问题
hi i have to add a gesture to my listview,i want to implement the same functionality of contact application. when i left swipe it should send a message,right swipe it should call. can anyone help me how to do those gesture detection... i have implemented it in various other views... but i couldn\'t do for listView... i don\'t what going worng... my code is`
/** Called when the activity is first created. */
public void onCreate(Bundle icicle) {
super.onCreate(icicle);
setContentView(R.layout.main);
// Create an array of Strings, that will be put to our ListActivity
String[] names = new String[] { \"Linux\", \"Windows7\", \"Eclipse\", \"Suse\", \"Ubuntu\", \"Solaris\", \"Android\", \"iPhone\"};
// Create an ArrayAdapter, that will actually make the Strings above
// appear in the ListView
this.setListAdapter(new ArrayAdapter<String>(this, R.id.MyList, names));
gestureListener = new ListView.OnTouchListener() {
public boolean onTouch(View v, MotionEvent event) {
if (gestureDetector.onTouchEvent(event)) {
return true;
}
return false;
}
};
}
@Override
protected void onListItemClick(ListView l, View v, int position, long id) {
super.onListItemClick(l, v, position, id);
// Get the item that was clicked
Object o = this.getListAdapter().getItem(position);
String keyword = o.toString();
Toast.makeText(this, \"You selected: \" + keyword, Toast.LENGTH_LONG).show();
}
@Override
public boolean onTouchEvent(MotionEvent event) {
if (gestureDetector.onTouchEvent(event))
return true;
else
return false;
}
class MyGestureDetector extends SimpleOnGestureListener {
@Override
public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY) {
try {
if (Math.abs(e1.getY() - e2.getY()) > SWIPE_MAX_OFF_PATH) {
return false;
// right to left swipe
}
if (e1.getX() - e2.getX() > SWIPE_MIN_DISTANCE && Math.abs(velocityX) > SWIPE_THRESHOLD_VELOCITY) {
Context ctx = getApplicationContext();
CharSequence txt = \"Right to Left Swipe\";
int duration = Toast.LENGTH_LONG;
Toast toast = Toast.makeText(ctx, txt, duration);
toast.show();
Toast.makeText(this.getItem(lv.pointToPosition((int)e1.getX(),(int) e1.getY())));
// return super.onFling();
} else if (e2.getX() - e1.getX() > SWIPE_MIN_DISTANCE && Math.abs(velocityX) > SWIPE_THRESHOLD_VELOCITY) {
Context ctx = getApplicationContext();
CharSequence txt = \"Left to Right Swipe\";
int duration = Toast.LENGTH_LONG;
Toast toast = Toast.makeText(ctx, txt, duration);
toast.show();
}
} catch (Exception e) {
// nothing
}
return false;
}
}
回答1:
Based on answers from post [#937313][1] (thanks go to gav and paiego), I whipped up the following code to recognize simple gestures (horizontal swipes) on ListView.
However, after a fling operation, the ListView's onItemClick() listener will be called too! Therefore, you end up with a fling and an extra onItemClick(). I think this is because Android sends an item-click event on every button-up, no matter how far way the user has moved his finger. To remedy this, instead of registering a usual OnItemClickListener(), I provided my own method myOnItemClick(). Then I override the SimpleOnGestureListener.onSingleTapUp() method, so that when the finger is up, this method will call myOnItemClick() manually.
So far this method works fine for me. No complaints :-).
public class PracticeActivity extends ListActivity {
private int REL_SWIPE_MIN_DISTANCE;
private int REL_SWIPE_MAX_OFF_PATH;
private int REL_SWIPE_THRESHOLD_VELOCITY;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// As paiego pointed out, it's better to use density-aware measurements.
DisplayMetrics dm = getResources().getDisplayMetrics();
REL_SWIPE_MIN_DISTANCE = (int)(120.0f * dm.densityDpi / 160.0f + 0.5);
REL_SWIPE_MAX_OFF_PATH = (int)(250.0f * dm.densityDpi / 160.0f + 0.5);
REL_SWIPE_THRESHOLD_VELOCITY = (int)(200.0f * dm.densityDpi / 160.0f + 0.5);
ListView lv = getListView();
lv.setAdapter(new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1,
m_Starbucks));
final GestureDetector gestureDetector = new GestureDetector(new MyGestureDetector());
View.OnTouchListener gestureListener = new View.OnTouchListener() {
public boolean onTouch(View v, MotionEvent event) {
return gestureDetector.onTouchEvent(event);
}};
lv.setOnTouchListener(gestureListener);
// Long-click still works in the usual way.
lv.setOnItemLongClickListener(new AdapterView.OnItemLongClickListener() {
public boolean onItemLongClick(AdapterView<?> parent, View view, int position, long id) {
String str = MessageFormat.format("Item long clicked = {0,number}", position);
Toast.makeText(PracticeActivity.this, str, Toast.LENGTH_SHORT).show();
return true;
}
});
}
// Do not use LitView.setOnItemClickListener(). Instead, I override
// SimpleOnGestureListener.onSingleTapUp() method, and it will call to this method when
// it detects a tap-up event.
private void myOnItemClick(int position) {
String str = MessageFormat.format("Item clicked = {0,number}", position);
Toast.makeText(this, str, Toast.LENGTH_SHORT).show();
}
private void onLTRFling() {
Toast.makeText(this, "Left-to-right fling", Toast.LENGTH_SHORT).show();
}
private void onRTLFling() {
Toast.makeText(this, "Right-to-left fling", Toast.LENGTH_SHORT).show();
}
class MyGestureDetector extends SimpleOnGestureListener{
// Detect a single-click and call my own handler.
@Override
public boolean onSingleTapUp(MotionEvent e) {
ListView lv = getListView();
int pos = lv.pointToPosition((int)e.getX(), (int)e.getY());
myOnItemClick(pos);
return false;
}
@Override
public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY) {
if (Math.abs(e1.getY() - e2.getY()) > REL_SWIPE_MAX_OFF_PATH)
return false;
if(e1.getX() - e2.getX() > REL_SWIPE_MIN_DISTANCE &&
Math.abs(velocityX) > REL_SWIPE_THRESHOLD_VELOCITY) {
onRTLFling();
} else if (e2.getX() - e1.getX() > REL_SWIPE_MIN_DISTANCE &&
Math.abs(velocityX) > REL_SWIPE_THRESHOLD_VELOCITY) {
onLTRFling();
}
return false;
}
}
private static final String[] m_Starbucks = {
"Latte", "Cappuccino", "Caramel Macchiato", "Americano", "Mocha", "White Mocha",
"Mocha Valencia", "Cinnamon Spice Mocha", "Toffee Nut Latte", "Espresso",
"Espresso Macchiato", "Espresso Con Panna"
};
}
回答2:
--Edited--- If you came here from google, just want to tell you that although this solution still works, that specific constructor of GestureDetector is deprecated.
If you want to implement swipe gestures on your android app you could consider using this library: https://github.com/liuzc/android-swipelistview
Or this one (swipes work just like gmail): https://github.com/nhaarman/ListViewAnimations
来源：https://stackoverflow.com/questions/3921138/gesture-in-listview-android