xutils3.0 的使用及demo

xutils3.0使用前要先初始化配置，例如：

public class MyApplication extends Application {
    private DbManager.DaoConfig daoConfig;
    private DbManager db;
    public DbManager.DaoConfig getDaoConfig() {
        return daoConfig;
    }

    @Override
    public void onCreate() {
        super.onCreate();
        x.Ext.init(this);//Xutils初始化
        daoConfig = new DbManager.DaoConfig()
                .setDbName("xiaoyu_db")//创建数据库的名称
                .setDbVersion(1)//数据库版本号
                .setDbUpgradeListener(new DbManager.DbUpgradeListener() {
                    @Override
                    public void onUpgrade(DbManager db, int oldVersion, int newVersion) {
                        // TODO: ...
                        // db.addColumn(...);
                        // db.dropTable(...);
                        // ...
                    }
                });//数据库更新操作


        db = x.getDb(((MyApplication) getApplicationContext()).getDaoConfig());
        try {
            db.save(new Person(22, "测试1"));   //插入测试数据
            db.save(new Person(23, "测试2"));
        } catch (DbException e) {
            e.printStackTrace();
        }

    }
}

xutils的几大功能：

一、http：

点击按钮，访问网络。并将返回值解析后设置到TextView上：

public class HttpFragment extends Fragment {

    private Button get;
    private Button post;
    private TextView tv;

    @Nullable
    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        View v = inflater.inflate(R.layout.httpfragment, container, false); //布局适配

        get = (Button) v.findViewById(R.id.http_get);
        post = (Button) v.findViewById(R.id.http_post);
        tv = (TextView) v.findViewById(R.id.tv);

        get.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {  //get请求
                Toast.makeText(getActivity(),"数据较大，请稍后...",Toast.LENGTH_LONG).show();
                RequestParams params = new RequestParams("http://blog.csdn.net/mobile/experts.html");
                x.http().get(params, new Callback.CommonCallback() {
                    public void onSuccess(String result) {
                        Document doc = Jsoup.parse(result);
                        org.jsoup.nodes.Element div = doc.select("div.list_3").get(0);
                        Elements imgs = div.getElementsByTag("img");
                        String title = doc.title();
                        StringBuffer sb = new StringBuffer();
                        for (int i = 0; i < imgs.size(); i++) {
                            org.jsoup.nodes.Element img = imgs.get(i);
                            Log.i("xiaoyu", img.attr("alt"));
                            sb = sb.append(img.attr("alt")+",");
                        }
                        tv.setText("所访问网站为："+title+"  博主名单为："+sb);
                    }
                    @Override
                    public void onError(Throwable ex, boolean isOnCallback) {
                    }
                    @Override
                    public void onCancelled(Callback.CancelledException cex) {
                    }
                    @Override
                    public void onFinished() {
                    }
                });
            }
        });

        post.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {  //post请求
                Toast.makeText(getActivity(), "数据较大，请稍后...", Toast.LENGTH_LONG).show();
                RequestParams params = new RequestParams("http://www.apkbus.com/Android-42-1.html");
                x.http().post(params, new Callback.CommonCallback() {
                    public void onSuccess(String result) {
                        Document doc = Jsoup.parse(result);
                        String title = doc.title();

                        tv.setText("所访问网站为：" + title);
                    }

                    @Override
                    public void onError(Throwable ex, boolean isOnCallback) {
                    }

                    @Override
                    public void onCancelled(Callback.CancelledException cex) {
                    }

                    @Override
                    public void onFinished() {
                    }
                });
            }
        });


        return v;
    }




}

二、database：

数据库的增删改查

public class DataBaseFragment extends Fragment {

    public static final String TAG = "DataBaseFragment";

    private Button find;
    private Button insert;
    private EditText username;
    private EditText userage;
    private ListView lv;
    private MyAdapter myAdapter;
    private List data;
    private DbManager db;
    private DbManager.DaoConfig daoConfig;
    public DbManager.DaoConfig getDaoConfig() {
        return daoConfig;
    }


    @Override
    public void onResume() {
        super.onResume();
        init();
        myAdapter.setData(data);
        myAdapter.notifyDataSetChanged();

