private boolean tryToMove(float deltaY) {

        // has reached the bottom
        if ((deltaY > 0 && mCurrentPos == 0)) {
            if (DEBUG) {
                Log.d(LOG_TAG, String.format("has reached the bottom"));
            }
            return false;
        }

        // has reached the top
        if ((deltaY < 0 && mCurrentPos == -mHeaderHeight)) {
            if (DEBUG) {
                Log.d(LOG_TAG, String.format("has reached the top"));
            }
            return false;
        }

        int to = mCurrentPos + (int) deltaY;

        // over top
        if (to < -mHeaderHeight) {
            if (DEBUG) {
                Log.d(LOG_TAG, String.format("over top"));
            }
            to = -mHeaderHeight;
        }

        // over bottom
        if (to > 0) {
            if (DEBUG) {
                Log.d(LOG_TAG, String.format("over bottom"));
            }
            to = 0;
        }
        return moveTo(to);
    }
private boolean tryToMove(float deltaY) {

        
        if ((deltaY > 0 && mCurrentPos == 0)) {
            if (DEBUG) {
                Log.d(LOG_TAG, String.format("has reached the bottom"));
            }
            return false;
        }

        
        if ((deltaY < 0 && mCurrentPos == -mHeaderHeight)) {
            if (DEBUG) {
                Log.d(LOG_TAG, String.format("has reached the top"));
            }
            return false;
        }

        int to = mCurrentPos + (int) deltaY;

        
        if (to < -mHeaderHeight) {
            if (DEBUG) {
                Log.d(LOG_TAG, String.format("over top"));
            }
            to = -mHeaderHeight;
        }

        
        if (to > 0) {
            if (DEBUG) {
                Log.d(LOG_TAG, String.format("over bottom"));
            }
            to = 0;
        }
        return moveTo(to);
    }
private boolean tryToMove ( float deltaY ) { // has reached the bottom if ( ( deltaY > 0 && mCurrentPos == 0 ) ) { if ( DEBUG ) { Log . d ( LOG_TAG , String . format ( "has reached the bottom" ) ) ; } return false ; } // has reached the top if ( ( deltaY < 0 && mCurrentPos == - mHeaderHeight ) ) { if ( DEBUG ) { Log . d ( LOG_TAG , String . format ( "has reached the top" ) ) ; } return false ; } int to = mCurrentPos + ( int ) deltaY ; // over top if ( to < - mHeaderHeight ) { if ( DEBUG ) { Log . d ( LOG_TAG , String . format ( "over top" ) ) ; } to = - mHeaderHeight ; } // over bottom if ( to > 0 ) { if ( DEBUG ) { Log . d ( LOG_TAG , String . format ( "over bottom" ) ) ; } to = 0 ; } return moveTo ( to ) ; }
if deltaY > 0, tryToMove the content down
if deltaY > 0 tryToMove the content down