前言

Model：负责数据逻辑

View：负责视图逻辑

Presenter：负责业务逻辑

持有关系：

1、View 持有 Presenter

2、Model 持有 Presenter

3、Presenter 持有 View

4、Presenter 持有 Model

辅助工具：ViewBinding

执行流程：View  ==> Presenter ==> Model ==> Presenter ==> View

案例效果图：

1、定义IPresenter接口

/**
 * 代理接口 负责业务逻辑
 */
public interface IPresenter extends IBasePresenter {

    void setView(IView view);  // 持有 View

    void setModel(IModel model);  // 持有 Model


    void onDataChanged(String data); // 时时修改Model的数据，由View通知 Presenter

    void onDataChangedUpdateText(String data); // 修改View的TextView数据，由Model通知 Presenter


    void submitFromData(); // 执行Model的 提交表单服务，由View通知 Presenter


    void showSubmitFromLoading(String data); // 执行View的显示loading方法，由Model通知 Presenter

    void hideSubmitFromLoading(); // 执行View的隐藏loading方法，由Model通知 Presenter


    void clearData(); // 执行Model的 清空数据方法，由View通知 Presenter

    void clearTextData(); // 执行View的清空TextView内容方法，由Model通知 Presenter

}

1.1、实现IPresenter接口

/**
 * 具体业务逻辑实现
 */
public class IPresenterImp implements IPresenter {

    private IView view;
    private IModel model;

    @Override
    public void setView(IView view) {
        this.view = view;
    }

    @Override
    public void removeHandlerMsgAndCallback() {
        model.removeHandlerMsgAndCallback();
    }

    @Override
    public void setModel(IModel model) {
        this.model = model;
    }

    @Override
    public void onDataChanged(String data) {
        model.onDataChanged(data);
    }

    @Override
    public void onDataChangedUpdateText(String data) {
        view.onDataChangedUpdateText(data);
    }

    @Override
    public void submitFromData() {
        model.submitFromData();
    }

    @Override
    public void showSubmitFromLoading(String data) {
        view.showSubmitFromLoading(data);
    }

    @Override
    public void hideSubmitFromLoading() {
        view.hideSubmitFromLoading();
    }

    @Override
    public void clearData() {
        model.clearData();
    }

    @Override
    public void clearTextData() {
        view.clearFromData();
    }

}

2、定义Model接口

/**
 * 数据模型接口 负责数据逻辑
 */
public interface IModel extends IBaseModel {

    default void setPresenter(IPresenter presenter) {}  // 持有 Presenter

    /**
     * 这些都是方法，都是由 Presenter 调用的
     */

    void onDataChanged(String data); // 监听文本变化，时时更新数据

    void submitFromData(); // 提交表单数据

    void clearData(); // 清空数据

}

2.1、实现Model接口

/**
 * 数据模型逻辑 具体实现
 */
public class IModelImp implements IModel {

    private String mData = "";
    private IPresenter presenter;
    private Handler handler = new Handler();

    @Override
    public void setPresenter(IPresenter presenter) {
        this.presenter = presenter;
    }

    @Override
    public void onDataChanged(String data) {
        mData = data;
        presenter.onDataChangedUpdateText(mData);
    }

    @Override
    public void removeHandlerMsgAndCallback() {
        handler.removeCallbacksAndMessages(null);
    }

    @Override
    public void submitFromData() {
        presenter.showSubmitFromLoading(mData);
        handler.removeCallbacksAndMessages(null);
        handler.postDelayed(new Runnable() {
            @Override
            public void run() {
                presenter.hideSubmitFromLoading();
            }
        }, 1500);
    }

    @Override
    public void clearData() {
        mData = "";
        presenter.clearTextData();
    }
}

3、定义View接口

/**
 * 视图接口 负责视图逻辑
 */
public interface IView extends IBaseView {

    default void setPresenter(IPresenter presenter) {} // 持有 Presenter

    /**
     * 这些都是方法，都是由 Presenter 调用的
     */

    void onDataChangedUpdateText(String data); // 根据时时数据更新TextView

    void showSubmitFromLoading(String data); // 显示提交表单loading

    void hideSubmitFromLoading(); // 隐藏提交表单loading

    void clearFromData(); // 清空EditText数据

}

3.1、实现View接口

/**
 * 视图逻辑 具体实现
 */
public class MVPActivity extends AppCompatActivity implements IView, View.OnClickListener {

    private ActivityMvpBinding binding;
    private IModel iModel;
    private IPresenter iPresenter;
    private AlertDialog dialog;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        binding = ActivityMvpBinding.inflate(getLayoutInflater());
        setContentView(binding.getRoot());

        iPresenter = new IPresenterImp();
        iModel = new IModelImp();

