精通Android开发之界面速成 有米分享

1、精通Android开发之界面速成试阅：全部同步完毕后，进入到Android目录下，使用make命令编译，你会发现出现如下错误提示： host C: libneo_cgi = external/clearsilver/cgi/cgi.c external/clearsilver/cgi/cgi.c:22:18: error: zlib.h: No such file or directory 这个错误是因为我们缺少zlib1g-dev，需要使用apt-get命令从软件仓库中安装正文：笔者最近需要移植一个J2ME的项目到Android平台上，所以抽空研究了一下Android平台的接口规范。 And

2、roid平台除了在一些接口上采用了和J2ME不一样的名称之外，基本的接口内容还是一样的，那么移植J2ME到Android平台最方便的方法就是利用Android平台的接口重写J2ME的接口，本着这个思路笔者写了一个Wrap包，利用这个Wrap包，基本上J2ME程序不用修改，只需要重新导入一下 重写后的Graphics、Image等类，就可以无缝的运行在Android平台上，所以笔者题目中所说的“两个小时精通Android”的前提是先精通J2ME。 既然要重写J2ME下的这些接口，那么就要先了解Android和J2ME平台到底有哪些不同，然后重写这部 分不同的接口即可。 Font类Android平

3、台里不再提供J2ME下面的Font类，而是以Typeface代替，这为读者提供了更多的选择空间，因为Typeface是可以自定义的，但是为了无缝移植J2ME程序到Android平台上，笔者封装了以个类似于J2ME平台下的Font类，如下： import android.graphics.Typeface; public class Font public static final int STYLE_PLAIN = 0; public static final int STYLE_BOLD = 1; public static final int STYLE_ITALIC = 2; publi

4、c static final int STYLE_UNDERLINED = 4; public static final int SIZE_SMALL = 22; public static final int SIZE_MEDIUM = 31; public static final int SIZE_LARGE = 40; public static final int FACE_SYSTEM = 0; private int face; private int style; private int size; private int baseline; private int width

5、; private int height; public void setWidth(int width) this.width = size; public void setHeight(int height) this.height = height; public int getWidth() return size; public int getHeight() return height; private Typeface iTypeface = Typeface.DEFAULT; public Typeface getTypeface() return iTypeface; pub

6、lic void setSize(int fontSize) size = fontSize; public int getSize() return size; private static final Font DEFAULT_FONT = new Font(null,22); public Font(Typeface aTypeface,int aSize) if(iTypeface != null) iTypeface = aTypeface; size = aSize; public static Font getFont(int fontSepcifier) switch(font

7、Sepcifier) case SIZE_SMALL: return new Font(null,22); case SIZE_MEDIUM: return new Font(null,31); case SIZE_LARGE: return new Font(null,40); return DEFAULT_FONT; public static Font getDefaultFont() return DEFAULT_FONT; public static Font getFont(int face,int style,int size) switch(style) case STYLE_

8、PLAIN: return new Font(Typeface.defaultFromStyle(Typeface.NORMAL),size); case STYLE_BOLD: return new Font(Typeface.defaultFromStyle(Typeface.BOLD),size); case STYLE_ITALIC: return new Font(Typeface.defaultFromStyle(Typeface.ITALIC),size); return DEFAULT_FONT; public int charWidth(char arg) return si

9、ze; public int stringWidth(String arg) return size*(arg.length(); Graphics类Android平台下不再提供Graphics类进行“视图上下文”的控制，而是以Canvas、Paint联合进行控制，笔者封装的Graphics类如下： import android.graphics.Bitmap;import android.graphics.Canvas;import android.graphics.Color;import android.graphics.Paint;import android.graphics.Rec

10、t;import android.graphics.RectF;import android.graphics.Paint.Align;import android.graphics.Paint.FontMetrics;import android.graphics.Paint.Style; public class Graphics public static final int HCENTER = 1; public static final int VCENTER = 2; public static final int LEFT = 4; public static final int

11、 RIGHT = 8; public static final int TOP = 16; public static final int BOTTOM = 32; public static final int BASELINE = 64; public static final int SOLID = 0; public static final int DOTTED = 1; private Bitmap bitmap; private Canvas canvas; private Paint paint; private Rect clip; private Font font; pu

12、blic Graphics(Bitmap bitmap) this.bitmap = bitmap; this.canvas = new Canvas(bitmap); this.canvas.clipRect(0, 0, bitmap.getWidth(), bitmap.getHeight(); this.canvas.save(Canvas.CLIP_SAVE_FLAG); this.paint = new Paint(); this.clip = canvas.getClipBounds(); public void setAlign(int align) if(LEFT = alig

