【发布时间】：2016-06-14 15:00:44
【问题描述】：
我有一个扫描 qrcodes 和 nfc 标签的应用程序。当我扫描二维码时，我创建了一个意图，将一些字符串作为附加内容（二维码的内容）放入，将setAction 设置为com.carefreegroup.QRCODE_ACTION，这是一个自定义操作，然后调用startActivity(intent)。
在接收活动中，intent.getAction() 返回 null。我已经为清单中的接收活动设置了一个意图过滤器，其操作与调用活动相同。
为什么 getAction 为空？
public static final String CUSTOM_QRCODE_ACTION = "com.carefreegroup.QRCODE_ACTION";
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.qrloggedinmain);
nfcscannerapplication = (NfcScannerApplication) getApplication();
////////////////////////get company options///////////////////////////////
SharedPreferences appSharedPrefs = PreferenceManager.getDefaultSharedPreferences(this.getApplicationContext());
tagTouchInterval = appSharedPrefs.getString("10", null);
Long tagtouchinteval = new Long(tagTouchInterval);
companyOptionTime = 1000* 60 * tagtouchinteval ;
Button ScanQrCode = (Button)findViewById(R.id.buttonqrscanner);
ScanQrCode.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
Log.e(TAG, "onclicked scan");
Intent intent = new Intent(
"com.google.zxing.client.android.SCAN");
intent.putExtra("SCAN_MODE", "QR_CODE_MODE");
startActivityForResult(intent, 0);
}
});
}// end of onCreate
public void onActivityResult(int requestCode, int resultCode, Intent intent) {
Log.e(TAG, "in onActivityResult");
if (requestCode == 0) {
if (resultCode == RESULT_OK) {
Log.e(TAG, "result ok");
///////////////////////////////
tagScanTime = new DateTime();
thirtySecsAgo = tagScanTime.minus(30000);
DateTimeFormatter df = DateTimeFormat.forPattern("dd/MMM/yy h:mmaa");
String formattedScanTime = df.print(tagScanTime);
Log.e(TAG, "formatted tag scan time = " + formattedScanTime);
String formattedthirtysecsAgoTime = df.print(thirtySecsAgo);
Log.e(TAG, "formatted thity secs ago time = " + formattedthirtysecsAgoTime);
String contents = intent.getStringExtra("SCAN_RESULT");
Toast.makeText(this, "scanner has found " + contents,
Toast.LENGTH_LONG).show();
String[] splitPayload = contents.split("@");
type = splitPayload[0];
compId = splitPayload[1];
personId = splitPayload[2];
personName = splitPayload[3];
Intent QRDataIntent = new Intent(this,
NfcscannerActivity.class);
intent.putExtra("type", type);
intent.putExtra("compId", compId);
intent.putExtra("personId", personId);
intent.putExtra("personName", personName);
intent.setAction(CUSTOM_QRCODE_ACTION);
intent.setType("text/plain");
startActivity(QRDataIntent);
.
String intentAction = intent.getAction();
if ( intentAction.equalsIgnoreCase(QRCODE_ACTION)) {
Log.e(TAG, "QR Code scanned");
String _type = intent.getStringExtra("type");
String _compId = intent.getStringExtra("compId");
String _personId = intent.getStringExtra("personId");
String _personName = intent.getStringExtra("personName");
Log.e(TAG, "payload = " + _type + " " + _compId + " " + _personId + " " + _personName);
.
<activity android:name=".NfcscannerActivity" >
<intent-filter>
<action android:name="android.nfc.action.NDEF_DISCOVERED" />
<category android:name="android.intent.category.DEFAULT" />
<data android:mimeType="text/plain" />
</intent-filter>
<intent-filter>
<action android:name="com.carefreegroup.QRCODE_ACTION" />
<category android:name="android.intent.category.DEFAULT" />
<data android:mimeType="text/plain" />
</intent-filter>
</activity>
[更新1] 这是使用ZXing库扫描二维码的整个活动。然后它将 Intent 中捕获的数据设置为额外数据，然后使用 startActivity() 显式调用下一个活动。
package com.carefreegroup;
import org.joda.time.DateTime;
import org.joda.time.format.DateTimeFormat;
import org.joda.time.format.DateTimeFormatter;
import android.app.Activity;
import android.app.AlertDialog;
import android.content.ContentValues;
import android.content.DialogInterface;
import android.content.Intent;
import android.content.SharedPreferences;
import android.database.Cursor;
import android.os.Bundle;
import android.preference.PreferenceManager;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;
public class QrLoggedIn extends Activity{
private static final String TAG = QrLoggedIn.class.getSimpleName();
private NfcScannerApplication nfcscannerapplication;
private String tagTouchInterval;
private long companyOptionTime;
private DateTime tagScanTime;
private DateTime thirtySecsAgo;
private Boolean carerLoggedIn;
private String type;
private String personId;
private String personName;
private String compId;
private Cursor cursor;
static final String CARER_TYPE = "2";
static final String CLIENT_TYPE = "1";
private final String IN = "in";
private final String OUT = "out";
private ContentValues values;
