android - 在Android中实施文件选择器并将所选文件复制到其他位置

android - 在Android中实施文件选择器并将所选文件复制到其他位置,第1张

我试图在我的Android项目中实现文件选择器。到目前为止我能做的是:

Intent chooseFile;
Intent intent;
chooseFile = new Intent(Intent.ACTION_GET_CONTENT);
chooseFile.setType("*/*");
intent = Intent.createChooser(chooseFile, "Choose a file");
startActivityForResult(intent, PICKFILE_RESULT_CODE);

然后在我的onActivityResult()

switch(requestCode){
 case PICKFILE_RESULT_CODE:
   if(resultCode==-1){
      Uri uri = data.getData();
      String filePath = uri.getPath();
      Toast.makeText(getActivity(), filePath,
                        Toast.LENGTH_LONG).show();
    }
 break;
}

这是打开文件选择器,但它不是我想要的。例如,我想选择一个文件(.txt),然后获取File然后使用它。有了这段代码,我想我会得到完整路径,但它并没有发生;例如,我得到:/document/5318/。但是通过这条路径,我无法获得该文件。我创建了一个名为PathToFile()的方法,它返回File

 private File PathToFile(String path) {
    File tempFileToUpload;
    tempFileToUpload = new File(path);
    return tempFileToUpload;
}

我尝试做的是让用户从任何地方选择FileDropBoxDriveSDCardMega,等等...而且我找不到正确的方法,我试图获得Path然后通过此File获得Path ...但它没有& #39;工作,所以我认为最好是获取File本身,然后使用此File以编程方式Copy这个或Delete。< / p>

编辑(当前代码)

我的Intent

 Intent chooseFile = new Intent(Intent.ACTION_GET_CONTENT);
 chooseFile.addCategory(Intent.CATEGORY_OPENABLE);
 chooseFile.setType("text/plain");
 startActivityForResult(
      Intent.createChooser(chooseFile, "Choose a file"),
      PICKFILE_RESULT_CODE
 );

在那里我有一个问题,因为我不知道支持text/plain的是什么,但我会调查它,但它并不重要那一刻。

在我的onActivityResult()上,我使用了与@Lukas Knuth answer相同的内容,但我不知道是否可以使用Copy FileSDcard另一部分来自我的@Override public void onActivityResult(int requestCode, int resultCode, Intent data) { super.onActivityResult(requestCode, resultCode, data); if (requestCode == PICKFILE_RESULT_CODE && resultCode == Activity.RESULT_OK){ Uri content_describer = data.getData(); //get the path Log.d("Path???", content_describer.getPath()); BufferedReader reader = null; try { // open the user-picked file for reading: InputStream in = getActivity().getContentResolver().openInputStream(content_describer); // now read the content: reader = new BufferedReader(new InputStreamReader(in)); String line; StringBuilder builder = new StringBuilder(); while ((line = reader.readLine()) != null){ builder.append(line); } // Do something with the content in text.setText(builder.toString()); } catch (FileNotFoundException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } finally { if (reader != null) { try { reader.close(); } catch (IOException e) { e.printStackTrace(); } } } } } 我正在等待他的回答。

getPath()
来自@ Y.S的

String[] projection = { MediaStore.Files.FileColumns.DATA }; Cursor cursor = getActivity().getContentResolver().query(content_describer, projection, null, null, null); int column_index = cursor.getColumnIndexOrThrow(projection[0]); cursor.moveToFirst(); cursor.close(); Log.d( "PATH-->",cursor.getString(column_index));

我这样做:

NullPointerException

获得Intent

  

java.lang.RuntimeException:将结果ResultInfo {who = null,request = 131073,result = -1,data = Intent {dat = file:/// path typ = text / plain flg = 0x3}}发送到activity {info.androidhive.tabsswipe / info.androidhive.tabsswipe.MainActivity2}:java.lang.NullPointerException

感谢@Y.S.@Lukas Knuth@CommonsWare编辑代码。

这是text/plain,我只接受文件Intent chooseFile = new Intent(Intent.ACTION_GET_CONTENT); chooseFile.addCategory(Intent.CATEGORY_OPENABLE); chooseFile.setType("text/plain"); startActivityForResult( Intent.createChooser(chooseFile, "Choose a file"), PICKFILE_RESULT_CODE );

onActivityResult()

