使用Android中的可序列化将对象从第二个活动传递回主活动

Question

下面的第一段代码是我的主要活动，在其中创建了第二个活动的意图。 在此活动中，我将在列表视图中显示费用，但由于未完全实现，因此我暂时将其忽略了。 我简单想做的是启动第二个活动，然后让用户输入详细信息，然后按一个按钮以将该活动添加到列表视图中。 @Override public boolean onOptionsItemSelected（MenuItem item）{int id = item.getItemId（）;

        if (id == R.id.addExpense) {
            Intent intent = new Intent(this, ExpenseActivity.class);
            startActivityForResult(intent, 1);
            return true;
        }
        return super.onOptionsItemSelected(item);
    }

    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
    super.onActivityResult(requestCode, resultCode, data);
    // check that it is the SecondActivity with an OK result
    if (requestCode == 1) {
        if (resultCode == RESULT_OK) {
            Expense expense = (Expense) data.getSerializableExtra("sampleObject");
            Expenses.add(expense);
        }
    }
}


 final Button btnAddExpense = (Button) findViewById(R.id.btnAddExpense);
    btnAddExpense.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
           String amountV = txtAmountVat.getText().toString();
           int amountVTwo = Integer.parseInt(amountV);
           String amountI = txtAmount.getText().toString();
           int amountITwo = Integer.parseInt(amountI);

            Expense expense = new Expense(amountITwo, amountVTwo, txtDateOfExpense.getText().toString(), txtDateAdded.getText().toString(), datePaid, paid, txtDes.getText().toString(), imageUri );

            Intent intent = new Intent();
            intent.putExtra("Expense", expense);
            setResult(MainActivity.RESULT_OK, intent);
            finish();
        }
        });

这是我的第二项活动，用户在其中输入数据。 当我尝试传递费用对象时，仿真器指出应用已停止工作。 由于我不知道是什么原因引起的，请给我一些帮助。 这是我班的样子。

public class Expense implements Serializable {

private int _amount, _amountVat;
private String _dateOfExpense, _dateAdded, _datePaid, _expenseDescription;
private Boolean _paid;
private Uri _imageUri;

public Expense(int amount, int amountVat, String dateOfExpense, String dateAdded, String datePaid, Boolean paid, String expenseDescription, Uri imageUri){

    _amount = amount;
    _amountVat = amountVat;
    _dateOfExpense = dateOfExpense;
    _dateAdded = dateAdded;
    _datePaid = datePaid;
    _paid = paid;
    _expenseDescription = expenseDescription;
    _imageUri = imageUri;
}

public int get_amount() {
    return _amount;
}

public void set_amount(int _amount) {
    this._amount = _amount;
}

public int get_amountVat() {
    return _amountVat;
}

public void set_amountVat(int _amountVat) {
    this._amountVat = _amountVat;
}

public String get_dateOfExpense() {
    return _dateOfExpense;
}

public void set_dateOfExpense(String _dateOfExpense) {
    this._dateOfExpense = _dateOfExpense;
}

public String get_dateAdded() {
    return _dateAdded;
}

public void set_dateAdded(String _dateAdded) {
    this._dateAdded = _dateAdded;
}

public String get_datePaid() {
    return _datePaid;
}

public void set_datePaid(String _datePaid) {
    this._datePaid = _datePaid;
}

public Boolean get_paid() {
    return _paid;
}

public void set_paid(Boolean _paid) {
    this._paid = _paid;
}

public Uri get_imageUri() {
    return _imageUri;
}

public void set_imageUri(Uri _imageUri) {
    this._imageUri = _imageUri;
}

public String get_expenseDescription() {return _expenseDescription;}

public void set_expenseDescription(String _expenseDescription) {this._expenseDescription = _expenseDescription;}

}

Answer 1

如果没有适当的日志详细信息，就无法说出很多有关您的问题的信息。 但是您可以通过这些步骤。 Serializable方法的问题在于使用了反射，这是一个缓慢的过程。 这种方法会创建许多临时对象，并导致大量垃圾回收。 因此，可能是由于此。 尝试在真实设备上运行并查看其是否仍然存在。 另外，您可以将Parcelable实现到您的类，这比Serializable更快。