DYWOA/app/src/main/java/com/rehome/dywoa/BaseNfcActivity.java

package com.rehome.dywoa;


import static com.rehome.dywoa.utils.NfcUtil.stringsToBytes;

import android.app.PendingIntent;
import android.content.Intent;
import android.content.IntentFilter;
import android.nfc.FormatException;
import android.nfc.NdefMessage;
import android.nfc.NfcAdapter;
import android.nfc.Tag;
import android.nfc.tech.IsoDep;
import android.nfc.tech.MifareClassic;
import android.nfc.tech.MifareUltralight;
import android.nfc.tech.Ndef;
import android.nfc.tech.NdefFormatable;
import android.nfc.tech.NfcA;
import android.nfc.tech.NfcB;
import android.nfc.tech.NfcF;
import android.nfc.tech.NfcV;
import android.os.Parcelable;
import android.text.TextUtils;
import android.util.Log;
import android.widget.Toast;

import androidx.appcompat.app.AppCompatActivity;

import com.rehome.dywoa.utils.NfcUtil;

import org.json.JSONException;
import org.json.JSONObject;

import java.util.Arrays;
import java.util.Objects;

/**
 * Description:
 * 子类在onNewIntent方法中进行NFC标签相关操作。
 * launchMode设置为singleTop或singelTask，保证Activity的重用唯一
 * 在onNewIntent方法中执行intent传递过来的Tag数据
 * 将NFC标签卡靠近手机后部（NFC标签卡可网上自行购买）
 */
public class BaseNfcActivity extends AppCompatActivity {
    private NfcAdapter nfcAdapter;
    private String readResult = "";
    private PendingIntent pendingIntent;
    private IntentFilter[] mFilters;
    private String[][] mTechLists;
    private boolean isFirst = true;
    private IntentFilter ndef;

    Tag mTag;
    Tag getTagHandle() {
        return mTag;
    }

    /**
     * 检测工作,判断设备的NFC支持情况
     *
     * @return
     */
    private Boolean ifNFCUse() {
        if (nfcAdapter == null) {
            Toast.makeText(this, "设备不支持NFC！", Toast.LENGTH_SHORT).show();
            return false;
        }
        if (!nfcAdapter.isEnabled()) {
            Toast.makeText(this, "请在系统设置中先启用NFC功能！", Toast.LENGTH_SHORT).show();
            return false;
        }
        return true;
    }

    /**
     * 初始化过程
     */
    public void initNFC() {

        //NFC适配器，所有的关于NFC的操作从该适配器进行
        nfcAdapter = NfcAdapter.getDefaultAdapter(this);
        if (!ifNFCUse()) {
            return;
        }
        //将被调用的Intent，用于重复被Intent触发后将要执行的跳转


        if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.S) {
            pendingIntent = PendingIntent.getActivity(this, 0, new Intent(this, getClass()).addFlags(Intent.FLAG_ACTIVITY_SINGLE_TOP), PendingIntent.FLAG_MUTABLE | PendingIntent.FLAG_UPDATE_CURRENT);
        } else {
            pendingIntent = PendingIntent.getActivity(this, 0, new Intent(this, getClass()).addFlags(Intent.FLAG_ACTIVITY_SINGLE_TOP), PendingIntent.FLAG_UPDATE_CURRENT);
        }


        //设定要过滤的标签动作，这里只接收ACTION_NDEF_DISCOVERED类型
        ndef = new IntentFilter(NfcAdapter.ACTION_NDEF_DISCOVERED);
        ndef.addCategory("*/*");
        mFilters = new IntentFilter[]{ndef};// 过滤器
        mTechLists = new String[][]{new String[]{NfcA.class.getName()},
                new String[]{NfcF.class.getName()},
                new String[]{NfcB.class.getName()},
                new String[]{NfcV.class.getName()},
                new String[]{MifareClassic.class.getName()},
                new String[]{MifareUltralight.class.getName()},
                new String[]{IsoDep.class.getName()}};// 允许扫描的标签类型

        if (isFirst) {
            if (NfcAdapter.ACTION_NDEF_DISCOVERED.equals(getIntent()
                    .getAction())) {
                ndef = new IntentFilter();
                if (readFromTag(getIntent())) {
                    Toast.makeText(this, readResult, Toast.LENGTH_SHORT).show();
                } else {
                    Toast.makeText(this, "标签数据为空", Toast.LENGTH_SHORT).show();
                }
            }
            isFirst = false;
        }
    }

    private String ByteArrayToHexString(byte[] inarray) { //converts byte arrays to string
        int i, j, in;
        String[] hex = {"0", "1", "2", "3", "4", "5", "6", "7", "8", "9", "A", "B", "C", "D", "E", "F"};
        String out = "";
        for (j = 0; j < inarray.length; ++j) {
            in = (int) inarray[j] & 0xff;
            i = (in >> 4) & 0x0f;
            out += hex[i];
            i = in & 0x0f;
            out += hex[i];
        }
        return out;
    }


    @Override
    protected void onPause() {
        super.onPause();
        if (nfcAdapter != null) {
            nfcAdapter.disableForegroundDispatch(this);
        }
    }

    /*
     * 重写onResume回调函数的意义在于处理多次读取NFC标签时的情况
     */
    @Override
    protected void onResume() {
        super.onResume();

        //设置强制竖屏
//        setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_PORTRAIT);

        // 前台分发系统,这里的作用在于第二次检测NFC标签时该应用有最高的捕获优先权.
        if (nfcAdapter != null && pendingIntent != null && mFilters != null && mTechLists != null) {
            nfcAdapter.enableForegroundDispatch(this, pendingIntent, mFilters,
                    mTechLists);
        }

