Alexander Lucas | 97842ff | 2014-03-07 14:56:55 -0800 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright (C) 2013 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 | |
| 17 | package com.example.android.common.view; |
| 18 | |
| 19 | import android.R; |
| 20 | import android.content.Context; |
| 21 | import android.graphics.Canvas; |
| 22 | import android.graphics.Color; |
| 23 | import android.graphics.Paint; |
| 24 | import android.util.AttributeSet; |
| 25 | import android.util.TypedValue; |
| 26 | import android.view.View; |
| 27 | import android.widget.LinearLayout; |
| 28 | |
| 29 | class SlidingTabStrip extends LinearLayout { |
| 30 | |
| 31 | private static final int DEFAULT_BOTTOM_BORDER_THICKNESS_DIPS = 2; |
| 32 | private static final byte DEFAULT_BOTTOM_BORDER_COLOR_ALPHA = 0x26; |
| 33 | private static final int SELECTED_INDICATOR_THICKNESS_DIPS = 8; |
| 34 | private static final int DEFAULT_SELECTED_INDICATOR_COLOR = 0xFF33B5E5; |
| 35 | |
| 36 | private static final int DEFAULT_DIVIDER_THICKNESS_DIPS = 1; |
| 37 | private static final byte DEFAULT_DIVIDER_COLOR_ALPHA = 0x20; |
| 38 | private static final float DEFAULT_DIVIDER_HEIGHT = 0.5f; |
| 39 | |
| 40 | private final int mBottomBorderThickness; |
| 41 | private final Paint mBottomBorderPaint; |
| 42 | |
| 43 | private final int mSelectedIndicatorThickness; |
| 44 | private final Paint mSelectedIndicatorPaint; |
| 45 | |
| 46 | private final int mDefaultBottomBorderColor; |
| 47 | |
| 48 | private final Paint mDividerPaint; |
| 49 | private final float mDividerHeight; |
| 50 | |
| 51 | private int mSelectedPosition; |
| 52 | private float mSelectionOffset; |
| 53 | |
| 54 | private SlidingTabLayout.TabColorizer mCustomTabColorizer; |
| 55 | private final SimpleTabColorizer mDefaultTabColorizer; |
| 56 | |
| 57 | SlidingTabStrip(Context context) { |
| 58 | this(context, null); |
| 59 | } |
| 60 | |
| 61 | SlidingTabStrip(Context context, AttributeSet attrs) { |
| 62 | super(context, attrs); |
| 63 | setWillNotDraw(false); |
| 64 | |
| 65 | final float density = getResources().getDisplayMetrics().density; |
| 66 | |
| 67 | TypedValue outValue = new TypedValue(); |
| 68 | context.getTheme().resolveAttribute(R.attr.colorForeground, outValue, true); |
| 69 | final int themeForegroundColor = outValue.data; |
| 70 | |
| 71 | mDefaultBottomBorderColor = setColorAlpha(themeForegroundColor, |
| 72 | DEFAULT_BOTTOM_BORDER_COLOR_ALPHA); |
| 73 | |
| 74 | mDefaultTabColorizer = new SimpleTabColorizer(); |
| 75 | mDefaultTabColorizer.setIndicatorColors(DEFAULT_SELECTED_INDICATOR_COLOR); |
| 76 | mDefaultTabColorizer.setDividerColors(setColorAlpha(themeForegroundColor, |
| 77 | DEFAULT_DIVIDER_COLOR_ALPHA)); |
| 78 | |
| 79 | mBottomBorderThickness = (int) (DEFAULT_BOTTOM_BORDER_THICKNESS_DIPS * density); |
| 80 | mBottomBorderPaint = new Paint(); |
| 81 | mBottomBorderPaint.setColor(mDefaultBottomBorderColor); |
| 82 | |
| 83 | mSelectedIndicatorThickness = (int) (SELECTED_INDICATOR_THICKNESS_DIPS * density); |
| 84 | mSelectedIndicatorPaint = new Paint(); |
| 85 | |
| 86 | mDividerHeight = DEFAULT_DIVIDER_HEIGHT; |
| 87 | mDividerPaint = new Paint(); |
| 88 | mDividerPaint.setStrokeWidth((int) (DEFAULT_DIVIDER_THICKNESS_DIPS * density)); |
| 89 | } |
| 90 | |
| 91 | void setCustomTabColorizer(SlidingTabLayout.TabColorizer customTabColorizer) { |
| 92 | mCustomTabColorizer = customTabColorizer; |
| 93 | invalidate(); |
| 94 | } |
| 95 | |
| 96 | void setSelectedIndicatorColors(int... colors) { |
| 97 | // Make sure that the custom colorizer is removed |
| 98 | mCustomTabColorizer = null; |
| 99 | mDefaultTabColorizer.setIndicatorColors(colors); |
| 100 | invalidate(); |
| 101 | } |
| 102 | |
| 103 | void setDividerColors(int... colors) { |
| 104 | // Make sure that the custom colorizer is removed |
| 105 | mCustomTabColorizer = null; |
| 106 | mDefaultTabColorizer.setDividerColors(colors); |
| 107 | invalidate(); |
| 108 | } |
| 109 | |
| 110 | void onViewPagerPageChanged(int position, float positionOffset) { |
| 111 | mSelectedPosition = position; |
