolbar) findViewById(R.id.my_toolbar);
setSupportActionBar(myToolbar);
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
myToolbar.setNavigationIcon(R.drawable.ic_arrow_back_white_24dp);
final Button buttonDownload = (Button) findViewById(R.id.buttonDownload);
buttonDownload.setOnClickListener(new View.OnClickListener(){
@Override
public void onClick(View view) {
try {
//this is the file you want to download from the remote server
String path ="http://www.manilafame.com/website-assets/downloads/exhibitor-application-kit/local/201704/1-Summary-of-Participation-Details-April-2017_MN_002.pdfp";
//this is the name of the local file you will create
String targetFileName = null;
boolean eof = false;
URL u = new URL(path);
HttpURLConnection c = (HttpURLConnection) u.openConnection();
c.setRequestMethod("GET");
c.setDoOutput(true);
c.connect();
FileOutputStream f = new FileOutputStream(new File("c:\\junk\\"+targetFileName));
InputStream in = c.getInputStream();
byte[] buffer = new byte[1024];
int len1 = 0;
while ( (len1 = in.read(buffer)) > 0 ) {
f.write(buffer,0, len1);
}
f.close();
} catch (MalformedURLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (ProtocolException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
});
}
}
我还从此处和推荐答案
如果要恢复，下载速度... 请按照以下步骤 创建一个类 DownloadManager.java 在 onClick()中使用此代码DownloadManager downloadManager =新的DownloadManager(url，filepath); use this code in onClick()
DownloadManager downloadManager = new DownloadManager(url,filepath); 设置事件 通过 start download by 库设置 Tools.java public class DownloadManager extends AsyncTask<String,String,String>{
String downloadlink,fileDestination;
public static final int ON_INIT=100,ON_ERROR=102,ON_PROGRASS=103,ON_COMPLETED=104,STATUS_DOWNLOADED=1500,STATUS_NOT_YET=1501;
private onUpdateListener onUpdateListener;
private String downloadedPath="";
private long downloaded=0;
private File file;
private String returnData=null;
private File cacheDownloadFile;
public DownloadManager(String downloadlink,String fileDestinationPath){
this.downloadlink=downloadlink;
this.fileDestination=fileDestinationPath;
file=new File(fileDestination, Tools.getFileName(downloadlink));
cacheDownloadFile=new File(AppCostants.CHACHE_PATH+Tools.getFileName(downloadlink));
try {
if(cacheDownloadFile.isFile())
downloaded=Tools.getFileSize(cacheDownloadFile);
else
downloaded=0;
Log.d("FILE_DOWNLOAD_TAG_p",downloaded+" <- "+cacheDownloadFile.getAbsolutePath());
} catch (IOException e) {
e.printStackTrace();
}
fireOnUpdate(ON_INIT,"init ...");
}
@Override
protected String doInBackground(String... params) {
try {
File dir=new File(fileDestination);
File chacheDir=new File(AppCostants.CHACHE_PATH);
if(!chacheDir.isDirectory())
chacheDir.mkdirs();
if(!dir.isDirectory()){
dir.mkdirs();
}
if(file.exists()) {
Log.d("FILE_DOWNLOAD_TAG","File exist return complete");
return "COMPLETED";//file exist
}
if(!cacheDownloadFile.exists()){
cacheDownloadFile.createNewFile();
}
Log.d("FILE_DOWNLOAD_TAG","LINK "+downloadlink);
URL url=new URL(downloadlink);
HttpURLConnection urlConnection= (HttpURLConnection) url.openConnection();
if(downloaded>0)
urlConnection.setRequestProperty("Range","byte="+downloaded);
urlConnection.connect();
int status = urlConnection.getResponseCode();
InputStream inputStream=urlConnection.getInputStream();
int totalSize=urlConnection.getContentLength();
if(totalSize<=downloaded){