    }

    /*
     * 有必要要了解onNewIntent回调函数的调用时机,请自行上网查询
     */
    @Override
    protected void onNewIntent(Intent intent) {
        super.onNewIntent(intent);
        if (NfcAdapter.ACTION_NDEF_DISCOVERED.equals(intent.getAction()) ||
                NfcAdapter.ACTION_TECH_DISCOVERED.equals(intent.getAction())) {

            String id = ByteArrayToHexString(Objects.requireNonNull(intent.getByteArrayExtra(NfcAdapter.EXTRA_ID)));

            if (readFromTag(intent)) {
                // Toast.makeText(this, readResult, Toast.LENGTH_SHORT).show();
                handleNfc(readResult, null);
            } else {
                Toast.makeText(this, "ID:" + id + "  标签数据为空", Toast.LENGTH_SHORT).show();
            }
        }
    }

    private JSONObject ndef2Html(Ndef ndef, Parcelable[] messages) {
        return buildNdefJSON(ndef, messages);
    }

    JSONObject buildNdefJSON(Ndef ndef, Parcelable[] messages) {
        JSONObject json = NfcUtil.ndefToJSON(ndef);

        if (messages != null) {
            try {
                if (messages.length == 1) {
                    NdefMessage message = (NdefMessage) messages[0];
                    json.put("ndefMessage", NfcUtil.messageToJSON(message));
                    json.put("type", "NDEF");
                }
            } catch (JSONException e) {
                Log.e("BaseNfcActivity", "Failed to convert ndefMessage into json", e);
            }
        }
        return json;
    }

    public void getNdefMessage(Intent intent) {
        synchronized (this) {
            try {
                String action = intent.getAction();
                if (action != null) {
                    Tag detectedTag = intent.getParcelableExtra(NfcAdapter.EXTRA_TAG);
                    if (detectedTag != null) {
                        mTag = detectedTag;
                    }
                }
                Ndef ndef = Ndef.get(getTagHandle());
                Parcelable[] message = new NdefMessage[] {ndef.getNdefMessage()};
                handleNfc(String.valueOf(ndef2Html(ndef, message)), null);
            } catch (Exception exception) {
                Log.d("BaseNfcActivity", exception.toString());
                handleNfc(null, exception.toString());
            }
        }
    }



    /**
     * 读取NFC标签数据的操作
     */
    private boolean readFromTag(Intent intent) {
        String action = intent.getAction();
        if (action == null) {
            return false;
        }
        Tag tag = intent.getParcelableExtra(NfcAdapter.EXTRA_TAG);
        if (tag == null) {
            return false;
        }
        mTag = tag;
        Ndef ndef;
        switch (action) {
            case NfcAdapter.ACTION_NDEF_DISCOVERED -> {
                ndef = Ndef.get(tag);
                Parcelable[] message = intent.getParcelableArrayExtra((NfcAdapter.EXTRA_NDEF_MESSAGES));
                readResult = String.valueOf(ndef2Html(ndef, message));
            }
            case NfcAdapter.ACTION_TECH_DISCOVERED -> {
                if (Arrays.asList(tag.getTechList()).contains(Ndef.class.getName())) {
                    ndef = Ndef.get(tag);
                    readResult = String.valueOf(ndef2Html(ndef, new NdefMessage[]{ndef.getCachedNdefMessage()}));
                } else {
                    Log.i("app ACTION_TECH_DISCOVERED 2", String.valueOf(tag));
                }
            }
        }
        return readResult != null;
    }

    //处理NFC
    public void handleNfc(String result, String errorMessage) {
        //showToast(result);
        //Toast.makeText(this, result, Toast.LENGTH_LONG).show();
    }

    public void showLog(String logText) {
        if (BuildConfig.LOG_ERROR) {
            if(TextUtils.isEmpty(logText)){
                Log.i("app", "logText is null");
            }else{
                Log.i("app", logText);
            }
        }
    }

    /**
     * 显示toast
     *
     * @param text
     */
    public void showToast(String text) {
        if (text != null && !text.trim().equals("")) {
            Toast.makeText(this, text, Toast.LENGTH_SHORT).show();
        }
    }



    /**
     * 往标签写数据的方法
     */
    public void writeNFCTag(String command) throws FormatException, JSONException {
        if (mTag == null) {
            return;
        }
        NdefMessage ndefMessage = new NdefMessage(stringsToBytes(command));
        //转换成字节获得大小
        int size = ndefMessage.toByteArray().length;
        try {
            //2.判断NFC标签的数据类型（通过Ndef.get方法）
            Ndef ndef = Ndef.get(getTagHandle());
            //判断是否为NDEF标签
            if (ndef != null) {
                ndef.connect();
                //判断是否支持可写
                if (!ndef.isWritable()) {
                    return;
                }
                //判断标签的容量是否够用
                if (ndef.getMaxSize() < size) {
                    return;
                }
                //3.写入数据
                ndef.writeNdefMessage(ndefMessage);
                Toast.makeText(this, "写入成功", Toast.LENGTH_SHORT).show();

                ndef.close();
                ndef.connect();
            } else { //当我们买回来的NFC标签是没有格式化的，或者没有分区的执行此步
                //Ndef格式类
                NdefFormatable format = NdefFormatable.get(mTag);
                //判断是否获得了NdefFormatable对象，有一些标签是只读的或者不允许格式化的
                if (format != null) {
                    //连接
                    format.connect();
                    //格式化并将信息写入标签
                    format.format(ndefMessage);
                    Toast.makeText(this, "写入成功",
                            Toast.LENGTH_SHORT).show();
                } else {
                    Toast.makeText(this, "写入失败", Toast.LENGTH_SHORT).show();
                }
            }
        } catch (Exception e) {
        }
    }
}