1. (@v vakame)
Android
2011 8 25

2. •
•
•
http://www.slideshare.net/vvakame/debugging-strategy
2011 8 25

3. 2011 8 25

4. 2011 8 25

5. …
2011 8 25

6. •
• initA() initB() init()
A, B public
• 2
• ( )
•
• …
2011 8 25

7. /**
* bitmap .
*
* @param bitmapArrays
*/
static void dot1PixelA(Bitmap[][] bitmapArrays) {
for (int i = 0; i < bitmapArrays.length; i++) { for
for (int j = 0; j < bitmapArrays[i].length; i++) {
bitmapArrays[j][i].setPixel(0, 0, Color.RED);
}
}
}
/**
* bitmap .
*
* @param bitmapArrays
*/
static void dot1PixelB(Bitmap[][] bitmapArrays) {
for (Bitmap[] bitmapArray : bitmapArrays) {
for (Bitmap bitmap : bitmapArray) {
for-each
bitmap.setPixel(0, 0, Color.RED);
}
}
}
2011 8 25

8. /**
* bitmap .
*
* @param bitmapArrays
*/
static void dot1PixelA(Bitmap[][] bitmapArrays) {
for (int i = 0; i < bitmapArrays.length; i++) { for
for (int j = 0; j < bitmapArrays[i].length; i++) {
bitmapArrays[j][i].setPixel(0, 0, Color.RED);
}
}
}
/**
* bitmap .
*
* @param bitmapArrays
*/
static void dot1PixelB(Bitmap[][] bitmapArrays) {
for (Bitmap[] bitmapArray : bitmapArrays) {
for (Bitmap bitmap : bitmapArray) {
for-each
bitmap.setPixel(0, 0, Color.RED);
}
}
}
2011 8 25

9. Bitmap[][] bitmapArrays = new Bitmap[10][10];
for (int i = 0; i < bitmapArrays.length; i++) {
for (int j = 0; j < bitmapArrays[i].length; j++) {
bitmapArrays[i][j] = Bitmap.createBitmap(3, 3, Config.ARGB_8888);
}
}
…
2011 8 25

10. ADT
2011/08/25 rev12
2011 8 25

11. 2011 8 25

12. •
•
•
• null
2011 8 25

13. • LogCat
2011 8 25

14. •
L07 @Override
L08 public void onCreate(Bundle savedInstanceState) {
L09 super.onCreate(savedInstanceState);
L10 setContentView(R.layout.main);
L11
L12 try {
L13 throw new NullPointerException();
L14 } catch (Exception e1) {
L15 try {
L16 throw new IllegalArgumentException(e1);
L17 } catch (Exception e2) {
L18 try {
L19 throw new IllegalStateException(e2);
L20 } catch (Exception e3) {
L21 throw new RuntimeException(e3);
L22 }
L23 }
L24 }
L25 }
Caused
2011 8 25

15. •
L08 @Override
L09 public void onCreate(Bundle savedInstanceState) {
L10 super.onCreate(savedInstanceState);
L11 setContentView(R.layout.main);
L12 requestWindowFeature(Window.FEATURE_NO_TITLE);
L13 }
L11 L12
2011 8 25

16. L22 …
L09 @Override
L10 public void onCreate(Bundle savedInstanceState) {
L11 super.onCreate(savedInstanceState);
L12
L13 LinearLayout layout1 = new LinearLayout(this);
L14 LinearLayout layout2 = new LinearLayout(this);
L15 LinearLayout layout3 = new LinearLayout(this);
L16 Button button = new Button(this);
L17
L18 layout1.addView(layout2);
L19
L20
layout2.addView(layout1);
layout3.addView(button);
layout1 → layout2 → layout1
L21
L22 setContentView(layout1); layout1 → layout2 → layout3 …
L23 }
2011 8 25

