Scroll HorizontalScrollView using the buttons on the sides

Question

I am using HorizontalScrollView within a Fragment . When I view this view instead of scrolling items in a HorizontalScrollView , the entire fragment scrolls left or right. Now I thought about using buttons on both sides of the layout. But I can’t get how to scroll my scroll view from both sides.

Any help in this regard would be greatly appreciated.

EDIT

Below is my xml file.

 <?xml version="1.0" encoding="utf-8"?> <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" android:layout_width="wrap_content" android:layout_height="wrap_content" > <ImageButton android:id="@+id/btn_left" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_alignParentLeft="true" android:src="@drawable/left_arrow" /> <ImageButton android:id="@+id/btn_right" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_alignParentRight="true" android:src="@drawable/right_arrow" /> <HorizontalScrollView android:id="@+id/horizontal_scrollview" android:layout_width="fill_parent" android:layout_height="wrap_content" android:layout_toLeftOf="@id/btn_right" android:layout_toRightOf="@id/btn_left" android:fadeScrollbars="false" android:padding="5dp" android:scrollbarAlwaysDrawHorizontalTrack="true" android:scrollbars="horizontal" > <LinearLayout android:id="@+id/dynamic_generation" android:layout_width="wrap_content" android:layout_height="wrap_content" android:orientation="horizontal" > </LinearLayout> </HorizontalScrollView> 

and my java file

 public class MyGallery extends Activity { private LinearLayout linearLayout; private ImageButton leftBtn; private ImageButton rightBtn; private HorizontalScrollView hsv; int currentScrollX = 0; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.horizontalscrolling); leftBtn = (ImageButton) findViewById(R.id.btn_left); rightBtn = (ImageButton) findViewById(R.id.btn_right); hsv = (HorizontalScrollView) findViewById(R.id.horizontal_scrollview); linearLayout = (LinearLayout) findViewById(R.id.dynamic_generation); leftBtn.setOnClickListener(new OnClickListener() { @Override public void onClick(View v) { // TODO Auto-generated method stub } }); rightBtn.setOnClickListener(new OnClickListener() { @Override public void onClick(View v) { } }); String[] users = new String[20]; for (int i = 0; i < 20; i++) { users[i] = "user " + (i + 1); } for (int i = 0; i < users.length; i++) { final TextView userId = new TextView(MyGallery.this); userId.setText(users[i]); ImageView imageView = new ImageView(MyGallery.this); linearLayout.addView(userId); linearLayout.addView(imageView); userId.setOnClickListener(new OnClickListener() { @Override public void onClick(View v) { // TODO Auto-generated method stub Toast.makeText(MyGallery.this, userId.getText() + " has been clicked!", Toast.LENGTH_LONG).show(); // hsv. } }); } } } 

What I need

When I press any left or right button, the scroll scroll should scroll left or right, respectively.

Answer 1

If you add the following line of code to an existing handler, your view will scroll to the right each time the button is clicked:

 rightBtn.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { hsv.scrollTo((int)hsv.getScrollX() + 10, (int)hsv.getScrollY()); } }); 

If you want it to scroll more smoothly, you can use onTouchListener instead:

 rightBtn.setOnTouchListener(new View.OnTouchListener() { private Handler mHandler; private long mInitialDelay = 300; private long mRepeatDelay = 100; @Override public boolean onTouch(View v, MotionEvent event) { switch (event.getAction()) { case MotionEvent.ACTION_DOWN: if (mHandler != null) return true; mHandler = new Handler(); mHandler.postDelayed(mAction, mInitialDelay); break; case MotionEvent.ACTION_UP: if (mHandler == null) return true; mHandler.removeCallbacks(mAction); mHandler = null; break; } return false; } Runnable mAction = new Runnable() { @Override public void run() { hsv.scrollTo((int) hsv.getScrollX() + 10, (int) hsv.getScrollY()); mHandler.postDelayed(mAction, mRepeatDelay); } }; }); 

Change the delays you like to get the smoothness and responsiveness you want.