내장 기능을 사용하여 Android 활동에 PDF를 표시하는 방법은 무엇입니까?

public class OpenPdf extends Activity {
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        Button button = (Button) findViewById(R.id.OpenPdfButton);
        button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                File file = new File("/sdcard/example.pdf");
                if (file.exists()) {
                    Uri path = Uri.fromFile(file);
                    Intent intent = new Intent(Intent.ACTION_VIEW);
                    intent.setDataAndType(path, "application/pdf");
                    intent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
                    try {
                        startActivity(intent);
                    } 
                    catch (ActivityNotFoundException e) {
                        Toast.makeText(OpenPdf.this, "No Application Available to View PDF", Toast.LENGTH_SHORT).show();
                    }
                }
            }
        });
    }
}