android开发常用代码(经常更新)

android开发中我们需要一些代码来使我们的界面更美观，控件更漂亮。

除了android开发，还有程序中经常用到的东西。

比如圆角的button啊，view的布局啊等等。

下面是一些常用的代码

1.圆角button

android开发中我们需要一些代码来使我们的界面更美观，控件更漂亮。

比如圆角的button啊，view的布局啊等等。比如圆角的button啊，view的布局啊等等。

下面是一些常用的代码下面是一些常用的代码

1.圆角button1.圆角button

<?xml version="1.0" encoding="UTF-8"?><shape     xmlns:android="http://schemas.android.com/apk/res/android"     android:shape="rectangle">     <!-- 填充的颜色 -->     <solid android:color="#3881fe" />     <!-- 设置按钮的四个角为弧形 -->     <!-- android:radius 弧形的半径 -->     <corners android:radius="5dip" />       <!-- padding：Button里面的文字与Button边界的间隔 --> <padding    android:left="10dp"    android:top="10dp"    android:right="10dp"    android:bottom="10dp" /> </shape> 

2.canvas画圆角矩形

RectF backRect = new RectF(1, 0, (float) (getWidth() - 1), getHeight() - 4.5f);canvas.drawRoundRect(backRect, 7, 7, mPaint);

3.popupWindow使用

public void showPopupWindow(Context context, View parent) {LayoutInflater inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);final View view = inflater.inflate(R.layout.popwindow, null, false);int screenWidth = getResources().getDisplayMetrics().widthPixels;final PopupWindow pw = new PopupWindow(view, screenWidth - 50, 300,true);pw.setFocusable(true);pw.setTouchable(true);//点击popupwindow以外区域消失pw.setBackgroundDrawable(new BitmapDrawable());pw.setOutsideTouchable(true);pw.showAtLocation(MainActivity.this.findViewById(R.id.main),Gravity.BOTTOM | Gravity.CENTER_HORIZONTAL, 0, 0);// 显示popupWindow对话框}

4.LayoutInflater 的使用

LayoutInflater inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);final View view = inflater.inflate(R.layout.xxxx, null, false);

5.生成圆角图片

public static Bitmap GetRoundedCornerBitmap(Bitmap bitmap) {      try {          Bitmap output = Bitmap.createBitmap(bitmap.getWidth(),                  bitmap.getHeight(), Config.ARGB_8888);          Canvas canvas = new Canvas(output);                           final Paint paint = new Paint();          final Rect rect = new Rect(0, 0, bitmap.getWidth(),                  bitmap.getHeight());                  final RectF rectF = new RectF(new Rect(0, 0, bitmap.getWidth(),                  bitmap.getHeight()));          final float roundPx = 14;          paint.setAntiAlias(true);          canvas.drawARGB(0, 0, 0, 0);          paint.setColor(Color.BLACK);                  canvas.drawRoundRect(rectF, roundPx, roundPx, paint);          paint.setXfermode(new PorterDuffXfermode(Mode.SRC_IN));                         final Rect src = new Rect(0, 0, bitmap.getWidth(),                  bitmap.getHeight());                    canvas.drawBitmap(bitmap, src, rect, paint);              return output;      } catch (Exception e) {                   return bitmap;      }  }  

6.得到SD路径

public static String getSDPath() {File SDPath = null;boolean isSDExist = Environment.getExternalStorageState().equals(android.os.Environment.MEDIA_MOUNTED);if (isSDExist == true) {SDPath = Environment.getExternalStorageDirectory();}return SDPath.toString();}

7.将string写到文件末尾

/** * 将字符串写到文件末尾 * @param txt 原始字符串 * @param fileName 带路径的文件名 * @return true 写入成功 */public static boolean stringToFileEnd(String txt, String fileName) {File file = new File(fileName);if (file.exists()) {try {FileOutputStream outputStream = new FileOutputStream(fileName,true);outputStream.write(txt.getBytes());outputStream.close();} catch (Exception e) {e.printStackTrace();}return true;} else {return false;}}

8.得到手机屏幕高度宽度以及scale

scale = getResources().getDisplayMetrics().density;screenHeight = getResources().getDisplayMetrics().heightPixels;screenWidth = getResources().getDisplayMetrics().widthPixels;

9.onMeasure常用方法 获取当前控件高度和宽度等等

protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {height = screenHeight / 4;width = measureWidth(widthMeasureSpec);setMeasuredDimension(width, height);}private int measureHeight(int measureSpec) {int specMode = MeasureSpec.getMode(measureSpec);int specSize = MeasureSpec.getSize(measureSpec);// Default size if no limits are specified.int result = 500;if (specMode == MeasureSpec.AT_MOST) {// Calculate the ideal size of your// control within this maximum size.// If your control fills the available// space return the outer bound.result = specSize;} else if (specMode == MeasureSpec.EXACTLY) {// If your control can fit within these bounds return that value.result = specSize;}return result;}private int measureWidth(int measureSpec) {int specMode = MeasureSpec.getMode(measureSpec);int specSize = MeasureSpec.getSize(measureSpec);// Default size if no limits are specified.int result = 500;if (specMode == MeasureSpec.AT_MOST) {// Calculate the ideal size of your control// within this maximum size.// If your control fills the available space// return the outer bound.result = specSize;}else if (specMode == MeasureSpec.EXACTLY) {// If your control can fit within these bounds return that value.result = specSize;}return result;}

10.bitmap的缩放

/** * 按照指定长宽压缩 *  * @param srcBitmap * @param newWidth * @param newHeight * @return */public static Bitmap bitmapZoomBySize(Bitmap srcBitmap, int newWidth,int newHeight) {int srcWidth = srcBitmap.getWidth();int srcHeight = srcBitmap.getHeight();float scaleWidth = ((float) newWidth) / srcWidth;float scaleHeight = ((float) newHeight) / srcHeight;return bitmapZoomByScale(srcBitmap, scaleWidth, scaleHeight);}/** * 使用长宽缩放比缩放 *  * @param srcBitmap * @param scaleWidth * @param scaleHeight * @return */public static Bitmap bitmapZoomByScale(Bitmap srcBitmap, float scaleWidth,float scaleHeight) {int srcWidth = srcBitmap.getWidth();int srcHeight = srcBitmap.getHeight();Matrix matrix = new Matrix();matrix.postScale(scaleWidth, scaleHeight);Bitmap resizedBitmap = Bitmap.createBitmap(srcBitmap, 0, 0, srcWidth,srcHeight, matrix, true);if (resizedBitmap != null) {return resizedBitmap;} else {return srcBitmap;}}

11.文件读写相关操作

//判断文件是否存在public boolean isFileExits(String fileName) {File file = new File(SDPath + fileName);return file.exists();}//新建文件夹public void makeDir(String dirName){File file = new File(SDPath + dirName);if (!file.exists())file.mkdir();}//获得文件数量public int getNumOfFiles(String dir){File file = new File(SDPath + dir);File[] numFile = file.listFiles();return numFile.length;}

//删除一个文件

<span style="white-space:pre"></span>public boolean deleteFile(String fileName){File file = new File(SDPath + fileName);if (file.exists()){System.out.println("file name is  " + file.getName());try {file.delete();} catch (Exception e) {e.printStackTrace();}return true;}else {return false;}}//读取一个文件public String readFromFile(String fileName){String res = "";try {FileInputStream inputStream = new FileInputStream(SDPath + fileName);int len = inputStream.available();byte buffer[] = new byte[len];inputStream.read(buffer);res = EncodingUtils.getString(buffer, "UTF-8");inputStream.close();} catch (Exception e) {e.printStackTrace();}System.out.println("res ----->" + res);return res;}//将字符串写到文件末尾public boolean stringToFileEnd(String txt,String fileName){File file = new File(SDPath + fileName);if (file.exists()){try {FileOutputStream outputStream = new FileOutputStream(SDPath + fileName,true);outputStream.write(txt.getBytes());outputStream.close();} catch (Exception e) {e.printStackTrace();}return true;}else {return false;}}//将字符串从文件头部开始写public boolean stringToFile(String txtString,String fileName){File file = new File(SDPath + fileName);if (file.exists()){try {FileOutputStream outputStream = new FileOutputStream(SDPath + fileName);outputStream.write(txtString.getBytes());outputStream.close();} catch (Exception e) {e.printStackTrace();}return true;}else {return false;}}//删除文件public File createFile(String fileName){File file = new File(SDPath + fileName);try {file.createNewFile();} catch (Exception e) {// TODO: handle exceptione.printStackTrace();}return file;}

返回事件捕捉

public void onBackPressed() {// TODO Auto-generated method stubSystem.out.println("hehehehhehehehhe");super.onBackPressed();}