    }

    @Nullable
    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        View v = inflater.inflate(R.layout.databasefragment, container, false);



        username = (EditText) v.findViewById(R.id.username);
        userage = (EditText) v.findViewById(R.id.password);

        find = (Button) v.findViewById(R.id.find);
        insert = (Button) v.findViewById(R.id.insert);

        lv = (ListView) v.findViewById(R.id.database_list);
        init();
        myAdapter = new MyAdapter( getActivity(),data ){
            public void deletePerson(Person person){
                deletePerson1(person);
            }
        };
        lv.setAdapter(myAdapter);





        find.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {//查询操作

                /*String name = username.getText().toString().trim();
                String age = userage.getText().toString().trim();
                DbUtils utils = new DbUtils();
                Person p = utils.findPerson(getActivity().getApplicationContext(),name,age);
                data.clear();
                data.add(p);
                myAdapter.notifyDataSetChanged();*/


                String name = username.getText().toString().trim();
                String age = userage.getText().toString().trim();

                if (!("".equals(name) && "".equals(age))){
                    try {
                        db = x.getDb(((MyApplication) getActivity().getApplicationContext()).getDaoConfig());
                        Person p = db.selector(Person.class)
                                .where("name", "=", name)
                                .and("age", "=", age)
                                .findFirst();
                        data.clear();
                        data.add(p);
                        lv.setAdapter(myAdapter);

                    } catch (DbException e) {
                        e.printStackTrace();
                    }
            }else {
                    Toast.makeText(getActivity(),"请正确输入。",Toast.LENGTH_SHORT).show();
                }

            }

        });

        insert.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {//新增操作
                db = x.getDb(((MyApplication) getActivity().getApplicationContext()).getDaoConfig());
                String name = username.getText().toString().trim();
                String age = userage.getText().toString().trim();

                if( !("".equals(name) && "".equals(age)) ) {

                    try {
                        db.save(new Person(Integer.parseInt(age), name));

                        init();

                        Person p = data.remove(data.size() - 1);
                        data.add(0, p);

                        myAdapter.setData(data);
                        myAdapter.notifyDataSetChanged();
                        //lv.setAdapter(myAdapter);


                    } catch (DbException e) {
                        e.printStackTrace();
                    }
                }else {
                    Toast.makeText(getActivity(),"不能为空",Toast.LENGTH_SHORT).show();
                }
            }
        });

        return v;
    }

    public void init(){
            db = x.getDb(((MyApplication) getActivity().getApplicationContext()).getDaoConfig());
        try {

            data = db.selector(Person.class).findAll();
            Log.d(TAG , data+"");

        } catch (DbException e) {
            e.printStackTrace();
        }

    }



    public void deletePerson1( Person person ){
        db = x.getDb(((MyApplication) getActivity().getApplicationContext()).getDaoConfig());
        try {
            Person p = db.selector(Person.class)
                                  .where("id","=",person.getId())
                                  .findFirst();
            db.delete(p);
            init();
            myAdapter.setData(data);
            myAdapter.notifyDataSetChanged();


        } catch (DbException e) {
            e.printStackTrace();
        }

    }

}

工具类：

public class DbUtils {

    public Person findPerson( Context context, String name,String age ){

        DbManager db = x.getDb(((MyApplication)context).getDaoConfig());
        try {
            Person p = db.selector(Person.class)
                    .where("name", "=", name)
                    .and("age", "=", age)
                    .findFirst();
            /*long count = db.selector(Person.class) //查总数
                    .where("name", "LIKE", "w%")
                    .and("age", ">", 32)
                    .count();  */
            /*List testList = db.selector(Person.class) //between
                    .where("id", "between", new String[]{"1", "5"})
                    .findAll();*/
            return p;

        } catch (DbException e) {
            e.printStackTrace();
        }

        return null;
    }

    public  void addPerson(Context context ,String name,String age){

        DbManager db = x.getDb(((MyApplication)context).getDaoConfig());
        try {//new Object[]{name,age}
            db.save(new Person(Integer.parseInt(age), name));

        } catch (DbException e) {
            e.printStackTrace();
        }


    }


    public  List findAllPerson( Context context){
        DbManager db = x.getDb(((MyApplication)context).getDaoConfig());
        try {
            List data = db.selector(Person.class).findAll();
            return data;
        } catch (DbException e) {
            e.printStackTrace();
        }
        return null;

    }

}

适配器：

public abstract class MyAdapter extends BaseAdapter{

    public abstract void deletePerson(Person person);

    private List data = new ArrayList();
    private LayoutInflater inflater;
    private Context context;

    public MyAdapter( Context context,List data) {

        this.data = data;
        this.context = context;
        inflater = LayoutInflater.from(context);

    }

    @Override
    public int getCount() {
        return null == data ? 0 : data.size();
    }

    @Override
    public Object getItem(int position) {
        return  null == data ? null : data.get(position);
    }

    @Override
    public long getItemId(int position) {
        return position;
    }

    @Override
    public View getView(final int position, View convertView, ViewGroup parent) {


