Question

我正在开发一个应用程序，该应用程序将手机中的.txt文件作为输入并将其打印在TextView上，

public class MainActivity extends AppCompatActivity {
Button button;
Intent intent;private StringBuilder text = new StringBuilder();



private InputStream getResources(String s) {
    return null;
}

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    button = (Button) findViewById(R.id.btn);

    button.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {

            intent = new Intent(Intent.ACTION_GET_CONTENT);
            intent.setType("text/plain");
            startActivityForResult(intent, 7);
            Log.v("###", "parent "  + getParent());
        }

    });
} @Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
    String Fpath = data.getDataString();
  //  final String fileName = ""+Fpath;
    Log.v("###", "yo " +Fpath);

    super.onActivityResult(requestCode, resultCode, data);

    switch (requestCode) {
        case 7:

            if (resultCode == RESULT_OK) {
                setContentView(R.layout.activity_main);


                Log.v("###", "hellow");
                setContentView(R.layout.activity_main);
                BufferedReader reader = null;

                try {

                    reader = new BufferedReader(

             new InputStreamReader(getAssets().open("filename.txt")));
                    //change code
                    // do reading
                    String mLine;
                    while ((mLine = reader.readLine()) != null) {
                        text.append(mLine);
                        text.append('\n');
                    }
                } catch (IOException e) {
                    String PathHolder = data.getData().getPath();
                    Toast.makeText(MainActivity.this, PathHolder, Toast.LENGTH_LONG).show();
                    e.printStackTrace();
                } finally {


                    if (reader != null) {
                        try {
                            reader.close();
                        } catch (IOException e) {
                            //log the exception
                        }
                    }

                    TextView output = (TextView) findViewById(R.id.Txt);
                    output.setText((CharSequence) text);

                }
            }
    }
}
}

一切都很好，但行

新的InputStreamReader（getAssets（）。open（“ filename.txt”）））;

从Assets文件夹中获取文件，帮我从手机中获取文件，

“资产”文件夹中的文件可以正常打开，但我希望从手机中选择该文件

Answer 1

您可以在文件管理器中选择的onActivityResult中获取文件路径。

 Uri PathHolder = data.getData();

更新

上一行为您提供了从存储中选择的 uri文件。然后，您可以轻松地从该Uri获取文件。

只是忘记了getAssets，请使用以下方法从文件中读取。

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
    super.onActivityResult(requestCode, resultCode, data);
    Uri PathHolder = data.getData();
    FileInputStream fileInputStream = null;
    StringBuilder text = new StringBuilder();
    try {
        InputStream inputStream = getContentResolver().openInputStream(PathHolder);
        BufferedReader r = new BufferedReader(new InputStreamReader(inputStream));
        String mLine;
        while ((mLine = r.readLine()) != null) {
            text.append(mLine);
            text.append('\n');
        }
    } catch (FileNotFoundException e) {
        e.printStackTrace();
    } catch (IOException e) {
        e.printStackTrace();
    }

}

Answer 2

您可以尝试这种方法：

 public static String getMimeType(String url) {
    String type = null;
    String extension = MimeTypeMap.getFileExtensionFromUrl(url);
    if (extension != null) {
        type = MimeTypeMap.getSingleton().getMimeTypeFromExtension(extension);
    }
    return type;
}

 public static Uri getFileUri(String filePath) {
    Uri fileUri = null;
    File file = new File(filePath);
    try {
        if (Build.VERSION.SDK_INT >= 24) {
            Method m = StrictMode.class.getMethod("disableDeathOnFileUriExposure");
            m.invoke(null);
        }
        fileUri = Uri.fromFile(file);
    } catch (Exception e) {
        e.printStackTrace();
    }
    return fileUri;
}

并出于意图：

if (path.endsWith(".txt") || path.endsWith(".TXT")) {
        Intent intent = new Intent(Intent.ACTION_VIEW);
        intent.setDataAndType(getFileUri(path.trim()), getMimeType(path.trim()));
        intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TASK);

        if (intent.resolveActivity(context.getPackageManager()) != null) {
            context.startActivity(intent);
        } else
            Toast.makeText(context, "There is no application available to handle your request!!", Toast.LENGTH_SHORT).show();

    }

Answer 3

onActivityResult稍有变化，首先将此代码粘贴到您的活动中。

voice_record

现在将您的onActivityResult更改为此。

    public static String getPath(final Context context, final Uri uri) {

            final boolean isKitKat = true;

            // DocumentProvider
            if (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];
                    }

                    // TODO handle non-primary volumes
                }
                // 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 getDataColumn(context, uri, null, null);
            }
            // File
            else if ("file".equalsIgnoreCase(uri.getScheme())) {
                return uri.getPath();
            }

            return null;
        }
  public static boolean isExternalStorageDocument(Uri uri) {
        return "com.android.externalstorage.documents".equals(uri.getAuthority());
    }
 public static boolean isDownloadsDocument(Uri uri) {
        return "com.android.providers.downloads.documents".equals(uri.getAuthority());
    }
  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 column_index = cursor.getColumnIndexOrThrow(column);
                return cursor.getString(column_index);
            }
        } finally {
            if (cursor != null) {
                cursor.close();
            }
        }
        return null;
    }
public static boolean isMediaDocument(Uri uri) {
        return "com.android.providers.media.documents".equals(uri.getAuthority());
    }

Android-使用意图从手机内存中打开文件

3 个答案: