android - 如何读取保存到设备内部存储的PDF文件？

Question

我正在使用以下代码从设备的内部存储中下载和读取 PDF 文件。

我能够成功将文件下载到目录:

data/data/packagename/app_books/file.pdf

但我无法使用 Adob​​e Reader 等 PDF 阅读器应用程序阅读该文件。

下载文件代码

//Creating an internal dir;
File mydir = getApplicationContext().getDir("books", Context.MODE_WORLD_READABLE);

try {
    File file = new File(mydir, outputFileName);
    URL downloadUrl = new URL(url);
    URLConnection ucon = downloadUrl.openConnection();
    ucon.connect();

    InputStream is = ucon.getInputStream();

    FileOutputStream fos = new FileOutputStream(file);  

    byte data[] = new byte[1024];

    int current = 0;
    while ((current = is.read(data)) != -1) {
        fos.write(data, 0, current);
    }        
    is.close();
    fos.flush();
    fos.close();
    isFileDownloaded=true;
} catch (IOException e) {
    e.printStackTrace();
    isFileDownloaded = false;
    System.out.println(outputFileName + " not downloaded");
}
if (isFileDownloaded)
    System.out.println(outputFileName + " downloaded");
return isFileDownloaded;

读取文件的代码

PackageManager packageManager = getPackageManager();

Intent testIntent = new Intent(Intent.ACTION_VIEW);
testIntent.setType("application/pdf");

List list = packageManager.queryIntentActivities(testIntent,
        PackageManager.MATCH_DEFAULT_ONLY);

try {
    Intent intent = new Intent();
    intent.setAction(Intent.ACTION_VIEW);                        

    File fileToRead = new File(
            "/data/data/com.example.filedownloader/app_books/Book.pdf");
    Uri uri = Uri.fromFile(fileToRead.getAbsoluteFile());

    intent.setDataAndType(uri, "application/pdf");
    startActivity(intent);
} catch (Exception ex) {
    Log.i(getClass().toString(), ex.toString());
    Toast.makeText(MainActivity.this,
            "Cannot open your selected file, try again later",
            Toast.LENGTH_SHORT).show();
}

一切正常，但阅读器应用程序显示“文件路径无效”。

Answer 1

您的路径仅对您的应用有效。将文件放在其他应用程序可以“看到”的地方。使用 GetExternalFilesDir() 或 getExternalStorageDirectory()。