android 一些工具类汇总

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

<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android" 
  android:shape="rectangle" >
  <!-- 圆角 -->
<corners
    android:radius="9dp"
    android:topLeftRadius="2dp"
    android:topRightRadius="2dp"
    android:bottomLeftRadius="2dp"
    android:bottomRightRadius="2dp"/>
<!-- 设置圆角半径 --><!-- 渐变 -->
<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"/>
<!-- 间隔 -->
<padding
    android:left="2dp"
    android:top="2dp"
    android:right="2dp"
    android:bottom="2dp"/>
<!-- 各方向的间隔 --><!-- 大小 -->
<size
    android:width="50dp"
    android:height="50dp"/>
<!-- 宽度和高度 --><!-- 填充 -->
<solid
    android:color="@android:color/white"/>
<!-- 填充的颜色 --><!-- 描边 -->
<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

<?xml version="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

<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android" 
  android:shape="rectangle" >
  <!-- 指定4個角的弧度 -->
  <corners android:topLeftRadius="2px"
    android:topRightRadius="2px"
    android:bottomLeftRadius="2px"
    android:bottomRightRadius="2px"/>
  <!-- 指定背景顏色 -->
  <solid android:color="#FFFFFF"/>
  <!-- 指定框條的顏色的寬度 -->
  <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

<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="http://schemas.android.com/apk/res/android"
  android:shareInterpolator="false">
  <!-- 100%p 的 p 是指从父类view 的 指定位置 0 到 起始位 100%-->
  <!-- 位移 -->
   <translate
    android:fromXDelta="0%p"
    android:toXDelta="100%p"
    android:duration="1000"
    />
   <!-- 透明度 -->
   <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");

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