一 Paint ，Canvas

public class drawView extends View{ private Paint paint1; public drawView(Context context,AttributeSet set ){ super(context,set); } public void onDraw(Canvas canvas){ super.onDraw(canvas); //new 一个画笔对象 paint1= new Paint(); canvas.drawColor(Color.TRANSPARENT); //给画笔设置 属性 paint1.setAntiAlias(true); paint1.setColor(Color.GRAY); paint1.setStyle(Paint.Style.FILL); paint1.setStrokeWidth(3); //画一个圆 //canvas.drawCircle(arg0, arg1, arg2, arg3); canvas.drawCircle(10, 10, 5, paint1); } }

二 AsyncImageTask

/* * //默认开启的线程数为128条如果超过128条会放进队列进行排队 //继承AsyncTask时指定三个参数第一个为要传入的参数类型 第二个为进度的参数类型 第三个为返回结果的参数类型 //当调用execute时首先执行preExecute然后在执行去启用线程池的execute //这时会启动子线程去执行doinbackground--执行完后AsyncTask内部会有Handler将结果返回到UI线程中 //也就是onPostExecute的这个方法然后在进行UI界面的更新 */ private void asyncImageLoad(ImageView imageView, String path) { AsyncImageTask asyncImageTask = new AsyncImageTask(imageView); asyncImageTask.execute(path); } private final class AsyncImageTask extends AsyncTask<String, Integer, Uri>{ private ImageView imageView; public AsyncImageTask(ImageView imageView) { this.imageView = imageView; } protected Uri doInBackground(String... params) {//子线程中执行的 try { Uri uu = ContactService.getImage(params[0], cache);//将URI路径抛给主线程 System.out.println(uu+" zuuuuuuuu"); return uu; } catch (Exception e) { e.printStackTrace(); } return null; } protected void onPostExecute(Uri result) {//运行在主线程,获取 URI 路径 ，进行图片更新 Log.i("Test", result+""); if(result!=null && imageView!= null) imageView.setImageURI(result);//setImageURI这个方法会根据路径加载图片 } }

三 截取字符串

//截取字符串 从 0 到 第一个 "/" 字符 String name = result.substring(0,result.indexOf("/")); //截取字符串 从 第一个 字符 “/” 到 最后一个 “/” 字符 String name = result.substring(result.indexOf("/")+1, result.lastIndexOf("/")));

四 MD5广泛用于加密

import java.security.MessageDigest; import java.security.NoSuchAlgorithmException; public class MD5 { public static String getMD5(String content) { try { MessageDigest digest = MessageDigest.getInstance("MD5"); digest.update(content.getBytes()); return getHashString(digest); } catch (NoSuchAlgorithmException e) { e.printStackTrace(); } return null; } private static String getHashString(MessageDigest digest) { StringBuilder builder = new StringBuilder(); for (byte b : digest.digest()) { builder.append(Integer.toHexString((b >> 4) & 0xf)); builder.append(Integer.toHexString(b & 0xf)); } return builder.toString(); } }

五 读取流中的字节:

import java.io.ByteArrayOutputStream; import java.io.InputStream; public class StreamTool { /** * 读取流中的数据 * @param inStream * @return * @throws Exception */ public static byte[] read(InputStream inStream) throws Exception{ ByteArrayOutputStream outStream = new ByteArrayOutputStream(); byte[] buffer = new byte[1024]; int len = 0; while( (len = inStream.read(buffer)) != -1){ outStream.write(buffer, 0, len); } inStream.close(); return outStream.toByteArray(); } }

六 解析服务器传过来的 xml 数据流

/* * 得到解析 xml 后 的 Contact list 集合 */ public static List<Contact> getContacts() throws Exception { String path = StringTools.getURL_list_xml; URL url = new URL(path); //URLConnection与HttPURLConnection都是抽象类，无法直接实例化对象。 //其对象主要通过URL的openconnection方法获得。 //利用HttpURLConnection对象从网络中获取网页数据 HttpURLConnection con = (HttpURLConnection) url.openConnection(); con.setReadTimeout(5000); con.setRequestMethod("GET"); if(con.getResponseCode() == 200){ //http协议,里面有相应状态码的解释, //这里如楼上所说是判断是否正常响应请求数据. return parseXML(con.getInputStream()); //FFF //return StreamTool.read(con.getInputStream()); } return null; }

其中 parseXML(con.getInputStream());

/* * 解析XMl */ private static List<Contact> parseXML(InputStream xml) throws Exception { List<Contact> contacts = new ArrayList<Contact>(); Contact contact = null; XmlPullParser pullParser = Xml.newPullParser(); pullParser.setInput(xml,"UTF-8"); int event = pullParser.getEventType(); while(event != XmlPullParser.END_DOCUMENT){ switch (event) { case XmlPullParser.START_TAG : if("contact".equals(pullParser.getName())){ contact = new Contact(); contact.id = new Integer(pullParser.getAttributeValue(0)); }else if("name".equals(pullParser.getName())){ contact.name = pullParser.nextText();// .nextText 不是 .getText ！！！！ }else if("image".equals(pullParser.getName())){ contact.imageUrl = pullParser.getAttributeValue(0);//FFF } break; case XmlPullParser.END_TAG : if("contact".equals(pullParser.getName())){ contacts.add(contact); contact = null; } break; } event = pullParser.next(); } return contacts; }