获取当前时间:

Time t=new Time("GMT+8"); // or Time t=new Time("GMT+8"); 加上Time Zone资料。  t.setToNow(); // 取得系统时间。  int year = t.year;  int month = t.month;  int date = t.monthDay;  int hour = t.hour; // 0-23  int minute = t.minute;  int second = t.second;

唯一不足的是月份少一月，小时得加8

22.获取星期几

public class DateString {      private static String mYear;      private static String mMonth;      private static String mDay;      private static String mWay;             public static String StringDate(){          final Calendar c = Calendar.getInstance();          c.setTimeZone(TimeZone.getTimeZone("GMT+8:00"));          mYear = String.valueOf(c.get(Calendar.YEAR)); // 获取当前年份          mMonth = String.valueOf(c.get(Calendar.MONTH) + 1);// 获取当前月份          mDay = String.valueOf(c.get(Calendar.DAY_OF_MONTH));// 获取当前月份的日期号码          mWay = String.valueOf(c.get(Calendar.DAY_OF_WEEK));          if("1".equals(mWay)){              mWay ="SUN";          }else if("2".equals(mWay)){              mWay ="MON";          }else if("3".equals(mWay)){              mWay ="TUE";          }else if("4".equals(mWay)){              mWay ="WED";          }else if("5".equals(mWay)){              mWay ="THU";          }else if("6".equals(mWay)){              mWay ="FRI";          }else if("7".equals(mWay)){              mWay ="SAT";          }          return mYear + "年" + mMonth + "月" + mDay+"日"+"/星期"+mWay;      }         }

22.判断当前是否联网

public boolean inNetwork() {ConnectivityManager cManager = (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);NetworkInfo info = cManager.getActiveNetworkInfo();if (info != null && info.isAvailable()) {// do something// 能联网return true;} else {// do something// 不能联网return false;}}

23.listview一些常用属性设置

        去掉item分割线        android:divider="@null"        去掉顶部和底部边缘模糊        android:overScrollMode="never"        去掉滑动栏        android:scrollbars="none"

hashmap遍历

public static void printHash(HashMap<String, String> hashMap) {Iterator iter = hashMap.entrySet().iterator();while (iter.hasNext()) {Map.Entry entry = (Map.Entry) iter.next();Object key = entry.getKey();Object val = entry.getValue();System.out.println("key = " + key + " val = " + val);}}

解析json字符串

private static Map<String, String> parseJSONString(String JSONString)throws JSONException {Map<String, String> resultMap = new HashMap<String, String>();JSONArray jsonArray = new JSONArray();try {// 直接把JSON字符串转化为一个JSONObject对象JSONObject person = new JSONObject(JSONString);System.out.println("the info is "+ person.getJSONArray("infoBaseTime").toString());jsonArray = person.getJSONArray("infoBaseTime");} catch (JSONException e) {e.printStackTrace();}for (int i = 0; i < jsonArray.length(); i++) {JSONObject jsonObject = jsonArray.getJSONObject(i);Map<String, String> map = new HashMap<String, String>();for (Iterator<?> iter = jsonObject.keys(); iter.hasNext();) {String key = (String) iter.next();String value = jsonObject.get(key).toString();resultMap.put(key, value);System.out.println("key is " + key + " value is " + value);}// rsList.add(map);}printHash(resultMap);return resultMap;}

http发起网络请求

/** * 想数据库写入手机参数 *  * @param IMEI *            手机的IMEI * @param basetime *            手机滑动基数 * @param deviceID *            手机设备号 * @throws IOException */public static void PostBaseTime(String IMEI, float basetime, String deviceID)throws IOException {String responseRes = "";HttpClient httpClient = new DefaultHttpClient();HttpPost httpPost = new HttpPost(HTTP_POST_BASETIME);List<BasicNameValuePair> formparams = new ArrayList<BasicNameValuePair>();formparams.add(new BasicNameValuePair("baseTime", basetime + ""));formparams.add(new BasicNameValuePair("IMEI", IMEI));formparams.add(new BasicNameValuePair("deviceID", deviceID));UrlEncodedFormEntity uefEntity = new UrlEncodedFormEntity(formparams,HTTP.UTF_8);httpPost.setEntity(uefEntity);HttpResponse response = (HttpResponse) httpClient.execute(httpPost);if (response.getStatusLine().getStatusCode() == 200) {responseRes = EntityUtils.toString(response.getEntity(), HTTP.UTF_8);System.out.println("the res is " + responseRes);}}