        Person item = data.get(position);  //得到当前条目对象

        if( convertView == null ){
            convertView = inflater.inflate(R.layout.item_database,null);
        }
        TextView t1 = (TextView) convertView.findViewById(R.id.item_database_id);
        TextView t2 = (TextView) convertView.findViewById(R.id.item_database_name);
        TextView t3 = (TextView) convertView.findViewById(R.id.item_database_age);

        ImageView update = (ImageView) convertView.findViewById(R.id.update);
        ImageView delete = (ImageView) convertView.findViewById(R.id.delete);

            t1.setText(item.getId()+"");
            t2.setText(item.getName()+"");
            t3.setText(item.getAge()+"");


        update.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {//修改条目操作

                Intent intent = new Intent();
                intent.setClass(context, UpdateActivity.class);
                Bundle b = new Bundle();
                b.putInt("id",data.get(position).getId());
                intent.putExtra("b", b);
                context.startActivity(intent);

            }
        });

        delete.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {//删除条目操作

                deletePerson(data.get(position));

            }
        });

        return convertView;
    }

    public void setData(List data) {
        this.data = data;
    }
}

三、bitmap：

public class BitmapFragment extends Fragment {

    private GridView gv;
    private List data = new ArrayList();
    private ImageAdapter adapter;
    private String[] imgSites = {
            "http://image.baidu.com/",
            "http://www.22mm.cc/",
            "http://www.moko.cc/",
            "http://eladies.sina.com.cn/photo/",
            "http://www.youzi4.com/"
    };



    @Nullable
    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        View v = inflater.inflate(R.layout.bitmapfragment, container, false);

        gv = (GridView) v.findViewById(R.id.gv);


        Toast.makeText(getActivity(), "数据较大，请稍后...", Toast.LENGTH_LONG).show();
        Toast.makeText(getActivity(), "图片来源于网络...", Toast.LENGTH_LONG).show();
        for (String url : imgSites) {
            getImageList(url);
        }
        adapter = new ImageAdapter( getActivity(),data );
        gv.setAdapter(adapter);
        return v;
    }


    public void addSrc( List data ){

        this.data.addAll(data);

    }


    public void getImageList( String url ){

        RequestParams params = new RequestParams(url);
        x.http().get(params, new Callback.CacheCallback() {
            @Override
            public void onSuccess(String s) {
                addSrc(getImageUrl(s));
                adapter.notifyDataSetChanged();
            }

            @Override
            public void onError(Throwable throwable, boolean b) {

            }

            @Override
            public void onCancelled(CancelledException e) {

            }

            @Override
            public void onFinished() {

            }

            @Override
            public boolean onCache(String s) {
                return false;
            }
        });

    }


    public List getImageUrl( String htmlStr ){
        List pics = new ArrayList();

        String regEx_img = "\"http://(.*?).jpg\""; // 图片链接地址
        Pattern p_image = Pattern.compile(regEx_img, Pattern.CASE_INSENSITIVE);
        Matcher m_image = p_image.matcher(htmlStr);
        while (m_image.find()) {
            String src = m_image.group(1);
            if (src.length() < 100) {
                pics.add("http://" + src + ".jpg");
            }
        }
        return pics;



    }


}

图片适配器：

public class ImageAdapter extends BaseAdapter{

    private Context mContext;
    private List data = new ArrayList();
    private LayoutInflater inflater;

    public ImageAdapter( Context context,List data) {
        this.data = data;
        inflater = LayoutInflater.from(context);
    }

    @Override
    public int getCount() {
        return data.size();
    }

    @Override
    public Object getItem(int position) {
        return data.get(position);
    }

    @Override
    public long getItemId(int position) {
        return position;
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {

        if( convertView == null ){
            convertView = inflater.inflate(R.layout.imageinf,null);
        }

        ImageView iv = (ImageView) convertView.findViewById(R.id.item_img);

        x.image().bind(iv , data.get(position));
        return convertView;
    }
}

mainactivity：

public class MainActivity extends FragmentActivity {

    private FragmentManager fm;
    private LinearLayout http;
    private LinearLayout database;
    private LinearLayout bitmap;
    private ImageView img_http;
    private ImageView img_database;
    private ImageView img_bitmap;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        http = (LinearLayout) findViewById(R.id.http);
        database = (LinearLayout) findViewById(R.id.database);
        bitmap = (LinearLayout) findViewById(R.id.bitmap);
        img_http = (ImageView) findViewById(R.id.img_http);
        img_database = (ImageView) findViewById(R.id.img_database);
        img_bitmap = (ImageView) findViewById(R.id.img_bitmap);
        fm = getSupportFragmentManager();
        FragmentTransaction ft = fm.beginTransaction();
        HttpFragment hf = new HttpFragment();
        ft.add(R.id.f1, hf);
        ft.commit();


