按钮onclick查看pdf文件Android

Question

Hi I am trying to code a button in Android Studio that will launch a pdf file. I have made a new afile under "res" folder and I am hoping that the button will call on that pdf file. However it keeps coming up pdf not found? Is there something wrong with my code?

Button btn=(Button)findViewById(R.id.button1);

        btn.setOnClickListener(new View.OnClickListener()
        {
          public void onClick(View v) {
           File file = new File("@Eng_Curr/Eng_Curr.pdf");
           Intent intent = new Intent(Intent.ACTION_VIEW);
           intent.setDataAndType(Uri.fromFile(file),"@Eng_Curr/Eng_Curr.pdf");
           intent.setFlags(Intent.FLAG_ACTIVITY_NO_HISTORY);
           startActivity(intent);
            }
        });

Answer 1

Is there something wrong with my code?

Three things:

1. "@Eng_Curr/Eng_Curr.pdf" is not a path to a file on Android, yet you are trying to use it with the File constructor as if it is were a path.

2. "@Eng_Curr/Eng_Curr.pdf" is not a MIME type, but you are passing it into setDataAndType() as if it were a MIME type.

3. You do not have a PDF file, but rather some resource ( raw , I assume), and there is no easy way to get that to a PDF viewing app.

If you are just trying to play around a bit on Android, I would recommend trying some other app.

If you really need to serve up a PDF file that you ship with your app as a raw resource, you can arrange to copy it to a file on internal storage (eg, getFilesDir() ) when your activity is first run, then use FileProvider to make that file available to third-party apps, and set up your Intent to use a Uri supplied by FileProvider .

Answer 2

Hi Folks so after taking all of your advice which is much appreciated I have found a work around for this. I used a swipe feature to swipe between png images and mViewFlipper along with SwipeGestureDetector. However one of the problems with this is memory shortage. I'm pretty sure it is down to the size of the png files but I may also need to find a way to terminate saved instances after each swipe. Still working on it and any suggestions would be helpful. Anyway hope this code helps.

public class English extends Activity {

    public class English extends Activity { 
    private static final int SWIPE_MIN_DISTANCE = 520;
    private static final int SWIPE_THRESHOLD_VELOCITY = 500;
    private ViewFlipper mViewFlipper;
    private Context mContext;

 private final GestureDetector detector = new GestureDetector(new SwipeGestureDetector());

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.infant_eng);
        mContext = this;
        mViewFlipper = (ViewFlipper) this.findViewById(R.id.view_flipper);




        mViewFlipper.setOnTouchListener(new View.OnTouchListener() {
            @Override
            public boolean onTouch(final View view, final MotionEvent event) {
                detector.onTouchEvent(event);
                return true;
            }
        });
    }

    class SwipeGestureDetector extends GestureDetector.SimpleOnGestureListener {

        public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY) {
            try {
                // right to left swipe
                if (e1.getX() - e2.getX()> SWIPE_MIN_DISTANCE && Math.abs(velocityX) > SWIPE_THRESHOLD_VELOCITY) {
                    mViewFlipper.setInAnimation(AnimationUtils.loadAnimation(mContext, R.anim.left_in));
                    mViewFlipper.setOutAnimation(AnimationUtils.loadAnimation(mContext, R.anim.left_out));
                    mViewFlipper.showNext();
                    return true;
                } else if (e2.getX() - e1.getX()> SWIPE_MIN_DISTANCE && Math.abs(velocityX) > SWIPE_THRESHOLD_VELOCITY) {
                    mViewFlipper.setInAnimation(AnimationUtils.loadAnimation(mContext, R.anim.right_in));
                    mViewFlipper.setOutAnimation(AnimationUtils.loadAnimation(mContext, R.anim.right_out));
                    mViewFlipper.showPrevious();
                    return true;
                }

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

            return false;
        }
    }
}