得到手机一些参数，屏幕大小等等

screenWidth = wm.getDefaultDisplay().getWidth();screenheight = wm.getDefaultDisplay().getHeight();System.out.println("screen width is " + screenWidth+ " screen height is " + screenheight);scale = getActivity().getResources().getDisplayMetrics().density;topHeight = (int) (scale * 50 + 0.5f);bottomHeight = (int) (scale * 55 + 0.5f);notiHeight = Resources.getSystem().getDimensionPixelSize(Resources.getSystem().getIdentifier("status_bar_height","dimen", "android"));

Android 拷贝assets目录下所有文件及文件夹到指定路径

1. public class AssetsCopyer {  
2.   
3.     private static final String TAG = "AssetsCopyer";  
4.       
5.     public static void releaseAssets(Context context, String assetsDir,  
6.             String releaseDir) {  
7.           
8. //      Log.d(TAG, "context: " + context + ", " + assetsDir);  
9.         if (TextUtils.isEmpty(releaseDir)) {  
10.             return;  
11.         } else if (releaseDir.endsWith("/")) {  
12.             releaseDir = releaseDir.substring(0, releaseDir.length() - 1);  
13.         }  
14.    
15.         if (TextUtils.isEmpty(assetsDir) || assetsDir.equals("/")) {  
16.             assetsDir = "";  
17.         } else if (assetsDir.endsWith("/")) {  
18.             assetsDir = assetsDir.substring(0, assetsDir.length() - 1);  
19.         }  
20.    
21.         AssetManager assets = context.getAssets();  
22.         try {  
23.             String[] fileNames = assets.list(assetsDir);//只能获取到文件(夹)名,所以还得判断是文件夹还是文件  
24.             if (fileNames.length > 0) {// is dir  
25.                 for (String name : fileNames) {  
26.                     if (!TextUtils.isEmpty(assetsDir)) {  
27.                         name = assetsDir + File.separator + name;//补全assets资源路径  
28.                     }  
29. //                    Log.i(, brian name= + name);  
30.                     String[] childNames = assets.list(name);//判断是文件还是文件夹  
31.                     if (!TextUtils.isEmpty(name) && childNames.length > 0) {  
32.                         checkFolderExists(releaseDir + File.separator + name);  
33.                         releaseAssets(context, name, releaseDir);//递归, 因为资源都是带着全路径,   
34.                                                                                            //所以不需要在递归是设置目标文件夹的路径  
35.                     } else {  
36.                         InputStream is = assets.open(name);  
37. //                        FileUtil.writeFile(releaseDir + File.separator + name, is);  
38.                         writeFile(releaseDir + File.separator + name, is);  
39.                     }  
40.                 }  
41.             } else {// is file  
42.                 InputStream is = assets.open(assetsDir);  
43.                 // 写入文件前, 需要提前级联创建好路径, 下面有代码贴出  
44. //                FileUtil.writeFile(releaseDir + File.separator + assetsDir, is);  
45.                 writeFile(releaseDir + File.separator + assetsDir, is);  
46.             }  
47.    
48.         } catch (Exception e) {  
49.             e.printStackTrace();  
50.         }  
51.     }  
52.       
53.     private static boolean writeFile(String fileName, InputStream in) throws IOException  
54.     {  
55.         boolean bRet = true;  
56.         try {  
57.             OutputStream os = new FileOutputStream(fileName);  
58.             byte[] buffer = new byte[4112];  
59.             int read;  
60.             while((read = in.read(buffer)) != -1)  
61.             {  
62.                 os.write(buffer, 0, read);  
63.             }  
64.             in.close();  
65.             in = null;  
66.             os.flush();  
67.             os.close();  
68.             os = null;  
69. //          Log.v(TAG, "copyed file: " + fileName);  
70.         } catch (FileNotFoundException e) {  
71.             // TODO Auto-generated catch block  
72.             e.printStackTrace();  
73.             bRet = false;  
74.         }  
75.         return bRet;  
76.     }  
77.       
78.     private static void checkFolderExists(String path)  
79.     {  
80.         File file = new File(path);  
81.         if((file.exists() && !file.isDirectory()) || !file.exists())  
82.         {  
83.             file.mkdirs();  
84.         }  
85.     }  
86. }