Java 跨文件发送数据

我现在正在创建一个应用程序，我有点困惑。我有两个文件，MainActivity和QRCodeGenerator。我这样做是为了一个数据采集应用程序。用户将数据输入MainActivity，并与QrCodeGenerator共享数据，然后QrCodeGenerator创建qr代码。问题是二维码一直为空。任何帮助都将不胜感激。MainACtivity是第一个（我已经包括了与问题相关的snipet，而不是我的全部代码）

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我想你想把数据从一个屏幕发送到另一个屏幕

查看意图，您可以使用它们来启动其他活动（转到其他屏幕），还可以在屏幕之间传递数据，如链接所示

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在您的情况下，您只需将字符串附加项或字符串集合作为一个附加项添加到意图中

我不太确定。我需要传递字符串数据的意图吗？我之所以这么问，是因为它引用了QrCodeGenerator文件中的字符串数据。“跨文件发送数据”毫无意义。请澄清，好的。现在我已经有了。我有一个改变观点的意图。它起作用了。问题是二维码生成器不会生成二维码，因为没有数据。现在我正试图解决这个问题。intent可以解决这个问题吗？是的，您将数据作为额外数据放在那里，然后使用getIntent（）在其他活动中接收数据。查看链接，您可以在那里找到示例

 public static String finalOutput;

 public void output (View view) {
        EditText editSN = findViewById(R.id.editSN);
        EditText editTN = findViewById(R.id.editTN);
        RadioGroup alliance = findViewById(R.id.alliance);
        RadioButton allianceI = findViewById(alliance.getCheckedRadioButtonId());
        RadioGroup driverStation = findViewById(R.id.driverStation);
        RadioButton driverStationI = findViewById(driverStation.getCheckedRadioButtonId());
        EditText matchNumber = findViewById(R.id.editMatchNumber);
        RadioGroup driverOff = findViewById(R.id.crossLine);
        RadioButton driveOffI = findViewById(driverOff.getCheckedRadioButtonId());
        EditText autoPowerPortBottom = findViewById(R.id.editAutoPowerPortBottom);
        EditText autoPowerPortOuter = findViewById(R.id.editAutoPowerPortOuter);
        EditText autoPowerPortInner = findViewById(R.id.editAutoPowerPortInner);
        EditText autoDroppedPowerCells = findViewById(R.id.editAutoDroppedPowerCells);
        RadioGroup autoConflict = findViewById(R.id.autoConflict);
        RadioButton autoConflictS = findViewById(autoConflict.getCheckedRadioButtonId());
        EditText PowerPortBottom = findViewById(R.id.editPowerPortBottom);
        EditText PowerPortOuter = findViewById(R.id.editPowerPortOuter);
        EditText PowerPortInner = findViewById(R.id.editPowerPortInner);
        EditText droppedPowerCells = findViewById(R.id.editDroppedPowerCells);
        CheckBox boxTrench = findViewById(R.id.boxTrench);
        CheckBox boxCenter = findViewById(R.id.boxCenter);
        CheckBox boxOnTheirSide = findViewById(R.id.boxOnTheirSide);
        RadioGroup climb = findViewById(R.id.climb);
        RadioButton climbS = findViewById(climb.getCheckedRadioButtonId());
        RadioGroup multiClimb = findViewById(R.id.multiClimb);
        RadioButton multiClimbS = findViewById(multiClimb.getCheckedRadioButtonId());
        RadioGroup driverSkill = findViewById(R.id.driverSkill);
        RadioButton driverSkillI = findViewById(driverSkill.getCheckedRadioButtonId());
        RadioGroup focusOnDefense = findViewById(R.id.groupFocusOnDefense);
        RadioButton focusOnDefenseI = findViewById(focusOnDefense.getCheckedRadioButtonId());
        EditText beached = findViewById(R.id.editBeached);
        EditText disabled = findViewById(R.id.editDisabled);
        EditText died = findViewById(R.id.editDied);
        EditText fouls = findViewById(R.id.editFouls);
        EditText techFouls = findViewById(R.id.editTechFoul);
        EditText notes = findViewById(R.id.editNotes);

        Button submit = findViewById(R.id.submit);


        String[] output = new String[]{
                editSN.getText().toString(),
                editTN.getText().toString(),
                allianceI.getText().toString(),
                driverStationI.getText().toString(),
                matchNumber.getText().toString(),
                driveOffI.toString(),
                autoPowerPortBottom.getText().toString(),
                autoPowerPortOuter.getText().toString(),
                autoPowerPortInner.getText().toString(),
                autoDroppedPowerCells.getText().toString(),
                autoConflictS.getText().toString(),
                PowerPortBottom.getText().toString(),
                PowerPortOuter.getText().toString(),
                PowerPortInner.getText().toString(),
                droppedPowerCells.getText().toString(),
                climbS.getText().toString(),
                multiClimbS.toString(),
                disabled.getText().toString(),
                died.getText().toString(),
                fouls.getText().toString(),
                techFouls.getText().toString(),
                notes.getText().toString()
        };

        for (int i = 0; i < output.length; i++) {
            finalOutput = finalOutput.concat(output[i].toString());
        }
    }

private String test;

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

    barcode=findViewById(R.id.barCode);
    textView=findViewById(R.id.dataText);
    test=MainActivity.finalOutput;


    String data_in_code=test;
    MultiFormatWriter multiFormatWriter=new MultiFormatWriter();
    try{
        BitMatrix bitMatrix=multiFormatWriter.encode(data_in_code, BarcodeFormat.QR_CODE,200,200);
        BarcodeEncoder barcodeEncoder=new BarcodeEncoder();
        Bitmap bitmap=barcodeEncoder.createBitmap(bitMatrix);
        barcode.setImageBitmap(bitmap);