        // 注意一下，写的顺序

        iModel.setPresenter(iPresenter); // 持有 Presenter
        setPresenter(iPresenter); // 持有 Presenter

        iPresenter.setModel(iModel); // 持有 Model
        iPresenter.setView(this); // 持有 View

        init();
    }

    @Override
    public void onClick(View v) {
        if (v == binding.submitBtn) {
            iPresenter.submitFromData();
        } else if (v == binding.clearBtn) {
            iPresenter.clearData();
        }
    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
        iPresenter.removeHandlerMsgAndCallback();
    }

    private void init() {
        binding.editMsg.setText("normal");
        binding.edit.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) {
                iPresenter.onDataChanged(s.toString());
            }

            @Override
            public void afterTextChanged(Editable s) {

            }
        });
        binding.submitBtn.setOnClickListener(this);
        binding.clearBtn.setOnClickListener(this);
    }

    @Override
    public void onDataChangedUpdateText(String data) {
        binding.editMsg.setText(data);
    }

    @Override
    public void showSubmitFromLoading(String data) {
        AlertDialog.Builder builder = new AlertDialog.Builder(this);
        TextView textView = new TextView(this);
        if (TextUtils.isEmpty(data)) {
            data = "normal";
        }
        textView.setText("正在提交：" + data);
        builder.setCancelable(false);
        builder.setView(textView);
        dialog = builder.show();
    }

    @Override
    public void hideSubmitFromLoading() {
        dialog.dismiss();
    }

    @Override
    public void clearFromData() {
        binding.edit.setText("");
        binding.editMsg.setText("normal");
    }

}

4、IBasePresenter

/**
 * Base 代理接口 负责业务逻辑
 */
public interface IBasePresenter {

    // 写一些，公用或者通用的方法，用于扩展

    default void removeHandlerMsgAndCallback() {} // 删除handler 回调和消息

}

5、IBaseModel

/**
 * Base 数据模型接口 负责数据逻辑
 */
public interface IBaseModel {

    // 写一些，公用或者通用的方法，用于扩展

    default void removeHandlerMsgAndCallback() {} // 删除handler 回调和消息

}

6、IBaseView

/**
 * Base 视图接口 负责视图逻辑
 */
public interface IBaseView {

    // 写一些，公用或者通用的方法，用于扩展

    default void testBaseView() {}

}

7、activity_mvp.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".ui.activity.MVPActivity">

    <androidx.appcompat.widget.Toolbar
        android:id="@+id/toolbar"
        android:layout_width="match_parent"
        android:layout_height="48dp"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        android:background="@color/material_dynamic_primary90"
        app:title="MVP" />

    <EditText
        android:id="@+id/edit"
        android:layout_width="match_parent"
        android:layout_height="50dp"
        android:layout_marginHorizontal="16dp"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toBottomOf="@id/toolbar" />

    <TextView
        android:id="@+id/edit_msg"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="8dp"
        app:layout_constraintLeft_toLeftOf="@id/edit"
        app:layout_constraintTop_toBottomOf="@id/edit" />

    <androidx.appcompat.widget.AppCompatButton
        android:id="@+id/submit_btn"
        android:layout_width="match_parent"
        android:layout_height="58dp"
        android:layout_marginHorizontal="16dp"
        android:layout_marginTop="8dp"
        android:text="submit"
        android:textAllCaps="false"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toBottomOf="@id/edit_msg" />

    <androidx.appcompat.widget.AppCompatButton
        android:id="@+id/clear_btn"
        android:layout_width="match_parent"
        android:layout_height="58dp"
        android:layout_marginHorizontal="16dp"
        android:layout_marginTop="8dp"
        android:text="clear"
        android:textAllCaps="false"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toBottomOf="@id/submit_btn" />

</androidx.constraintlayout.widget.ConstraintLayout>

8、源码地址

GitHub - LanSeLianMa/AndroidMVP: Android MVP 写法