android - 根据两个或多个 EditText 字段中的输入启用/禁用按钮的优雅方式

Question

我看过这个问题 How to disable Button if EditText is empty ?

但那里只有 1 个 EditText 字段。如果两个 EditText 字段都为空或包含文本，使用 TextWatcher 启用或禁用 Button 的优雅解决方案是什么？

这是我的方法并且有效，但它没有使用 onTextChanged 中传递的任何参数。你怎么看？

public class MainActivity extends AppCompatActivity implements TextWatcher {
private EditText editTextUsername;
private EditText editTextPassword;
private Button buttonConfirm;

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

    editTextUsername = findViewById(R.id.edit_text);
    editTextPassword = findViewById(R.id.edit_password);
    buttonConfirm = findViewById(R.id.button_confirm);


    editTextUsername.addTextChangedListener(this);
    editTextPassword.addTextChangedListener(this);
}

@Override
public void beforeTextChanged(CharSequence s, int start, int count, int after) {

}

@Override
public void onTextChanged(CharSequence s, int start, int before, int count) {
    String usernameInput = editTextUsername.getText().toString().trim();
    String passwordInput = editTextPassword.getText().toString().trim();

    buttonConfirm.setEnabled(!usernameInput.isEmpty() && !passwordInput.isEmpty());
}

@Override
public void afterTextChanged(Editable s) {

}
}

Answer 1

您可以将 listeners 设置为 EditText

editTextUsername.addTextChangedListener(new TextWatcher() {
            @Override
            public void beforeTextChanged(CharSequence s, int start, int count, int after) {

           }

            @Override
            public void onTextChanged(CharSequence s, int start, int before, int count) {
              button.setEnabled(editTextUsername.getText().toString().trim().length() > 0 
                  && editTextPassword .getText().toString().trim().length() > 0 ); 
            }

            @Override
            public void afterTextChanged(Editable s) {

             }
        });

    editTextPassword.addTextChangedListener(new TextWatcher() {
            @Override
            public void beforeTextChanged(CharSequence s, int start, int count, int after) {

           }

            @Override
            public void onTextChanged(CharSequence s, int start, int before, int count) {
              button.setEnabled(editTextUsername.getText().toString().trim().length() > 0 
                  && editTextPassword .getText().toString().trim().length() > 0 ); 
            }

            @Override
            public void afterTextChanged(Editable s) {

             }
        });