七 解析 服务器传过来的 Json 数据：

/* * 解析 Json 数据 */ private static List<SecondActivity_Goods_Bean> parseJson(InputStream inputStream) throws Exception { List<SecondActivity_Goods_Bean> SecondActivity_Goods_Beans = new ArrayList<SecondActivity_Goods_Bean>(); SecondActivity_Goods_Bean goodBean = null; byte[] data = StreamTool.read(inputStream); String json = new String(data); JSONArray array = new JSONArray(json); for(int i=0;i<array.length();i++){ JSONObject jsonObject = array.getJSONObject(i); jsonObject.getString("imageUrl"); jsonObject.getString("imageContent"); jsonObject.getString("goodsPrice"); goodBean = new SecondActivity_Goods_Bean(jsonObject.getString("imageUrl"), jsonObject.getString("imageContent"), jsonObject.getString("goodsPrice")); SecondActivity_Goods_Beans.add(goodBean); } return null; }

八 向服务器提交数据：

private static String sendPostRequest(String path,Map<String, String> parame, String encoding) throws Exception { //StringBuilder 来组合成这段数据 发给服务器 telephone_number=telephone_number&password=password StringBuilder data = new StringBuilder(); if(parame != null && !parame.isEmpty()){ for(Map.Entry<String, String> entry:parame.entrySet()){ data.append(entry.getKey()).append("="); data.append(URLEncoder.encode(entry.getValue(), encoding)); data.append("&"); } data.deleteCharAt(data.length() -1);//最后会多出 “&” } byte[] entity = data.toString().getBytes();//默认得到UTF-8的字节码 HttpURLConnection conn = (HttpURLConnection) new URL(path).openConnection(); conn.setConnectTimeout(5000); conn.setRequestMethod("POST"); //采用 POST 向服务器发送请求 conn.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");//设置Post请求的 头字段 conn.setRequestProperty("Content-Length", String.valueOf(entity.length));//设置Post请求的 头字段 OutputStream outStream = conn.getOutputStream();//得到数据输出流 outStream.write(entity);//将数据写给 http输出流缓冲区 if(conn.getResponseCode() == 200){ //的android客户端向服务器请求 请求码 时 数据输出流的缓冲区才把数据写给服务器 //String s = conn.getResponseMessage();//这个方法得到字符串 “OK” /* * 得到服务器返回的数据！！！ 得到服务器的返回值就可以判断数据是否上传成功 */ byte[] stringData = StreamTool.read(conn.getInputStream()); String stringFlag = new String(stringData,"UTF-8"); return stringFlag; // 数据发送成功 返回 true } return "Submit_Fail"; }

九 SharedPreferences

public class SharedPreferences_Service { private Context context; private SharedPreferences sp; public SharedPreferences_Service(Context applicationCon){ this.context = applicationCon; } /** * 将 文件存储在 File Explorer的data/data/相应的包名/Rsgistered_form.xml 下导出该文件 * @param name * @param telephone_number * @param password */ public void SetParament(String name,String telephone_number,String password){ sp = context.getSharedPreferences("Rsgistered_form", context.MODE_APPEND); Editor et = sp.edit(); et.putString("name", name); et.putString("telephone_number",telephone_number); et.putString("password",password); et.commit(); } /** * 在文件夹 File Explorer的data/data/相应的 Rsgistered_form.xml下取数据 * @return */ public Map<String, String> GetParament(){ Map<String, String> parmes = new HashMap<String, String>(); sp = context.getSharedPreferences("Rsgistered_form", context.MODE_APPEND); parmes.put("name", sp.getString("name", ""));//获得name字段，参数为空就返回空 parmes.put("telephone_number", sp.getString("telephone_number", "")); parmes.put("password", sp.getString("password", "")); return parmes; } }

十 <><>

<"1.0" encoding="utf-8"?> <shape xmlns:android="http://schemas.android.com/apk/res/android" android:shape="rectangle" > <> <corners android:radius="9dp" android:topLeftRadius="2dp" android:topRightRadius="2dp" android:bottomLeftRadius="2dp" android:bottomRightRadius="2dp"/> <><> <gradient android:startColor="@android:color/white" android:centerColor="@android:color/black" android:endColor="@android:color/black" android:useLevel="true" android:angle="45" android:type="radial" android:centerX="0" android:centerY="0" android:gradientRadius="90"/> <> <padding android:left="2dp" android:top="2dp" android:right="2dp" android:bottom="2dp"/> <><> <size android:width="50dp" android:height="50dp"/> <><> <solid android:color="@android:color/white"/> <><> <stroke android:width="2dp" android:color="@android:color/black" android:dashWidth="1dp" android:dashGap="2dp"/> </shape>

