android/source/src/java/org/libreoffice/PresentationActivity.java

   1 package org.libreoffice;
   2
   3 import android.content.Intent;
   4 import android.os.Bundle;
   5 import androidx.annotation.Nullable;
   6 import androidx.core.view.GestureDetectorCompat;
   7 import androidx.appcompat.app.AppCompatActivity;
   8 import android.view.GestureDetector;
   9 import android.view.KeyEvent;
  10 import android.view.MotionEvent;
  11 import android.view.View;
  12 import android.webkit.WebView;
  13 import android.widget.Button;
  14 import android.widget.ImageButton;
  15
  16 public class PresentationActivity extends AppCompatActivity {
  17
  18     private static final String LOGTAG = PresentationActivity.class.getSimpleName();
  19     WebView mWebView;
  20     View mGestureView;
  21
  22     @Override
  23     protected void onCreate(@Nullable Bundle savedInstanceState) {
  24         super.onCreate(savedInstanceState);
  25
  26         View decorView = getWindow().getDecorView();
  27         // Hide the status bar.
  28         int uiOptions = View.SYSTEM_UI_FLAG_FULLSCREEN;
  29         decorView.setSystemUiVisibility(uiOptions);
  30
  31         setContentView(R.layout.presentation_mode);
  32
  33         // get intent and url
  34         Intent intent = getIntent();
  35         String filePath = intent.getDataString();
  36
  37         // set up WebView
  38         mWebView = findViewById(R.id.presentation_view);
  39         mWebView.getSettings().setJavaScriptEnabled(true);
  40         mWebView.setOnTouchListener(new View.OnTouchListener() {
  41             @Override
  42             public boolean onTouch(View v, MotionEvent event) {
  43                 return true;
  44             }
  45         });
  46
  47         // set up buttons within presentation_gesture_view
  48         ImageButton prevButton = findViewById(R.id.slide_show_nav_prev);
  49         ImageButton nextButton = findViewById(R.id.slide_show_nav_next);
  50         Button backButton = findViewById(R.id.slide_show_nav_back);
  51
  52         prevButton.setOnClickListener(new View.OnClickListener() {
  53             @Override
  54             public void onClick(View v) {
  55                 pageLeft();
  56             }
  57         });
  58         nextButton.setOnClickListener(new View.OnClickListener() {
  59             @Override
  60             public void onClick(View v) {
  61                 pageRight();
  62             }
  63         });
  64         backButton.setOnClickListener(new View.OnClickListener() {
  65             @Override
  66             public void onClick(View v) {
  67                 onBackPressed();
  68             }
  69         });
  70
  71         // set up presentation_gesture_view
  72         mGestureView = findViewById(R.id.presentation_gesture_view);
  73         final GestureDetectorCompat gestureDetector =
  74                 new GestureDetectorCompat(this, new PresentationGestureViewListener());
  75         mGestureView.setOnTouchListener(new View.OnTouchListener() {
  76             @Override
  77             public boolean onTouch(View v, MotionEvent event) {
  78                 return gestureDetector.onTouchEvent(event);
  79             }
  80         });
  81
  82         // load url
  83         mWebView.loadUrl(filePath);
  84     }
  85
  86     private class PresentationGestureViewListener extends GestureDetector.SimpleOnGestureListener {
  87         private static final int SWIPE_VELOCITY_THRESHOLD = 100;
  88         private static final int SCROLL_THRESHOLD = 10; // if scrollCounter is larger than this, a page switch is triggered
  89         private int scrollCounter = 0; // a counter for measuring scrolling distance
  90
  91         @Override
  92         public boolean onDown(MotionEvent e) {
  93             return true;
  94         }
  95
  96         @Override
  97         public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY) {
  98             boolean result = false;
  99             try {
 100                 float diffY = e2.getY() - e1.getY();
 101                 float diffX = e2.getX() - e1.getX();
 102                 if (Math.abs(diffX) > Math.abs(diffY)) {
 103                     if (Math.abs(velocityX) > SWIPE_VELOCITY_THRESHOLD) {
 104                         if (diffX > 0) {
 105                             pageRight();
 106                         } else {
 107                             pageLeft();
 108                         }
 109                         result = true;
 110                     }
 111                 }
 112             } catch (Exception exception) {
 113                 exception.printStackTrace();
 114             }
 115             return result;
 116         }
 117
 118         @Override
 119         public boolean onScroll(MotionEvent e1, MotionEvent e2, float distanceX, float distanceY) {
 120             boolean result = false;
 121             try {
 122                 float diffY = e2.getY() - e1.getY();
 123                 float diffX = e2.getX() - e1.getX();
 124                 if (Math.abs(diffX) < Math.abs(diffY)) {
 125                     if (distanceY > 0) {
 126                         scrollCounter++;
 127                         if (scrollCounter >= SCROLL_THRESHOLD) {
 128                             pageRight();
 129                             scrollCounter = 0;
 130                         }
 131                     } else {
 132                         scrollCounter--;
 133                         if (scrollCounter <= -SCROLL_THRESHOLD) {
 134                             pageLeft();
 135                             scrollCounter = 0;
 136                         }
 137                     }
 138                     result = true;
 139                 }
 140             } catch (Exception exception) {
 141                 exception.printStackTrace();
 142             }
 143             return result;
 144         }
 145
 146         @Override
 147         public boolean onSingleTapUp(MotionEvent e) {
 148             if (e.getX() < mGestureView.getWidth()/3) {
 149                 pageLeft();
 150             } else if (e.getX() < mGestureView.getWidth()*2/3) {
 151                 hideControlButtons();
 152             } else {
 153                 pageRight();
 154             }
 155             return true;
 156         }
 157     }
 158
 159     private void hideControlButtons() {
 160         View[] views= {findViewById(R.id.slide_show_nav_prev),findViewById(R.id.slide_show_nav_next),findViewById(R.id.slide_show_nav_back)} ;
 161         for (View view : views) {
 162             if (view.getVisibility() == View.GONE) {
 163                 view.setVisibility(View.VISIBLE);
 164             } else if (view.getVisibility() == View.VISIBLE) {
 165                 view.setVisibility(View.GONE);
 166             }
 167         }
 168     }
 169
 170     private void pageLeft() {
 171         mWebView.dispatchKeyEvent(new KeyEvent(KeyEvent.ACTION_DOWN, KeyEvent.KEYCODE_DPAD_LEFT));
 172     }
 173
 174     private void pageRight() {
 175         mWebView.dispatchKeyEvent(new KeyEvent(KeyEvent.ACTION_DOWN, KeyEvent.KEYCODE_DPAD_RIGHT));
 176     }
 177 }