在我的URI我创建了一个Intent我获取了File的数据,我创建了一个content_describer.getPath();,其中我保存了绝对路径正在执行TextView,然后我保留了content_describer.getLastPathSegment(); File中使用它的路径名称(这真是太棒了@YS不知道该功能) ,我创建了第二个destination,我打电话给AbsolutePath,我发送File即可创建此@Override public void onActivityResult(int requestCode, int resultCode, Intent data) { super.onActivityResult(requestCode, resultCode, data); if (requestCode == PICKFILE_RESULT_CODE && resultCode == Activity.RESULT_OK){ Uri content_describer = data.getData(); String src = content_describer.getPath(); source = new File(src); Log.d("src is ", source.toString()); String filename = content_describer.getLastPathSegment(); text.setText(filename); Log.d("FileName is ",filename); destination = new File(Environment.getExternalStorageDirectory().getAbsolutePath() "/Test/TestTest/" filename); Log.d("Destination is ", destination.toString()); SetToFolder.setEnabled(true); } }

source file

此外,我已创建了一项功能,您必须先发送我们之前创建的destination fileprivate void copy(File source, File destination) throws IOException { FileChannel in = new FileInputStream(source).getChannel(); FileChannel out = new FileOutputStream(destination).getChannel(); try { in.transferTo(0, in.size(), out); } catch(Exception e){ Log.d("Exception", e.toString()); } finally { if (in != null) in.close(); if (out != null) out.close(); } } ,然后将其复制到新文件夹。

destination file

我还创建了一个函数,告诉我这个文件夹是否存在(我必须发送private void DirectoryExist (File destination) { if(!destination.isDirectory()) { if(destination.mkdirs()){ Log.d("Carpeta creada","...."); }else{ Log.d("Carpeta no creada","...."); } } ,如果它不存在我创建这个文件夹,如果它存在不是我什么都不做。

Task.WhenAll

再次感谢您的帮助,希望您喜欢与大家一起制作的代码:)

最佳答案:

7 个答案:

答案 0 :(得分:31)

第1步 - 使用隐式Intent

要从设备中选择文件,您应使用隐式Intent

Intent chooseFile = new Intent(Intent.ACTION_GET_CONTENT);
chooseFile.setType("*/*");
chooseFile = Intent.createChooser(chooseFile, "Choose a file");
startActivityForResult(chooseFile, PICKFILE_RESULT_CODE);

第2步 - 获取绝对文件路径:

要从Uri获取文件路径,请先尝试使用

Uri uri = data.getData();
String src = uri.getPath();

其中dataIntent中返回的onActivityResult()

如果不起作用,请使用以下方法:

public String getPath(Uri uri) {

    String path = null;
    String[] projection = { MediaStore.Files.FileColumns.DATA };
    Cursor cursor = getContentResolver().query(uri, projection, null, null, null);

    if(cursor == null){
        path = uri.getPath()
    }
    else{
        cursor.moveToFirst();
        int column_index = cursor.getColumnIndexOrThrow(projection[0]);
        path = cursor.getString(column_index);
        cursor.close();
    }

    return ((path == null || path.isEmpty()) ? (uri.getPath()) : path);
}

这两种方法中至少有一种应该能为您提供正确的完整路径。

第3步 - 复​​制文件:

我认为,您想要的是将文件从一个位置复制到另一个位置。

要做到这一点,绝对有必要拥有源位置和目标位置的绝对文件路径

首先,使用我的getPath()方法或uri.getPath()获取绝对文件路径:

String src = getPath(uri);    /* Method defined above. */

Uri uri = data.getData();
String src = uri.getPath();

然后,按如下方式创建两个File个对象:

File source = new File(src);
String filename = uri.getLastPathSegment();
File destination = new File(Environment.getExternalStorageDirectory().getAbsolutePath()   "/CustomFolder/"   filename);

