<activity android:name=".TabWidget"
              android:label="@string/app_name"
          android:theme="@android:style/Theme.NoTitleBar">
        <intent-filter>
            <action android:name="android.intent.action.MAIN" />
            <category android:name="android.intent.category.LAUNCHER" />
        </intent-filter>
</activity>
<activity android:name=".Map" />
<activity android:name=".Schedule" />
 

Canvas 作為繪製文字時，使用FontMetrics物件，計算位置的座標。

它的思路和java.awt.FontMetrics的基本相同。

FontMetrics物件

它以四個基本座標為基準，分別為：

・FontMetrics.top
・FontMetrics.ascent
・FontMetrics.descent
・FontMetrics.bottom

該圖片將如下

1. Paint textPaint = new Paint( Paint.ANTI_ALIAS_FLAG);  
2. textPaint.setTextSize( 35);  
3. textPaint.setColor( Color.WHITE);  
4. // FontMetrics物件  
5. FontMetrics fontMetrics = textPaint.getFontMetrics();  
6. String text = "abcdefghijklmnopqrstu";  
7. // 計算每一個座標  
8. float baseX = 0;  
9. float baseY = 100;  
10. float topY = baseY + fontMetrics.top;  
11. float ascentY = baseY + fontMetrics.ascent;  
12. float descentY = baseY + fontMetrics.descent;  
13. float bottomY = baseY + fontMetrics.bottom;  
14. // 繪製文字  
15. canvas.drawText( text, baseX, baseY, textPaint);  
16. // BaseLine描畫  
17. Paint baseLinePaint = new Paint( Paint.ANTI_ALIAS_FLAG);>  
18. baseLinePaint.setColor( Color.RED);  
19. canvas.drawLine(0, baseY, getWidth(), baseY, baseLinePaint);  
20. // Base描畫  
21. canvas.drawCircle( baseX, baseY, 5, baseLinePaint);  
22. // TopLine描畫  
23. Paint topLinePaint = new Paint( Paint.ANTI_ALIAS_FLAG);  
24. topLinePaint.setColor( Color.LTGRAY);  
25. canvas.drawLine(0, topY, getWidth(), topY, topLinePaint);  
26. // AscentLine描畫  
27. Paint ascentLinePaint = new Paint( Paint.ANTI_ALIAS_FLAG);  
28. ascentLinePaint.setColor( Color.GREEN);  
29. canvas.drawLine(0, ascentY, getWidth(), ascentY, ascentLinePaint);  
30. // DescentLine描畫  
31. Paint descentLinePaint = new Paint( Paint.ANTI_ALIAS_FLAG);  
32. descentLinePaint.setColor( Color.YELLOW);  
33. canvas.drawLine(0, descentY, getWidth(), descentY, descentLinePaint);  
34. // ButtomLine描畫  
35. Paint bottomLinePaint = new Paint( Paint.ANTI_ALIAS_FLAG);  
36. bottomLinePaint.setColor( Color.MAGENTA);  
37. canvas.drawLine(0, bottomY, getWidth(), bottomY, bottomLinePaint);