| FontMetrics对象
它以四个基本坐标为基准，分别为： ・FontMetrics.top
・FontMetrics.ascent
・FontMetrics.descent
・FontMetrics.bottom
实例JAVA代码如下：
Paint textPaint = new Paint( Paint.ANTI_ALIAS_FLAG);
textPaint.setTextSize( 35);
textPaint.setColor( Color.WHITE);
// FontMetrics对象
FontMetrics fontMetrics = textPaint.getFontMetrics();
String text = "abcdefghijklmnopqrstu";
// 计算每一个坐标
float baseX = 0;
float baseY = 100;
float topY = baseY + fontMetrics.top;
float ascentY = baseY + fontMetrics.ascent;
float descentY = baseY + fontMetrics.descent;
float bottomY = baseY + fontMetrics.bottom;
// 绘制文本
canvas.drawText( text, baseX, baseY, textPaint);
// BaseLine描画
Paint baseLinePaint = new Paint( Paint.ANTI_ALIAS_FLAG);
baseLinePaint.setColor( Color.RED);
canvas.drawLine(0, baseY, getWidth(), baseY, baseLinePaint);
// Base描画
canvas.drawCircle( baseX, baseY, 5, baseLinePaint);
// TopLine描画
Paint topLinePaint = new Paint( Paint.ANTI_ALIAS_FLAG);
topLinePaint.setColor( Color.LTGRAY);
canvas.drawLine(0, topY, getWidth(), topY, topLinePaint);
// AscentLine描画
Paint ascentLinePaint = new Paint( Paint.ANTI_ALIAS_FLAG);
ascentLinePaint.setColor( Color.GREEN);
canvas.drawLine(0, ascentY, getWidth(), ascentY, ascentLinePaint);
// DescentLine描画
Paint descentLinePaint = new Paint( Paint.ANTI_ALIAS_FLAG);
descentLinePaint.setColor( Color.YELLOW);
canvas.drawLine(0, descentY, getWidth(), descentY, descentLinePaint);
// ButtomLine描画
Paint bottomLinePaint = new Paint( Paint.ANTI_ALIAS_FLAG);
bottomLinePaint.setColor( Color.MAGENTA);
canvas.drawLine(0, bottomY, getWidth(), bottomY, bottomLinePaint);
二。繪製文本。 1.TextUtil 類 package com.wistron.test.DrawText; import java.util.Vector; import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Paint.FontMetrics;
import android.view.KeyEvent; public class TextUtil {
private int mTextPosx = 0;// x坐标
private int mTextPosy = 0;// y坐标
private int mTextWidth = 0;// 绘制宽度
private int mTextHeight = 0;// 绘制高度
private int mFontHeight = 0;// 绘制字体高度
private int mPageLineNum = 0;// 每一页显示的行数
private int mCanvasBGColor = 0;// 背景颜色
private int mFontColor = 0;// 字体颜色
private int mAlpha = 0;// Alpha值
private int mRealLine = 0;// 字符串真实的行数
private int mCurrentLine = 0;// 当前行
private int mTextSize = 0;// 字体大小
private String mStrText = "";
private Vector mString = null;
private Paint mPaint = null; public TextUtil(String StrText, int x, int y, int w, int h, int bgcolor,
int textcolor, int alpha, int textsize) {
mPaint = new Paint();
mString = new Vector();
this.mStrText = StrText;
this.mTextPosx = x;
this.mTextPosy = y;
this.mTextWidth = w;
this.mTextHeight = h;
this.mCanvasBGColor = bgcolor;
this.mFontColor = textcolor;
this.mAlpha = alpha;
this.mTextSize = textsize;
} public void InitText() {
mString.clear();// 清空Vector
// 对画笔属性的设置
// mPaint.setARGB(this.mAlpha, Color.red(this.mFontColor), Color
// .green(this.mFontColor), Color.blue(this.mFontColor));
mPaint.setTextSize(this.mTextSize);
mPaint.setColor(Color.BLUE);
this.GetTextIfon();
} /**
* 得到字符串信息包括行数，页数等信息
*/
public void GetTextIfon() {
char ch;
int w = 0;
int istart = 0;
FontMetrics fm = mPaint.getFontMetrics();// 得到系统默认字体属性