也可以在 drawable 文件夹下 在定义个 xxx.xml 使用 selector

<"1.0" encoding="utf-8"?> <selector xmlns:android="http://schemas.android.com/apk/res/android"> <item android:drawable="@drawable/button_pressed_bg" android:state_pressed="true"></item> <item android:drawable="@drawable/shape_image"></item> </selector>

定义一个有四个角弧度的 长方形背景

<"1.0" encoding="utf-8"?> <shape xmlns:android="http://schemas.android.com/apk/res/android" android:shape="rectangle" > <> <corners android:topLeftRadius="2px" android:topRightRadius="2px" android:bottomLeftRadius="2px" android:bottomRightRadius="2px"/> <> <solid android:color="#FFFFFF"/> <> <stroke android:width="0.5dp" android:color="#7A7A7A"/> </shape>

十一 anim文件

// anim 文件夹下 的 out.xml 动画文件

<"1.0" encoding="utf-8"?> <set xmlns:android="http://schemas.android.com/apk/res/android" android:shareInterpolator="false"> <> <> <translate android:fromXDelta="0%p" android:toXDelta="100%p" android:duration="1000" /> <> <alpha android:fromAlpha="1.0" android:toAlpha="0.5" android:duration="500" /> </set>

十二 ，将 Raw 加载数据库 导入 手机文件夹下

private SQLiteDatabase openDatabase(String dbfile) { try { if (!(new File(dbfile).exists())) { //判断数据库文件是否存在，若不存在则执行导入，否则直接打开数据库 InputStream is = this.context.getResources().openRawResource(R.raw.china_city); //欲导入的数据库 FileOutputStream fos = new FileOutputStream(dbfile); byte[] buffer = new byte[BUFFER_SIZE]; int count = 0; while ((count = is.read(buffer)) > 0) { fos.write(buffer, 0, count); } fos.close(); is.close(); } return SQLiteDatabase.openOrCreateDatabase(dbfile, null); } catch (FileNotFoundException e) { PLog.e("File not found"); e.printStackTrace(); } catch (IOException e) { PLog.e("IO exception"); e.printStackTrace(); } return null; }

十三 ， 双击退出应用

public class DoubleClickExit { /** * 双击退出检测, 阈值 2000ms */ public static long lastClick = 0L; private static final int THRESHOLD = 2000;// 2000ms public static boolean check() { long now = System.currentTimeMillis(); boolean b = now - lastClick < THRESHOLD; lastClick = now; return b; } } @Override public void onBackPressed() { if (!DoubleClickExit.check()) { ToastUtil.showShort(getString(R.string.double_exit)); } else { finish(); } }

十四 EditText 一些设置：

//设置点击后 软键盘的 显示类型 ，numberDecimal带小数点的数字 android:inputType="numberDecimal" // 设置alertDialog中的 editView 自动弹出软键盘 editView.setOnFocusChangeListener(new View.OnFocusChangeListener() { @Override public void onFocusChange(View v, boolean hasFocus) { if (hasFocus) { // 设置 弹出软键盘 alertDialog.getWindow().setSoftInputMode(WindowManager.LayoutParams.SOFT_INPUT_STATE_ALWAYS_VISIBLE); } } });

十五 Calendar

mCalendar= Calendar.getInstance();//获取当前日期 int_YEAR = mCalendar.get(Calendar.YEAR); int_MONTH = mCalendar.get(Calendar.MONTH); int_DAT = mCalendar.get(Calendar.DAY_OF_MONTH); int_lastday=mCalendar.getActualMaximum(Calendar.DAY_OF_MONTH); int_week = mCalendar.get(Calendar.DAY_OF_WEEK);

十六 DialogFragment ，DialogFragment官方推荐使用的，好处就不多说

public class YourDialogFragment extends DialogFragment { public interface DialogFragmentDataImp{//定义一个与Activity通信的接口，使用该DialogFragment的Activity须实现该接口 void showMessage(String message); } public static YourDialogFragment newInstance(String message){ //创建一个带有参数的Fragment实例 YourDialogFragment fragment = new YourDialogFragment (); Bundle bundle = new Bundle(); bundle.putString("message", message); fragment.setArguments(bundle);//把参数传递给该DialogFragment return fragment; } @Override public Dialog onCreateDialog(Bundle savedInstanceState) { View customView = LayoutInflater.from(getActivity()).inflate( R.layout.fragment_edit_bill_dialog, null); //ButterKnife.bind(this,customView); mContext = getActivity(); initView(); return new AlertDialog.Builder(getActivity()).setView(customView) .create(); }

使用（在 activity 或 fragment 调用）：

YourDialogFragment dialog = new YourDialogFragment(); dialog.show(getFragmentManager(), "loginDialog");