Help us understand the problem. What is going on with this article?

【Android】NFCのUIDを読み込んでTextViewに表示するプログラム

Activity_main.xml
<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <TextView
        android:id="@+id/test001"
        android:layout_width="wrap_content"
        android:layout_height="18dp"
        android:text="@string/test002"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <Button
        android:id="@+id/button2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginBottom="8dp"
        android:layout_marginTop="8dp"
        android:onClick="clearId"
        android:text="クリア"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/test001" />

</android.support.constraint.ConstraintLayout>
AndroidManifest.xml
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.XXXXX.mynfc">

    <uses-feature android:name="android.hardware.nfc" android:required="true"/>
    <uses-permission android:name="android.permission.NFC"/>

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">
        <activity android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

</manifest>
MainActivity.java
package com.example.XXXXX.mynfc;

import android.app.PendingIntent;
import android.content.Intent;
import android.nfc.NfcAdapter;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
import android.widget.Toast;
import java.util.Arrays;

public class MainActivity extends AppCompatActivity {

    private NfcAdapter mNfcAdapter; 

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        // ボタンを設定
        Button button = findViewById(R.id.button2);

        // インスタンスを取得
        mNfcAdapter = android.nfc.NfcAdapter.getDefaultAdapter(this);
    }

    @Override
    protected void onResume() {
        super.onResume();

        // NFCかざし設定
        Intent intent = new Intent(this,this.getClass());

        intent.setFlags(Intent.FLAG_ACTIVITY_SINGLE_TOP);

        PendingIntent pendingIntent = PendingIntent.getActivity(getApplicationContext(), 0,intent, 0);

        mNfcAdapter.enableForegroundDispatch(this, pendingIntent, null, null );
    }

    @Override
    protected void onPause() {

        super.onPause();

        mNfcAdapter.disableForegroundDispatch(this); //ディスパッチを無効化する
    }

    @Override
    protected void onNewIntent(Intent intent){
        super.onNewIntent(intent);

        byte[] uid = intent.getByteArrayExtra(NfcAdapter.EXTRA_ID); // NFCのUID

        Toast.makeText(this, Arrays.toString(uid), Toast.LENGTH_SHORT).show(); // 表示

        StringBuilder tagId = new StringBuilder("ID(" + uid.length + "bytes):");

        for (int i=0; i<uid.length; i++){
             tagId.append(String.format("%02x",uid[i] & 0xff));
        }

        Toast.makeText(this, tagId, Toast.LENGTH_SHORT).show();  // 表示 その2

        TextView tv = (TextView)findViewById(R.id.test001);

        tv.setText(tagId);
    }

    public void clearId(View view) {
        TextView tv = (TextView) findViewById(R.id.test001);
        tv.setText("");
    }
}

Why not register and get more from Qiita?
  1. We will deliver articles that match you
    By following users and tags, you can catch up information on technical fields that you are interested in as a whole
  2. you can read useful information later efficiently
    By "stocking" the articles you like, you can search right away
Comments
No comments
Sign up for free and join this conversation.
If you already have a Qiita account
Why do not you register as a user and use Qiita more conveniently?
You need to log in to use this function. Qiita can be used more conveniently after logging in.
You seem to be reading articles frequently this month. Qiita can be used more conveniently after logging in.
  1. We will deliver articles that match you
    By following users and tags, you can catch up information on technical fields that you are interested in as a whole
  2. you can read useful information later efficiently
    By "stocking" the articles you like, you can search right away
ユーザーは見つかりませんでした