其中CustomFolder是外部驱动器上要复制文件的目录。

然后使用以下方法将文件从一个地方复制到另一个地方:

private void copy(File source, File destination) {

   FileChannel in = new FileInputStream(source).getChannel();
   FileChannel out = new FileOutputStream(destination).getChannel();

   try {
      in.transferTo(0, in.size(), out);
   } catch(Exception){
      // post to log
   } finally {
      if (in != null)
         in.close();
      if (out != null)
         out.close();
   }
}

试试这个。这应该有用。

注意:与Lukas的回答相比 - 他所做的是使用名为openInputStream()的方法,该方法返回{{> 的{em>内容 1}},Uri代表文件或网址。

另一种有前途的方法 - Uri

还有一种方法可以从另一个应用程序获取文件。如果应用程序通过FileProvider共享其文件,则可以获取保存有关此文件的特定信息的FileDescriptor对象。

为此,请使用以下FileProvider

Intent

和您的Intent mRequestFileIntent = new Intent(Intent.ACTION_GET_CONTENT); mRequestFileIntent.setType("*/*"); startActivityForResult(mRequestFileIntent, 0);

onActivityResult()

其中@Override public void onActivityResult(int requestCode, int resultCode, Intent returnIntent) { // If the selection didn't work if (resultCode != RESULT_OK) { // Exit without doing anything else return; } else { // Get the file's content URI from the incoming Intent Uri returnUri = returnIntent.getData(); /* * Try to open the file for "read" access using the * returned URI. If the file isn't found, write to the * error log and return. */ try { /* * Get the content resolver instance for this context, and use it * to get a ParcelFileDescriptor for the file. */ mInputPFD = getContentResolver().openFileDescriptor(returnUri, "r"); } catch (FileNotFoundException e) { e.printStackTrace(); Log.e("MainActivity", "File not found."); return; } // Get a regular file descriptor for the file FileDescriptor fd = mInputPFD.getFileDescriptor(); ... } } mInputPFD

<强>参考文献:

1。 Common Intents - File Storage

2。 FileChannel

3。 FileProvider

4。 Requesting a Shared File

答案 1 :(得分:5)

我做了同样的事情让用户从文件夹中选择一张图片:

1)有一个按钮OPEN:

@Override
public void onClick(View v) {
    switch (v.getId()) {
    case R.id.btn_open:
        myOpenImagePicker();
        break;
    }
}

2)打开图片文件夹功能:

@SuppressLint("InlinedApi")
public void myOpenImagePicker() {

    if (Build.VERSION.SDK_INT < 19) {
        Intent intent = new Intent();
        intent.setType("image/*");
        intent.setAction(Intent.ACTION_GET_CONTENT);
        startActivityForResult(
                Intent.createChooser(intent, "Select Picture"),
                SELECT_FOLDER);

    } else {
        Intent intent = new Intent(Intent.ACTION_OPEN_DOCUMENT);
        intent.addCategory(Intent.CATEGORY_OPENABLE);
        intent.setType("image/*");
        startActivityForResult(intent, SELECT_FOLDER);
    }
}

3)活动结果我获取图像文件路径并使用图像路径执行任何操作:

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
    switch (requestCode) {
    case SELECT_FOLDER:
        if (resultCode == RESULT_OK && data != null) {

            Uri originalUri = data.getData();
            String id01 = W_ImgFilePathUtil.getPath(
                    getApplicationContext(), originalUri);
            Bitmap unscaledBitmap = W_ImgScalingUtil.decodeResource(id01,
                    xdrawing.getViewWidth(), xdrawing.getViewHeight(),
                    ScalingLogic.FIT);
            if (unscaledBitmap == null) {
                zprefsutil.ShowToast("IMAGE ERROR", 1);
            } else {
                setExternalScaledBitmap(W_ImgScalingUtil
                        .createScaledBitmap(unscaledBitmap,
                                xdrawing.getViewWidth(),
                                xdrawing.getViewHeight(), ScalingLogic.FIT));
                unscaledBitmap.recycle();
                xdrawing.invalidate();
            }

