將文件從內部存儲復制到外部存儲

Question

我試圖使用Adobe Reader讀取從服務器下載的pdf文件，問題是當我將其存儲在內部存儲器中時，其他應用程序無法讀取該文件。 現在，我想知道如何將該文件 復制 到外部存儲設備（/ sdcard /）中，以便pdf查看器查看。

出於安全原因，我將文件存儲在內部存儲中，之后將其刪除到外部存儲中。

我的問題是如何在不使用原始或資產放入輸入流的情況下復制保存在內部存儲器中的文件。

    InputStream myInput = getResources().openRawResource(R.raw.p13);

        FileOutputStream fos = openFileOutput("sample", Context.MODE_PRIVATE);

        // transfer bytes from the input file to the output file
        byte[] buffer = new byte[1024];
        int length;
        while ((length = myInput.read(buffer)) > 0)
        {
            fos.write(buffer, 0, length);
        }
        // Close the streams
        fos.flush();
        fos.close();
        myInput.close();

Answer 1

您將pdf文件存儲在哪個路徑？

請參閱下面的一個，以從android Assets獲取文件並將其復制到特定的sdcard位置。

我將首先檢查pdf文件，該文件是否已在所需路徑中可用。

 File file1 = new File("/sdcard/SampleProjectApp/WindsorONE_Mobile_Molding.pdf");
    File file2 = new File("/sdcard/SampleProjectApp/WindsorONE_Mobile_PK.pdf");
    File file3 = new File("/sdcard/SampleProjectApp/Alone.mp4");

    if(!((file1.exists())) || !((file2.exists())) || !((file3.exists()))) {
        ArrayList<String> files = new ArrayList<String>();
        files.add("WindsorONE_Mobile_Molding.pdf");         
        files.add("WindsorONE_Mobile_PK.pdf"); 
        files.add("Alone.mp4");
        new myAsyncTask().execute(files);
    }

現在，如果該位置不存在該文件，則它將執行myAsyncTask將文件從資產復制到SdCard。

 // AsyncTass for the Progress Dialog and to do Background Process
private class myAsyncTask extends AsyncTask<ArrayList<String>, Void, Void> {         
    ArrayList<String> files;         
    ProgressDialog dialog;         
    @Override         
    protected void onPreExecute() {             
        dialog = ProgressDialog.show(ListSample.this, "W1 SALES (beta)", "Loading...");         
    }         
    @Override         
    protected Void doInBackground(ArrayList<String>... params) {              
        files = params[0];             
        for (int i = 0; i < files.size(); i++) {                 
            copyFileFromAssetsToSDCard(files.get(i));                
        }             return null;         
    }         
    @Override         
    protected void onPostExecute(Void result) {             
        dialog.dismiss();         
    }      
} 



 // Function to copy file from Assets to the SDCard
public void copyFileFromAssetsToSDCard(String fileFromAssets){
    AssetManager is = this.getAssets();
    InputStream fis;
    try {

        fis = is.open(fileFromAssets);
        FileOutputStream fos;
        if (!APP_FILE_PATH.exists()) {
            APP_FILE_PATH.mkdirs();
        }
        fos = new FileOutputStream(new File(Environment.getExternalStorageDirectory()+"/SampleProjectApp", fileFromAssets));
        byte[] b = new byte[8];
        int i;
        while ((i = fis.read(b)) != -1) {
            fos.write(b, 0, i);
        }
        fos.flush();
        fos.close();
        fis.close();
    } 
    catch (IOException e1) {
        e1.printStackTrace();
    }
}

更新

就您而言：

替換SampleProjectApp / WindsorONE_Mobile_Molding.pdf

同

安卓/數據/ com.project.projectname /緩存/ YOUR_PDF_FILE.pdf

希望有道理。

更新2

下面的代碼是將文件從一個路徑復制到另一路徑。 您只需要傳遞文件所在的路徑和必須復制的路徑。

碼：

public static boolean copyFile(String from, String to) {
try {
    int bytesum = 0;
    int byteread = 0;
    File oldfile = new File(from);
    if (oldfile.exists()) {
        InputStream inStream = new FileInputStream(from);
        FileOutputStream fs = new FileOutputStream(to);
        byte[] buffer = new byte[1444];
        while ((byteread = inStream.read(buffer)) != -1) {
            bytesum += byteread;
            fs.write(buffer, 0, byteread);
        }
        inStream.close();
        fs.close();
    }
    return true;
} catch (Exception e) {
    return false;
}

}

Answer 2

你可以用這種方法

boolean isSDPresent = android.os.Environment.getExternalStorageState().equals(android.os.Environment.MEDIA_MOUNTED);

if(isSDPresent)
{
    InputStream in = null;
    OutputStream out = null;
      in = //Place your file in the inputstream
      out = new FileOutputStream(Environment.getExternalStorageDirectory().getAbsolutePath() + filename);
      byte[] buffer = new byte[1024];
      int read;
      while((read = in.read(buffer)) != -1){
        out.write(buffer, 0, read);
      }
      in.close();
      in = null;
      out.flush();
      out.close();
      out = null;
}
else
{
Toast.makeText(getApplicationContext(), "SD Card not present", Toast.LENGTH_LONG).show();
}