BubbleTextView.java revision 38b4f7c5eab773ad36048b5ab8713750dcaaf748 
1/*
2 * Copyright (C) 2008 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17package com.android.launcher2;
18
19import com.android.launcher.R;
20
21import android.content.Context;
22import android.content.res.Resources;
23import android.graphics.Bitmap;
24import android.graphics.Canvas;
25import android.graphics.Color;
26import android.graphics.Paint;
27import android.graphics.Rect;
28import android.graphics.Region.Op;
29import android.graphics.drawable.Drawable;
30import android.util.AttributeSet;
31import android.view.MotionEvent;
32
33/**
34 * TextView that draws a bubble behind the text. We cannot use a LineBackgroundSpan
35 * because we want to make the bubble taller than the text and TextView's clip is
36 * too aggressive.
37 */
38public class BubbleTextView extends CacheableTextView {
39    static final float CORNER_RADIUS = 4.0f;
40    static final float SHADOW_LARGE_RADIUS = 4.0f;
41    static final float SHADOW_SMALL_RADIUS = 1.75f;
42    static final float SHADOW_Y_OFFSET = 2.0f;
43    static final int SHADOW_LARGE_COLOUR = 0xCC000000;
44    static final int SHADOW_SMALL_COLOUR = 0xBB000000;
45    static final float PADDING_H = 8.0f;
46    static final float PADDING_V = 3.0f;
47
48    private Paint mPaint;
49    private float mBubbleColorAlpha;
50    private int mPrevAlpha = -1;
51
52    private final HolographicOutlineHelper mOutlineHelper = new HolographicOutlineHelper();
53    private final Canvas mTempCanvas = new Canvas();
54    private final Rect mTempRect = new Rect();
55    private final Paint mTempPaint = new Paint();
56    private boolean mDidInvalidateForPressedState;
57    private Bitmap mPressedOrFocusedBackground;
58    private int mFocusedOutlineColor;
59    private int mFocusedGlowColor;
60    private int mPressedOutlineColor;
61    private int mPressedGlowColor;
62
63    private boolean mBackgroundSizeChanged;
64    private Drawable mBackground;
65
66    public BubbleTextView(Context context) {
67        super(context);
68        init();
69    }
70
71    public BubbleTextView(Context context, AttributeSet attrs) {
72        super(context, attrs);
73        init();
74    }
75
76    public BubbleTextView(Context context, AttributeSet attrs, int defStyle) {
77        super(context, attrs, defStyle);
78        init();
79    }
80
81    private void init() {
82        mBackground = getBackground();
83        setFocusable(true);
84        setBackgroundDrawable(null);
85
86        final Resources res = getContext().getResources();
87        int bubbleColor = res.getColor(R.color.bubble_dark_background);
88        mPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
89        mPaint.setColor(bubbleColor);
90        mBubbleColorAlpha = Color.alpha(bubbleColor) / 255.0f;
91        mFocusedOutlineColor =
92            getResources().getColor(R.color.workspace_item_focused_outline_color);
93        mFocusedGlowColor = getResources().getColor(R.color.workspace_item_focused_glow_color);
94        mPressedOutlineColor =
95            getResources().getColor(R.color.workspace_item_pressed_outline_color);
96        mPressedGlowColor =
97            getResources().getColor(R.color.workspace_item_pressed_glow_color);
98    }
99
100    protected int getCacheTopPadding() {
101        return (int) PADDING_V;
102    }
103    protected int getCacheBottomPadding() {
104        return (int) (PADDING_V + SHADOW_LARGE_RADIUS + SHADOW_Y_OFFSET);
105    }
106    protected int getCacheLeftPadding() {
107        return (int) (PADDING_H + SHADOW_LARGE_RADIUS);
108    }
109    protected int getCacheRightPadding() {
110        return (int) (PADDING_H + SHADOW_LARGE_RADIUS);
111    }
112
113    public void applyFromShortcutInfo(ShortcutInfo info, IconCache iconCache) {
114        Bitmap b = info.getIcon(iconCache);
115
116        setCompoundDrawablesWithIntrinsicBounds(null,
117                new FastBitmapDrawable(b),
118                null, null);
119        setText(info.title);
120        buildAndEnableCache();
121        setTag(info);
122    }
123
124    @Override
125    protected boolean setFrame(int left, int top, int right, int bottom) {
126        if (mLeft != left || mRight != right || mTop != top || mBottom != bottom) {
127            mBackgroundSizeChanged = true;
128        }
129        return super.setFrame(left, top, right, bottom);
130    }
131
132    @Override
133    protected boolean verifyDrawable(Drawable who) {
134        return who == mBackground || super.verifyDrawable(who);
135    }
136
137    @Override
138    protected void drawableStateChanged() {
139        if (isPressed()) {
140            // In this case, we have already created the pressed outline on ACTION_DOWN,
141            // so we just need to do an invalidate to trigger draw
142            if (!mDidInvalidateForPressedState) {
143                invalidate();
144            }
145        } else {
146            // Otherwise, either clear the pressed/focused background, or create a background
147            // for the focused state
148            final boolean backgroundEmptyBefore = mPressedOrFocusedBackground == null;
149            mPressedOrFocusedBackground = null;
150            if (isFocused()) {
151                mPressedOrFocusedBackground = createGlowingOutline(
152                        mTempCanvas, mFocusedGlowColor, mFocusedOutlineColor);
153                invalidate();
154            }
155            final boolean backgroundEmptyNow = mPressedOrFocusedBackground == null;
156            if (!backgroundEmptyBefore && backgroundEmptyNow) {
157                invalidate();
158            }
159        }
160
161        Drawable d = mBackground;
162        if (d != null && d.isStateful()) {
163            d.setState(getDrawableState());
164        }
165        super.drawableStateChanged();
166    }
167
168    /**
169     * Draw the View v into the given Canvas.
