You can use listView.setScrollY(int value) in onTouchListener().You may intercept the touch event and measure the height of your item view,then setScrollY(current height of listview + the height of item).
ListView Items in Android Scroll one at a Time
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28-06-2022 - |
Question
Is there any way in which we scroll ListView
items only one at a time.
Like when you swipe up it'll only scroll One item up and not normal scroll similar for scroll down only one item shifts down.
Please Help!
Here is My Code :
public class ListViewTestExample extends Activity {
ListView listView;
private GestureDetectorCompat mDetector;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main_list_view_test);
mDetector = new GestureDetectorCompat(this, new MyGestureListener());
// Grid ListView object from XML
listView = (ListView) findViewById(R.id.list);
mDetector = new GestureDetectorCompat(this, new MyGestureListener());
// Defined Array values to show in ListView
String[] values = new String[] { "Android List View",
"Adapter implementation", "Simple List View In Android",
"Create List View Android", "Android Example",
"List View Source Code", "List View Array Adapter",
"Android Example List View" };
ArrayAdapter<String> adapter = new ArrayAdapter<String>(this,
android.R.layout.simple_list_item_1, android.R.id.text1, values);
listView.setAdapter(adapter);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
public boolean onTouchEvent(MotionEvent event) {
this.mDetector.onTouchEvent(event);
return super.onTouchEvent(event);
}
class MyGestureListener extends GestureDetector.SimpleOnGestureListener {
Context context = getApplicationContext();
public boolean onDown(MotionEvent event) {
return true;
}
public void onLongPress(MotionEvent event) {
Toast.makeText(context, "Long Press", Toast.LENGTH_SHORT).show();
}
public boolean onFling(MotionEvent event1, MotionEvent event2,
float velocityX, float velocityY) {
float sensitvity = 50;
// TODO Auto-generated method stub
if ((event1.getX() - event2.getX()) > sensitvity) {
Toast.makeText(context, "Swipe Left", Toast.LENGTH_SHORT)
.show();
} else if ((event2.getX() - event1.getX()) > sensitvity) {
Toast.makeText(context, "Swipe Right", Toast.LENGTH_SHORT)
.show();
}
if ((event1.getY() - event2.getY()) > sensitvity) {
if (event2.getPressure() > event1.getPressure()) {
Toast.makeText(context, "Swipe Up + Hold",
Toast.LENGTH_SHORT).show();
} else {
Toast.makeText(context, "Swipe Up", Toast.LENGTH_SHORT).show();
}
} else if ((event2.getY() - event1.getY()) > sensitvity) {
if (event2.getPressure() > event1.getPressure()) {
Toast.makeText(context, "Swipe Down + Hold",
Toast.LENGTH_SHORT).show();
} else {
Toast.makeText(context, "Swipe Down", Toast.LENGTH_SHORT).show();
}
}
return true;
}
public boolean onSingleTapConfirmed(MotionEvent event) {
Toast.makeText(context, "Single Tap Confirmed", Toast.LENGTH_SHORT)
.show();
return true;
}
public boolean onDoubleTap(MotionEvent event) {
Toast.makeText(context, "Double Tap Confirmed", Toast.LENGTH_SHORT).show();
return true;
}
}
}
Solution 2
OTHER TIPS
I know this is now an old post, but I have searched the net and not really found a solution to this. So I have found a solution that works for me. You need to make a custom ListView and override the dispatchTouchEvent function. My version checks to see if the user has flicked with a min velocity and if they have then smooth scroll to the next item. If under this velocity then check to see if the item is over half way then do a smooth scroll. Otherwise return to the current item. This code assumes that the item fills the view.
import android.content.Context;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.VelocityTracker;
import android.view.View;
import android.widget.ListView;
/**
* Created by bradj on 11/12/13.
*/
public class SingleScrollListView extends ListView
{
private boolean mSingleScroll = false;
private VelocityTracker mVelocity = null;
final private float mEscapeVelocity = 2000.0f;
final private int mMinDistanceMoved = 20;
private float mStartY = 0;
public SingleScrollListView(Context context)
{
super(context);
}
public SingleScrollListView(Context context, AttributeSet attrs)
{
super(context, attrs);
}
public SingleScrollListView(Context context, AttributeSet attrs, int defStyle)
{
super(context, attrs, defStyle);
}
public void setSingleScroll(boolean aSingleScroll) { mSingleScroll = aSingleScroll; }
public int getVerticalScrollOffset() { return getFirstVisiblePosition(); }
@Override
public boolean dispatchTouchEvent(MotionEvent aMotionEvent)
{
if (aMotionEvent.getAction() == MotionEvent.ACTION_DOWN)
{
if (mSingleScroll && mVelocity == null)
mVelocity = VelocityTracker.obtain();
mStartY = aMotionEvent.getY();
return super.dispatchTouchEvent(aMotionEvent);
}
if (aMotionEvent.getAction() == MotionEvent.ACTION_UP)
{
if (mVelocity != null)
{
if (Math.abs(aMotionEvent.getY() - mStartY) > mMinDistanceMoved)
{
mVelocity.computeCurrentVelocity(1000);
float velocity = mVelocity.getYVelocity();
if (aMotionEvent.getY() > mStartY)
{
// always lock
if (velocity > mEscapeVelocity)
smoothScrollToPosition(getFirstVisiblePosition());
else
{
// lock if over half way there
View view = getChildAt(0);
if (view != null)
{
if (view.getBottom() >= getHeight() / 2)
smoothScrollToPosition(getFirstVisiblePosition());
else
smoothScrollToPosition(getLastVisiblePosition());
}
}
}
else
{
if (velocity < -mEscapeVelocity)
smoothScrollToPosition(getLastVisiblePosition());
else
{
// lock if over half way there
View view = getChildAt(1);
if (view != null)
{
if (view.getTop() <= getHeight() / 2)
smoothScrollToPosition(getLastVisiblePosition());
else
smoothScrollToPosition(getFirstVisiblePosition());
}
}
}
}
mVelocity.recycle();
}
mVelocity = null;
if (mSingleScroll)
{
if (Math.abs(aMotionEvent.getY() - mStartY) > mMinDistanceMoved)
return super.dispatchTouchEvent(aMotionEvent);
}
else
return super.dispatchTouchEvent(aMotionEvent);
}
if (mSingleScroll)
{
if (mVelocity == null)
{
mVelocity = VelocityTracker.obtain();
mStartY = aMotionEvent.getY();
}
mVelocity.addMovement(aMotionEvent);
}
return super.dispatchTouchEvent(aMotionEvent);
}
}
So the code simple becomes as below. (Don't forget to change the ListView in the xml to SingleScrollListView) There is no need for a gesture listener.
listView = (SingleScrollListView) findViewById(R.id.list);
listView.setSingleScroll(true);