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
17package com.example.android.apis.view;
18
19// Need the following import to get access to the app resources, since this
20// class is in a sub-package.
21import android.content.Context;
22import android.content.res.TypedArray;
23import android.graphics.Canvas;
24import android.graphics.Paint;
25import android.util.AttributeSet;
26import android.view.View;
27
28import com.example.android.apis.R;
29
30
31/**
32 * Example of how to write a custom subclass of View. LabelView
33 * is used to draw simple text views. Note that it does not handle
34 * styled text or right-to-left writing systems.
35 *
36 */
37public class LabelView extends View {
38    private Paint mTextPaint;
39    private String mText;
40    private int mAscent;
41
42    /**
43     * Constructor.  This version is only needed if you will be instantiating
44     * the object manually (not from a layout XML file).
45     * @param context
46     */
47    public LabelView(Context context) {
48        super(context);
49        initLabelView();
50    }
51
52    /**
53     * Construct object, initializing with any attributes we understand from a
54     * layout file. These attributes are defined in
55     * SDK/assets/res/any/classes.xml.
56     *
57     * @see android.view.View#View(android.content.Context, android.util.AttributeSet)
58     */
59    public LabelView(Context context, AttributeSet attrs) {
60        super(context, attrs);
61        initLabelView();
62
63        TypedArray a = context.obtainStyledAttributes(attrs,
64                R.styleable.LabelView);
65
66        CharSequence s = a.getString(R.styleable.LabelView_text);
67        if (s != null) {
68            setText(s.toString());
69        }
70
71        // Retrieve the color(s) to be used for this view and apply them.
72        // Note, if you only care about supporting a single color, that you
73        // can instead call a.getColor() and pass that to setTextColor().
74        setTextColor(a.getColor(R.styleable.LabelView_textColor, 0xFF000000));
75
76        int textSize = a.getDimensionPixelOffset(R.styleable.LabelView_textSize, 0);
77        if (textSize > 0) {
78            setTextSize(textSize);
79        }
80
81        a.recycle();
82    }
83
84    private final void initLabelView() {
85        mTextPaint = new Paint();
86        mTextPaint.setAntiAlias(true);
87        // Must manually scale the desired text size to match screen density
88        mTextPaint.setTextSize(16 * getResources().getDisplayMetrics().density);
89        mTextPaint.setColor(0xFF000000);
90        setPadding(3, 3, 3, 3);
91    }
92
93    /**
94     * Sets the text to display in this label
95     * @param text The text to display. This will be drawn as one line.
96     */
97    public void setText(String text) {
98        mText = text;
99        requestLayout();
100        invalidate();
101    }
102
103    /**
104     * Sets the text size for this label
105     * @param size Font size
106     */
107    public void setTextSize(int size) {
108        // This text size has been pre-scaled by the getDimensionPixelOffset method
109        mTextPaint.setTextSize(size);
110        requestLayout();
111        invalidate();
112    }
113
114    /**
115     * Sets the text color for this label.
116     * @param color ARGB value for the text
117     */
118    public void setTextColor(int color) {
119        mTextPaint.setColor(color);
120        invalidate();
121    }
122
123    /**
124     * @see android.view.View#measure(int, int)
125     */
126    @Override
127    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
128        setMeasuredDimension(measureWidth(widthMeasureSpec),
129                measureHeight(heightMeasureSpec));
130    }
131
132    /**
133     * Determines the width of this view
134     * @param measureSpec A measureSpec packed into an int
135     * @return The width of the view, honoring constraints from measureSpec
136     */
137    private int measureWidth(int measureSpec) {
138        int result = 0;
139        int specMode = MeasureSpec.getMode(measureSpec);
140        int specSize = MeasureSpec.getSize(measureSpec);
141
142        if (specMode == MeasureSpec.EXACTLY) {
143            // We were told how big to be
144            result = specSize;
145        } else {
146            // Measure the text
147            result = (int) mTextPaint.measureText(mText) + getPaddingLeft()
148                    + getPaddingRight();
149            if (specMode == MeasureSpec.AT_MOST) {
150                // Respect AT_MOST value if that was what is called for by measureSpec
151                result = Math.min(result, specSize);
152            }
153        }
154
155        return result;
156    }
157
158    /**
159     * Determines the height of this view
160     * @param measureSpec A measureSpec packed into an int
161     * @return The height of the view, honoring constraints from measureSpec
162     */
163    private int measureHeight(int measureSpec) {
164        int result = 0;
165        int specMode = MeasureSpec.getMode(measureSpec);
166        int specSize = MeasureSpec.getSize(measureSpec);
167
168        mAscent = (int) mTextPaint.ascent();
169        if (specMode == MeasureSpec.EXACTLY) {
170            // We were told how big to be
171            result = specSize;
172        } else {
173            // Measure the text (beware: ascent is a negative number)
174            result = (int) (-mAscent + mTextPaint.descent()) + getPaddingTop()
175                    + getPaddingBottom();
176            if (specMode == MeasureSpec.AT_MOST) {
177                // Respect AT_MOST value if that was what is called for by measureSpec
178                result = Math.min(result, specSize);
179            }
180        }
181        return result;
182    }
183
184    /**
185     * Render the text
186     *
187     * @see android.view.View#onDraw(android.graphics.Canvas)
188     */
189    @Override
190    protected void onDraw(Canvas canvas) {
191        super.onDraw(canvas);
192        canvas.drawText(mText, getPaddingLeft(), getPaddingTop() - mAscent, mTextPaint);
193    }
194}
195