        http.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                img_http.setImageResource( R.drawable.http_press );
                img_database.setImageResource(R.drawable.database);
                img_bitmap.setImageResource(R.drawable.bitmap);
                FragmentTransaction ft = fm.beginTransaction();
                HttpFragment hf = new HttpFragment();
                ft.replace(R.id.f1, hf);
                ft.commit();
            }
        });
        database.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                img_http.setImageResource( R.drawable.http );
                img_database.setImageResource(R.drawable.database_press);
                img_bitmap.setImageResource(R.drawable.bitmap);
                FragmentTransaction ft = fm.beginTransaction();
                DataBaseFragment db = new DataBaseFragment();
                ft.replace(R.id.f1,db);
                ft.commit();

            }
        });
        bitmap.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                img_http.setImageResource( R.drawable.http );
                img_database.setImageResource(R.drawable.database);
                img_bitmap.setImageResource(R.drawable.bitmap_press);
                FragmentTransaction ft = fm.beginTransaction();
                BitmapFragment bitmap = new BitmapFragment();
                ft.replace(R.id.f1,bitmap);
                ft.commit();
            }
        });

    }


}

布局文件：

activity_main：

xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent"
    android:layout_height="match_parent" android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context=".MainActivity"
    android:orientation="vertical">

            android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:orientation="vertical"
        android:layout_weight="1"
        >

                    android:id="@+id/f1"
            android:layout_width="fill_parent"
            android:layout_height="fill_parent"
            >
        

    

            android:layout_width="fill_parent"
        android:layout_height="70dp"
        android:orientation="horizontal"
        >

                    android:layout_width="50dp"
            android:layout_height="70dp"
            android:orientation="vertical"
            android:layout_weight="1"
            android:gravity="center_horizontal"
            android:clickable="true"
            android:id="@+id/http">

                            android:layout_width="40dp"
                android:layout_height="40dp"
                android:src="@drawable/http_press"
                android:id="@+id/img_http" />
                            android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="Http"
                />
        

                    android:layout_width="50dp"
            android:layout_height="70dp"
            android:orientation="vertical"
            android:layout_weight="1"
            android:gravity="center_horizontal"
            android:id="@+id/database">

                            android:layout_width="40dp"
                android:layout_height="40dp"
                android:src="@drawable/database"
                android:id="@+id/img_database" />
                            android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="DataBase"
                />
        

                    android:layout_width="50dp"
            android:layout_height="70dp"
            android:orientation="vertical"
            android:layout_weight="1"
            android:gravity="center_horizontal"
            android:id="@+id/bitmap">

                            android:layout_width="40dp"
                android:layout_height="40dp"
                android:src="@drawable/bitmap"
                android:id="@+id/img_bitmap" />
                            android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="Bitmap"
                />
        






    

httpfragment：

xml version="1.0" encoding="utf-8"?>
xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical" android:layout_width="match_parent"
    android:layout_height="match_parent">

            android:layout_width="fill_parent"
        android:layout_height="wrap_content">

            android:id="@+id/http_get"
        android:layout_width="0dp"
        android:layout_height="50dp"
        android:background="@drawable/shape"
        android:layout_weight="1"
        android:layout_margin="20dp"
        android:text="test get"
        />
            android:id="@+id/http_post"
        android:layout_width="0dp"
        android:layout_height="50dp"
        android:background="@drawable/shape"
        android:layout_weight="1"
        android:layout_margin="20dp"
        android:text="test post"/>
    

            android:layout_width="fill_parent"
        android:layout_height="0dp"
        android:orientation="vertical"
        android:layout_weight="1">

                    android:layout_width="fill_parent"
            android:layout_height="fill_parent">
                            android:id="@+id/tv"
                android:layout_width="fill_parent"
                android:layout_height="fill_parent"
                android:background="@drawable/text"
                android:textSize="20sp"
                />
        


    

databasefragment：

xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical" android:layout_width="match_parent"
    android:layout_height="match_parent">

            android:id="@+id/username"
        android:layout_width="fill_parent"
        android:layout_height="50dp"
        android:hint="请输入名字"
        android:cursorVisible="true"
        android:background="@android:drawable/editbox_background"
        android:layout_marginLeft="10dp"
        android:layout_marginRight="10dp"
        />
            android:id="@+id/password"
        android:layout_width="fill_parent"
        android:layout_height="50dp"
        android:hint="请输入年龄"
        android:background="@android:drawable/editbox_background"
        android:layout_marginLeft="10dp"
        android:layout_marginRight="10dp"
        />