public static final String CUSTOM_QRCODE_ACTION = "com.carefreegroup.QRCODE_ACTION";
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.qrloggedinmain);
nfcscannerapplication = (NfcScannerApplication) getApplication();
////////////////////////get company options///////////////////////////////
SharedPreferences appSharedPrefs = PreferenceManager.getDefaultSharedPreferences(this.getApplicationContext());
tagTouchInterval = appSharedPrefs.getString("10", null);
Long tagtouchinteval = new Long(tagTouchInterval);
companyOptionTime = 1000* 60 * tagtouchinteval ;
Button ScanQrCode = (Button)findViewById(R.id.buttonqrscanner);
ScanQrCode.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
Log.e(TAG, "onclicked scan");
Intent intent = new Intent(
"com.google.zxing.client.android.SCAN");
intent.putExtra("SCAN_MODE", "QR_CODE_MODE");
startActivityForResult(intent, 0);
}
});
}// end of onCreate
public void onActivityResult(int requestCode, int resultCode, Intent intent) {
Log.e(TAG, "in onActivityResult");
if (requestCode == 0) {
if (resultCode == RESULT_OK) {
Log.e(TAG, "result ok");
///////////////////////////////
tagScanTime = new DateTime();
thirtySecsAgo = tagScanTime.minus(30000);
DateTimeFormatter df = DateTimeFormat.forPattern("dd/MMM/yy h:mmaa");
String formattedScanTime = df.print(tagScanTime);
Log.e(TAG, "formatted tag scan time = " + formattedScanTime);
String formattedthirtysecsAgoTime = df.print(thirtySecsAgo);
Log.e(TAG, "formatted thity secs ago time = " + formattedthirtysecsAgoTime);
String contents = intent.getStringExtra("SCAN_RESULT");
Toast.makeText(this, "scanner has found " + contents,
Toast.LENGTH_LONG).show();
String[] splitPayload = contents.split("@");
type = splitPayload[0];
compId = splitPayload[1];
personId = splitPayload[2];
personName = splitPayload[3];
Intent QRDataIntent = new Intent(this,
NfcscannerActivity.class);
intent.putExtra("type", type);
intent.putExtra("compId", compId);
intent.putExtra("personId", personId);
intent.putExtra("personName", personName);
intent.setAction(CUSTOM_QRCODE_ACTION);
intent.setType("text/plain");
startActivity(QRDataIntent);
} else if (resultCode == RESULT_CANCELED) {
// Handle cancel
Log.e(TAG, "There's a problem with the scan. Scan result failed");
Toast.makeText(this, "There's a problem with the scan. Scan result failed",
Toast.LENGTH_LONG).show();
}
}
}
}
.
这是来自接收活动的 sn-p。
String intentAction = intent.getAction();
Log.e(TAG, "action of intent = " + intentAction);
if( intentAction.equalsIgnoreCase(NFC_ACTION)){
Tag tag = intent.getParcelableExtra(NfcAdapter.EXTRA_TAG);
tagId = bytesToHexString(tag.getId());
if (NfcAdapter.ACTION_NDEF_DISCOVERED.equals(getIntent().getAction())) {
Log.e(TAG, "NFC Tag scanned");
// //////////////////////////////////////////////////////////////////////
// get the messages from the intent
Parcelable[] rawMsgs = intent
.getParcelableArrayExtra(NfcAdapter.EXTRA_NDEF_MESSAGES);
if (rawMsgs != null) {
msgs = new NdefMessage[rawMsgs.length];
for (int i = 0; i < rawMsgs.length; i++) {
msgs[i] = (NdefMessage) rawMsgs[i];
}
}
} else {
Log.e(TAG, "ndef not discovered!!!!!!");
}
// ////////////////////////////////////////////////////////////////////////////////////
// process the msgs array
for (int i = 0; i < msgs.length; i++) {
NdefRecord[] records = msgs[i].getRecords();
Log.e(TAG, "ndefrecord has a length of " + records.length);
tr = parse(records[i]);
payload = tr.getText();
Log.e(TAG, "TextRecord.text = " + tr.getText());
}
// /////////////////////////////////////////////////// split the payload
// using delimiter. assign value at position[0] to tagType
String[] splitPayload = payload.split("¦");
tagType = splitPayload[0];
tagCompany = splitPayload[1];
tagPerson = splitPayload[2];
tagUserName = splitPayload[3];
}else if ( intentAction.equalsIgnoreCase(QRCODE_ACTION)) {
Log.e(TAG, "QR Code scanned");
String _type = intent.getStringExtra("type");
String _compId = intent.getStringExtra("compId");
String _personId = intent.getStringExtra("personId");
String _personName = intent.getStringExtra("personName");
Log.e(TAG, "payload = " + _type + " " + _compId + " " + _personId + " " + _personName);
【问题讨论】：
-
这段代码在什么方法中：
String intentAction = intent.getAction(); if ( intentAction.equalsIgnoreCase(QRCODE_ACTION)) {？变量intent是如何设置的？ -
@DavidWasser 嗨，我已经更新了我的帖子以包含两个 sn-ps 代码，显示如何设置和接收意图。谢谢。
-
@DavidWasser 哦，是的，抱歉，intent.getAction() 在接收活动的 onCreate 方法中。
-
但是接收Activity的
onCreate()中的变量intent是怎么设置的呢？ -
@DavidWasser 我使用 Intent intent = this.getIntent();