Android：如何创建 MotionEvent？

Question

MotionEvent doesn't get a constructor, I wanted to manually create a MotionEvent in my unit test, then how to get that? Thanks.

Answer 1

You should use one of the static obtain methods of the MotionEvent class to create a new event.

The simplest way (besides wrapping a new event from an existing one) is:

static public MotionEvent obtain(long downTime, long eventTime, int action,
        float x, float y, int metaState) {

API Docs :

Create a new MotionEvent, filling in a subset of the basic motion values. Those not specified here are: device id (always 0), pressure and size (always 1), x and y precision (always 1), and edgeFlags (always 0).

Parameters :

• downTime The time (in ms) when the user originally pressed down to start a stream of position events. This must be obtained from SystemClock.uptimeMillis().
• eventTime The the time (in ms) when this specific event was generated. This must be obtained from SystemClock.uptimeMillis() .
• action The kind of action being performed -- one of either ACTION_DOWN , ACTION_MOVE , ACTION_UP , or ACTION_CANCEL .
• x The X coordinate of this event.
• y The Y coordinate of this event.
• metaState The state of any meta / modifier keys that were in effect when the event was generated.

Link to API Docs

Answer 2

Supplemental answer

Here is an example illustrating the accepted answer:

// get the coordinates of the view
int[] coordinates = new int[2];
myView.getLocationOnScreen(coordinates);

// MotionEvent parameters
long downTime = SystemClock.uptimeMillis();
long eventTime = SystemClock.uptimeMillis();
int action = MotionEvent.ACTION_DOWN;
int x = coordinates[0];
int y = coordinates[1];
int metaState = 0;

// dispatch the event
MotionEvent event = MotionEvent.obtain(downTime, eventTime, action, x, y, metaState);
myView.dispatchTouchEvent(event);

Notes

• Other meta states include things like KeyEvent.META_SHIFT_ON , etc.
• Thanks to this answer for help with the example.