看了我Android低代码开发 - 让IDE帮你写代码这篇文章的小伙伴，大概都对Dora全家桶开发框架有基本的认识了吧。本篇文章将会讲解如何使用dora-studio-plugin快捷创建一个下拉刷新列表界面。

效果演示

这样直接通过图形界面的方式就创建好了下拉刷新上拉加载+空态界面+列表的基础代码，接下来开发起来就方便了。

依赖库

DoraTitleBar：建议用最新版本1.37

DoraEmptyLayout：必须用1.12版本

SwipeLayout和PullableRecyclerView：用1.0版本就好

IntelliJ IDEA插件1.4版本更新内容

生成布局文件的模板

/*
 * Copyright (C) 2022 The Dora Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.dorachat.templates.recipes.app_package.res.layout

fun swipeLayoutActivityXml(
        packageName: String,
  activityClass: String
) = """
<?xml version="1.0" encoding="utf-8"?>
<layout 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"
    tools:context="${packageName}.${activityClass}">

    <data>
    
    </data>
    
    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:orientation="vertical">

        <dora.widget.DoraTitleBar
            android:id="@+id/titleBar"
            android:layout_width="match_parent"
            android:layout_height="50dp"
            app:dview_title="@string/app_name"
            android:background="@color/colorPrimary"/>

        <dora.widget.DoraEmptyLayout
            android:id="@+id/emptyLayout"
            android:layout_width="match_parent"
            android:layout_height="match_parent">
            <dora.widget.pull.SwipeLayout
                android:id="@+id/swipeLayout"
                android:layout_width="match_parent"
                android:layout_height="match_parent">
                <include layout="@layout/layout_swipe_layout_header" />
                <dora.widget.pull.PullableRecyclerView
                    android:id="@+id/recyclerView"
                    android:layout_width="match_parent"
                    android:layout_height="match_parent"
                    android:background="@color/colorPanelBg" />
                <include layout="@layout/layout_swipe_layout_footer" />
            </dora.widget.pull.SwipeLayout>
        </dora.widget.DoraEmptyLayout>
    </LinearLayout>
</layout>
"""

生成Java和Kotlin代码的模板

/*
 * Copyright (C) 2022 The Dora Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.dorachat.templates.recipes.app_package.src

fun swipeLayoutActivityKt(
        applicationPackage: String,
  packageName: String,
        activityClass: String,
  bindingName: String,
  layoutName: String
) = """
package ${packageName}

import android.os.Bundle

import dora.BaseActivity
import dora.widget.pull.SwipeLayout

import ${applicationPackage}.R
import ${applicationPackage}.databinding.${bindingName}

class ${activityClass} : BaseActivity<${bindingName}>() {

   override fun getLayoutId(): Int {
          return R.layout.${layoutName}
   }

   override fun initData(savedInstanceState: Bundle?, binding: ${bindingName}) {
          TODO("Not yet implemented")
            // For Example:
            // binding.swipeLayout.setOnSwipeListener(object : SwipeLayout.OnSwipeListener {
            //
            //     override fun onRefresh(swipeLayout: SwipeLayout) {
            //     }
            //
            //     override fun onLoadMore(swipeLayout: SwipeLayout) {
            //     }
            // })
   }
}
"""

fun swipeLayoutActivity(
        applicationPackage: String,
        packageName: String,
        activityClass: String,
        bindingName: String,
        layoutName: String
) = """
package ${packageName};

import android.os.Bundle;
import androidx.annotation.Nullable;

import dora.BaseActivity;
import dora.widget.pull.SwipeLayout;

import ${applicationPackage}.R;
import ${applicationPackage}.databinding.${bindingName};

public class ${activityClass} extends BaseActivity<${bindingName}> {

   @Override
    protected int getLayoutId() {
        return R.layout.${layoutName};
    }

