OLD | NEW |
---|---|
(Empty) | |
1 // Copyright 2017 The Chromium Authors. All rights reserved. | |
2 // Use of this source code is governed by a BSD-style license that can be | |
3 // found in the LICENSE file. | |
4 | |
5 package org.chromium.chrome.browser.widget; | |
6 | |
7 import android.content.Context; | |
8 import android.graphics.Canvas; | |
9 import android.graphics.Color; | |
10 import android.graphics.Paint; | |
11 import android.util.AttributeSet; | |
12 import android.widget.ScrollView; | |
13 | |
14 import org.chromium.base.ApiCompatibilityUtils; | |
15 import org.chromium.chrome.R; | |
16 | |
17 /** | |
18 * An extension of the ScrollView that supports edge boundaries coming in. | |
19 */ | |
20 public class FadingEdgeScrollView extends ScrollView { | |
21 public static final int DRAW_NO_EDGE = 0; | |
Ted C
2017/03/20 19:10:31
I would one-liner javadoc these and IntDef'em.
gone
2017/03/20 20:06:19
Done.
| |
22 public static final int DRAW_FADING_EDGE = 1; | |
23 public static final int DRAW_HARD_EDGE = 2; | |
24 | |
25 private static final int POSITION_TOP = 0; | |
26 private static final int POSITION_BOTTOM = 1; | |
27 | |
28 private final Paint mSeparatorPaint = new Paint(); | |
29 private final int mSeparatorColor; | |
30 private final int mSeparatorHeight; | |
31 | |
32 private int mDrawTopEdge = DRAW_FADING_EDGE; | |
33 private int mDrawBottomEdge = DRAW_FADING_EDGE; | |
34 | |
35 public FadingEdgeScrollView(Context context, AttributeSet attrs) { | |
36 super(context, attrs); | |
37 | |
38 mSeparatorColor = | |
39 ApiCompatibilityUtils.getColor(getResources(), R.color.toolbar_s hadow_color); | |
40 mSeparatorHeight = getResources().getDimensionPixelSize(R.dimen.separato r_height); | |
41 } | |
42 | |
43 @Override | |
44 protected void dispatchDraw(Canvas canvas) { | |
45 super.dispatchDraw(canvas); | |
46 setVerticalFadingEdgeEnabled(true); | |
47 float topEdgeStrength = getTopFadingEdgeStrength(); | |
48 float bottomEdgeStrength = getBottomFadingEdgeStrength(); | |
49 setVerticalFadingEdgeEnabled(false); | |
50 | |
51 drawBoundaryLine(canvas, POSITION_TOP, topEdgeStrength, mDrawTopEdge); | |
52 drawBoundaryLine(canvas, POSITION_BOTTOM, bottomEdgeStrength, mDrawBotto mEdge); | |
53 } | |
54 | |
55 /** | |
56 * Sets which edge should be drawn. | |
57 * @param topEdgeState Whether to draw the edge on the top part of the vi ew. | |
58 * @param bottomEdgeState Whether to draw the edge on the bottom part of the view. | |
59 */ | |
60 public void setEdgeVisibility(int topEdgeState, int bottomEdgeState) { | |
61 mDrawTopEdge = topEdgeState; | |
62 mDrawBottomEdge = bottomEdgeState; | |
63 invalidate(); | |
64 } | |
65 | |
66 /** | |
67 * Draws a line at the top or bottom of the view. This should be called from dispatchDraw() so | |
68 * it gets drawn on top of the View's children. | |
69 * | |
70 * @param canvas The canvas on which to draw. | |
71 * @param position Where to draw the line: either POSITION_TOP or POSITI ON_BOTTOM. | |
72 * @param edgeStrength A value between 0 and 1 indicating the relative size of the line. 0 | |
73 * means no line at all. 1 means a fully opaque line. | |
74 * @param edgeState How to draw the line. | |
75 */ | |
76 private void drawBoundaryLine(Canvas canvas, int position, float edgeStrengt h, int edgeState) { | |
77 if (edgeState == DRAW_NO_EDGE) { | |
78 return; | |
79 } else if (edgeState == DRAW_FADING_EDGE) { | |
80 edgeStrength = Math.max(0.0f, Math.min(1.0f, edgeStrength)); | |
81 } else { | |
82 edgeStrength = 1.0f; | |
83 } | |
84 if (edgeStrength <= 0.0f) return; | |
85 | |
86 int adjustedA = (int) (Color.alpha(mSeparatorColor) * edgeStrength); | |
87 int adjustedR = (int) (Color.red(mSeparatorColor) * edgeStrength); | |
88 int adjustedG = (int) (Color.green(mSeparatorColor) * edgeStrength); | |
89 int adjustedB = (int) (Color.blue(mSeparatorColor) * edgeStrength); | |
90 mSeparatorPaint.setColor(Color.argb(adjustedA, adjustedR, adjustedG, adj ustedB)); | |
91 | |
92 int left = getScrollX(); | |
93 int right = left + getRight(); | |
94 | |
95 if (position == POSITION_BOTTOM) { | |
96 int bottom = getScrollY() + getBottom() - getTop(); | |
97 canvas.drawRect(left, bottom - mSeparatorHeight, right, bottom, mSep aratorPaint); | |
98 } else if (position == POSITION_TOP) { | |
99 int top = getScrollY(); | |
100 canvas.drawRect(left, top, right, top + mSeparatorHeight, mSeparator Paint); | |
101 } | |
102 } | |
103 } | |
OLD | NEW |