13、n |(Graphics.LEFT | Graphics.TOP) = align |(Graphics.LEFT | Graphics.BOTTOM) = align) paint.setTextAlign(Align.LEFT); else if(HCENTER = align |(Graphics.HCENTER|Graphics.TOP) = align) paint.setTextAlign(Align.CENTER); else if(RIGHT = align |(Graphics.RIGHT | Graphics.TOP) = align) paint.setTextAlign

14、(Align.RIGHT); public void fillRoundRect(int x,int y,int width,int height,int arcWidth,int arcHeight) paint.setStyle(Style.FILL); canvas.drawRoundRect(new RectF(x,y,x+width,y+height), arcWidth, arcHeight, paint); public void drawRoundRect(int x,int y,int width,int height,int arcWidth,int arcHeight)

15、paint.setStyle(Style.STROKE); canvas.drawRoundRect(new RectF(x,y,x+width,y+height), arcWidth, arcHeight, paint); public void fillTriangle(int x1,int y1,int x2,int y2,int x3,int y3) paint.setStyle(Style.FILL); canvas.drawLine(x1, y1, x2, y2, paint); canvas.drawLine(x2, y2, x3, y3, paint); canvas.draw

16、Line(x3, y3, x1, y1, paint); public void setFont(Font font) paint.setTypeface(font.getTypeface(); paint.setTextSize(font.getSize(); FontMetrics fontMetrics = paint.getFontMetrics(); float height = fontMetrics.bottom-fontMetrics.top; font.setHeight(int)height); public void fillArc(int x,int y,int wid

17、th,int height,int startAngle,int arcAngle) paint.setStyle(Style.FILL); canvas.drawArc(new RectF(x,y,width,height), startAngle, arcAngle, true, paint); public void drawArc(int x,int y,int width,int height,int startAngle,int arcAngle) paint.setStyle(Style.STROKE); canvas.drawArc(new RectF(x,y,width,he

18、ight), startAngle, arcAngle, true, paint); public Font getFont() return font; public void setAntiAlias(boolean flag) paint.setAntiAlias(flag); public void setAlphaValue(int alpha) paint.setAlpha(alpha); public void setAlpha(float alpha) setAlphaValue(int) (255 * alpha); public void translate(int x,i

19、nt y) canvas.translate(x,y); public void setColor(int rgb) paint.setColor(rgb); public void setColor(int r,int g,int b) int argb = (0xff)+(r16)+(g x2) x1+; else x2+; if (y1 y2) y1+; else y2+; canvas.drawLine(x1, y1, x2, y2, paint); public void drawRect(int x, int y, int width, int height) paint.setS

20、tyle(Paint.Style.STROKE); canvas.drawRect(x, y, x + width, y + height, paint); public void drawString(String str, int x, int y) canvas.drawText(str, x, y, paint); public void drawString(String str, int x, int y,int align) setAlign(align); canvas.drawText(str, x, y, paint); public void drawClear() pa

21、int.setColor(Color.BLACK); canvas.drawColor(Color.BLACK); public void fillRect(int x, int y, int width, int height) paint.setStyle(Paint.Style.FILL); canvas.drawRect(x, y, x + width, y + height, paint); public int getClipHeight() return clip.bottom - clip.top; public int getClipWidth() return clip.r

22、ight - clip.left; public int getClipX() return clip.left; public int getClipY() return clip.top; public int getColor() return paint.getColor(); public void dispose() paint = null; canvas = null; public void clearRect(int x, int y, int width, int height) canvas.clipRect(x, y, x + width, y + height);

23、canvas.drawARGB(0xff, 0xff, 0xff, 0xff); public void copyArea(int x, int y, int width, int height, int dx, int dy) if (x 0) width += x; x = 0; if (y bitmap.getWidth() width = bitmap.getWidth() - x; if (y + height bitmap.getHeight() height = bitmap.getHeight() - y; Bitmap copy = Bitmap.createBitmap(b

24、itmap, x, y, width, height); canvas.drawBitmap(copy, x + dx, y + dy, null); public void clipRect(int x, int y, int width, int height) canvas.clipRect(x, y, x + width, y + height); clip = canvas.getClipBounds(); public void setClip(int x, int y, int width, int height) if (x = clip.left & x + width =

25、clip.right & y = clip.top & y + height = clip.bottom) return; if (x clip.right | y clip.bottom) canvas.restore(); canvas.save(Canvas.CLIP_SAVE_FLAG); clip.left = x; clip.top = y; clip.right = x + width; clip.bottom = y + height; canvas.clipRect(clip); public void drawOval(int x, int y, int width, in

