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September 22, 2010 05:43
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/* | |
* Copyright (C) 2007 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 com.example.android.apis.view; | |
// Need the following import to get access to the app resources, since this | |
// class is in a sub-package. | |
import android.content.Context; | |
import android.content.res.TypedArray; | |
import android.graphics.Canvas; | |
import android.graphics.Paint; | |
import android.util.AttributeSet; | |
import android.view.View; | |
import com.example.android.apis.R; | |
/** | |
* Example of how to write a custom subclass of View. LabelView | |
* is used to draw simple text views. Note that it does not handle | |
* styled text or right-to-left writing systems. | |
* | |
*/ | |
public class LabelView extends View { | |
private Paint mTextPaint; | |
private String mText; | |
private int mAscent; | |
/** | |
* Constructor. This version is only needed if you will be instantiating | |
* the object manually (not from a layout XML file). | |
* @param context | |
*/ | |
public LabelView(Context context) { | |
super(context); | |
initLabelView(); | |
} | |
/** | |
* Construct object, initializing with any attributes we understand from a | |
* layout file. These attributes are defined in | |
* SDK/assets/res/any/classes.xml. | |
* | |
* @see android.view.View#View(android.content.Context, android.util.AttributeSet) | |
*/ | |
public LabelView(Context context, AttributeSet attrs) { | |
super(context, attrs); | |
initLabelView(); | |
TypedArray a = context.obtainStyledAttributes(attrs, | |
R.styleable.LabelView); | |
CharSequence s = a.getString(R.styleable.LabelView_text); | |
if (s != null) { | |
setText(s.toString()); | |
} | |
// Retrieve the color(s) to be used for this view and apply them. | |
// Note, if you only care about supporting a single color, that you | |
// can instead call a.getColor() and pass that to setTextColor(). | |
setTextColor(a.getColor(R.styleable.LabelView_textColor, 0xFF000000)); | |
int textSize = a.getDimensionPixelOffset(R.styleable.LabelView_textSize, 0); | |
if (textSize > 0) { | |
setTextSize(textSize); | |
} | |
a.recycle(); | |
} | |
private final void initLabelView() { | |
mTextPaint = new Paint(); | |
mTextPaint.setAntiAlias(true); | |
mTextPaint.setTextSize(16); | |
mTextPaint.setColor(0xFF000000); | |
setPadding(3, 3, 3, 3); | |
} | |
/** | |
* Sets the text to display in this label | |
* @param text The text to display. This will be drawn as one line. | |
*/ | |
public void setText(String text) { | |
mText = text; | |
requestLayout(); | |
invalidate(); | |
} | |
/** | |
* Sets the text size for this label | |
* @param size Font size | |
*/ | |
public void setTextSize(int size) { | |
mTextPaint.setTextSize(size); | |
requestLayout(); | |
invalidate(); | |
} | |
/** | |
* Sets the text color for this label. | |
* @param color ARGB value for the text | |
*/ | |
public void setTextColor(int color) { | |
mTextPaint.setColor(color); | |
invalidate(); | |
} | |
/** | |
* @see android.view.View#measure(int, int) | |
*/ | |
@Override | |
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { | |
setMeasuredDimension(measureWidth(widthMeasureSpec), | |
measureHeight(heightMeasureSpec)); | |
} | |
/** | |
* Determines the width of this view | |
* @param measureSpec A measureSpec packed into an int | |
* @return The width of the view, honoring constraints from measureSpec | |
*/ | |
private int measureWidth(int measureSpec) { | |
int result = 0; | |
int specMode = MeasureSpec.getMode(measureSpec); | |
int specSize = MeasureSpec.getSize(measureSpec); | |
if (specMode == MeasureSpec.EXACTLY) { | |
// We were told how big to be | |
result = specSize; | |
} else { | |
// Measure the text | |
result = (int) mTextPaint.measureText(mText) + getPaddingLeft() | |
+ getPaddingRight(); | |
if (specMode == MeasureSpec.AT_MOST) { | |
// Respect AT_MOST value if that was what is called for by measureSpec | |
result = Math.min(result, specSize); | |
} | |
} | |
return result; | |
} | |
/** | |
* Determines the height of this view | |
* @param measureSpec A measureSpec packed into an int | |
* @return The height of the view, honoring constraints from measureSpec | |
*/ | |
private int measureHeight(int measureSpec) { | |
int result = 0; | |
int specMode = MeasureSpec.getMode(measureSpec); | |
int specSize = MeasureSpec.getSize(measureSpec); | |
mAscent = (int) mTextPaint.ascent(); | |
if (specMode == MeasureSpec.EXACTLY) { | |
// We were told how big to be | |
result = specSize; | |
} else { | |
// Measure the text (beware: ascent is a negative number) | |
result = (int) (-mAscent + mTextPaint.descent()) + getPaddingTop() | |
+ getPaddingBottom(); | |
if (specMode == MeasureSpec.AT_MOST) { | |
// Respect AT_MOST value if that was what is called for by measureSpec | |
result = Math.min(result, specSize); | |
} | |
} | |
return result; | |
} | |
/** | |
* Render the text | |
* | |
* @see android.view.View#onDraw(android.graphics.Canvas) | |
*/ | |
@Override | |
protected void onDraw(Canvas canvas) { | |
super.onDraw(canvas); | |
canvas.drawText(mText, getPaddingLeft(), getPaddingTop() - mAscent, mTextPaint); | |
} | |
} |
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