170     *
171     * @param v the view to draw
172     * @param destCanvas the canvas to draw on
173     * @param padding the horizontal and vertical padding to use when drawing
174     */
175    private void drawWithPadding(Canvas destCanvas, int padding) {
176        final Rect clipRect = mTempRect;
177        getDrawingRect(clipRect);
178
179        // adjust the clip rect so that we don't include the text label
180        clipRect.bottom =
181            getExtendedPaddingTop() - (int) BubbleTextView.PADDING_V + getLayout().getLineTop(0);
182
183        // Draw the View into the bitmap.
184        // The translate of scrollX and scrollY is necessary when drawing TextViews, because
185        // they set scrollX and scrollY to large values to achieve centered text
186        destCanvas.save();
187        destCanvas.translate(-getScrollX() + padding / 2, -getScrollY() + padding / 2);
188        destCanvas.clipRect(clipRect, Op.REPLACE);
189        draw(destCanvas);
190        destCanvas.restore();
191    }
192
193    /**
194     * Returns a new bitmap to be used as the object outline, e.g. to visualize the drop location.
195     * Responsibility for the bitmap is transferred to the caller.
196     */
197    private Bitmap createGlowingOutline(Canvas canvas, int outlineColor, int glowColor) {
198        final int padding = HolographicOutlineHelper.MAX_OUTER_BLUR_RADIUS;
199        final Bitmap b = Bitmap.createBitmap(
200                getWidth() + padding, getHeight() + padding, Bitmap.Config.ARGB_8888);
201
202        canvas.setBitmap(b);
203        drawWithPadding(canvas, padding);
204        mOutlineHelper.applyExtraThickExpensiveOutlineWithBlur(b, canvas, glowColor, outlineColor);
205
206        return b;
207    }
208
209    @Override
210    public boolean onTouchEvent(MotionEvent event) {
211        // Call the superclass onTouchEvent first, because sometimes it changes the state to
212        // isPressed() on an ACTION_UP
213        boolean result = super.onTouchEvent(event);
214
215        switch (event.getAction()) {
216            case MotionEvent.ACTION_DOWN:
217                // So that the pressed outline is visible immediately when isPressed() is true,
218                // we pre-create it on ACTION_DOWN (it takes a small but perceptible amount of time
219                // to create it)
220                if (mPressedOrFocusedBackground == null) {
221                    mPressedOrFocusedBackground = createGlowingOutline(
222                            mTempCanvas, mPressedGlowColor, mPressedOutlineColor);
223                }
224                // Invalidate so the pressed state is visible, or set a flag so we know that we
225                // have to call invalidate as soon as the state is "pressed"
226                if (isPressed()) {
227                    mDidInvalidateForPressedState = true;
228                    invalidate();
229                } else {
230                    mDidInvalidateForPressedState = false;
231                }
232                break;
233            case MotionEvent.ACTION_CANCEL:
234            case MotionEvent.ACTION_UP:
235                // If we've touched down and up on an item, and it's still not "pressed", then
236                // destroy the pressed outline
237                if (!isPressed()) {
238                    mPressedOrFocusedBackground = null;
239                }
240                break;
241        }
242        return result;
243    }
244
245    @Override
246    public void draw(Canvas canvas) {
247        if (mPressedOrFocusedBackground != null && (isPressed() || isFocused())) {
248            canvas.drawBitmap(mPressedOrFocusedBackground,
249                    mScrollX - HolographicOutlineHelper.MAX_OUTER_BLUR_RADIUS / 2,
250                    mScrollY - HolographicOutlineHelper.MAX_OUTER_BLUR_RADIUS / 2,
251                    mTempPaint);
252        }
253        if (isBuildingCache()) {
254            // We enhance the shadow by drawing the shadow twice
255            this.setShadowLayer(SHADOW_LARGE_RADIUS, 0.0f, SHADOW_Y_OFFSET, SHADOW_LARGE_COLOUR);
256            super.draw(canvas);
257            this.setShadowLayer(SHADOW_SMALL_RADIUS, 0.0f, 0.0f, SHADOW_SMALL_COLOUR);
258            super.draw(canvas);
259        } else {
260            final Drawable background = mBackground;
261            if (background != null) {
262                final int scrollX = mScrollX;
263                final int scrollY = mScrollY;
264
265                if (mBackgroundSizeChanged) {
266                    background.setBounds(0, 0,  mRight - mLeft, mBottom - mTop);
267                    mBackgroundSizeChanged = false;
268                }
269
270                if ((scrollX | scrollY) == 0) {
271                    background.draw(canvas);
272                } else {
273                    canvas.translate(scrollX, scrollY);
274                    background.draw(canvas);
275                    canvas.translate(-scrollX, -scrollY);
276                }
277            }
278            super.draw(canvas);
279        }
280    }
281
282    @Override
283    protected void onAttachedToWindow() {
284        super.onAttachedToWindow();
285        if (mBackground != null) mBackground.setCallback(this);
286    }
287
288    @Override
289    protected void onDetachedFromWindow() {
290        super.onDetachedFromWindow();
291        if (mBackground != null) mBackground.setCallback(null);
292    }
293
294    @Override
295    protected boolean onSetAlpha(int alpha) {
296        if (mPrevAlpha != alpha) {
297            mPrevAlpha = alpha;
298            mPaint.setAlpha((int) (alpha * mBubbleColorAlpha));
299            super.onSetAlpha(alpha);
300        }
301        return true;
302    }
303}
304