android——MVP+DataBinding 的使用

天来说说MVP+DataBinding 的使用

以一个登录案例来讲解

布局：（ConstraintLayout 作为根布局）

<layout>
 <data>
 <variable
 name="onClick"
 type="com.zhangqie.mvplogin.LoginActivity.OnViewClick" />
 </data>
 <android.support.constraint.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=".LoginActivity">
 <TextView
 android:id="@+id/tv1"
 android:layout_width="wrap_content"
 android:layout_height="45dp"
 android:gravity="center"
 android:text="账号："
 android:textColor="@android:color/black"
 android:textSize="16dp"
 app:layout_constraintBottom_toBottomOf="parent"
 app:layout_constraintHorizontal_bias="0.2"
 app:layout_constraintLeft_toLeftOf="parent"
 app:layout_constraintRight_toRightOf="parent"
 app:layout_constraintTop_toTopOf="parent"
 app:layout_constraintVertical_bias="0.4" />
 <EditText
 android:id="@+id/et_name"
 android:layout_width="222dp"
 android:layout_height="45dp"
 app:layout_constraintBottom_toBottomOf="parent"
 app:layout_constraintLeft_toRightOf="@+id/tv1"
 app:layout_constraintTop_toTopOf="parent"
 app:layout_constraintVertical_bias="0.4" />
 <TextView
 android:id="@+id/tv2"
 android:layout_width="wrap_content"
 android:layout_height="45dp"
 android:gravity="center"
 android:text="密码："
 android:textColor="@android:color/black"
 android:textSize="16dp"
 app:layout_constraintHorizontal_bias="0.2"
 app:layout_constraintLeft_toLeftOf="parent"
 app:layout_constraintRight_toRightOf="parent"
 app:layout_constraintTop_toBottomOf="@+id/tv1" />
 <EditText
 android:id="@+id/et_pwd"
 android:layout_width="222dp"
 android:layout_height="45dp"
 app:layout_constraintLeft_toRightOf="@+id/tv2"
 app:layout_constraintTop_toBottomOf="@+id/et_name" />
 <Button
 android:id="@+id/btn_login"
 android:layout_width="match_parent"
 android:layout_height="wrap_content"
 android:layout_margin="25dp"
 android:onClick="@{onClick.OnClickCommand}"
 android:text="登录"
 app:layout_constraintTop_toBottomOf="@+id/et_pwd" />
 </android.support.constraint.ConstraintLayout>
</layout>

BaseActivity.Java

public abstract class BaseActivity<D extends ViewDataBinding,V,T extends BasePresenter<V>> extends AppCompatActivity{
 protected D viewDataBinding;
 protected T p;
 @Override
 protected void onCreate(@Nullable Bundle savedInstanceState) {
 super.onCreate(savedInstanceState);
 viewDataBinding = DataBindingUtil.setContentView(this, setMainLayout());
 p = createPresenter();
 p.attachView((V)this);
 initView();
 initBeforeData();
 }
 protected abstract T createPresenter();
 /***
 * 初始化布局
 */
 protected abstract int setMainLayout();
 /**
 * 初始化View
 */
 protected abstract void initView();
 /**
 * 初始化先前数据
 */
 protected abstract void initBeforeData();
 /***
 * 跳转Activity
 * @param mClass
 */
 protected void openActivity(Class<?> mClass) {
 openIntent(new Intent(this, mClass));
 }
 /**
 * 弹出toast 显示时长short
 *
 * @param msg
 */
 protected void showToastShort(String msg) {
 if (!TextUtils.isEmpty(msg)) {
 Toast.makeText(this, msg, Toast.LENGTH_SHORT).show();
 }
 }
 protected void showToastShort(int msg) {
 Toast.makeText(this, msg, Toast.LENGTH_SHORT).show();
 }
 protected void openIntent(Intent intent) {
 startActivity(intent);
 }
 protected void openForResultActivity(Intent intent, int requestCode){
 startActivityForResult(intent,requestCode);
 }
 @Override
 protected void onDestroy() {
 super.onDestroy();
 if (p != null){
 p.detachView();
 }
 }
}

Activity.java

public class LoginActivity extends BaseActivity<LoginMainBinding,IView,LoginPresenter> implements IView {
 @Override
 protected LoginPresenter createPresenter() {
 return new LoginPresenter();
 }
 @Override
 protected int setMainLayout() {
 return R.layout.login_main;
 }
 @Override
 protected void initView() {
 viewDataBinding.setOnClick(new OnViewClick());
 }
 @Override
 protected void initBeforeData() {
 }
 @Override
 public void showLoading(String msg) {
 showToastShort(msg);
 }
 public class OnViewClick {
 public void OnClickCommand(View view) {
 switch (view.getId()) {
 case R.id.btn_login:
 p.showLogin(viewDataBinding.etName.getText().toString(),viewDataBinding.etPwd.getText().toString());
 break;
 }
 }
 }
}

效果图：

源码地址： https://github.com/DickyQie/android-databinding

总结：

• 减少各层之间耦合，易于后续的需求变化，降低维护成本。
• Presenter层独立于Android代码之外，可以进行Junit测试。
• 接口和类较多，互相做回调，代码臃肿。
• Presenter层与View层是通过接口进行交互的，接口粒度不好控制。

有不足之处，望指正