samples/SoftKeyboard/src/com/example/android/softkeyboard/CandidateView.java - platform/development - Git at Google

 /*
  * Copyright (C) 2008-2009 Google Inc.
  *
  * Licensed under the Apache License, Version 2.0 (the "License"); you may not
  * use this file except in compliance with the License. You may obtain a copy of
  * the License at
  *
  * http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
  * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
  * License for the specific language governing permissions and limitations under
  * the License.
  */

 package com.example.android.softkeyboard;

 import android.content.Context;
 import android.content.res.Resources;
 import android.graphics.Canvas;
 import android.graphics.Paint;
 import android.graphics.Rect;
 import android.graphics.drawable.Drawable;
 import android.view.GestureDetector;
 import android.view.MotionEvent;
 import android.view.View;

 import java.util.ArrayList;
 import java.util.List;

 public class CandidateView extends View {

     private static final int OUT_OF_BOUNDS = -1;

     private SoftKeyboard mService;
     private List<String> mSuggestions;
     private int mSelectedIndex;
     private int mTouchX = OUT_OF_BOUNDS;
     private Drawable mSelectionHighlight;
     private boolean mTypedWordValid;

     private Rect mBgPadding;

     private static final int MAX_SUGGESTIONS = 32;
     private static final int SCROLL_PIXELS = 20;

     private int[] mWordWidth = new int[MAX_SUGGESTIONS];
     private int[] mWordX = new int[MAX_SUGGESTIONS];

     private static final int X_GAP = 10;

     private static final List<String> EMPTY_LIST = new ArrayList<String>();

     private int mColorNormal;
     private int mColorRecommended;
     private int mColorOther;
     private int mVerticalPadding;
     private Paint mPaint;
     private boolean mScrolled;
     private int mTargetScrollX;

     private int mTotalWidth;

     private GestureDetector mGestureDetector;

     /**
      * Construct a CandidateView for showing suggested words for completion.
      * @param context
      * @param attrs
      */
     public CandidateView(Context context) {
         super(context);
         mSelectionHighlight = context.getResources().getDrawable(
                 android.R.drawable.list_selector_background);
         mSelectionHighlight.setState(new int[] {
                 android.R.attr.state_enabled,
                 android.R.attr.state_focused,
                 android.R.attr.state_window_focused,
                 android.R.attr.state_pressed
         });

         Resources r = context.getResources();

         setBackgroundColor(r.getColor(R.color.candidate_background));

         mColorNormal = r.getColor(R.color.candidate_normal);
         mColorRecommended = r.getColor(R.color.candidate_recommended);
         mColorOther = r.getColor(R.color.candidate_other);
         mVerticalPadding = r.getDimensionPixelSize(R.dimen.candidate_vertical_padding);

         mPaint = new Paint();
         mPaint.setColor(mColorNormal);
         mPaint.setAntiAlias(true);
         mPaint.setTextSize(r.getDimensionPixelSize(R.dimen.candidate_font_height));
         mPaint.setStrokeWidth(0);

         mGestureDetector = new GestureDetector(new GestureDetector.SimpleOnGestureListener() {
             @Override
             public boolean onScroll(MotionEvent e1, MotionEvent e2,
                     float distanceX, float distanceY) {
                 mScrolled = true;
                 int sx = getScrollX();
                 sx += distanceX;
                 if (sx < 0) {
                     sx = 0;
                 }
                 if (sx + getWidth() > mTotalWidth) {
                     sx -= distanceX;
                 }
                 mTargetScrollX = sx;
                 scrollTo(sx, getScrollY());
                 invalidate();
                 return true;
             }
         });
         setHorizontalFadingEdgeEnabled(true);
         setWillNotDraw(false);
         setHorizontalScrollBarEnabled(false);
         setVerticalScrollBarEnabled(false);
     }

     /**
      * A connection back to the service to communicate with the text field
      * @param listener
      */
     public void setService(SoftKeyboard listener) {
         mService = listener;
     }

     @Override
     public int computeHorizontalScrollRange() {
         return mTotalWidth;
     }

     @Override
     protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
         int measuredWidth = resolveSize(50, widthMeasureSpec);

         // Get the desired height of the icon menu view (last row of items does
         // not have a divider below)
         Rect padding = new Rect();
         mSelectionHighlight.getPadding(padding);
         final int desiredHeight = ((int)mPaint.getTextSize()) + mVerticalPadding
                 + padding.top + padding.bottom;

         // Maximum possible width and desired height
         setMeasuredDimension(measuredWidth,
                 resolveSize(desiredHeight, heightMeasureSpec));
     }