returnData= "COMPLETED";
publishProgress("File checked "+Tools.getFileName(file.getAbsolutePath()));
return returnData;
}
this.downloadedPath=cacheDownloadFile.getAbsolutePath();
byte[] buffer=new byte[1024];
int bufferLength=0;
FileOutputStream fileOutput=new FileOutputStream(cacheDownloadFile);
long d=0;
long starttime=System.currentTimeMillis();
while ((bufferLength=inputStream.read(buffer))>0){
fileOutput.write(buffer,0,bufferLength);
downloaded+=bufferLength;
d+=bufferLength;
//String l=" "+Tools.getFileName(file.getAbsolutePath())+" ( "+Tools.convertMemory(downloaded)+" / "+Tools.convertMemory(totalSize)+" )";
String l=" "+Tools.convertMemory(downloaded)+" / "+Tools.convertMemory(totalSize)+" ( "+getDownloadSpeed(starttime,d)+" )";
publishProgress(l);
if(downloaded>=totalSize){
break;
}
}
Log.d("FILE_DOWNLOAD_TAG","DWONLOADED TO "+downloadedPath+" ("+cacheDownloadFile.length()+")");
fileOutput.close();
if(Tools.fileCopy(file,cacheDownloadFile)){
Log.d("FILE_DOWNLOAD_TAG","file Copied, delete cache");
cacheDownloadFile.delete();
}
returnData="COMPLETED";
} catch (MalformedURLException e) {
returnData=null;
e.printStackTrace();
publishProgress(e.toString());
Log.d("###################",e+"");
} catch (IOException e) {
returnData=null;
e.printStackTrace();
publishProgress(e.toString());
}
return returnData;
}
@Override
protected void onProgressUpdate(String... values) {
super.onProgressUpdate(values);
fireOnUpdate(ON_PROGRASS,values[0]);
}
@Override
protected void onPostExecute(String s) {
super.onPostExecute(s);
if(s!=null){
fireOnUpdate(ON_COMPLETED,downloadedPath);
}else{
fireOnUpdate(ON_ERROR,"Download failed");
}
}
public interface onUpdateListener{
void onUpdate(int code,String message);
}
public void setOnUpdateListener(onUpdateListener onUpdateListener){
this.onUpdateListener=onUpdateListener;
}
private void fireOnUpdate(int code,String message){
if(onUpdateListener!=null)
onUpdateListener.onUpdate(code,message);
}
private String getDownloadSpeed(long starttime,float totalDownloaded) {
long elapsedTime = System.currentTimeMillis() - starttime;
//byte :
float speed=1000f * totalDownloaded / elapsedTime;
return convert(speed);
}
private String convert(float value){
long kb=1024
,mb=kb*1024
,gb=mb*1024;
if(value<kb){
String speed=(value+"");
speed=speed.substring(0,speed.indexOf('.')+2);
return speed+" B/s";
}else if(value<mb){
value=value/kb;
String speed=(value+"");
speed=speed.substring(0,speed.indexOf('.'));
return (speed)+" KB/s";
}else if(value<gb){
value=(value/mb);
String speed=(value+"");
speed=speed.substring(0,speed.indexOf('.'));
return speed+" MB/s";
}
return "";
}
}
downloadManager.setOnUpdateListener(new DownloadManager.onUpdateListener() {
@Override
public void onUpdate(int code, String message) {
if (code == DownloadManager.ON_COMPLETED) {
}
if(DownloadManager.ON_PROGRASS==code){}
}
});
downloadManager.execute();
compile "commons-io:commons-io:+"
public static long getFileSize(File file) throws IOException {
FileOutputStream fileOutputStream=new FileOutputStream(file);
fileOutputStream.close();
return file.length();
}
public static boolean fileCopy(File dest,File source){
try {
FileUtils.copyFile(source,dest);
return true;
} catch (IOException e) {
e.printStackTrace();
return false;
}
}
这篇关于单击按钮后如何下载文件(Android Studio)的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
