从TextView的存储中读取文本文件

Question

我处于打开sdcard的状态，需要从其中单击.txt文件之一，然后单击该文件的文本将其写入textview。我已经使用此代码尝试了很多，但是当我单击.txt时，没有任何内容输入textview。请提出您的建议，我错了？

这里有趣的是，它从onActivityResult上打印吐司：Toast.makeText(this, "" + path, Toast.LENGTH_SHORT).show();方法，但不会将内容从.txt打印到TextView。

TextView tv_out;
Button button;

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

      performFileSearch();

    } else {

      requestPermission2();

                    }
  }

这是从textview将文本保存到.txt的权限

private void requestPermission() {
    if (ActivityCompat.shouldShowRequestPermissionRationale(this, Manifest.permission.WRITE_EXTERNAL_STORAGE)) {
        Toasty.info(this, "Write External Storage permission allows us to create files.", Toast.LENGTH_LONG).show();
    } else {
        ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE}, PERMISSION_REQUEST_CODE);
    }
}

这是从textview .txt读取文本到textview的权限

private void requestPermission2() {
    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M && ContextCompat.checkSelfPermission(this, Manifest.permission.READ_EXTERNAL_STORAGE)
            != PackageManager.PERMISSION_GRANTED) {
        ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.READ_EXTERNAL_STORAGE}, PERMISSION_REQUEST_STORAGE);
    }
}


@Override
public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
    switch (requestCode) {
        case 1: {
            if (grantResults.length > 0
                    && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
            } else {
                Toasty.warning(this, getString(R.string.text), Toast.LENGTH_SHORT).show();
            }
            return;
        }
    }

    switch (requestCode) {
        case PERMISSION_REQUEST_CODE:
            if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
                Log.e("value", "Permission Granted, Now you can use local drive .");

                Toasty.info(this, getString(R.string.save_click), Toast.LENGTH_LONG).show();

            } else {
                Log.e("value", "Permission Denied, You cannot use local drive .");
            }
            break;
    }

    switch (requestCode) {
        case PERMISSION_REQUEST_STORAGE:
                if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
                    Toasty.info(this, "Permission granted!", Toast.LENGTH_LONG).show();
                } else {
                    Toasty.info(this, "Permission Denied", Toast.LENGTH_LONG).show();
                    finish();
                }
    }

}

这是阅读文本

private String readText(String input) {
    File file = new File(Environment.getExternalStorageDirectory(), input);
    StringBuilder text = new StringBuilder();
    try {
        BufferedReader br = new BufferedReader(new FileReader(file));
        String line;
        while ((line = br.readLine()) != null) {
            text.append(line);

        }
        br.close();
    } catch (IOException e) {
        e.printStackTrace();
    }
    return text.toString();
}

private void performFileSearch() {
    Intent chooser = new Intent(Intent.ACTION_OPEN_DOCUMENT);
    ........
}

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
    super.onActivityResult(requestCode, resultCode, data);
    if (requestCode == READ_REQUEST_CODE && resultCode == Activity.RESULT_OK) {
        if (data != null) {
            Uri uri = data.getData();
            String path = uri.getPath();
            path = path.substring(path.indexOf(":") + 1);
            if (path.contains("emulated")){
                path = path.substring(path.indexOf("0") + 1);
            }
            Toast.makeText(this, "" + path, Toast.LENGTH_SHORT).show();
            tv_out.setText(readText(path));
        }
    }
}

Answer 1

[请尝试使用以下方法来获取字符串中的文本文件内容。您可以将此字符串设置为textview。

private String readText(Uri fileUri){
        BufferedReader reader = null;
        StringBuilder stringBuilder = new StringBuilder();
        try {
            reader = new BufferedReader(new InputStreamReader(getContentResolver().openInputStream(fileUri)));
            String line = "";

            while ((line = reader.readLine()) != null) {
                stringBuilder.append(line);
            }

        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            if (reader != null){
                try {
                    reader.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
        return stringBuilder.toString();
    }