   @Override
    public void initData(@Nullable Bundle savedInstanceState, ${bindingName} binding) {
        // TODO: Not yet implemented
        // For Example:
        // binding.swipeLayout.setOnSwipeListener(new SwipeLayout.OnSwipeListener() {
        //
        //     @Override
        //     public void onRefresh(SwipeLayout swipeLayout) {
        //     }
        //     
        //     @Override
        //     public void onLoadMore(SwipeLayout swipeLayout) {
        //     }
        // });
   }
}
"""

DoraTemplateRecipe.kt新增生成代码的方法

fun RecipeExecutor.swipeLayoutActivityRecipe(
    moduleData: ModuleTemplateData,
    activityClass: String,
    activityTitle: String,
    layoutName: String,
    packageName: String
) {
    val (projectData, srcOut, resOut) = moduleData

    generateManifest(
        moduleData = moduleData,
        activityClass = activityClass,
        packageName = packageName,
        isLauncher = false,
        hasNoActionBar = false,
        generateActivityTitle = false
    )

    if (projectData.language == Language.Kotlin) {
        save(
            swipeLayoutActivityKt(projectData.applicationPackage ?: packageName, packageName, activityClass,
                buildBindingName(layoutName), layoutName), srcOut.resolve("${activityClass}.${projectData.language.extension}"))
    }
    if (projectData.language == Language.Java) {
        save(swipeLayoutActivity(projectData.applicationPackage ?: packageName, packageName, activityClass,
            buildBindingName(layoutName), layoutName), srcOut.resolve("${activityClass}.${projectData.language.extension}"))
    }
    save(swipeLayoutActivityXml(packageName, activityClass), resOut.resolve("layout/${layoutName}.xml"))

    open(resOut.resolve("layout/${layoutName}.xml"))

}

新增一个向导界面模板

/*
 * Copyright (C) 2022 The Dora Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.dorachat.templates.recipes

import com.android.tools.idea.wizard.template.*
import com.android.tools.idea.wizard.template.impl.activities.common.MIN_API
import java.io.File

object SwipeLayoutActivityTemplate : Template {
    override val category: Category
        get() = Category.Activity
    override val constraints: Collection<TemplateConstraint>
        get() = emptyList()     // AndroidX, kotlin
    override val description: String
        get() = "创建一个dora.BaseActivity，来自https://github.com/dora4/dora"
    override val documentationUrl: String?
        get() = null
    override val formFactor: FormFactor
        get() = FormFactor.Mobile
    override val minSdk: Int
        get() = MIN_API
    override val name: String
        get() = "SwipeLayout DataBinding Activity"
    override val recipe: Recipe
        get() = {
            swipeLayoutActivityRecipe(
                    it as ModuleTemplateData,
                    activityClassInputParameter.value,
                    activityTitleInputParameter.value,
                    layoutNameInputParameter.value,
                    packageName.value
            )
        }
    override val uiContexts: Collection<WizardUiContext>
        get() = listOf(WizardUiContext.ActivityGallery, WizardUiContext.MenuEntry, WizardUiContext.NewProject, WizardUiContext.NewModule)
    override val useGenericInstrumentedTests: Boolean
        get() = false
    override val useGenericLocalTests: Boolean
        get() = false

    override val widgets: Collection<Widget<*>>
        get() = listOf(
                TextFieldWidget(activityTitleInputParameter),
                TextFieldWidget(activityClassInputParameter),
                TextFieldWidget(layoutNameInputParameter),
                PackageNameWidget(packageName),
                LanguageWidget()
        )

    override fun thumb(): Thumb {
        return Thumb { findResource(this.javaClass, File("template_activity.png")) }
    }

    val activityClassInputParameter = stringParameter {
        name = "Activity Name"
        default = "MainActivity"
        help = "The name of the activity class to create"
        constraints = listOf(Constraint.CLASS, Constraint.UNIQUE, Constraint.NONEMPTY)
        suggest = { layoutToActivity(layoutNameInputParameter.value) }
    }