mFontHeight = (int) (Math.ceil(fm.descent - fm.top) + 2);// 获得字体高度
mPageLineNum = mTextHeight / mFontHeight;// 获得行数
int count = this.mStrText.length();
for (int i = 0; i < count; i++) {
ch = this.mStrText.charAt(i);
float[] widths = new float[1];
String str = String.valueOf(ch);
mPaint.getTextWidths(str, widths);
if (ch == '\n') {
mRealLine++;// 真实的行数加一
mString.addElement(this.mStrText.substring(istart, i));
istart = i + 1;
w = 0;
} else {
w += (int) Math.ceil(widths[0]);
if (w > this.mTextWidth) {
mRealLine++;// 真实的行数加一
mString.addElement(this.mStrText.substring(istart, i));
istart = i;
i--;
w = 0;
} else {
if (i == count - 1) {
mRealLine++;// 真实的行数加一
mString.addElement(this.mStrText.substring(istart,
count));
}
}
}
}
} /**
* 绘制字符串
*
* @param canvas
*/
public void DrawText(Canvas canvas) {
for (int i = this.mCurrentLine, j = 0; i < this.mRealLine; i++, j++) {
if (j > this.mPageLineNum) {
break;
}
canvas.drawText((String) (mString.elementAt(i)), this.mTextPosx,
this.mTextPosy + this.mFontHeight * j, mPaint);
}
} /**
* 翻页等按键处理
*
* @param keyCode
* @param event
* @return
*/
public boolean KeyDown(int keyCode, KeyEvent event) {
if (keyCode == KeyEvent.KEYCODE_DPAD_UP) {
if (this.mCurrentLine > 0) {
this.mCurrentLine--;
}
} else if (keyCode == KeyEvent.KEYCODE_DPAD_DOWN) {
if ((this.mCurrentLine + this.mPageLineNum) < (this.mRealLine - 1)) {
this.mCurrentLine++;
}
}
return false;
} } 2. MyView 類 package com.wistron.test.DrawText; import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.view.KeyEvent;
import android.view.View; public class MyView extends View implements Runnable {
private final Paint mPaint;
private int mICount = 0;
private final TextUtil mTextUtil; public MyView(Context context) {
super(context);
mPaint = new Paint();
String string = "测试自动换行(第1行)\n\n测试自动换行(第2行)\n测试自动换行(第3行)\n测试自动换行(第4行)\n测试自动换行(第5行)\n测试自动换行(第6行)\n测试自动换行(第7行)"
+ "生活教會了我們什麼，自己的感覺現在已經徹底的隕滅，生命中彷彿是蒸發了為自己幸福而爭的念頭，一切就這樣的循規蹈矩！";
mTextUtil = new TextUtil(string, 15, 150, 300, 80, Color.LTGRAY,
0xff00ff, 255, 16);
mTextUtil.InitText();
new Thread(this).start();
} @Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
canvas.drawColor(Color.LTGRAY);
mPaint.setAntiAlias(true);
if (mICount < 100) {
mICount++;
}
mPaint.setColor(Color.RED);
canvas.drawText("裝載進度：" + mICount + "%......", 10, 20, mPaint);
mTextUtil.DrawText(canvas);
} @Override
public void run() {
Thread.currentThread();
while (!Thread.interrupted()) {
try {
Thread.sleep(10);
} catch (Exception ex) {
ex.printStackTrace();
Thread.currentThread().interrupt();
}
this.postInvalidate();
}
} @Override
public boolean onKeyDown(int keyCode, KeyEvent event) { return mTextUtil.KeyDown(keyCode, event);
} }
3. DrawText Activity. package com.wistron.test.DrawText; import android.app.Activity;
import android.os.Bundle;
import android.view.KeyEvent; public class DrawText extends Activity {
/** Called when the activity is first created. */
private MyView mv; @Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
mv = new MyView(this);
setContentView(mv);
} @Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
mv.onKeyDown(keyCode, event);
return super.onKeyDown(keyCode, event);
} } | 