17. “ ”
• ( ω ´)
•
•
• ←
• …… ……
• … orz ←
2011 8 25

18. “ ”
•
•
•
•
…
•
2011 8 25

19. void sort() {
List<String> list = new ArrayList<String>();
list.add("cupcake");
list.add(null);
list.add("donuts");
list.add(null);
list.add("froyo");
Collections.sort(list, new Comparator<String>() {
@Override
public int compare(String str1, String str2) {
if (str1 == null) {
return -1;
}
return str1.compareTo(str2);
}
});
Log.d("Debug", list.toString());
}
NullPointerException …
LogCat …
2011 8 25

20. 2011 8 25

21. str2 null
String#compareTo(String) null …
2011 8 25

22. NPE(NullPointerException)
2011 8 25

23. 2011 8 25

24. …
public class Util {
/**
* 2 1 .
* @param list1 1
* @param list2 2
* @return 1
*/
public static List<Object> merge(List<Object> list1, List<Object> list2) {
list1.addAll(list2);
return list1;
}
/**
* 1 .
* @param lists
* @return 1
*/
public static List<Object> merge(List<?>... lists) {
List<Object> result = new ArrayList<Object>();
for (List<?> list : lists) {
result.addAll(list);
}
return result;
}
}
2011 8 25

25. public void test() {
List<Object> list1 = new ArrayList<Object>();
list1.add("a");
list1.add("b");
List<Object> list2 = new ArrayList<Object>();
list2.add(1);
list2.add(2);
List<Object> list3 = new ArrayList<Object>();
list3.add(1.25);
list3.add(2.5);
List<Object> merged1 = Util.merge(list1, list2);
List<Object> merged2 = Util.merge(list1, list2, list3);
assertEquals(merged1.size(), 4);
assertEquals(merged1.get(0), "a");
assertEquals(merged1.get(1), "b");
assertEquals(merged1.get(2), 1);
assertEquals(merged1.get(3), 2);
assertEquals(merged2.size(), 6);
assertEquals(merged2.get(0), "a");
assertEquals(merged2.get(1), "b");
assertEquals(merged2.get(2), 1);
assertEquals(merged2.get(3), 2);
assertEquals(merged2.get(4), 1.25);
assertEquals(merged2.get(5), 2.5);
}
2011 8 25

26. public void test() {
List<Object> list1 = new ArrayList<Object>();
list1.add("a");
list1.add("b");
List<Object> list2 = new ArrayList<Object>();
list2.add(1);
list2.add(2);
List<Object> list3 = new ArrayList<Object>();
list3.add(1.25);
list3.add(2.5);
List<Object> merged1 = Util.merge(list1, list2);
List<Object> merged2 = Util.merge(list1, list2, list3);
assertEquals(merged1.size(), 4);
assertEquals(merged1.get(0), "a");
assertEquals(merged1.get(1), "b");
assertEquals(merged1.get(2), 1);
assertEquals(merged1.get(3), 2);
size 8
assertEquals(merged2.size(), 6);
assertEquals(merged2.get(0), "a");
assertEquals(merged2.get(1), "b");
assertEquals(merged2.get(2), 1);
assertEquals(merged2.get(3), 2);
assertEquals(merged2.get(4), 1.25);
assertEquals(merged2.get(5), 2.5);
}
2011 8 25

27. Debug As ...
2011 8 25

28. • F8
• F5 1 ( )
• F6 1 ( )
• F7
2011 8 25

29. 8 …
2011 8 25

30. ( )
2011 8 25

31. •
• , ,
• Variables
•
•
2011 8 25

32. …
¨ ¨ ¨ ¨ ¨ ¨ ¨ ¨...
2011 8 25

33. →Inspect
2011 8 25

34. 2011 8 25

35. •
•
•
•
•
•
2011 8 25

36. 2011 8 25

37. OpenGL
2011 8 25

38. OpenGL
http://t.co/bet4051
2011 8 25

39. 2011 8 25