Home | History | Annotate | Download | only in launcher3 
      1 package com.android.launcher3;
      2 
      3 import com.android.launcher3.Utilities;
      4 
      5 import android.util.Log;
      6 import android.view.MotionEvent;
      7 import android.view.View;
      8 import android.view.ViewConfiguration;
      9 
     10 /**
     11  * Helper for identifying when a stylus touches a view while the primary stylus button is pressed.
     12  * This can occur in {@value MotionEvent#ACTION_DOWN} or {@value MotionEvent#ACTION_MOVE}. On a
     13  * stylus button press this performs the view's {@link View#performLongClick()} method, if the view
     14  * is long clickable.
     15  */
     16 public class StylusEventHelper {
     17     private boolean mIsButtonPressed;
     18     private View mView;
     19 
     20     public StylusEventHelper(View view) {
     21         mView = view;
     22     }
     23 
     24     /**
     25      * Call this in onTouchEvent method of a view to identify a stylus button press and perform a
     26      * long click (if the view is long clickable).
     27      *
     28      * @param event The event to check for a stylus button press.
     29      * @return Whether a stylus event occurred and was handled.
     30      */
     31     public boolean checkAndPerformStylusEvent(MotionEvent event) {
     32         final float slop = ViewConfiguration.get(mView.getContext()).getScaledTouchSlop();
     33 
     34         if (!mView.isLongClickable()) {
     35             // We don't do anything unless the view is long clickable.
     36             return false;
     37         }
     38 
     39         final boolean stylusButtonPressed = isStylusButtonPressed(event);
     40         switch (event.getAction()) {
     41             case MotionEvent.ACTION_DOWN:
     42                 mIsButtonPressed = false;
     43                 if (stylusButtonPressed && mView.performLongClick()) {
     44                     mIsButtonPressed = true;
     45                     return true;
     46                 }
     47                 break;
     48             case MotionEvent.ACTION_MOVE:
     49                 if (Utilities.pointInView(mView, event.getX(), event.getY(), slop)) {
     50                     if (!mIsButtonPressed && stylusButtonPressed && mView.performLongClick()) {
     51                         mIsButtonPressed = true;
     52                         return true;
     53                     } else if (mIsButtonPressed && !stylusButtonPressed) {
     54                         mIsButtonPressed = false;
     55                     }
     56                 }
     57                 break;
     58             case MotionEvent.ACTION_UP:
     59             case MotionEvent.ACTION_CANCEL:
     60                 mIsButtonPressed = false;
     61                 break;
     62         }
     63         return false;
     64     }
     65 
     66     /**
     67      * Whether a stylus button press is occurring.
     68      */
     69     public boolean inStylusButtonPressed() {
     70         return mIsButtonPressed;
     71     }
     72 
     73     /**
     74      * Identifies if the provided {@link MotionEvent} is a stylus with the primary stylus button
     75      * pressed.
     76      *
     77      * @param event The event to check.
     78      * @return Whether a stylus button press occurred.
     79      */
     80     public static boolean isStylusButtonPressed(MotionEvent event) {
     81         return event.getToolType(0) == MotionEvent.TOOL_TYPE_STYLUS
     82                 && event.isButtonPressed(MotionEvent.BUTTON_SECONDARY);
     83     }
     84 }