        }
        break;
    default:
        break;
    }
}

4)现在是最重要的部分,W_ImgFilePathUtil类,代码不是来自我,但它允许您检索任何选定文件的完整路径,无论是在SD卡,谷歌驱动器,... :

public class W_ImgFilePathUtil {

    /**
     * Method for return file path of Gallery image
     * 
     * @param context
     * @param uri
     * @return path of the selected image file from gallery
     */
    @SuppressLint("NewApi")
    public static String getPath(final Context context, final Uri uri) {

        // check here to KITKAT or new version
        final boolean isKitKatorUp = Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT;

        // DocumentProvider
        if (isKitKatorUp && DocumentsContract.isDocumentUri(context, uri)) {

            // ExternalStorageProvider
            if (isExternalStorageDocument(uri)) {
                final String docId = DocumentsContract.getDocumentId(uri);
                final String[] split = docId.split(":");
                final String type = split[0];

                if ("primary".equalsIgnoreCase(type)) {
                    return Environment.getExternalStorageDirectory()   "/"
                              split[1];
                }
            }
            // DownloadsProvider
            else if (isDownloadsDocument(uri)) {

                final String id = DocumentsContract.getDocumentId(uri);
                final Uri contentUri = ContentUris.withAppendedId(
                        Uri.parse("content://downloads/public_downloads"),
                        Long.valueOf(id));

                return getDataColumn(context, contentUri, null, null);
            }
            // MediaProvider
            else if (isMediaDocument(uri)) {
                final String docId = DocumentsContract.getDocumentId(uri);
                final String[] split = docId.split(":");
                final String type = split[0];

                Uri contentUri = null;
                if ("image".equals(type)) {
                    contentUri = MediaStore.Images.Media.EXTERNAL_CONTENT_URI;
                } else if ("video".equals(type)) {
                    contentUri = MediaStore.Video.Media.EXTERNAL_CONTENT_URI;
                } else if ("audio".equals(type)) {
                    contentUri = MediaStore.Audio.Media.EXTERNAL_CONTENT_URI;
                }

                final String selection = "_id=?";
                final String[] selectionArgs = new String[] { split[1] };

                return getDataColumn(context, contentUri, selection,
                        selectionArgs);
            }
        }

        // MediaStore (and general)
        else if ("content".equalsIgnoreCase(uri.getScheme())) {

            // Return the remote address
            if (isGooglePhotosUri(uri))
                return uri.getLastPathSegment();

            return getDataColumn(context, uri, null, null);
        }
        // File
        else if ("file".equalsIgnoreCase(uri.getScheme())) {
            return uri.getPath();
        }

        return null;
    }

    /**
     * Get the value of the data column for this Uri. This is useful for
     * MediaStore Uris, and other file-based ContentProviders.
     * 
     * @param context
     *            The context.
     * @param uri
     *            The Uri to query.
     * @param selection
     *            (Optional) Filter used in the query.
     * @param selectionArgs
     *            (Optional) Selection arguments used in the query.
     * @return The value of the _data column, which is typically a file path.
     */
    public static String getDataColumn(Context context, Uri uri,
            String selection, String[] selectionArgs) {

        Cursor cursor = null;
        final String column = "_data";
        final String[] projection = { column };

        try {
            cursor = context.getContentResolver().query(uri, projection,
                    selection, selectionArgs, null);
            if (cursor != null && cursor.moveToFirst()) {
                final int index = cursor.getColumnIndexOrThrow(column);
                return cursor.getString(index);
            }
        } finally {
            if (cursor != null)
                cursor.close();
        }
        return null;
    }

    /**
     * @param uri
     *            The Uri to check.
     * @return Whether the Uri authority is ExternalStorageProvider.
     */
    public static boolean isExternalStorageDocument(Uri uri) {
        return "com.android.externalstorage.documents".equals(uri
                .getAuthority());
    }

    /**
     * @param uri
     *            The Uri to check.
     * @return Whether the Uri authority is DownloadsProvider.
     */
    public static boolean isDownloadsDocument(Uri uri) {
        return "com.android.providers.downloads.documents".equals(uri
                .getAuthority());
    }

    /**
     * @param uri
     *            The Uri to check.
     * @return Whether the Uri authority is MediaProvider.
     */
    public static boolean isMediaDocument(Uri uri) {
        return "com.android.providers.media.documents".equals(uri
                .getAuthority());
    }

