Java tutorial
/* * Copyright (C) 2015 The Android Open Source Project * * 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 android.support.v7.widget; import android.content.Context; import android.content.res.ColorStateList; import android.graphics.Color; import android.support.v4.graphics.ColorUtils; import android.util.TypedValue; class ThemeUtils { private static final ThreadLocal<TypedValue> TL_TYPED_VALUE = new ThreadLocal<>(); static final int[] DISABLED_STATE_SET = new int[] { -android.R.attr.state_enabled }; static final int[] FOCUSED_STATE_SET = new int[] { android.R.attr.state_focused }; static final int[] ACTIVATED_STATE_SET = new int[] { android.R.attr.state_activated }; static final int[] PRESSED_STATE_SET = new int[] { android.R.attr.state_pressed }; static final int[] CHECKED_STATE_SET = new int[] { android.R.attr.state_checked }; static final int[] SELECTED_STATE_SET = new int[] { android.R.attr.state_selected }; static final int[] NOT_PRESSED_OR_FOCUSED_STATE_SET = new int[] { -android.R.attr.state_pressed, -android.R.attr.state_focused }; static final int[] EMPTY_STATE_SET = new int[0]; private static final int[] TEMP_ARRAY = new int[1]; public static ColorStateList createDisabledStateList(int textColor, int disabledTextColor) { // Now create a new ColorStateList with the default color, and the new disabled // color final int[][] states = new int[2][]; final int[] colors = new int[2]; int i = 0; // Disabled state states[i] = DISABLED_STATE_SET; colors[i] = disabledTextColor; i++; // Default state states[i] = EMPTY_STATE_SET; colors[i] = textColor; i++; return new ColorStateList(states, colors); } public static int getThemeAttrColor(Context context, int attr) { TEMP_ARRAY[0] = attr; TintTypedArray a = TintTypedArray.obtainStyledAttributes(context, null, TEMP_ARRAY); try { return a.getColor(0, 0); } finally { a.recycle(); } } public static ColorStateList getThemeAttrColorStateList(Context context, int attr) { TEMP_ARRAY[0] = attr; TintTypedArray a = TintTypedArray.obtainStyledAttributes(context, null, TEMP_ARRAY); try { return a.getColorStateList(0); } finally { a.recycle(); } } public static int getDisabledThemeAttrColor(Context context, int attr) { final ColorStateList csl = getThemeAttrColorStateList(context, attr); if (csl != null && csl.isStateful()) { // If the CSL is stateful, we'll assume it has a disabled state and use it return csl.getColorForState(DISABLED_STATE_SET, csl.getDefaultColor()); } else { // Else, we'll generate the color using disabledAlpha from the theme final TypedValue tv = getTypedValue(); // Now retrieve the disabledAlpha value from the theme context.getTheme().resolveAttribute(android.R.attr.disabledAlpha, tv, true); final float disabledAlpha = tv.getFloat(); return getThemeAttrColor(context, attr, disabledAlpha); } } private static TypedValue getTypedValue() { TypedValue typedValue = TL_TYPED_VALUE.get(); if (typedValue == null) { typedValue = new TypedValue(); TL_TYPED_VALUE.set(typedValue); } return typedValue; } static int getThemeAttrColor(Context context, int attr, float alpha) { final int color = getThemeAttrColor(context, attr); final int originalAlpha = Color.alpha(color); return ColorUtils.setAlphaComponent(color, Math.round(originalAlpha * alpha)); } }