    var layoutNameInputParameter: StringParameter = stringParameter {
        name = "Layout Name"
        default = "activity_main"
        help = "The name of the layout to create for the activity"
        constraints = listOf(Constraint.LAYOUT, Constraint.UNIQUE, Constraint.NONEMPTY)
        suggest = { activityToLayout(activityClassInputParameter.value) }
    }

    val activityTitleInputParameter = stringParameter {
        name = "Title"
        default = "Main"
        help = "The name of the activity. For launcher activities, the application title"
        visible = { false }
        constraints = listOf(Constraint.NONEMPTY)
        suggest = { buildClassNameWithoutSuffix(activityClassInputParameter.value, "Activity") }
    }
    val packageName = defaultPackageNameParameter
}

将向导界面模板添加到向导模板提供者

/*
 * Copyright (C) 2022 The Dora Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.dorachat.templates.recipes

import com.android.tools.idea.wizard.template.WizardTemplateProvider

class DoraTemplateWizardProvider: WizardTemplateProvider() {
    override fun getTemplates() = listOf(
            DataBindingActivityTemplate,
            DataBindingFragmentTemplate,
            MenuPanelActivityTemplate,
            SwipeLayoutActivityTemplate,
            MVVMActivityTemplate,
            MVVMFragmentTemplate)
}

更新版本日志

patchPluginXml {
    version.set("${project.version}")
    sinceBuild.set("213")
    untilBuild.set("223.*")
    changeNotes.set("""
    <h3>1.4</h3>
  新增对SwipeLayout的支持<br/>
    <h3>1.3</h3>
  新增对MenuPanel的支持<br/>
    <h3>1.2</h3>
  新增对BaseVMActivity和BaseVMFragment的支持<br/>
    <h3>1.1</h3>
  initData()方法中增加databinding参数<br/>
    <h3>1.0</h3>
  初始版本，能够创建Java和Kotlin版本的MVVM Activiy和MVVM Fragment<br/>
  """)
}

代码讲解

DoraEmptyLayout为什么可以识别SwipeLayout里面的RecyclerView?

open fun showContent() {
    runMain {
        if (contentView is RecyclerView) {
            if ((contentView as RecyclerView).adapter == null ||
                    (contentView as RecyclerView).adapter!!.itemCount == 0) {
                showEmpty()
                return@runMain
            }
        }
        // 1.12开始支持遍历容器，确保一个EmptyLayout里面只能放一个RecyclerView
        if (contentView is ViewGroup) {
            for (i in 0 until childCount) {
                val view = getChildAt(i)
                if (view is RecyclerView) {
                    if (view.adapter == null ||
                        view.adapter!!.itemCount == 0) {
                        showEmpty()
                        return@runMain
                    }
                }
            }
        }
        val view = showStateView(STATE_CONTENT)
        this.content?.invoke(view)
    }
}

我们可以看到DoraEmptyLayout类从1.11升级到1.12版本的过程中，新增了以下代码来支持SwipeLayout。

if (contentView is ViewGroup) {
    for (i in 0 until childCount) {
        val view = getChildAt(i)
        if (view is RecyclerView) {
            if (view.adapter == null ||
                        view.adapter!!.itemCount == 0) {
                showEmpty()
                return@runMain
            }
        }
    }
}        

这样就不难理解了，如果遇到了刷新布局，如SwipeLayout，就再解析一层找RecyclerView。当然，一个DoraEmptyLayout里面只能放一个RecyclerView。

SwipeLayout是何方神圣？

• 支持暗色模式
• 支持英语、阿拉伯语、德语、西班牙语、法语、意大利语、日语、韩语、葡萄牙语、俄语、泰语、越南语、简体中文和繁体中文等世界10几个主流语种
• 支持自定义可拉动的内容布局
• 支持插件创建
• 与DoraEmptyLayout空态布局完美兼容（需要使用v1.12以上版本）
• 界面丝滑

