How to do a drag slide view in Android

Question

I need to be able to drag-slide a listview to the left and out of view while exposing another listview that is underneath the first listview. How can I go about doing this?

Answer 1

You can use a OnTouchListener and resize or move some view on ACTION_MOVE. Remember to call setClickable(true) to make sure ACTION_MOVE gets called.

There goes an example with the sliding view at the bottom:

Layout:

<RelativeLayout
        xmlns:android="http://schemas.android.com/apk/res/android"
        android:layout_width="match_parent"
        android:layout_height="match_parent">

    <LinearLayout
            android:id="@+id/background_view"
            android:layout_width="match_parent"
            android:layout_height="match_parent">

        (more content)

    </LinearLayout>
    <LinearLayout
            android:id="@+id/sliding_view"
            android:layout_alignParentBottom="true"
            android:layout_width="match_parent"
            android:layout_height="wrap_content">

        <View
                android:id="@+id/draggable_view"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"/>

        (more content)

    </LinearLayout>

</RelativeLayout>

Setting up the views:

View slidingView = ...
View draggableView = ... //placed inside slidingView, this is where you touch and drag
draggableView.setOnTouchListener(new TouchListener(slidingView));
draggableView.setClickable(true); //if not set, only ACTION_DOWN gets called, ACTION_MOVE doesn't

Listener:

private class TouchListener implements View.OnTouchListener{

        View slidingView;

        int initHeight;
        float initPos;
        ViewGroup.LayoutParams params;

        private TouchListener(View slidingView) {
            this.slidingView = slidingView;
        }

        @Override
        public boolean onTouch(View v, MotionEvent event) {
            if(params == null){
                params = slidingView.getLayoutParams();
            }

            switch (event.getActionMasked()){
                case ACTION_DOWN: //get initial state
                    initHeight = slidingView.getHeight();
                    initPos = event.getRawY();
                    break;
                case ACTION_MOVE: //do the sliding
                    float dPos = initPos - event.getRawY();
                    params.height = Math.round(initHeight + dPos);
                    slidingView.requestLayout(); //refresh layout
                    break;
            }

            return false;
        }
    }

Note: If ACTION_MOVE still doesn't get called, try calling setFocusable in addition to setClickable. I didn't need to do this when my "draggable view" was a TextView though.