     /**
      * If the canvas is null, then only touch calculations are performed to pick the target
      * candidate.
      */
     @Override
     protected void onDraw(Canvas canvas) {
         if (canvas != null) {
             super.onDraw(canvas);
         }
         mTotalWidth = 0;
         if (mSuggestions == null) return;

         if (mBgPadding == null) {
             mBgPadding = new Rect(0, 0, 0, 0);
             if (getBackground() != null) {
                 getBackground().getPadding(mBgPadding);
             }
         }
         int x = 0;
         final int count = mSuggestions.size();
         final int height = getHeight();
         final Rect bgPadding = mBgPadding;
         final Paint paint = mPaint;
         final int touchX = mTouchX;
         final int scrollX = getScrollX();
         final boolean scrolled = mScrolled;
         final boolean typedWordValid = mTypedWordValid;
         final int y = (int) (((height - mPaint.getTextSize()) / 2) - mPaint.ascent());

         for (int i = 0; i < count; i++) {
             String suggestion = mSuggestions.get(i);
             float textWidth = paint.measureText(suggestion);
             final int wordWidth = (int) textWidth + X_GAP * 2;

             mWordX[i] = x;
             mWordWidth[i] = wordWidth;
             paint.setColor(mColorNormal);
             if (touchX + scrollX >= x && touchX + scrollX < x + wordWidth && !scrolled) {
                 if (canvas != null) {
                     canvas.translate(x, 0);
                     mSelectionHighlight.setBounds(0, bgPadding.top, wordWidth, height);
                     mSelectionHighlight.draw(canvas);
                     canvas.translate(-x, 0);
                 }
                 mSelectedIndex = i;
             }

             if (canvas != null) {
                 if ((i == 1 && !typedWordValid) || (i == 0 && typedWordValid)) {
                     paint.setFakeBoldText(true);
                     paint.setColor(mColorRecommended);
                 } else if (i != 0) {
                     paint.setColor(mColorOther);
                 }
                 canvas.drawText(suggestion, x + X_GAP, y, paint);
                 paint.setColor(mColorOther);
                 canvas.drawLine(x + wordWidth + 0.5f, bgPadding.top,
                         x + wordWidth + 0.5f, height + 1, paint);
                 paint.setFakeBoldText(false);
             }
             x += wordWidth;
         }
         mTotalWidth = x;
         if (mTargetScrollX != getScrollX()) {
             scrollToTarget();
         }
     }

     private void scrollToTarget() {
         int sx = getScrollX();
         if (mTargetScrollX > sx) {
             sx += SCROLL_PIXELS;
             if (sx >= mTargetScrollX) {
                 sx = mTargetScrollX;
                 requestLayout();
             }
         } else {
             sx -= SCROLL_PIXELS;
             if (sx <= mTargetScrollX) {
                 sx = mTargetScrollX;
                 requestLayout();
             }
         }
         scrollTo(sx, getScrollY());
         invalidate();
     }

     public void setSuggestions(List<String> suggestions, boolean completions,
             boolean typedWordValid) {
         clear();
         if (suggestions != null) {
             mSuggestions = new ArrayList<String>(suggestions);
         }
         mTypedWordValid = typedWordValid;
         scrollTo(0, 0);
         mTargetScrollX = 0;
         // Compute the total width
         onDraw(null);
         invalidate();
         requestLayout();
     }

     public void clear() {
         mSuggestions = EMPTY_LIST;
         mTouchX = OUT_OF_BOUNDS;
         mSelectedIndex = -1;
         invalidate();
     }

     @Override
     public boolean onTouchEvent(MotionEvent me) {

         if (mGestureDetector.onTouchEvent(me)) {
             return true;
         }

         int action = me.getAction();
         int x = (int) me.getX();
         int y = (int) me.getY();
         mTouchX = x;

         switch (action) {
         case MotionEvent.ACTION_DOWN:
             mScrolled = false;
             invalidate();
             break;
         case MotionEvent.ACTION_MOVE:
             if (y <= 0) {
                 // Fling up!?
                 if (mSelectedIndex >= 0) {
                     mService.pickSuggestionManually(mSelectedIndex);
                     mSelectedIndex = -1;
                 }
             }
             invalidate();
             break;
         case MotionEvent.ACTION_UP:
             if (!mScrolled) {
                 if (mSelectedIndex >= 0) {
                     mService.pickSuggestionManually(mSelectedIndex);
                 }
             }
             mSelectedIndex = -1;
             removeHighlight();
             requestLayout();
             break;
         }
         return true;
     }