    /**
     * @param uri
     *            The Uri to check.
     * @return Whether the Uri authority is Google Photos.
     */
    public static boolean isGooglePhotosUri(Uri uri) {
        return "com.google.android.apps.photos.content".equals(uri
                .getAuthority());
    }
}

结论:代码适用于图像路径,但确实适用于任何类型的文件。

希望这有助于解决您的问题。

和平。

答案 2 :(得分:4)

正如 @CommonsWare 已经注意到的那样,Android会返回Uri,这是一个比文件路径更抽象的概念。

它也可以描述一个简单的文件路径,但它也可以描述通过应用程序访问的资源(如content://media/external/audio/media/710)。

如果您希望用户从手机中选择任何文件以从您的应用程序中读取它,您可以通过询问文件(正如您所做的那样)来执行此操作,然后使用ContentResolver获取{ {1}}表示选择器返回的InputStream

以下是一个例子:

Uri

重要:某些提供商(如Dropbox)将其数据存储/缓存在外部存储上。您需要在清单中声明Intent chooseFile = new Intent(Intent.ACTION_GET_CONTENT); // Ask specifically for something that can be opened: chooseFile.addCategory(Intent.CATEGORY_OPENABLE); chooseFile.setType("*/*"); startActivityForResult( Intent.createChooser(chooseFile, "Choose a file"), PICKFILE_REQUEST_CODE ); // And then somewhere, in your activity: @Override protected void onActivityResult(int requestCode, int resultCode, Intent data) { super.onActivityResult(requestCode, resultCode, data); if (requestCode == PICKFILE_REQUEST_CODE && resultCode == RESULT_OK){ Uri content_describer = data.getData(); BufferedReader reader = null; try { // open the user-picked file for reading: InputStream in = getContentResolver().openInputStream(content_describer); // now read the content: reader = new BufferedReader(new InputStreamReader(in)); String line; StringBuilder builder = new StringBuilder(); while ((line = reader.readLine()) != null){ builder.append(line); } // Do something with the content in some_view.setText(builder.toString()); } catch (FileNotFoundException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } finally { if (reader != null) { try { reader.close(); } catch (IOException e) { e.printStackTrace(); } } } } } - 权限,否则即使文件存在,您也会获得android.permission.READ_EXTERNAL_STORAGE

更新:是的,您可以通过从一个流中读取文件并将其写入另一个流来复制该文件:

FileNotFoundException

可能无法删除文件,因为文件不属于属于,它属于与您共享文件的应用程序。因此,拥有的应用程序负责删除文件。

答案 3 :(得分:2)

在此方法中传递onActivityResult中返回的URI

<li></li>

答案 4 :(得分:2)

使用 ActivityResultLauncher 是这样的:

ActivityResultLauncher<Intent> startActivityForResult = requireActivity().registerForActivityResult(new ActivityResultContracts.StartActivityForResult(), result -> {
    if (result.getResultCode() == Activity.RESULT_OK) {
        Intent data = result.getData();
        Uri contentUri = data.getData();
        ...
    }
});

用法示例:

Intent data = new Intent(Intent.ACTION_GET_CONTENT);
data.addCategory(Intent.CATEGORY_OPENABLE);
data.setType("*/*");
Intent intent = Intent.createChooser(data, "Choose a file");
startActivityForResult.launch(intent);

需要以下依赖项(有或没有 -ktx):

implementation "androidx.activity:activity:1.2.3"

答案 5 :(得分:1)

A Uri is not a file。 import matplotlib.pyplot as plt import numpy as np from scipy.optimize import curve_fit x = np.arange(0,10,.05) wave = np.sin(x) noise = np.random.normal(0,.05,200) y = noise wave noise2 = np.random.normal(0,.05,200) y2 = noise2 wave noise3 = np.random.normal(0,.05,200) y3 = noise3 wave y_avg = (np.array(y) np.array(y2) np.array(y3)) / 3 for i in range(5, 15): mean = np.mean(y_avg) print mean plt.plot(x, y, color = 'red', label= 'line 1') plt.plot(x, y2, color = 'pink', label = 'line 2') plt.plot(x, y3, color = 'magenta', label = 'line 3') plt.plot(x, y_avg, color = 'blue', label = 'average') plt.legend() plt.show() 更接近Web服务器URL。它是一个不透明的地址,只对服务器&#34;有意义。 (或者在这种情况下,Uri)。

