1. Introduction
This article is a simple encapsulation used by databinding, mainly in the base classes BaseActivity and BaseFragment
2. Specific steps
1. Enable databinding in build.gradle
dataBinding {
enabled = true }
2. In the encapsulation of BaseActivity, it is mainly acquired through reflection. as follows
package com.zw.databindingdemo.java;
import android.os.Bundle;
import android.view.LayoutInflater;
import androidx.annotation.Nullable;
import androidx.appcompat.app.AppCompatActivity;
import androidx.databinding.ViewDataBinding;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.lang.reflect.ParameterizedType;
/**
* 描述:
* @author: dd
* @time: 2023/6/8 16:33
*/
public abstract class BaseActivity<VB extends ViewDataBinding> extends AppCompatActivity {
public VB mBinding;
@Override
protected void onCreate(@Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
createBinding();
}
private void createBinding() {
Class<VB> vbClass = getVbClass();
try {
if (vbClass == null) {
return;
}
Method method = vbClass.getMethod("inflate", LayoutInflater.class);
mBinding = (VB) method.invoke(null, getLayoutInflater());
setContentView(mBinding.getRoot());
} catch (NoSuchMethodException | InvocationTargetException | IllegalAccessException e) {
e.printStackTrace();
}
}
private Class<VB> getVbClass() {
ParameterizedType parameterizedType = (ParameterizedType) this.getClass().getGenericSuperclass();
if (parameterizedType == null) {
return null;
}
Class<VB> vbClass = (Class<VB>) parameterizedType.getActualTypeArguments()[0];
return vbClass;
}
}
3. Use the following in Activity
package com.zw.databindingdemo.java;
import android.os.Bundle;
import androidx.annotation.Nullable;
import androidx.fragment.app.FragmentManager;
import androidx.fragment.app.FragmentTransaction;
import com.zw.databindingdemo.databinding.ActivityTestBinding;
/**
* 描述:
* @author: dd
* @time: 2023/6/8 16:33
*/
public class TestActivity extends BaseActivity<ActivityTestBinding> {
@Override
protected void onCreate(@Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
mBinding.tvName.setText("测试 java Activity");
mBinding.btnGo.setOnClickListener(v -> {
initFragment();
});
}
private void initFragment() {
FragmentManager fm = getSupportFragmentManager();
FragmentTransaction ft = fm.beginTransaction();
ft.replace(mBinding.frameLayout.getId(), new TestFragment());
ft.commit();
}
}
4. Encapsulation in BaseFragment
package com.zw.databindingdemo.java;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import androidx.databinding.ViewDataBinding;
import androidx.fragment.app.Fragment;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.lang.reflect.ParameterizedType;
/**
* 描述:
* @author: dd
* @time: 2023/6/8 16:33
*/
public abstract class BaseFragment<VB extends ViewDataBinding> extends Fragment {
public VB mBinding;
@Nullable
@Override
public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
createBinding(inflater, container);
return mBinding.getRoot();
}
private void createBinding(LayoutInflater inflater, ViewGroup container) {
Class<VB> vbClass = getVbClass();
try {
if (vbClass == null) {
return;
}
/* Method method = vbClass.getMethod("inflate", LayoutInflater.class, ViewGroup.class, Boolean.class);*/
Method method = vbClass.getMethod("inflate", LayoutInflater.class);
mBinding = (VB) method.invoke(null, inflater);
} catch (NoSuchMethodException | InvocationTargetException | IllegalAccessException e) {
e.printStackTrace();
}
}
private Class<VB> getVbClass() {
ParameterizedType parameterizedType = (ParameterizedType) this.getClass().getGenericSuperclass();
if (parameterizedType == null) {
return null;
}
return (Class<VB>) parameterizedType.getActualTypeArguments()[0];
}
}
5. The use in Fragment is as follows
package com.zw.databindingdemo.java;
import android.os.Bundle;
import android.view.View;
import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import com.zw.databindingdemo.databinding.FragmentTestBinding;
/**
* 描述:
* @author: dd
* @time: 2023/6/8 16:33
*/
public class TestFragment extends BaseFragment<FragmentTestBinding> {
@Override
public void onViewCreated(@NonNull View view, @Nullable Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
mBinding.tvName.setText("测试 java Fragment");
}
}
6. Kotlin version
package com.zw.databindingdemo.kotlin
import android.os.Bundle
import android.view.LayoutInflater
import androidx.appcompat.app.AppCompatActivity
import androidx.databinding.ViewDataBinding
import java.lang.reflect.ParameterizedType
/**
* 描述:
* @author: dd
* @time: 2023/6/8 16:33
*/
abstract class BaseActivityKotlin<VB : ViewDataBinding> : AppCompatActivity() {
public lateinit var mBinding: VB
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
mBinding = createBinding()
setContentView(mBinding.root)
}
private fun createBinding(): VB {
val vbClass = getVBClass()
val method = vbClass.getMethod("inflate", LayoutInflater::class.java)
return method.invoke(null, layoutInflater) as VB
}
@Suppress("UNCHECKED_CAST")
private fun getVBClass(): Class<VB> {
val type = javaClass.genericSuperclass as ParameterizedType
return type.actualTypeArguments[0] as Class<VB>
}
}
package com.zw.databindingdemo.kotlin
import android.os.Bundle
import com.zw.databindingdemo.databinding.ActivityTestKotlinBinding
/**
* 描述:
* @author: dd
* @time: 2023/6/8 16:33
*/
class TestActivityKotlin: BaseActivityKotlin<ActivityTestKotlinBinding>() {
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
mBinding.tvName.text = "测试 Kotlin Activity"
mBinding.btnGo.setOnClickListener {
initFragment() }
}
private fun initFragment() {
val fm = supportFragmentManager
val ft = fm.beginTransaction()
ft.replace(mBinding.frameLayout.id, TestFragmentKotlin())
ft.commit()
}
}
package com.zw.databindingdemo.kotlin
import android.os.Bundle
import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup
import androidx.databinding.ViewDataBinding
import androidx.fragment.app.Fragment
import java.lang.reflect.ParameterizedType
/**
* 描述:
* @author: dd
* @time: 2023/6/8 16:33
*/
abstract class BaseFragmentKotlin<VB : ViewDataBinding> : Fragment() {
public lateinit var mBinding: VB
override fun onCreateView(
inflater: LayoutInflater,
container: ViewGroup?,
savedInstanceState: Bundle?
): View? {
mBinding = createBinding(inflater, container)
return mBinding.root
}
private fun createBinding(inflater: LayoutInflater, container: ViewGroup?): VB {
val vbClass = getVBClass()
val method = vbClass.getMethod(
"inflate",
LayoutInflater::class.java,
ViewGroup::class.java,
Boolean::class.java
)
return method.invoke(null, inflater, container, false) as VB
}
@Suppress("UNCHECKED_CAST")
private fun getVBClass(): Class<VB> {
val type = javaClass.genericSuperclass as ParameterizedType
return type.actualTypeArguments[0] as Class<VB>
}
}
package com.zw.databindingdemo.kotlin
import android.os.Bundle
import android.view.View
import com.zw.databindingdemo.databinding.FragmentTestKotlinBinding
/**
* 描述:
* @author: dd
* @time: 2023/6/8 16:33
*/
class TestFragmentKotlin : BaseFragmentKotlin<FragmentTestKotlinBinding>() {
override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
super.onViewCreated(view, savedInstanceState)
mBinding.tvName.text = "测试 Kotlin Fragment"
}
}
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