Question

我创建了两个活动。 Activity Main有按钮，点击这个按钮我调用另一个类的方法，扩展到AppCompActivity。方法名称为mailconfig，如下所示。机密信息已从参数中删除。

public class ButtonActionFrontPage extends AppCompatActivity{


  protected void onCreate(Bundle bundle) {
        super.onCreate(bundle);
    }

    public void mailconfig(String message) throws EmailException {

        String username = "";
        String password = "";
        String from = "";
        String replyto = "";

        String mailto = "";
        String subject = "";

        Email email = new SimpleEmail();
        email.setSSLOnConnect(true);
        email.isStartTLSEnabled();
        email.setHostName("");
        email.setSmtpPort(26);
        email.setSubject(subject);
        email.addReplyTo(replyto);
        email.setFrom(from);
        email.setAuthenticator(new DefaultAuthenticator(username, password));
        email.setMsg(message);
        email.addTo(mailto);
        email.send();

       Toast.makeText(ButtonActionFrontPage.this,"Thanks for submitting ",Toast.LENGTH_SHORT).show();
        System.out.println("Sent");

    }
}

我使用下面的代码来调用上面的方法。

feedbackbtn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                try {
                    ButtonActionFrontPage buttonActionFrontPage = new ButtonActionFrontPage();
                  String  message = quickfbet.getText().toString();
                    buttonActionFrontPage.mailconfig(message);
                } catch (EmailException e) {
                    e.printStackTrace();
                }


            }
        });

此代码有什么问题，为什么不执行。

Answer 1

类就像这样

public class ButtonActionFrontPage {


    public void mailconfig(Context context,String message) throws EmailException {

        String username = "";
        String password = "";
        String from = "";
        String replyto = "";

        String mailto = "";
        String subject = "";

        Email email = new SimpleEmail();
        email.setSSLOnConnect(true);
        email.isStartTLSEnabled();
        email.setHostName("");
        email.setSmtpPort(26);
        email.setSubject(subject);
        email.addReplyTo(replyto);
        email.setFrom(from);
        email.setAuthenticator(new DefaultAuthenticator(username, password));
        email.setMsg(message);
        email.addTo(mailto);
        email.send();

       Toast.makeText(context,"Thanks for submitting ",Toast.LENGTH_SHORT).show();
        System.out.println("Sent");

    }
}

并且像这样调用函数

feedbackbtn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                try {
                    ButtonActionFrontPage buttonActionFrontPage = new ButtonActionFrontPage();
                  String  message = quickfbet.getText().toString();
                    buttonActionFrontPage.mailconfig(getApplicationContext(),message);
                } catch (EmailException e) {
                    e.printStackTrace();
                }


            }
        });

Answer 2

public class ButtonActionFrontPage extends AppCompatActivity{

static ButtonActionFrontPage instance;


  protected void onCreate(Bundle bundle) {
        super.onCreate(bundle);
        instance = this;
    }

  public static ButtonActionFrontPage getInstance() {
        return instance;
    }

@Override
    protected void onDestroy() {
        super.onDestroy();
        instance = null;
    }
}

并调用函数：

feedbackbtn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                try {
                    ButtonActionFrontPage buttonActionFrontPage =  ButtonActionFrontPage.getInstance();                     String  message = quickfbet.getText().toString();
                    buttonActionFrontPage.mailconfig(message);
                } catch (EmailException e) {
                    e.printStackTrace();
                }
            }
        });

Answer 3

Java类与Android Activity不同。由于Android Activity有一个名为life cycle的东西。

如果必须实施某些功能，您甚至不能创建活动。只是一个普通的Java类就足够了。

当存在用户交互时，可以使用活动（事实上并非总是如此，但纯粹取决于业务逻辑）。为了启动活动，使用Intent。这将通过内存分配和其他相关功能启动活动。

对于您的情况，按钮的启动应该在ButtonActionFrontPage的onCreate中完成，并通过点击监听器完成，如下所示

Button feedbackbtn;
protected void onCreate(Bundle bundle) {
        super.onCreate(bundle);
        feedbackbtn=(Button)findViewById(R.id.button_ID);
        feedbackbtn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                 new PlainJavaClass().mailconfig("msg",ButtonActionFrontPage.class);
                }
        });
    }

对于业务逻辑，只需使用PlainJavaClass方法和context，如果您必须显示任何Toast / Dialog / ProgressBar

class PlainJavaClass{

      public void mailconfig(String message, Context context)  {

        Log.v("TAG","mailconfig with message="+message);
        //Your logic
        Toast.makeText(context,"Thanks for submitting ",Toast.LENGTH_SHORT).show();
    }

}

按钮单击时不从mainactivity调用方法

3 个答案: