如何将 bitmap 保存到 android 中的应用程序文件夹

Question

I have a bitmap that I want to save it to the app folder. I try with these codes:

 ContextWrapper contextWrapper = new ContextWrapper(context.getApplicationContext());
 File directory = contextWrapper.getDir("tabs", Context.MODE_PRIVATE);
 if (!directory.exists())
     directory.mkdir();
     String fname = "Image.jpg";
     File file = new File(directory, fname);
     FileOutputStream fos = null;
     try {
         fos = new FileOutputStream(file);
         bitmap.compress(Bitmap.CompressFormat.JPEG, 50, fos);
         fos.close();
     } catch (Exception e) {
            Log.e("SAVE_IMAGE", e.getMessage(), e);
     }

Now, I have two problems.

1. Why this warning show and how to fix it?

Result of 'File.mkdir()' is ignored

2. Directory "app_tabs" was created in the application folder, But not saved bitmap and There is no photo in the folder. How do I save this bitmap?

Answer 1

You can just do this:

try {
     FileOutputStream fileOutputStream = context.openFileOutput("Your File Name", Context.MODE_PRIVATE);
     bitmap.compress(Bitmap.CompressFormat.PNG, 100, fileOutputStream);
     fileOutputStream.close();
 } catch (Exception e) {
     e.printStackTrace();
 }

It saves your bitmap in the "files" directory in app folder.

Answer 2

Technically your codes is correct, also I had tried on my own device all is correct.

So I suspect you find the other path, or you need to click 'Synchronize' menu if you use Android Studio to check file.

By the way, you can just use context or context.getApplicationContext() to call getDir(), no need to new a ContextWrapper. like this:

File directory = context.getDir("tabs", Context.MODE_PRIVATE);

Answer 3

 String path = Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DOWNLOADS).toString() + "/tabs";
        File dir = new File(path);
        if (!dir.exists())
            dir.mkdirs();

        File futureStudioIconFile = new File(path, "Image.jpg);
        if (futureStudioIconFile.exists())
            futureStudioIconFile.delete();
        futureStudioIconFile.createNewFile();

try this,, i wish it helps

Answer 4

this is my answer

1. Result of 'File.mkdir()' is ignored : Because mkdir() return a boolean, true if the folder is created and false otherwwise.

2. This is how I save bitmap

        File storageDir = getFilesDir();

        File filePath = File.createTempFile(
                imageFileName,  /* prefix */
                ".jpg",         /* suffix */
                storageDir      /* directory */
        );


        try (FileOutputStream out = new FileOutputStream(filePath)) {
            capturedImg.compress(Bitmap.CompressFormat.JPEG, quality, out);
        } catch (IOException e) {
            e.printStackTrace();
        }

or if you just want to save the bitmap at original resolution

    public static void copy(Uri uri, File dst, Context context) {
        try (InputStream in = context.getContentResolver().openInputStream(uri);
             OutputStream out = new FileOutputStream(dst)) {
            // Transfer bytes from in to out
            byte[] buf = new byte[1024];
            int len;
            while ((len = in.read(buf)) > 0) {
                out.write(buf, 0, len);
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }