1 /* 2 * Copyright (C) 2007 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.widget; 18 19 import android.content.Context; 20 import android.graphics.Canvas; 21 import android.graphics.Paint; 22 import android.view.View; 23 24 /** 25 * Example of how to write a custom subclass of View. LabelView 26 * is used to draw simple text views. Note that it does not handle 27 * styled text or right-to-left writing systems. 28 * 29 */ 30 public class LabelView extends View { 31 /** 32 * Constructor. This version is only needed if you will be instantiating 33 * the object manually (not from a layout XML file). 34 * @param context the application environment 35 */ 36 public LabelView(Context context) { 37 super(context); 38 initLabelView(); 39 } 40 41 /** 42 * Construct object, initializing with any attributes we understand from a 43 * layout file. These attributes are defined in 44 * SDK/assets/res/any/classes.xml. 45 * 46 * @see android.view.View#View(android.content.Context, android.util.AttributeSet) 47 public LabelView(Context context, AttributeSet attrs) { 48 super(context, attrs); 49 initLabelView(); 50 51 Resources.StyledAttributes a = context.obtainStyledAttributes(attrs, 52 R.styleable.LabelView); 53 54 CharSequence s = a.getString(R.styleable.LabelView_text); 55 if (s != null) { 56 setText(s.toString()); 57 } 58 59 ColorStateList textColor = a.getColorList(R.styleable. 60 LabelView_textColor); 61 if (textColor != null) { 62 setTextColor(textColor.getDefaultColor(0)); 63 } 64 65 int textSize = a.getInt(R.styleable.LabelView_textSize, 0); 66 if (textSize > 0) { 67 setTextSize(textSize); 68 } 69 70 a.recycle(); 71 } 72 73 */ 74 private void initLabelView() { 75 mTextPaint = new Paint(); 76 mTextPaint.setAntiAlias(true); 77 mTextPaint.setTextSize(16); 78 mTextPaint.setColor(0xFF000000); 79 80 mPaddingLeft = 3; 81 mPaddingTop = 3; 82 mPaddingRight = 3; 83 mPaddingBottom = 3; 84 } 85 86 /** 87 * Sets the text to display in this label 88 * @param text The text to display. This will be drawn as one line. 89 */ 90 public void setText(String text) { 91 mText = text; 92 requestLayout(); 93 invalidate(); 94 } 95 96 /** 97 * Sets the text size for this label 98 * @param size Font size 99 */ 100 public void setTextSize(int size) { 101 mTextPaint.setTextSize(size); 102 requestLayout(); 103 invalidate(); 104 } 105 106 /** 107 * Sets the text color for this label 108 * @param color ARGB value for the text 109 */ 110 public void setTextColor(int color) { 111 mTextPaint.setColor(color); 112 invalidate(); 113 } 114 115 116 /** 117 * @see android.view.View#measure(int, int) 118 */ 119 @Override 120 protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { 121 setMeasuredDimension(measureWidth(widthMeasureSpec), 122 measureHeight(heightMeasureSpec)); 123 } 124 125 /** 126 * Determines the width of this view 127 * @param measureSpec A measureSpec packed into an int 128 * @return The width of the view, honoring constraints from measureSpec 129 */ 130 private int measureWidth(int measureSpec) { 131 int result; 132 int specMode = MeasureSpec.getMode(measureSpec); 133 int specSize = MeasureSpec.getSize(measureSpec); 134 135 if (specMode == MeasureSpec.EXACTLY) { 136 // We were told how big to be 137 result = specSize; 138 } else { 139 // Measure the text 140 result = (int) mTextPaint.measureText(mText) + mPaddingLeft 141 + mPaddingRight; 142 if (specMode == MeasureSpec.AT_MOST) { 143 // Respect AT_MOST value if that was what is called for by measureSpec 144 result = Math.min(result, specSize); 145 } 146 } 147 148 return result; 149 } 150 151 /** 152 * Determines the height of this view 153 * @param measureSpec A measureSpec packed into an int 154 * @return The height of the view, honoring constraints from measureSpec 155 */ 156 private int measureHeight(int measureSpec) { 157 int result; 158 int specMode = MeasureSpec.getMode(measureSpec); 159 int specSize = MeasureSpec.getSize(measureSpec); 160 161 mAscent = (int) mTextPaint.ascent(); 162 if (specMode == MeasureSpec.EXACTLY) { 163 // We were told how big to be 164 result = specSize; 165 } else { 166 // Measure the text (beware: ascent is a negative number) 167 result = (int) (-mAscent + mTextPaint.descent()) + mPaddingTop 168 + mPaddingBottom; 169 if (specMode == MeasureSpec.AT_MOST) { 170 // Respect AT_MOST value if that was what is called for by measureSpec 171 result = Math.min(result, specSize); 172 } 173 } 174 return result; 175 } 176 177 /** 178 * Render the text 179 * 180 * @see android.view.View#onDraw(android.graphics.Canvas) 181 */ 182 @Override 183 protected void onDraw(Canvas canvas) { 184 super.onDraw(canvas); 185 canvas.drawText(mText, mPaddingLeft, mPaddingTop - mAscent, mTextPaint); 186 } 187 188 private Paint mTextPaint; 189 private String mText; 190 private int mAscent; 191 } 192