     /**
      * For flick through from keyboard, call this method with the x coordinate of the flick
      * gesture.
      * @param x
      */
     public void takeSuggestionAt(float x) {
         mTouchX = (int) x;
         // To detect candidate
         onDraw(null);
         if (mSelectedIndex >= 0) {
             mService.pickSuggestionManually(mSelectedIndex);
         }
         invalidate();
     }

     private void removeHighlight() {
         mTouchX = OUT_OF_BOUNDS;
         invalidate();
     }
 }
	/*
	* Copyright (C) 2008-2009 Google Inc.
	*
	* Licensed under the Apache License, Version 2.0 (the "License"); you may not
	* use this file except in compliance with the License. You may obtain a copy of
	* the License at
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software
	* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
	* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
	* License for the specific language governing permissions and limitations under
	* the License.
	*/

	package com.example.android.softkeyboard;

	import android.content.Context;
	import android.content.res.Resources;
	import android.graphics.Canvas;
	import android.graphics.Paint;
	import android.graphics.Rect;
	import android.graphics.drawable.Drawable;
	import android.view.GestureDetector;
	import android.view.MotionEvent;
	import android.view.View;

	import java.util.ArrayList;
	import java.util.List;

	public class CandidateView extends View {

	private static final int OUT_OF_BOUNDS = -1;

	private SoftKeyboard mService;
	private List<String> mSuggestions;
	private int mSelectedIndex;
	private int mTouchX = OUT_OF_BOUNDS;
	private Drawable mSelectionHighlight;
	private boolean mTypedWordValid;

	private Rect mBgPadding;

	private static final int MAX_SUGGESTIONS = 32;
	private static final int SCROLL_PIXELS = 20;

	private int[] mWordWidth = new int[MAX_SUGGESTIONS];
	private int[] mWordX = new int[MAX_SUGGESTIONS];

	private static final int X_GAP = 10;

	private static final List<String> EMPTY_LIST = new ArrayList<String>();

	private int mColorNormal;
	private int mColorRecommended;
	private int mColorOther;
	private int mVerticalPadding;
	private Paint mPaint;
	private boolean mScrolled;
	private int mTargetScrollX;

	private int mTotalWidth;

	private GestureDetector mGestureDetector;

	/**
	* Construct a CandidateView for showing suggested words for completion.
	* @param context
	* @param attrs
	*/
	public CandidateView(Context context) {
	super(context);
	mSelectionHighlight = context.getResources().getDrawable(
	android.R.drawable.list_selector_background);
	mSelectionHighlight.setState(new int[] {
	android.R.attr.state_enabled,
	android.R.attr.state_focused,
	android.R.attr.state_window_focused,
	android.R.attr.state_pressed
	});

	Resources r = context.getResources();

	setBackgroundColor(r.getColor(R.color.candidate_background));

	mColorNormal = r.getColor(R.color.candidate_normal);
	mColorRecommended = r.getColor(R.color.candidate_recommended);
	mColorOther = r.getColor(R.color.candidate_other);
	mVerticalPadding = r.getDimensionPixelSize(R.dimen.candidate_vertical_padding);

	mPaint = new Paint();
	mPaint.setColor(mColorNormal);
	mPaint.setAntiAlias(true);
	mPaint.setTextSize(r.getDimensionPixelSize(R.dimen.candidate_font_height));
	mPaint.setStrokeWidth(0);

	mGestureDetector = new GestureDetector(new GestureDetector.SimpleOnGestureListener() {
	@Override
	public boolean onScroll(MotionEvent e1, MotionEvent e2,
	float distanceX, float distanceY) {
	mScrolled = true;
	int sx = getScrollX();
	sx += distanceX;
	if (sx < 0) {
	sx = 0;
	}
	if (sx + getWidth() > mTotalWidth) {
	sx -= distanceX;
	}
	mTargetScrollX = sx;
	scrollTo(sx, getScrollY());
	invalidate();
	return true;
	}
	});
	setHorizontalFadingEdgeEnabled(true);
	setWillNotDraw(false);
	setHorizontalScrollBarEnabled(false);
	setVerticalScrollBarEnabled(false);
	}

	/**
	* A connection back to the service to communicate with the text field
	* @param listener
	*/
	public void setService(SoftKeyboard listener) {
	mService = listener;
	}

	@Override
	public int computeHorizontalScrollRange() {
	return mTotalWidth;
	}

	@Override
	protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
	int measuredWidth = resolveSize(50, widthMeasureSpec);

	// Get the desired height of the icon menu view (last row of items does
	// not have a divider below)
	Rect padding = new Rect();
	mSelectionHighlight.getPadding(padding);
	final int desiredHeight = ((int)mPaint.getTextSize()) + mVerticalPadding
	+ padding.top + padding.bottom;

	// Maximum possible width and desired height
	setMeasuredDimension(measuredWidth,
	resolveSize(desiredHeight, heightMeasureSpec));
	}

