android - 从外部 URL 打开 PDF 显示 "Open File: No apps can perform this action"

Question

我正在尝试从外部 URL 打开 PDF 文件。代码如下:

private void cargaPdf(Uri url){
    //File file = new File(Environment.getExternalStorageDirectory().getAbsolutePath() +"/"+ filename);
    Intent target = new Intent(Intent.ACTION_VIEW);
    target.setDataAndType(url,"application/pdf");
    target.setFlags(Intent.FLAG_ACTIVITY_NO_HISTORY);

    Intent intent = Intent.createChooser(target, "Open File");
    try {
        startActivity(intent);
    } catch (ActivityNotFoundException e) {
        // Instruct the user to install a PDF reader here, or something
    }
}

我已经安装了 adobe 和 google PDF 查看器，但是当我按下使用此 url 调用“cargaPdf(Uri url)”函数的按钮时(如您所见，这是一个 pdf 文件):

Uri.parse(https://dl.dropboxusercontent.com/s/oulzgpgnq2ca1ly/KorfbalSpa.pdf?dl=0);

它以西类牙语“打开文件 Ninguna applicacion puede realizar esta accion”或英语“打开文件没有应用程序可以执行此操作”出现在屏幕上。发生了什么？

编辑 1: 好的，现在我知道我必须下载文件才能看到它，所以，我在 Activity 中做了这段代码:

public void cargaDescripcion(View view){
    Log.d("CargaDescripcion", "Antes del directorio");
    String extStorageDirectory = Environment.getExternalStorageDirectory()
            .toString();
    File folder = new File(extStorageDirectory, "Mypdf");
    folder.mkdir();
    File file = new File(folder, "Read.pdf");
    try {
        file.createNewFile();
        Log.d("CargaDescripcion", "File creado");
    } catch (IOException e1) {
        e1.printStackTrace();
    }
    Downloader.DownloadFile(deporte.getUrlDescEs(), file);
    Log.d("CargaDescripcion", "Despues de descargarlo");
    showPdf();
    //folder.delete();
}

public void showPdf()
{
    Log.d("showPdf", "Entramos en show pdf");
    File file = new File(Environment.getExternalStorageDirectory()+"/Mypdf/Read.pdf");
    PackageManager packageManager = getPackageManager();
    Intent testIntent = new Intent(Intent.ACTION_VIEW);
    testIntent.setType("application/pdf");
    List list = packageManager.queryIntentActivities(testIntent, PackageManager.MATCH_DEFAULT_ONLY);
    Intent intent = new Intent();
    intent.setAction(Intent.ACTION_VIEW);
    Uri uri = Uri.fromFile(file);
    intent.setDataAndType(uri, "application/pdf");
    startActivity(intent);
    //file.delete();
}

这个类用于下载 pdf:

public class Downloader {
public static void DownloadFile(String fileURL, File directory) {
    try {
        FileOutputStream f = new FileOutputStream(directory);
        URL u = new URL(fileURL);
        HttpURLConnection c = (HttpURLConnection) u.openConnection();
        c.setRequestMethod("GET");
        c.setDoOutput(true);
        c.connect();
        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 (Exception e) {
        e.printStackTrace();
    }
}

我从这里得到它Opening pdf file from server using android intent

编辑 2:现在这是下载和显示文件的代码:

public void cargaDescripcion(View view){
    download(deporte.getUrlDescEs());
    showPdf();
    //folder.delete();
}

public void download(String url)
{
    new DownloadFile().execute(url, "read.pdf");
}

public void showPdf()
{
    File pdfFile = new File(Environment.getExternalStorageDirectory() + "/Mypdf/" + "read.pdf");  // -> filename = maven.pdf
    Uri path = Uri.fromFile(pdfFile);
    Intent pdfIntent = new Intent(Intent.ACTION_VIEW);
    pdfIntent.setDataAndType(path, "application/pdf");
    pdfIntent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);

    try{
        startActivity(pdfIntent);
    }catch(ActivityNotFoundException e){
        Toast.makeText(SelectedSportActivity.this, "No Application available to view PDF", Toast.LENGTH_SHORT).show();
    }
}
private class DownloadFile extends AsyncTask<String, Void, Void> {

    @Override
    protected Void doInBackground(String... strings) {
        String fileUrl = strings[0];   // -> url del archivo
        String fileName = strings[1];  // -> nombre del archivo.pdf
        String extStorageDirectory = Environment.getExternalStorageDirectory().toString();
        File folder = new File(extStorageDirectory, "Mypdf");
        folder.mkdir();

        File pdfFile = new File(folder, fileName);

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

但是，文件系统不是由应用程序创建的，并且在应用程序到达下一个点之前不会下载文件，即“显示”。因此，当应用程序查找该文件时，该文件不存在。

编辑 3:为了解决显示问题，我使用了 asynctask 方法的 onPostExecute:

@Override
    protected void onPostExecute(Void aVoid) {
        super.onPostExecute(aVoid);
        showPdf();
    }

Answer 1

使用此代码，这对我适用于本地文件。

resumePdfFile 是保存文件的文件路径。

private void openPDF(String resumePdfFile) {
    //file should contain path of pdf file

    Uri path = Uri.fromFile(resumePdfFile);
    Log.e("create pdf uri path==>", "" + path);
    try {
        Intent intent = new Intent(Intent.ACTION_VIEW);
        intent.setDataAndType(path, "application/pdf");
        intent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
        startActivity(intent);
        finish();
    } catch (ActivityNotFoundException e) {
        Toast.makeText(getApplicationContext(),
                "There is no any PDF Viewer",
                Toast.LENGTH_SHORT).show();
        finish();
    }
}

您可以通过两种方式查看或下载 pdf 文件，即在设备默认浏览器中打开它，或通过将其嵌入您的应用程序在 WebView 中打开它。

要在浏览器中打开 pdf，

Intent browserIntent = new Intent(Intent.ACTION_VIEW, Uri.parse(pdf_url));
startActivity(browserIntent);

要在 WebView 中打开，

Webview webView = (WebView) findViewById(R.id.webView1);
webView.getSettings().setJavaScriptEnabled(true);
webView.loadUrl(pdf_url);