通过PullableRecyclerView源码来看怎么自定义可拉动的内容布局

package dora.widget.pull

import android.content.Context
import android.util.AttributeSet
import androidx.recyclerview.widget.LinearLayoutManager
import androidx.recyclerview.widget.RecyclerView
import dora.widget.swipelayout.R

class PullableRecyclerView @JvmOverloads constructor(context: Context, attrs: AttributeSet? = null,
                                                     defStyle: Int = 0)
                                                : RecyclerView(context, attrs, defStyle), Pullable {

    private var canPullDown = true
    private var canPullUp = true

    init {
        val a = context.obtainStyledAttributes(attrs, R.styleable.PullableRecyclerView, defStyle, 0)
        canPullDown = a.getBoolean(R.styleable.PullableRecyclerView_dview_canPullDown, canPullDown)
        canPullUp = a.getBoolean(R.styleable.PullableRecyclerView_dview_canPullUp, canPullUp)
        a.recycle()
    }

    fun setCanPullDown(canPullDown: Boolean) {
        this.canPullDown = canPullDown
    }

    fun setCanPullUp(canPullUp: Boolean) {
        this.canPullUp = canPullUp
    }

    override fun canPullDown(): Boolean {
        return if (canPullDown) {
            val layoutManager = layoutManager as LinearLayoutManager?
            val adapter = adapter
            if (adapter != null) {
                return if (adapter.itemCount == 0) {
                    false
                } else layoutManager!!.findFirstVisibleItemPosition() == 0
                    && getChildAt(0).top >= 0
            }
            false
        } else {
            false
        }
    }

    override fun canPullUp(): Boolean {
        if (canPullUp) {
            val layoutManager = layoutManager as LinearLayoutManager
            if (adapter != null && adapter?.itemCount!! == 0) {
                return false
            } else if (layoutManager.findLastVisibleItemPosition() == ((adapter as Adapter).itemCount - 1)) {
                // 滑到底部了
                if (getChildAt(layoutManager.findLastVisibleItemPosition() - layoutManager.findFirstVisibleItemPosition()) != null
                        && getChildAt(
                        layoutManager.findLastVisibleItemPosition()
                                - layoutManager.findFirstVisibleItemPosition()).bottom <= measuredHeight
                ) {
                    return true
                }
            }
            return false
        } else {
            return false
        }
    }
}

它实现了一个顶层接口Pullable，通过canPullDown()和canPullUp()两个方法来在运行时动态判断可不可以下拉刷新和上拉加载。

private var canPullDown = true
private var canPullUp = true

里面提供了两个属性，表示是否有下拉和上拉能力，如果设置为false，则无论条件达成与否都不能进行刷新和加载。

<dora.widget.pull.PullableRecyclerView
    android:id="@+id/recyclerView"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@color/colorPanelBg"
    app:dview_canPullDown="true"
    app:dview_canPullUp="false"/>

可以通过属性设置这两个变量，比如不需要上拉加载就把上拉的设置为false，app:dview_canPullUp=“false”。

设置完成刷新和加载的监听

binding.swipeLayout.setOnSwipeListener(new SwipeLayout.OnSwipeListener() {

    @Override
    public void onRefresh(SwipeLayout swipeLayout) {
    }

    @Override
    public void onLoadMore(SwipeLayout swipeLayout) {
    }
});

通过调用swipeLayout的refreshFinish(state)和loadMoreFinish(state)来结束刷新和加载状态。

const val SUCCEED = 0
const val FAIL = 1

有成功和失败两种状态可以设置。所以，你在onRefresh()或onLoadMore()的最后一行调用刷新状态即可。

源码链接

下拉刷新：https://github.com/dora4/dview-swipe-layout

空态布局：https://github.com/dora4/dview-empty-layout

代码生成插件：https://github.com/dora4/dora-studio-plugin