26、t height) paint.setStyle(Paint.Style.STROKE); canvas.drawOval(new RectF(x, y, x + width, y + height), paint); public void drawPolygon(int xpoints, int ypoints, int npoints) canvas.drawLine(xpointsnpoints - 1, ypointsnpoints - 1, xpoints0, ypoints0, paint); for (int i = 0; i npoints - 1; i+) canvas.d

27、rawLine(xpointsi, ypointsi, xpointsi + 1, ypointsi + 1, paint); public Canvas getGraphics() return canvas; public Paint getPaint() return paint; public Rect getClip() return clip; public Bitmap getBitmap() return bitmap; Connector类Android平台下不再提供这个静态接口类，而是提供HttpURLConnection以及URL进行网络通讯，这个类的封装如下： pack

28、age org.loon.framework.android.game; import .HttpURLConnection;import .URL; public class Connector public static final int READ = 1; public static final int WRITE = 2; public static final int READ_WRITE = 3; private static String platform; private static boolean j2me; public static H

29、ttpConnection open(String name,int mode,boolean timeouts) throws java.io.IOException URL url = new URL(name); HttpURLConnection conn = (HttpURLConnection) url.openConnection(); / Allow Inputs conn.setDoInput(true); / Allow Outputs conn.setDoOutput(true); conn.setConnectTimeout(); HttpConnection co =

30、 new HttpConnection(); 精通Android开发之按键映射篇笔者的上篇文章两个小时精通Android开发中讲解了利用Android的接口规范开发J2ME的Wrap包，从而解决了J2ME程序无法运行在Android平台上的技术难题，但是Android平台和J2ME另一个重要的不同点就是按键响应接口，如何让J2ME程序的按键响应可以无缝的移 植到Android上呢？答案也是Wrap包。 笔者这里通过按键映射把Android平台的键盘码转换成J2ME平台的键盘码，或者把Android平台的触摸事件通过代理传递给J2ME中相应的接口。 首先，需要在Android平台的GameCan

31、vas里进行如下定义： public class GameCanvas extends Screen public static final int UP = 1; public static final int DOWN = 6; public static final int LEFT = 2; public static final int RIGHT = 5; public static final int FIRE = 8; public static final int GAME_A = 9; public static final int GAME_B = 10; public

32、static final int GAME_C = 11; public static final int GAME_D = 12; public static final int KEY_NUM0 = 48; public static final int KEY_NUM1 = 49; public static final int KEY_NUM2 = 50; public static final int KEY_NUM3 = 51; public static final int KEY_NUM4 = 52; public static final int KEY_NUM5 = 53;

33、 public static final int KEY_NUM6 = 54; public static final int KEY_NUM7 = 55; public static final int KEY_NUM8 = 56; public static final int KEY_NUM9 = 57; public static final int KEY_STAR = 42; public static final int KEY_POUND = 35; 当然，为了适配J2ME里的接口笔者还定义如下的接口： protected abstract void keyRepeated(i

34、nt keyCode); protected abstract void keyPressed(int keyCode); protected abstract void keyReleased(int keyCode); protected abstract void pointerPressed(int x, int y); protected abstract void pointerReleased(int x, int y) protected abstract void pointerDragged(int x, int y); 笔者在上面定义的都是J2ME的视图类Canvas里的

35、按键响应接口，这里需要做的工作就是把Android里的按键进行映射转换成J2ME里的标准键值后传递给这些接口，并由继承自GameCanvas的界面类进行实现，完全和J2ME里一样了，基本不用修改任何代码。 键值映射的代码如下： public int keyActual = 0; public int keyAction = 0; public void keyPreparse(int keyCode,KeyEvent e) if(keyCode = KeyEvent.KEYCODE_0) keyActual = GameCanvas.KEY_NUM0; else if(keyCode = Ke

36、yEvent.KEYCODE_1) keyActual = GameCanvas.KEY_NUM1; else if(keyCode = KeyEvent.KEYCODE_2) keyActual = GameCanvas.KEY_NUM2; else if(keyCode = KeyEvent.KEYCODE_3) keyActual = GameCanvas.KEY_NUM3; else if(keyCode = KeyEvent.KEYCODE_4) keyActual = GameCanvas.KEY_NUM4; else if(keyCode = KeyEvent.KEYCODE_5

37、) keyActual = GameCanvas.KEY_NUM5; else if(keyCode = KeyEvent.KEYCODE_6) keyActual = GameCanvas.KEY_NUM6; else if(keyCode = KeyEvent.KEYCODE_7) keyActual = GameCanvas.KEY_NUM7; else if(keyCode = KeyEvent.KEYCODE_8) keyActual = GameCanvas.KEY_NUM8; else if(keyCode = KeyEvent.KEYCODE_9) keyActual = GameCanvas.KEY_NUM9; else if(