    <LinearLayout
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:orientation="horizontal"
        android:gravity="center">
            android:layout_width="100dp"
        android:layout_height="50dp"
        android:text="查询"
        android:background="@drawable/shape"
        android:layout_margin="10dp"
        android:textColor="#ffffff"
        android:textSize="20dp"
        android:onClick="userLogin"
        android:layout_weight="1"
        android:id="@+id/find" />
            android:layout_width="100dp"
        android:layout_height="50dp"
        android:text="新增"
        android:background="@drawable/shape"
        android:layout_margin="10dp"
        android:textColor="#ffffff"
        android:textSize="20dp"
        android:onClick="userLogin"
        android:layout_weight="1"
        android:id="@+id/insert"
        />
    LinearLayout>

    <LinearLayout
        android:layout_width="fill_parent"
        android:layout_height="0dp"
        android:layout_weight="1"
        android:layout_marginTop="10dp">
                    android:id="@+id/database_list"
            android:layout_width="fill_parent"
            android:layout_height="fill_parent"
            android:dividerHeight="0.5dp"
            android:divider="#ffffff">

        
    LinearLayout>


LinearLayout>

bitmapfragment：

xml version="1.0" encoding="utf-8"?>
xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical" android:layout_width="match_parent"
    android:layout_height="match_parent">


            android:id="@+id/gv"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        android:columnWidth="90dp"
        android:numColumns="auto_fit"
        android:verticalSpacing="10dp"
        android:horizontalSpacing="10dp"
        android:stretchMode="columnWidth"
        android:gravity="center"
        >
    

item_database:

xml version="1.0" encoding="utf-8"?>
xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="horizontal" android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="#cdcdcd">


    <TextView
        android:id="@+id/item_database_id"
        android:layout_width="fill_parent"
        android:layout_height="50dp"
        android:gravity="center"
        android:layout_weight="1"
        android:text="1"
        android:textSize="20sp"
        />
    <TextView
        android:id="@+id/item_database_name"
        android:layout_width="fill_parent"
        android:layout_height="50dp"
        android:gravity="center"
        android:layout_weight="1"
        android:text="张晓雨"
        android:textSize="20sp"
        />
    <TextView
        android:id="@+id/item_database_age"
        android:layout_width="fill_parent"
        android:layout_height="50dp"
        android:gravity="center"
        android:layout_weight="1"
        android:text="22"
        android:textSize="20sp"
        />
            android:layout_width="100dp"
        android:layout_height="50dp"
        android:orientation="horizontal"
        >

                    android:id="@+id/update"
            android:layout_width="40dp"
            android:layout_height="40dp"
            android:src="@android:drawable/stat_notify_sync_noanim"
            android:layout_gravity="center"
            android:clickable="true"/>
                    android:id="@+id/delete"
            android:layout_marginLeft="10dp"
            android:layout_width="40dp"
            android:layout_height="40dp"
            android:src="@android:drawable/ic_delete"
            android:layout_gravity="center"
            android:clickable="true"/>

    

update_person:

xml version="1.0" encoding="utf-8"?>
xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"

    >
            android:layout_width="fill_parent"
        android:layout_height="35dp"
        android:text="修改数据"
        android:background="#cdcdcd"
        android:gravity="center"
        android:textColor="#ffffff"
        android:textSize="20dp"
        />
            android:id="@+id/updated_name"
        android:layout_width="fill_parent"
        android:layout_height="50dp"
        android:background="@android:drawable/editbox_background"
        android:layout_margin="10dp"
        />
            android:id="@+id/updated_age"
        android:layout_width="fill_parent"
        android:layout_height="50dp"
        android:background="@android:drawable/editbox_background"
        android:layout_margin="10dp"
        />
            android:id="@+id/btn_update"
        android:layout_width="fill_parent"
        android:layout_height="50dp"
        android:text="提交"
        android:background="#cdcdcd"
        android:layout_margin="10dp"
        android:textColor="#ffffff"
        android:textSize="20dp"
        android:onClick="userLogin"
        />

imageinf:

xml version="1.0" encoding="utf-8"?>
xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical" android:layout_width="match_parent"
    android:layout_height="match_parent">



            android:id="@+id/item_img"
        android:layout_width="100dp"
        android:layout_height="100dp"
        android:src="@drawable/http_press"/>

运行效果图：

demo下载：http://download.csdn.net/download/a358333644/9451822