如何在不违反DRY原则的情况下从多个活动中开始一项活动？

Question

我正在开发一个Android应用程序，其中某些活动可能是从多个活动开始的，我知道如何使用Intent在活动之间进行切换。我只是在不违反DRY（请勿重做）原则的情况下努力编写代码。

下面显示了该代码，其中重复了从两个不同的活动启动同一活动的代码：

MainActivity.java启动SignInActivity.java

public class MainActivity extends AppCompatActivity {

private Button mSignUpButton;

private Button mSignInButton;

@Override

protected void onCreate(Bundle savedInstanceState) {

    setTheme(R.style.AppTheme_MainActivity);

    super.onCreate(savedInstanceState);

    setContentView(R.layout.activity_main);

    mSignUpButton = findViewById(R.id.sign_up_button);

    mSignInButton = findViewById(R.id.sign_in_button);

    mSignUpButton.setOnClickListener(new View.OnClickListener() {

        @Override

        public void onClick(View v) {

            startSignUp();

        }

    });

    mSignInButton.setOnClickListener(new View.OnClickListener() {

        @Override

        public void onClick(View v) {

            startSignIn();

        }

    });

}

private void startSignUp() {

    Intent signUpIntent = new Intent(this, SignUpActivity.class);

    startActivity(signUpIntent);

}

private void startSignIn() {

    Intent signInIntent = new Intent(this, SignInActivity.class);

    startActivity(signInIntent);

    }    

}

SignUpActivity.java启动SignInActivity.java

public class SignUpActivity extends AppCompatActivity {

private Button mSignInButton;

@Override

protected void onCreate(Bundle savedInstanceState) {

    super.onCreate(savedInstanceState);

    setContentView(R.layout.activity_sign_up);

    mSignInButton = findViewById(R.id.sign_in_button);

    mSignInButton.setOnClickListener(new View.OnClickListener() {

        @Override

        public void onClick(View v) {

            startSignIn();

        }

    });

}

private void startSignIn() {

    Intent signInIntent = new Intent(this, SignInActivity.class);

    startActivity(signInIntent);

    }

}

Answer 1

我对DRY原理没有任何了解，但是在阅读此答案时，我得到了DRY原理背后的想法，而在考虑您的问题解决方案时，我得到了创建util类的想法，该类具有在所需活动之间进行导航的方法：public class NavigationUtils{public static void navigate(Context source, Class<?> destination){&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; Intent intent = new Intent(source, destination);&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; source.startActivity(intent);&nbsp; &nbsp; &nbsp; &nbsp; }}希望这个答案对您有帮助。

Answer 2

首先-不要崇拜DRY。它是一个经验法则，并非最终都是好的编程。其次，通常我要做的是class SignInIntent extends Activity {&nbsp; &nbsp; public static Intent createIntent(Context context, parameters) {&nbsp; &nbsp; &nbsp; &nbsp; Intent intent = new Intent(context, SignInIntent.class);&nbsp; &nbsp; &nbsp; &nbsp; //Pass parameters here&nbsp; &nbsp; &nbsp; &nbsp; return intent;&nbsp; &nbsp; }}class SomeOtherActivity extends Activity {&nbsp; &nbsp; public void someFunc() {&nbsp; &nbsp; &nbsp; &nbsp; startActivity(SignInIntent.createIntent(this, params);&nbsp; &nbsp; }}通常，我希望它返回一个意图，而不是只是出于某些原因而等待他们开始活动。这样，您还可以在SignInActivity中保留所有需要的参数及其名称的所有知识。

Answer 3

好的考虑因素之一是使其具有BaseActivity通用功能。public class BaseActivity extends AppCompatActivity {&nbsp;public void startActivity(Class<?> mClass, Bundle extras){&nbsp; &nbsp; Intent intent = new Intent(this, mClass);&nbsp; &nbsp; intent.putExtras(extras);&nbsp; &nbsp; startActivity(intent);}public void startActivity(Class<?> mClass){&nbsp; &nbsp; Intent intent = new Intent(this, mClass);&nbsp; &nbsp; startActivity(intent);}}public class SignUpActivity extends BaseActivity {&nbsp; @Override&nbsp; protected void onCreate(Bundle savedInstanceState) {&nbsp; &nbsp; super.onCreate(savedInstanceState);&nbsp; &nbsp; setContentView(R.layout.activity_sign_up);&nbsp; &nbsp; mSignInButton = findViewById(R.id.sign_in_button);&nbsp; &nbsp; mSignInButton.setOnClickListener(new View.OnClickListener() {&nbsp; &nbsp; &nbsp; &nbsp; @Override&nbsp; &nbsp; &nbsp; &nbsp; public void onClick(View v) {&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; startActivity(SignInActivity.class);&nbsp; &nbsp; &nbsp; &nbsp; }&nbsp; &nbsp; });&nbsp; }}