Android MVP 基本用法

View -> Presenter -> Model -> Presenter -> View

View 包含 xml 布局文件和 Activity 或 Fragment，并与 Presenter 通信

public class MainActivity extends AppCompatActivity implements IContract.View{

    private Button mBtn;

    // 和 Presenter 通信
    private IContract.Presenter mPresenter;

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

        mPresenter=new Presenter(this);

        mBtn=(Button)findViewById(R.id.button);
        mBtn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {

                // 通过 mPresenter 调用
                mPresenter.loadClickString();
            }
        });


    }

    @Override
    protected void onStart() {
        super.onStart();
        mPresenter.start(); // Presenter的初始化
    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
        mPresenter.destroy(); //断开 Presenter 和 View 的连接
    }

    /**
     * 实现 接口 IContract.View
     * @param s
     */
    @Override
    public void updateBtnText(String s) {
        mBtn.setText(s);
    }

    @Override
    public void showToast(String s) {
        Toast.makeText(this,s,Toast.LENGTH_SHORT).show();
    }
}

Presenter 与 View 和 Model 通信

public class Presenter implements IContract.Presenter {

    // 和 View 通信
    private IContract.View mView;

    public Presenter(IContract.View view){
        mView=view;
    }

    /**
     * 实现 接口 IContract.Presenter
     */
    @Override
    public void start() {
        String s=ModelDataSource.ins().getBtnText();
        mView.updateBtnText(s);
    }

    @Override
    public void loadClickString() {
        String s=ModelDataSource.ins().getBtnClicked();
        mView.showToast(s);
    }

    @Override
    public void destroy() {
        mView = null;
    }
}

Model 单例，被 Presenter 调用

public class ModelDataSource {

    private static ModelDataSource mInstance;

    public static ModelDataSource ins(){
        if(mInstance==null){
            synchronized (ModelDataSource.class){
                if(mInstance==null){
                    mInstance=new ModelDataSource();
                }
            }
        }
        return mInstance;
    }

    public String getBtnText(){
        return " from ModelDataSource ";
    }

    public String getBtnClicked(){
        return " from ModelDataSource Hello mVP  ";
    }
}

参考博客 浅谈Android中的MVP