无法从Android中的网址下载文件

Question

import android.app.ProgressDialog;
import android.content.Context;
import android.os.AsyncTask;
import android.os.Environment;
import android.os.Handler;
import android.util.Log;
import android.widget.Toast;

import java.io.File;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.URL;

public class DownloadTask {

    private static final String TAG = "Download Task";
    private Context context;

    private String downloadUrl = "", downloadFileName = "";
    private ProgressDialog progressDialog;
    public DownloadTask(Context context, String downloadUrl) {
        this.context = context;

        this.downloadUrl = downloadUrl;


        downloadFileName = downloadUrl.substring(downloadUrl.lastIndexOf( '/' ),downloadUrl.length());//Create file name by picking download file name from URL
        Log.e(TAG, downloadFileName);

        //Start Downloading Task
        new DownloadingTask().execute();
    }

    private class DownloadingTask extends AsyncTask<Void, Void, Void> {

        File apkStorage = null;
        File outputFile = null;

        @Override
        protected void onPreExecute() {
            super.onPreExecute();
            progressDialog=new ProgressDialog(context);
            progressDialog.setMessage("Downloading...");
            progressDialog.show();
        }

        @Override
        protected void onPostExecute(Void result) {
            try {
                if (outputFile != null) {
                    progressDialog.dismiss();
                    Toast.makeText(context, "Downloaded Successfully", Toast.LENGTH_SHORT).show();
                } else {

                    new Handler().postDelayed(new Runnable() {
                        @Override
                        public void run() {

                        }
                    }, 3000);

                    Log.e(TAG, "Download Failed");

                }
            } catch (Exception e) {
                e.printStackTrace();
                Log.e(TAG, "Download Failed" +e);
                //Change button text if exception occurs

                new Handler().postDelayed(new Runnable() {
                    @Override
                    public void run() {

                    }
                }, 3000);
                Log.e(TAG, "Download Failed with Exception - " + e.getLocalizedMessage());

            }


            super.onPostExecute(result);
        }

        @Override
        protected Void doInBackground(Void... arg0) {
            try {
                URL url = new URL(downloadUrl);//Create Download URl
                HttpURLConnection c = (HttpURLConnection) url.openConnection();//Open Url Connection
                c.setRequestMethod("GET");//Set Request Method to "GET" since we are grtting data
                c.connect();//connect the URL Connection

                //If Connection response is not OK then show Logs
                if (c.getResponseCode() != HttpURLConnection.HTTP_OK) {
                    Log.e(TAG, "Server returned HTTP " + c.getResponseCode()
                            + " " + c.getResponseMessage());

                }


                //Get File if SD card is present
    /*if (new CheckForSDCard().isSDCardPresent()) {

                    apkStorage = new File(
                            Environment.getExternalStorageDirectory() + "/"
                                    + "NKDROID FILES");
                } else
                    Toast.makeText(context, "Oops!! There is no SD Card.", Toast.LENGTH_SHORT).show();*/


                //If File is not present create directory
                if (!apkStorage.exists()) {
                    apkStorage.mkdir();
                    Log.e(TAG, "Directory Created.");
                }

                outputFile = new File(apkStorage, downloadFileName);//Create Output file in Main File

                //Create New File if not present
                if (!outputFile.exists()) {
                    outputFile.createNewFile();
                    Log.e(TAG, "File Created");
                }

                FileOutputStream fos = new FileOutputStream(outputFile);//Get OutputStream for NewFile Location

                InputStream is = c.getInputStream();//Get InputStream for connection

                byte[] buffer = new byte[1024];//Set buffer type
                int len1 = 0;//init length
                while ((len1 = is.read(buffer)) != -1) {
                    fos.write(buffer, 0, len1);//Write new file
                }

                //Close all connection after doing task
                fos.close();
                is.close();

            } catch (Exception e) {

                //Read exception if something went wrong
                e.printStackTrace();
                outputFile = null;
                Log.e(TAG, "Download Error Exception " + e.getMessage());
            }

            return null;
        }
    }
}

我已经完成了以下编码，以从url下载文件...但是当我运行该应用程序时，它卡在了下载屏幕上...我正在尝试将文件下载到内部存储器中...我已经尝试了所有可能的方法来从ur; l下载...如果有人可以建议对上述代码或我可以使用的其他任何代码序列进行任何更改...

Answer 1

我不知道您的代码有什么问题。。但是您可以按照以下步骤解决您的问题。...只需在android chrome中打开您的pdf网址...下面将提到代码...

 try {
                    Intent i = new Intent("android.intent.action.MAIN");
                    i.setComponent(ComponentName.unflattenFromString("com.android.chrome/com.android.chrome.Main"));
                    i.addCategory("android.intent.category.LAUNCHER");
                    i.setData(Uri.parse("your pdf url"));
                    startActivity(i);
                }
                catch(ActivityNotFoundException e) {
                    // Chrome is not installed
                    Intent i = new Intent(Intent.ACTION_VIEW, Uri.parse("your pdf url"));
                    startActivity(i);
                }