| 112 | mSelectionOffset = positionOffset; |
| 113 | invalidate(); |
| 114 | } |
| 115 | |
| 116 | @Override |
| 117 | protected void onDraw(Canvas canvas) { |
| 118 | final int height = getHeight(); |
| 119 | final int childCount = getChildCount(); |
| 120 | final int dividerHeightPx = (int) (Math.min(Math.max(0f, mDividerHeight), 1f) * height); |
| 121 | final SlidingTabLayout.TabColorizer tabColorizer = mCustomTabColorizer != null |
| 122 | ? mCustomTabColorizer |
| 123 | : mDefaultTabColorizer; |
| 124 | |
| 125 | // Thick colored underline below the current selection |
| 126 | if (childCount > 0) { |
| 127 | View selectedTitle = getChildAt(mSelectedPosition); |
| 128 | int left = selectedTitle.getLeft(); |
| 129 | int right = selectedTitle.getRight(); |
| 130 | int color = tabColorizer.getIndicatorColor(mSelectedPosition); |
| 131 | |
| 132 | if (mSelectionOffset > 0f && mSelectedPosition < (getChildCount() - 1)) { |
| 133 | int nextColor = tabColorizer.getIndicatorColor(mSelectedPosition + 1); |
| 134 | if (color != nextColor) { |
| 135 | color = blendColors(nextColor, color, mSelectionOffset); |
| 136 | } |
| 137 | |
| 138 | // Draw the selection partway between the tabs |
| 139 | View nextTitle = getChildAt(mSelectedPosition + 1); |
| 140 | left = (int) (mSelectionOffset * nextTitle.getLeft() + |
| 141 | (1.0f - mSelectionOffset) * left); |
| 142 | right = (int) (mSelectionOffset * nextTitle.getRight() + |
| 143 | (1.0f - mSelectionOffset) * right); |
| 144 | } |
| 145 | |
| 146 | mSelectedIndicatorPaint.setColor(color); |
| 147 | |
| 148 | canvas.drawRect(left, height - mSelectedIndicatorThickness, right, |
| 149 | height, mSelectedIndicatorPaint); |
| 150 | } |
| 151 | |
| 152 | // Thin underline along the entire bottom edge |
| 153 | canvas.drawRect(0, height - mBottomBorderThickness, getWidth(), height, mBottomBorderPaint); |
| 154 | |
| 155 | // Vertical separators between the titles |
| 156 | int separatorTop = (height - dividerHeightPx) / 2; |
| 157 | for (int i = 0; i < childCount - 1; i++) { |
| 158 | View child = getChildAt(i); |
| 159 | mDividerPaint.setColor(tabColorizer.getDividerColor(i)); |
| 160 | canvas.drawLine(child.getRight(), separatorTop, child.getRight(), |
| 161 | separatorTop + dividerHeightPx, mDividerPaint); |
| 162 | } |
| 163 | } |
| 164 | |
| 165 | /** |
| 166 | * Set the alpha value of the {@code color} to be the given {@code alpha} value. |
| 167 | */ |
| 168 | private static int setColorAlpha(int color, byte alpha) { |
| 169 | return Color.argb(alpha, Color.red(color), Color.green(color), Color.blue(color)); |
| 170 | } |
| 171 | |
| 172 | /** |
| 173 | * Blend {@code color1} and {@code color2} using the given ratio. |
| 174 | * |
| 175 | * @param ratio of which to blend. 1.0 will return {@code color1}, 0.5 will give an even blend, |
| 176 | * 0.0 will return {@code color2}. |
| 177 | */ |
| 178 | private static int blendColors(int color1, int color2, float ratio) { |
| 179 | final float inverseRation = 1f - ratio; |
| 180 | float r = (Color.red(color1) * ratio) + (Color.red(color2) * inverseRation); |
| 181 | float g = (Color.green(color1) * ratio) + (Color.green(color2) * inverseRation); |
| 182 | float b = (Color.blue(color1) * ratio) + (Color.blue(color2) * inverseRation); |
| 183 | return Color.rgb((int) r, (int) g, (int) b); |
| 184 | } |
| 185 | |
| 186 | private static class SimpleTabColorizer implements SlidingTabLayout.TabColorizer { |
| 187 | private int[] mIndicatorColors; |
| 188 | private int[] mDividerColors; |
| 189 | |
| 190 | @Override |
| 191 | public final int getIndicatorColor(int position) { |
| 192 | return mIndicatorColors[position % mIndicatorColors.length]; |
| 193 | } |
| 194 | |
| 195 | @Override |
| 196 | public final int getDividerColor(int position) { |
| 197 | return mDividerColors[position % mDividerColors.length]; |
| 198 | } |
| 199 | |
| 200 | void setIndicatorColors(int... colors) { |
| 201 | mIndicatorColors = colors; |
| 202 | } |
| 203 | |
| 204 | void setDividerColors(int... colors) { |
| 205 | mDividerColors = colors; |
| 206 | } |
| 207 | } |
| 208 | } |