就像使用ContentProvider读取Web URL表示的字节一样,使用InputStream读取InputStream表示的字节。您可以通过在Uri上调用openInputStream()来获得此类流。

答案 6 :(得分:1)

这里是实现文件选择器并将所选文件移动到另一个位置(例如图片)的方法。

首先,在点击侦听器上向按钮添加文件选择器,如下所示:

用于选择文件的按钮:

@Override
public void onClick(View v) {
    switch (v.getId()) {
    case R.id.btn_choose_file:
        showFileChooser();
        break;
    }
}

private String filePath = null;
private File sourceFile;

private static final int FILE_SELECT_CODE = 0;

    private void showFileChooser() {
        Intent intent = new Intent(Intent.ACTION_GET_CONTENT);
        intent.setType("*/*");
        intent.addCategory(Intent.CATEGORY_OPENABLE);

        try {
            startActivityForResult(
                    Intent.createChooser(intent, "Select a File to Copy"),
                    FILE_SELECT_CODE);
        } catch (android.content.ActivityNotFoundException ex) {
            Toast.makeText(this, "Please install a File Manager.",
                    Toast.LENGTH_SHORT).show();
        }
    }

然后像这样处理onActivityResult:

    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        switch (requestCode) {
            case FILE_SELECT_CODE:
                if (resultCode == RESULT_OK) {
                    // Get the Uri of the selected file
                    Uri uri = data.getData();

                    File   file = new File(getCacheDir(), getFileName(uri));

                    int maxBufferSize = 1 * 1024 * 1024;

                    try {
                        InputStream inputStream = getContentResolver().openInputStream(uri);
                        Log.e("InputStream Size","Size "   inputStream);
                        int  bytesAvailable = inputStream.available();
                        int bufferSize = Math.min(bytesAvailable, maxBufferSize);
                        final byte[] buffers = new byte[bufferSize];

                        FileOutputStream outputStream = new FileOutputStream(file);
                        int read = 0;
                        while ((read = inputStream.read(buffers)) != -1) {
                            outputStream.write(buffers, 0, read);
                        }
                        Log.e("File Size","Size "   file.length());
                        inputStream.close();
                        outputStream.close();

                        file.getPath();
                        Log.e("File Path","Path "   file.getPath());
                        file.length();
                        Log.e("File Size","Size "   file.length());

                        if(file.length() > 0){

                            sourceFile = file;
                           saveFile(sourceFile);
                        }


                    } catch (FileNotFoundException e) {
                        e.printStackTrace();
                    } catch (IOException e) {
                        e.printStackTrace();
                    } catch (OutOfMemoryError e) {
                        e.printStackTrace();
                    }



                } else {


                }

                break;
        }
        super.onActivityResult(requestCode, resultCode, data);
    }





    private void saveFile (File sourceFile) {


                try {

                File currentFile = sourceFile;

                Bitmap myBitmap = BitmapFactory.decodeFile(currentFile.getAbsolutePath());


                String path = currentFile.getAbsolutePath();
                String idStr = path.substring(path.lastIndexOf('/')   1);
                File filepath = Environment.getExternalStorageDirectory();
                File dir = new File(filepath.getAbsolutePath()   "/"   "yourFolderName"   "/");
                if (!dir.exists()) {
                    dir.mkdirs();
                }
                String fileName = currentFile.getName();
                file = new File(dir, fileName);
                if (file.exists()) file.delete();
                FileOutputStream fos = new FileOutputStream(file);
                myBitmap.compress(CompressFormat.JPEG, 65, fos);
                fos.flush();
                fos.close();


            } catch (Exception e) {
                e.printStackTrace();
            }

    }

注意:请不要忘记将此权限添加到清单文件中。

    <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"/>
    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />

希望这会有所帮助。

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