Question

我正在尝试在完成对NFC标签的写入操作后启动新的activity。我尝试使用处理程序，但它不起作用，标记成功写入但处理程序没有启动它应该在写入操作后启动的activity

private void formatTag(Tag tag, NdefMessage ndefMessage)
    {
        NdefFormatable ndefFormatable = NdefFormatable.get(tag);

        if (ndefFormatable == null)
        {
            Toast.makeText(this, "Tag is not NDEF formatable", Toast.LENGTH_LONG).show();
            return;
        }

        try
        {
            ndefFormatable.connect();
            ndefFormatable.format(ndefMessage);
            ndefFormatable.close();
            Toast.makeText(this, "Tag has be written successfully!", Toast.LENGTH_LONG).show();
            writeHandler.sendEmptyMessage(0);

        }
        catch (Exception e)
        {
            Log.e("formatTag: ", e.getMessage());
        }


    }

    private Handler writeHandler = new Handler() {
        public void handleMessage(Message msg) {
            Intent nextActivity = new Intent(WriteCardActivity.this, MainActivity.class);
            startActivityForResult(nextActivity, 0);
            WriteCardActivity.this.finish();
        }
    };

这是清单

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.loyalty.cardplanet.membershipcard" >

    <uses-permission android:name="android.permission.NFC" />
    <uses-permission android:name="android.permission.INTERNET"/>

    <uses-feature
        android:name="android.hardware.nfc"
        android:required="false" />

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

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
        <activity
            android:name=".RegisterActivity"
            android:label="@string/title_activity_register" >
        </activity>
        <activity
            android:name=".RedeemActivity"
            android:label="@string/title_activity_redeem" >
        </activity>
        <activity
            android:name=".PurchaseActivity"
            android:label="@string/title_activity_purchase" >
        </activity>
        <activity
            android:name=".ResetPinActivity"
            android:label="@string/title_activity_reset_pin" >
        </activity>
        <activity
            android:name=".WriteCardActivity"
            android:label="@string/title_activity_write_card" >
        </activity>
    </application>

</manifest>

Answer 1

<<$number.format("currency", $My_data)>>上有IntentFilter，因此MainActivity应与活动的IntentFilter匹配。

所以你应该开始这样的活动：

Intent

Answer 2

我明白了。我决定使用AlertDialog代替Handler，因此我删除了Handler部分并将其添加到onNewIntent

@Override
    protected void onNewIntent(Intent intent) {


        Tag tag = intent.getParcelableExtra(NfcAdapter.EXTRA_TAG);

        NdefMessage ndefMessage = createNdefMessage(account+"");

        writeNdefMessage(tag, ndefMessage);

        AlertDialog.Builder alertDialog = new AlertDialog.Builder(WriteCardActivity.this);
        alertDialog.setMessage("Card Written Successfully!");

        alertDialog.setPositiveButton("Ok", new DialogInterface.OnClickListener() {
            public void onClick(DialogInterface dialog, int id) {
                Intent intent = new Intent(WriteCardActivity.this, MainActivity.class);
                Bundle b = new Bundle();
                b.putBoolean("new_window", true); //sets new window
                intent.putExtras(b);
                startActivity(intent);
            }
        });


        alertDialog.create();
        alertDialog.show();

        super.onNewIntent(intent);
    }

Answer 3

这段代码对我有用。并且不要在MainActivity的onCreate，onResume或onPause上调用WriteCardActivity。否则WriteCardActivity将重新开始。

private void formatTag(Tag tag, NdefMessage ndefMessage)
{
    NdefFormatable ndefFormatable = NdefFormatable.get(tag);

    if (ndefFormatable == null)
    {
        Toast.makeText(this, "Tag is not NDEF formatable", Toast.LENGTH_LONG).show();
        return;
    }

    try
    {
        ndefFormatable.connect();
        ndefFormatable.format(ndefMessage);
        ndefFormatable.close();
        Toast.makeText(this, "Tag has be written successfully!", Toast.LENGTH_LONG).show();

        Intent nextActivity = new Intent(WriteCardActivity.this, MainActivity.class);
        startActivityForResult(nextActivity, 0);
        WriteCardActivity.this.finish();

    }
    catch (Exception e)
    {
        Log.e("formatTag: ", e.getMessage());
    }


}

写入NFC标签后开始新的活动

3 个答案: