从内部存储器读取文件："/sys/class/"和"/dev/"文件夹

Question

我想知道如何读取内部内存内某些文件的值，但是这些文件位于"/data/data/data/data/m myapp/files"文件夹中，它们位于"/dev/"one_answers"/sys/class"文件夹中。

import...

public class Calentando extends AppCompatActivity {


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate( savedInstanceState );
        getWindow().setFlags( WindowManager.LayoutParams.FLAG_FULLSCREEN,
                WindowManager.LayoutParams.FLAG_FULLSCREEN );
        setContentView( R.layout.activity_calentando );


    @RequiresApi(api = Build.VERSION_CODES.KITKAT)
    private byte[] readFile(String path) {
        File file = new File( "/sys/class/gpio/gpio33/value" );
        try (FileInputStream fis = new FileInputStream( file );
             BufferedInputStream bis = new BufferedInputStream( fis )) {
            byte[] buffer = new byte[4096];
            int bytesRead;
            ByteArrayOutputStream baos = new ByteArrayOutputStream();
            while ((bytesRead = bis.read( buffer )) != -1) {
                baos.write( buffer, 0, bytesRead );
           TextView Tempview = (TextView) findViewById( R.id.temperatura );
                Tempview.setText( new String( readFile( path ), Charset.forName( "UTF-8" ) ) );
            }
            return baos.toByteArray();
        } catch (IOException e) {
            // handle the exception
            return null;
        }

    }
}

特别感谢@nandsito

Answer 1

由于您的应用程序已有根许可，因此您可以访问/dev和/sys/class目录。

您可以列出目录内容：

new File(path).listFiles();

您可以读取二进制文件内容：

private byte[] readFile(String path) {
    File file = new File(path);
    try (FileInputStream fis = new FileInputStream(file);
    BufferedInputStream bis = new BufferedInputStream(fis)) {
        byte[] buffer = new byte[4096];
        int bytesRead;
        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        while ((bytesRead = bis.read(buffer)) != -1) {
            baos.write(buffer, 0, bytesRead);
        }
        return baos.toByteArray();
    } catch (IOException e) {
        // handle the exception
        return null;
    }
}

您可以在TextView中设置文件内容（提供是文本文件）：

TextView Tempview;
Tempview = (TextView) findViewById( R.id.temperatura );
Tempview.setText(new String(readFile(path), Charset.forName("UTF-8")));