1 /* 2 * Copyright (C) 2006 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 android.text.style; 18 19 import android.annotation.ColorInt; 20 import android.annotation.NonNull; 21 import android.annotation.Px; 22 import android.graphics.Canvas; 23 import android.graphics.Paint; 24 import android.os.Parcel; 25 import android.text.ParcelableSpan; 26 import android.text.TextUtils; 27 28 /** 29 * Used to change the background of lines where the span is attached to. 30 */ 31 public interface LineBackgroundSpan extends ParagraphStyle 32 { 33 /** 34 * Draw the background on the canvas. 35 * 36 * @param canvas canvas on which the span should be rendered 37 * @param paint paint used to draw text, which should be left unchanged on exit 38 * @param left left position of the line relative to input canvas, in pixels 39 * @param right right position of the line relative to input canvas, in pixels 40 * @param top top position of the line relative to input canvas, in pixels 41 * @param baseline baseline of the text relative to input canvas, in pixels 42 * @param bottom bottom position of the line relative to input canvas, in pixels 43 * @param text current text 44 * @param start start character index of the line 45 * @param end end character index of the line 46 * @param lineNumber line number in the current text layout 47 */ drawBackground(@onNull Canvas canvas, @NonNull Paint paint, @Px int left, @Px int right, @Px int top, @Px int baseline, @Px int bottom, @NonNull CharSequence text, int start, int end, int lineNumber)48 void drawBackground(@NonNull Canvas canvas, @NonNull Paint paint, 49 @Px int left, @Px int right, 50 @Px int top, @Px int baseline, @Px int bottom, 51 @NonNull CharSequence text, int start, int end, 52 int lineNumber); 53 /** 54 * Default implementation of the {@link LineBackgroundSpan}, which changes the background 55 * color of the lines to which the span is attached. 56 * <p> 57 * For example, an <code>LineBackgroundSpan</code> can be used like this: 58 * <pre> 59 * String text = "This is a multiline text. LineBackgroundSpan is applied here. This is a multiline text."; 60 * SpannableString string = new SpannableString(text); 61 * string.setSpan(new LineBackgroundSpan.Standard(Color.YELLOW), 26, 61, Spanned.SPAN_EXCLUSIVE_EXCLUSIVE); 62 * </pre> 63 * <img src="{@docRoot}reference/android/images/text/style/linebackgroundspan.png" /> 64 * <figcaption>Text with <code>LineBackgroundSpan</code></figcaption> 65 */ 66 class Standard implements LineBackgroundSpan, ParcelableSpan { 67 68 private final int mColor; 69 70 /** 71 * Constructor taking a color integer. 72 * 73 * @param color Color integer that defines the background color. 74 */ Standard(@olorInt int color)75 public Standard(@ColorInt int color) { 76 mColor = color; 77 } 78 79 /** 80 * Creates a {@link LineBackgroundSpan.Standard} from a parcel 81 */ Standard(@onNull Parcel src)82 public Standard(@NonNull Parcel src) { 83 mColor = src.readInt(); 84 } 85 86 @Override getSpanTypeId()87 public int getSpanTypeId() { 88 return getSpanTypeIdInternal(); 89 } 90 91 /** @hide */ 92 @Override getSpanTypeIdInternal()93 public int getSpanTypeIdInternal() { 94 return TextUtils.LINE_BACKGROUND_SPAN; 95 } 96 97 @Override describeContents()98 public int describeContents() { 99 return 0; 100 } 101 102 @Override writeToParcel(@onNull Parcel dest, int flags)103 public void writeToParcel(@NonNull Parcel dest, int flags) { 104 writeToParcelInternal(dest, flags); 105 } 106 107 /** @hide */ 108 @Override writeToParcelInternal(@onNull Parcel dest, int flags)109 public void writeToParcelInternal(@NonNull Parcel dest, int flags) { 110 dest.writeInt(mColor); 111 } 112 113 /** 114 * @return the color of this span. 115 * @see Standard#Standard(int) 116 */ 117 @ColorInt getColor()118 public final int getColor() { 119 return mColor; 120 } 121 122 @Override drawBackground(@onNull Canvas canvas, @NonNull Paint paint, @Px int left, @Px int right, @Px int top, @Px int baseline, @Px int bottom, @NonNull CharSequence text, int start, int end, int lineNumber)123 public void drawBackground(@NonNull Canvas canvas, @NonNull Paint paint, 124 @Px int left, @Px int right, 125 @Px int top, @Px int baseline, @Px int bottom, 126 @NonNull CharSequence text, int start, int end, 127 int lineNumber) { 128 final int originColor = paint.getColor(); 129 paint.setColor(mColor); 130 canvas.drawRect(left, top, right, bottom, paint); 131 paint.setColor(originColor); 132 } 133 } 134 } 135
