CandidatesView.java

package idv.Zero.KerKerInput;

import java.util.ArrayList;
import java.util.List;
import android.util.Log;

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.drawable.Drawable;
import android.util.AttributeSet;
import android.view.Gravity;
import android.view.MotionEvent;
import android.view.View;
import android.view.ViewGroup.LayoutParams;
import android.widget.PopupWindow;
import android.widget.TextView;

public class CandidatesView extends View {
	private List<CharSequence> _cands;
	private Paint _pntText;
	private Drawable _drwHighlighted, _divider;
	private KerKerInputCore _core;
	private int _wordWidth = 34;
	private PopupWindow _winPreview;
	private TextView _txtPreview;
	private int _lastTouchedX;
	private int OUT_OF_BOUND = -1;
	private int[] _candIdxToX;
	private int[] _candIdxToWidth;
	private int[] _candIdxToPage;
	private int _scrollX;
	private int _currentCandidate;
	private int scrollStartCandID;
	private int _currentPage;
	
	public CandidatesView(Context c, AttributeSet attrs) {
		super(c, attrs);
		
		_drwHighlighted = c.getResources().getDrawable(R.drawable.highlight);
		_divider = c.getResources().getDrawable(R.drawable.divider);
		
		_cands = new ArrayList<CharSequence>();
		_candIdxToX = new int[0];
		_candIdxToWidth = new int[0];
		_candIdxToPage = new int[0];
		_currentPage = 0;
		
		_pntText = new Paint();
		_pntText.setColor(Color.WHITE);
		_pntText.setAntiAlias(true);
		_pntText.setTextSize(24);
		_pntText.setStrokeWidth(0);
				
		setHorizontalFadingEdgeEnabled(true);
		setHorizontalScrollBarEnabled(false);
		setVerticalScrollBarEnabled(false);
		
		_lastTouchedX = OUT_OF_BOUND;
		scrollStartCandID = 0;
	}
	
	public void initPopup()
	{
		Context c = _core.getFrontend();
		_winPreview = new PopupWindow(c);
		_winPreview.setWindowLayoutMode(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT);
		_winPreview.setBackgroundDrawable(null);
		_txtPreview = (TextView) _core.getInflater().inflate(R.layout.candidates_preview, null);
		_winPreview.setContentView(_txtPreview);
	}

	public void setCandidates(List<CharSequence> lst)
	{
		_cands = lst;
		_candIdxToX = new int[lst.size()];
		_candIdxToWidth = new int[lst.size()];
		_candIdxToPage = new int[lst.size()];
		_currentPage = 0;
		scrollStartCandID = 0;
		invalidate();
		Log.i("CandidateView", lst.toString());
	}
	
	public void setCore(KerKerInputCore core)
	{
		_core = core;
	}	
	
	@Override
	protected void onDraw(Canvas canvas)
	{
		super.onDraw(canvas);

		int x = 0, page = 0;
		int y = (int) (getHeight() + _pntText.getTextSize() - _pntText.descent()) / 2;
		int count = _cands.size();
		_divider.setBounds(0, 0, _divider.getIntrinsicWidth(), getHeight());
		
		for(int i=0;i<count;i++)
		{
			CharSequence cand = _cands.get(i);
			float textWidth = _pntText.measureText(cand.toString());
			float cellWidth = textWidth + 2;
			if (cellWidth < _wordWidth)
				cellWidth = _wordWidth;
			_candIdxToWidth[i] = (int)textWidth;
			_candIdxToX[i] = x;
			_candIdxToPage[i] = page;

			// FIXME: Failed if single candidate's textWidth > getWidth()
			if (x + textWidth > getWidth())
			{
				page++;
				x = 0;
				i--;
				continue;
			}
			
			if (i < scrollStartCandID || page != _currentPage) {
        x += cellWidth + _divider.getIntrinsicWidth();
        continue;
      }
			
			canvas.translate(x, 0);
			if (isCandSelected(x, x + (int)cellWidth))
			{
				_drwHighlighted.setBounds(0, 0, (int)cellWidth, getHeight());
				_drwHighlighted.draw(canvas);
				showPopup(i);
			}

			canvas.drawText(cand.toString(), (cellWidth-textWidth)/2, y, _pntText);
			
			canvas.translate(cellWidth, 0);
			_divider.draw(canvas);
			canvas.translate(-cellWidth, 0);

			canvas.translate(-x, 0);
      x += cellWidth + _divider.getIntrinsicWidth();
		}
		_core.getCurrentInputMethod().setTotalPages(page + 1);
	}

	private boolean isCandSelected(int x, int xe) {
		if (_lastTouchedX >= x && _lastTouchedX <= xe)
			return true;
		else
			return false;
	}

  @Override
  public boolean onTouchEvent(MotionEvent me) {
    
    if (me.getAction() == MotionEvent.ACTION_UP || me.getAction() == MotionEvent.ACTION_OUTSIDE)
    {
        if (me.getAction() == MotionEvent.ACTION_UP)
          commitCandidates();
        hidePopup();
    }
    else if (me.getAction() == MotionEvent.ACTION_DOWN || me.getAction() == MotionEvent.ACTION_MOVE)
        _lastTouchedX = (int) me.getX();
    
    
    invalidate();    	
    return true;
  }
  
  private void commitCandidates() {
    if (_currentCandidate == OUT_OF_BOUND)
      return;
    
    _core.commitCandidate(_currentCandidate);
	}

	private void showPopup(int candIndex)
  {
    _currentCandidate = candIndex;
      
    CharSequence str = _cands.get(candIndex);
    _txtPreview.setText(str);
    _txtPreview.measure(MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED), MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED));
    int wordWidth = (int)(_pntText.measureText(str.toString()));
    int popupWidth = wordWidth + _txtPreview.getPaddingLeft() + _txtPreview.getPaddingRight();
    int popupHeight = _txtPreview.getMeasuredHeight();
    int popupX = _candIdxToX[candIndex] - _scrollX + (popupWidth - _wordWidth) / 2 + 8; // 8?
    int popupY = -popupHeight;
    
    int[] offset = new int[2];
    getLocationInWindow(offset);
    popupY += offset[1];
    
    if (_winPreview.isShowing())
      _winPreview.update(popupX, popupY, popupWidth, popupHeight);
    else
    {
      _winPreview.setWidth(popupWidth);
      _winPreview.setHeight(popupHeight);
      _winPreview.showAtLocation(this, Gravity.NO_GRAVITY, popupX, popupY);
    }
    _txtPreview.setVisibility(VISIBLE);
  }
  
  private void hidePopup()
  {
    _winPreview.dismiss();
    _lastTouchedX = OUT_OF_BOUND;
    _currentCandidate = OUT_OF_BOUND;
  }

  public void prevPage()
  {
    if (_currentPage == 0) return;
    
    _currentPage--;
    while(scrollStartCandID >= 0 && _candIdxToPage[scrollStartCandID] > _currentPage - 1)
      scrollStartCandID--;
    
    scrollStartCandID++;
    _core.getCurrentInputMethod().setCurrentPage(_currentPage);
  }

  public void nextPage()
  {
    _currentPage++;
    while(scrollStartCandID < _cands.size() && _candIdxToPage[scrollStartCandID] < _currentPage)
      scrollStartCandID++;
    
    if (scrollStartCandID == _cands.size())
    {
      scrollStartCandID--;
      prevPage();
    }
    _core.getCurrentInputMethod().setCurrentPage(_currentPage);
  }
}