我正在尝试通过NFC读取一些信息,并创建了这样做的intent-filter,以及包含所需技术的xml。意图过滤器应该启动我的ReadActivity,但当我将卡放在手机附近时它不会这样做。 NFC被激活,所以这应该不是问题。我真的没有看到我的代码有问题,所以如果有人可以看看它并且可能给我一个正确方向的暗示会很棒。这是代码:
的AndroidManifest.xml:
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.johan.nfcreaderforunicard">
<uses-permission android:name="android.permission.NFC" />
<uses-feature android:name="android.hardware.nfc" android:required="true"/>
<uses-sdk android:minSdkVersion="10"/>
<application
android:allowBackup="true"
android:icon="@mipmap/apple"
android:label="@string/app_name"
android:supportsRtl="true"
android:theme="@style/Theme.AppCompat.Light.NoActionBar">
<activity android:name=".MainActivity">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity android:name=".ReadActivity">
<intent-filter>
<action android:name="android.nfc.action.TECH_DISCOVERED"/>
<category android:name="android.intent.category.DEFAULT" />
</intent-filter>
<meta-data android:name="android.nfc.action.TECH_DISCOVERED"
android:resource="@xml/tech"/>
</activity>
</manifest>
ReadActivity:
import android.nfc.NfcAdapter;
import android.nfc.Tag;
import android.nfc.tech.IsoDep;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.widget.TextView;
import android.content.Intent;
import android.os.Bundle;
import java.io.IOException;
public class ReadActivity extends AppCompatActivity {
private final byte[] selectAid = {(byte)90, (byte)95, (byte)-124, (byte)21};
private final byte[] creditPayload = {(byte)108, (byte)1};
private byte[] resultOk;
private byte[] creditBytes;
@Override
public void onCreate(Bundle savedInstanceState){
super.onCreate(savedInstanceState);
setContentView(R.layout.read_view);
Toolbar myToolbar = (Toolbar) findViewById(R.id.my_toolbar);
setSupportActionBar(myToolbar);
if(NfcAdapter.ACTION_TECH_DISCOVERED.equals(getIntent().getAction())){
IsoDep isodep = IsoDep.get((Tag)getIntent().getParcelableExtra(NfcAdapter.EXTRA_TAG));
if(isodep != null){
try{
isodep.connect();
resultOk = isodep.transceive(selectAid);
if(resultOk[0] == 0){
creditBytes = isodep.transceive(creditPayload);
}
}catch (IOException e){
}
}
}
float credit = (float)formatCredit(creditBytes);
TextView label = (TextView)findViewById(R.id.read_text);
label.setText("Dein Guthaben: "+String.valueOf(credit)+"€");
}
private double formatCredit(byte[] array) {
double credit = (double)(((0xff & array[4]) << 24) + ((0xff & array[3]) << 16) + ((0xff & array[2]) << 8) + (0xff & array[1])) / 1000D;
return credit;
}
@Override
public boolean onCreateOptionsMenu(Menu menu){
MenuInflater inflater = getMenuInflater();
inflater.inflate(R.menu.menu, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem menuItem){
switch(menuItem.getItemId()){
case(R.id.action_settings):
Intent startSettings = new Intent(ReadActivity.this, SettingsActivity.class);
startActivity(startSettings);
return true;
case(R.id.about):
Intent startAbout = new Intent(ReadActivity.this, AboutActivity.class);
startActivity(startAbout);
return true;
default:
return super.onOptionsItemSelected(menuItem);
}
}
@Override
public void onBackPressed(){
Intent backToMain = new Intent(getApplicationContext(), MainActivity.class);
startActivity(backToMain);
finish();
}
}
MainActivity:
import android.content.Intent;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.support.v7.widget.Toolbar;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.MenuItem;
public class MainActivity extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Toolbar myToolbar = (Toolbar) findViewById(R.id.my_toolbar);
setSupportActionBar(myToolbar);
}
@Override
public boolean onCreateOptionsMenu(Menu menu){
MenuInflater inflater = getMenuInflater();
inflater.inflate(R.menu.menu, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem menuItem){
switch(menuItem.getItemId()){
case(R.id.action_settings):
Intent startSettings = new Intent(MainActivity.this, SettingsActivity.class);
startActivity(startSettings);
return true;
case(R.id.about):
Intent startAbout = new Intent(MainActivity.this, AboutActivity.class);
startActivity(startAbout);
return true;
default:
return super.onOptionsItemSelected(menuItem);
}
}
@Override
public void onBackPressed(){
finish();
}
}
AboutActivity和SettingsActivity还没有任何内容,所以我没有在这篇文章中包含它们。我真的不知道问题出在哪里。
答案 0 :(得分:0)
重新启动手机和NFC设置解决了这个问题。