	/**
	* If the canvas is null, then only touch calculations are performed to pick the target
	* candidate.
	*/
	@Override
	protected void onDraw(Canvas canvas) {
	if (canvas != null) {
	super.onDraw(canvas);
	}
	mTotalWidth = 0;
	if (mSuggestions == null) return;

	if (mBgPadding == null) {
	mBgPadding = new Rect(0, 0, 0, 0);
	if (getBackground() != null) {
	getBackground().getPadding(mBgPadding);
	}
	}
	int x = 0;
	final int count = mSuggestions.size();
	final int height = getHeight();
	final Rect bgPadding = mBgPadding;
	final Paint paint = mPaint;
	final int touchX = mTouchX;
	final int scrollX = getScrollX();
	final boolean scrolled = mScrolled;
	final boolean typedWordValid = mTypedWordValid;
	final int y = (int) (((height - mPaint.getTextSize()) / 2) - mPaint.ascent());

	for (int i = 0; i < count; i++) {
	String suggestion = mSuggestions.get(i);
	float textWidth = paint.measureText(suggestion);
	final int wordWidth = (int) textWidth + X_GAP * 2;

	mWordX[i] = x;
	mWordWidth[i] = wordWidth;
	paint.setColor(mColorNormal);
	if (touchX + scrollX >= x && touchX + scrollX < x + wordWidth && !scrolled) {
	if (canvas != null) {
	canvas.translate(x, 0);
	mSelectionHighlight.setBounds(0, bgPadding.top, wordWidth, height);
	mSelectionHighlight.draw(canvas);
	canvas.translate(-x, 0);
	}
	mSelectedIndex = i;
	}

	if (canvas != null) {
	if ((i == 1 && !typedWordValid) \|\| (i == 0 && typedWordValid)) {
	paint.setFakeBoldText(true);
	paint.setColor(mColorRecommended);
	} else if (i != 0) {
	paint.setColor(mColorOther);
	}
	canvas.drawText(suggestion, x + X_GAP, y, paint);
	paint.setColor(mColorOther);
	canvas.drawLine(x + wordWidth + 0.5f, bgPadding.top,
	x + wordWidth + 0.5f, height + 1, paint);
	paint.setFakeBoldText(false);
	}
	x += wordWidth;
	}
	mTotalWidth = x;
	if (mTargetScrollX != getScrollX()) {
	scrollToTarget();
	}
	}

	private void scrollToTarget() {
	int sx = getScrollX();
	if (mTargetScrollX > sx) {
	sx += SCROLL_PIXELS;
	if (sx >= mTargetScrollX) {
	sx = mTargetScrollX;
	requestLayout();
	}
	} else {
	sx -= SCROLL_PIXELS;
	if (sx <= mTargetScrollX) {
	sx = mTargetScrollX;
	requestLayout();
	}
	}
	scrollTo(sx, getScrollY());
	invalidate();
	}

	public void setSuggestions(List<String> suggestions, boolean completions,
	boolean typedWordValid) {
	clear();
	if (suggestions != null) {
	mSuggestions = new ArrayList<String>(suggestions);
	}
	mTypedWordValid = typedWordValid;
	scrollTo(0, 0);
	mTargetScrollX = 0;
	// Compute the total width
	onDraw(null);
	invalidate();
	requestLayout();
	}

	public void clear() {
	mSuggestions = EMPTY_LIST;
	mTouchX = OUT_OF_BOUNDS;
	mSelectedIndex = -1;
	invalidate();
	}

	@Override
	public boolean onTouchEvent(MotionEvent me) {

	if (mGestureDetector.onTouchEvent(me)) {
	return true;
	}

	int action = me.getAction();
	int x = (int) me.getX();
	int y = (int) me.getY();
	mTouchX = x;

	switch (action) {
	case MotionEvent.ACTION_DOWN:
	mScrolled = false;
	invalidate();
	break;
	case MotionEvent.ACTION_MOVE:
	if (y <= 0) {
	// Fling up!?
	if (mSelectedIndex >= 0) {
	mService.pickSuggestionManually(mSelectedIndex);
	mSelectedIndex = -1;
	}
	}
	invalidate();
	break;
	case MotionEvent.ACTION_UP:
	if (!mScrolled) {
	if (mSelectedIndex >= 0) {
	mService.pickSuggestionManually(mSelectedIndex);
	}
	}
	mSelectedIndex = -1;
	removeHighlight();
	requestLayout();
	break;
	}
	return true;
	}

	/**
	* For flick through from keyboard, call this method with the x coordinate of the flick
	* gesture.
	* @param x
	*/
	public void takeSuggestionAt(float x) {
	mTouchX = (int) x;
	// To detect candidate
	onDraw(null);
	if (mSelectedIndex >= 0) {
	mService.pickSuggestionManually(mSelectedIndex);
	}
	invalidate();
	}

	private void removeHighlight() {
	mTouchX = OUT_OF_BOUNDS;
	invalidate();
	}
	}