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android 一些工具类汇总

作者：曾田生z　　发布时间：2023-08-29 11:32:05　

标签：android,工具类

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" >

<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

<?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" >

<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

<?xml version="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");

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android 一些工具类汇总

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