Question

我在一个非政府组织工作，为贫民窟儿童提供教育。最近我只学习了Android用于开发应用程序，用于提供由我的朋友和老师开发的免费电子书和笔记。我的非政府组织的名称是TRPWS（瑞星人民福利协会）。印度新德里。

我无法找到下载pdf并查看的代码。

请在开发此代码/应用程序时提供帮助来帮助我。

package org.example.ambika.pdf;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        pdfView.fromAsset(pdfName)
                .pages(0, 2, 1, 3, 3, 3)
                .defaultPage(1)
                .showMinimap(false)
                .enableSwipe(true)
                .onDraw(onDrawListener)
                .onLoad(onLoadCompleteListener)
                .onPageChange(onPageChangeListener)
                .load();
    }
}

我对Java和其他语言知之甚少。请帮助我。

Answer 1

试试这段代码，

new DownloadFile().execute(pdfUrl, pdffileName);
private class DownloadFile extends AsyncTask<String, Void, Void>{

        @Override
        protected Void doInBackground(String... strings) {
            String fileUrl = strings[0];  
            String fileName = strings[1];  // pdf name
            String extStorageDirectory = Environment.getExternalStorageDirectory().toString();
            File folder = new File(extStorageDirectory, "testthreepdf");
            folder.mkdir();

            File pdfFile = new File(folder, fileName);

            try{
                pdfFile.createNewFile();
            }catch (IOException e){
                e.printStackTrace();
            }
            FileDownloader.downloadFile(fileUrl, pdfFile);
            return null;
        }
    }



public class FileDownloader {
    private static final int  MEGABYTE = 1024 * 1024;

    public static void downloadFile(String fileUrl, File directory){
        try {

            URL url = new URL(fileUrl);
            HttpURLConnection urlConnection = (HttpURLConnection)url.openConnection();
            urlConnection.setRequestMethod("GET");
            urlConnection.setDoOutput(true);
            urlConnection.connect();

            InputStream inputStream = urlConnection.getInputStream();
            FileOutputStream fileOutputStream = new FileOutputStream(directory);
            int totalSize = urlConnection.getContentLength();

            byte[] buffer = new byte[MEGABYTE];
            int bufferLength = 0;
            while((bufferLength = inputStream.read(buffer))>0 ){
                fileOutputStream.write(buffer, 0, bufferLength);
            }
            fileOutputStream.close();
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (MalformedURLException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

//在Manifest中添加权限

<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
    <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
    <uses-permission android:name="android.permission.INTERNET" />

在最新的android

1 个答案: