接着上一篇文章，这一篇我把自己上传到npm上的react-native-segmented-android开发步骤和大家分享。
下载react-native组件命令：
$ npm install react-native-segmented-android --save
这是效果图：
Segmented.png
这次要实现的是View组件，所以要通过继承SimpleViewManager 来实现，步骤和（一）基本保持一致。
开始
Step 1 - 新建react-native工程 ReactNativeSegmentedAndroid
$ react-native init ReactNativeSegmentedAndroid
Step 2 - 将新建的工程导入android studio然后新建空library（以react-native-segmented-android为library的名称）
Step 3 - 新建空library（以react-native-segmented-android为library的名称）
在library目录下的build.gradle中添加react-native的依赖
// file: android/react-native-segmented-android/build.gradle
...
dependencies {
...
compile 'info.hoang8f:android-segmented:1.0.6'
compile 'com.facebook.react:react-native:0.16.+'
}
Step 4 - 创建AndroidSegmented类继承SegmentedGroup
public class AndroidSegmented extends SegmentedGroup{
public void setSegmentOrientation(String str){
if(str.equals("horizontal")){
setOrientation(RadioGroup.HORIZONTAL);
}else if(str.equals("vertical")){
setOrientation(RadioGroup.VERTICAL);
}
}
public AndroidSegmented(ThemedReactContext context) {
super(context);
setGravity(Gravity.CENTER);
setLayoutParams(new ViewGroup.LayoutParams(
ViewGroup.LayoutParams.WRAP_CONTENT,
ViewGroup.LayoutParams.WRAP_CONTENT
));
}
private final Runnable mLayoutRunnable = new Runnable() {
@Override
public void run() {
measure(MeasureSpec.makeMeasureSpec(getWidth(), MeasureSpec.EXACTLY),
MeasureSpec.makeMeasureSpec(getHeight(), MeasureSpec.EXACTLY));
layout(getLeft(), getTop(), getRight(), getBottom());
}
};
@Override
public void requestLayout() {
super.requestLayout();
post(mLayoutRunnable);
}
@Override
protected void onLayout(boolean changed, int l, int t, int r, int b) {
super.onLayout(changed, l, t, r, b);
}
}
Step 5 - 继承SimpleViewManager，注意这时就不是继承ReactContextBaseJavaModule了 ，大家可以很明显的发现setChildText（）方法上多了一个‘@ReactProp(name = "childText")’，加上了‘@ReactProp'的，segmented控件多了一个name为childText的属性，值为ReadableArray ( js端代码:childText={['One','Two','Three','Four',"Five"]})。
public class AndroidSegmentedManager extends SimpleViewManager<AndroidSegmented> {
public static final String REACT_CLASS = "AndroidSegmented";
private static final String COLOR_REGEX = "^#([0-9A-Fa-f]{6}|[0-9A-Fa-f]{8})$";
private Context context;
@Override
public String getName() {
return REACT_CLASS;
}
@Override
protected AndroidSegmented createViewInstance(ThemedReactContext reactContext) {
this.context = reactContext;
return new AndroidSegmented(reactContext);
}
@Override
protected void addEventEmitters(final ThemedReactContext reactContext, final AndroidSegmented view) {
view.setOnCheckedChangeListener(new RadioGroup.OnCheckedChangeListener() {
@Override
public void onCheckedChanged(RadioGroup group, int checkedId) {
int childCount = view.getChildCount();
for (int i = 0; i < childCount; i++) {
((RadioButton)view.getChildAt(i)).setChecked(false);
if (view.getChildAt(i).getId() == checkedId) {
((RadioButton)view.getChildAt(i)).setChecked(true);
reactContext.getNativeModule(UIManagerModule.class).getEventDispatcher()
.dispatchEvent(
new AndroidSegmentedEvent(
view.getId(),
SystemClock.uptimeMillis(),
i));
}
}
}
});
}
@ReactProp(name = "childText")
public void setChildText(AndroidSegmented view, ReadableArray data) {
int childCount = data.size();
Log.e("TAG", "___" + childCount);
for (int i = 0; i < childCount; i++) {
RadioButton child = (RadioButton) LayoutInflater.from(context).inflate(R.layout.radio_button, null);
child.setText(data.getString(i));
view.addView(child);
}
}
@ReactProp(name = "selectedPosition")
public void setSelectedChild(AndroidSegmented view, int position) {
RadioButton radioBt= (RadioButton)(view.getChildAt(position));
radioBt.setChecked(true);
}
@ReactProp(name = "orientation")
public void setOrientation(AndroidSegmented view, String orientation) {
view.setSegmentOrientation(orientation);
}
@ReactProp(name = "tintColor")
public void setTintColor(AndroidSegmented view, ReadableArray data) {
String type0 = data.getType(0).name();
String type1 = data.getType(1).name();
if ("String".equals(type0) && "String".equals(type1)) {
String color0 = data.getString(0);
String color1 = data.getString(1);
if (color0 != null && color1 != null) {
if (color0.matches(COLOR_REGEX) && color1.matches(COLOR_REGEX)) {
view.setTintColor(Color.parseColor(color0), Color.parseColor(color1));
} else {
throw new JSApplicationIllegalArgumentException("Invalid arrowColor property: " + color0);
}
}
}
}
}
Step 6 - 创建AndroidSegmentedEvent类继承Event<AndroidSegmentedEvent>
public class AndroidSegmentedEvent extends Event<AndroidSegmentedEvent> {
public static final String EVENT_NAME = "topChange";
private final int selectedPosition;
public AndroidSegmentedEvent(int viewId, long timestampMs, int selectedPosition) {
super(viewId, timestampMs);
this.selectedPosition = selectedPosition;
}
@Override
public String getEventName() {
return EVENT_NAME;
}
@Override
public void dispatch(RCTEventEmitter rctEventEmitter) {
rctEventEmitter.receiveEvent(getViewTag(), getEventName(), serializeEventData());
}
@Override
public short getCoalescingKey() {
return 0;
}
private WritableMap serializeEventData() {
WritableMap eventData = Arguments.createMap();
eventData.putInt("selected", getPosition());
Log.e("AAA","position="+getPosition());
return eventData;
}
private int getPosition() {
return selectedPosition;
}
}
Step 7 - 继承ReactPackage，注意createNativeModules（）返回的是加入了 AndroidToastModule 的集合，createJSModules（）与createViewManagers（）返回的都是空集合，如果Step 4 步继承的是BaseViewManager或其子类，那么createViewManagers（）中返回的就是加入了BaseViewManager的集合，其他的就是空集合，一般情况createJSModules（）的返回值都是空集合。
public class AndroidSegmentedPackage implements ReactPackage {
@Override
public List<NativeModule> createNativeModules(ReactApplicationContext reactContext) {
return Collections.emptyList();
}
@Override
public List<Class<? extends JavaScriptModule>> createJSModules() {
return Collections.emptyList();
}
@Override
public List<ViewManager> createViewManagers(ReactApplicationContext reactContext) {
return Arrays.<ViewManager>asList(new AndroidSegmentedManager());
}
}
Step 8 - 新建AndroidSegmented.js，文件位置
‘ android/react-native-segmented-android/AndroidSegmented.js ’代码如下，然后在 ‘android/react-native-segmented-android/’下运行如下命令生成package.json文件
$ npm init //生成package.json文件
//AndroidSegmented.js
'use strict';
var React = require('react-native');
var { requireNativeComponent, PropTypes, View } = React;
var NativeAndroidSegmented = requireNativeComponent('AndroidSegmented', AndroidSegmented);
class AndroidSegmented extends React.Component {
constructor() {
super();
this._onChange = this._onChange.bind(this);
}
_onChange(event) {
if (this.props.onChange) {
this.props.onChange(event.nativeEvent);
}
}
render() {
return (
<NativeAndroidSegmented
{...this.props}
onChange={this._onChange}/>
);
}
}
var colorType = function (props, propName, componentName) {
var checker = function() {
var color = props[propName];
var regex = /^#([0-9A-Fa-f]{6}|[0-9A-Fa-f]{8})$/;
if (!regex.test(color)) {
return new Error('Only accept color formats: #RRGGBB and #AARRGGBB');
}
};
return PropTypes.string(props, propName, componentName) || checker();
}
AndroidSegmented.propTypes = {
...View.propTypes,
childText: PropTypes.arrayOf(PropTypes.oneOfType([ PropTypes.string ])),
orientation:PropTypes.string,
tintColor:PropTypes.arrayOf(PropTypes.oneOfType([ PropTypes.string ])),
selectedPosition:PropTypes.number,
onChange: PropTypes.func,
}
AndroidSegmented.defaultProps = {
};
module.exports = AndroidSegmented;
//package.json内容
{
"name": "react-native-segmented-android",
"version": "1.0.3",
"description": "a high imitation of iOS segmented Controls",
"main": "AndroidSegmented.js",
"scripts": {
"test": "react-native start"
},
"repository": {
"type": "git",
"url": "https://github.com/zzyyppqq/react-native-segmented-android.git"
},
"keywords": [
"android",
"segmented",
"react-component",
"react-native"
],
"author": "zzyyppqq",
"license": "ISC",
"peerDependencies": {
"react-native": "^1.0.3"
}
}
Step 9 - 复制AndroidSegmented.js 文件到‘/ReactNativeSegmentedAndroid/ ’ 目录下，如下是index.android.js代码，然后运行测试
'use strict';
var React = require('react-native');
var {
AppRegistry,
StyleSheet,
Text,
Dimensions,
ToastAndroid,
View,
} = React;
//var AndroidSegmented = require('react-native-segmented-android');
var AndroidSegmented = require('./AndroidSegmented');
var deviceWidth = Dimensions.get('window').width;
var deviceHeight = Dimensions.get('window').height;
var ReactNativeSegmentedExample = React.createClass({
onSelectPosition:function(event){
console.log(event);
ToastAndroid.show('segment '+event.selected, ToastAndroid.SHORT)
},
render: function() {
return (
<View>
<AndroidSegmented
tintColor={['#ff0000','#ffffff']}
style={{width:deviceWidth,height:60,backgroundColor:'#fff000',
justifyContent: 'center',
alignItems: 'center'}}
childText={['One','Two','Three','Four',"Five"]}
orientation='horizontal'
selectedPosition={0}
onChange={this.onSelectPosition} />
<AndroidSegmented
tintColor={['#009688','#ffffff']}
style={{width:deviceWidth,height:200,backgroundColor:'#fff000',
justifyContent: 'center',
alignItems: 'center'}}
childText={['One','Two','Three','Four',"Five"]}
orientation='vertical'
selectedPosition={0}
onChange={this.onSelectPosition} />
</View>
);
}
});
Install
Step 1 - Install the npm package
$ npm install react-native-degment-android --save
Step 2 - Update Gradle Settings
// file: android/settings.gradle
...
include ':react-native-degment-android', ':app'
project(':react-native-degment-android').projectDir = new File(rootProject.projectDir,'../node_modules/react-native-degment-android')
Step 3 - Update app Gradle Build
// file: android/app/build.gradle
...
dependencies {
...
compile project(':react-native-degment-android')
}
Step 4 - Register React Package
...
import com.higo.zhangyp.segmented.AndroidSegmentedPackage; // <-- import
public class MainActivity extends FragmentActivity implements DefaultHardwareBackBtnHandler {
private ReactInstanceManager mReactInstanceManager;
private ReactRootView mReactRootView;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
mReactRootView = new ReactRootView(this);
mReactInstanceManager = ReactInstanceManager.builder()
.setApplication(getApplication())
.setBundleAssetName("index.android.bundle")
.setJSMainModuleName("index.android")
.addPackage(new MainReactPackage())
.addPackage(new AndroidSegmentedPackage()) // <-- Register package here
.setUseDeveloperSupport(BuildConfig.DEBUG)
.setInitialLifecycleState(LifecycleState.RESUMED)
.build();
mReactRootView.startReactApplication(mReactInstanceManager, "AwesomeProject", null);
setContentView(mReactRootView);
}
...
从react-native的官方文档中我们已经知道facebook的react-native团队已经为我们实现了很多组件，例如 Image、Text、ViewPagerAndroid等，我们在index.android.js中可以直接使用这些组件，这些组件为什么能直接使用呢？
大家会很自然的想到已经封装好了呗。那在哪封装的？如何封装的？其实只要通过命令react-native init ProjectName创建过react-native工程的同学来说，在哪儿封装的一目了然。我们来看react-native工程的结构图：
B3BB8C75-7E30-4BCF-8BFD-4E7AA9A1A563.png
react-native工程中，在node_modules下有一个很特别的react-native文件夹，android的工程中的build.gradle 文件多了一个依赖，不用想肯定在这两个地方封装的，这也是react-native的关键。
dependencies {
compile 'com.facebook.react:react-native:0.16.+'
}
首先我们从入口MainActivity开始，看了我的前两篇文章，如何自定义react-native的android组件（一）和（二），要使用一个自定义组件，必须在MainActivity中加入【.addPackage(new AndroidSegmentedPackage()) 】才能使用。
...
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
mReactRootView = new ReactRootView(this);
mReactInstanceManager = ReactInstanceManager.builder()
.setApplication(getApplication())
.setBundleAssetName("index.android.bundle")
.setJSMainModuleName("index.android")
.addPackage(new MainReactPackage())
.addPackage(new AndroidSegmentedPackage())
.setUseDeveloperSupport(BuildConfig.DEBUG)
.setInitialLifecycleState(LifecycleState.RESUMED)
.build();
mReactRootView.startReactApplication(mReactInstanceManager, "ReactNativeSegmented", null);
setContentView(mReactRootView);
}
...
那么官方的Android组件是如何实现的呢，我们肯定注意到了【.addPackage(new MainReactPackage())】和自定义的是不是很像，格式也一样，我想肯定在这里面有实现，进入MainReactPackage类中，代码如下：
//react-native 源码
public class MainReactPackage implements ReactPackage {
@Override
public List<NativeModule> createNativeModules(ReactApplicationContext reactContext) {
return Arrays.<NativeModule>asList(
new AsyncStorageModule(reactContext),
new FrescoModule(reactContext),
new IntentModule(reactContext),
new LocationModule(reactContext),
new NetworkingModule(reactContext),
new WebSocketModule(reactContext),
new ToastModule(reactContext));
}
@Override
public List<Class<? extends JavaScriptModule>> createJSModules() {
return Collections.emptyList();
}
@Override
public List<ViewManager> createViewManagers(ReactApplicationContext reactContext) {
return Arrays.<ViewManager>asList(
new ReactDrawerLayoutManager(),
new ReactHorizontalScrollViewManager(),
new ReactImageManager(),
new ReactProgressBarViewManager(),
new ReactRawTextManager(),
new ReactScrollViewManager(),
new ReactSwitchManager(),
new ReactTextInputManager(),
new ReactTextViewManager(),
new ReactToolbarManager(),
new ReactViewManager(),
new ReactViewPagerManager(),
new ReactTextInlineImageViewManager(),
new ReactVirtualTextViewManager(),
new SwipeRefreshLayoutManager());
}
}
看了MainReactPackage中的代码，果不其然，首先我们看createViewManagers（）方法中的集合，看看集合子集的命名是不是很熟悉，
看看这里一共实现了多少原生控件：DrawerLayout、HorizontalScrollView、HorizontalScrollView、Image等等，还有SwipeRefreshLayout官网上还没有更新这个组件，其实这个版本已经可以使用了。
1.public class ReactDrawerLayoutManager extends ViewGroupManager<ReactDrawerLayout>
2.public class ReactImageManager extends SimpleViewManager<ReactImageView>
3.public class ReactProgressBarViewManager extends BaseViewManager<ProgressBarContainerView, ProgressBarShadowNode>
...
//贴上一个ReactDrawerLayoutManager源码，大家看看实现
public class ReactDrawerLayoutManager extends ViewGroupManager<ReactDrawerLayout> {
private static final String REACT_CLASS = "AndroidDrawerLayout";
public static final int OPEN_DRAWER = 1;
public static final int CLOSE_DRAWER = 2;
@Override
public String getName() {
return REACT_CLASS;
}
@Override
protected void addEventEmitters(ThemedReactContext reactContext, ReactDrawerLayout view) {
view.setDrawerListener(
new DrawerEventEmitter(
view,
reactContext.getNativeModule(UIManagerModule.class).getEventDispatcher()));
}
@Override
protected ReactDrawerLayout createViewInstance(ThemedReactContext context) {
return new ReactDrawerLayout(context);
}
@ReactProp(name = "drawerPosition", defaultInt = Gravity.START)
public void setDrawerPosition(ReactDrawerLayout view, int drawerPosition) {
if (Gravity.START == drawerPosition || Gravity.END == drawerPosition) {
view.setDrawerPosition(drawerPosition);
} else {
throw new JSApplicationIllegalArgumentException("Unknown drawerPosition " + drawerPosition);
}
}
@ReactProp(name = "drawerWidth", defaultFloat = Float.NaN)
public void getDrawerWidth(ReactDrawerLayout view, float width) {
int widthInPx = Float.isNaN(width) ?
ReactDrawerLayout.DEFAULT_DRAWER_WIDTH : Math.round(PixelUtil.toPixelFromDIP(width));
view.setDrawerWidth(widthInPx);
}
@Override
public boolean needsCustomLayoutForChildren() {
// Return true, since DrawerLayout will lay out it's own children.
return true;
}
@Override
public @Nullable Map<String, Integer> getCommandsMap() {
return MapBuilder.of("openDrawer", OPEN_DRAWER, "closeDrawer", CLOSE_DRAWER);
}
@Override
public void receiveCommand(
ReactDrawerLayout root,
int commandId,
@Nullable ReadableArray args) {
switch (commandId) {
case OPEN_DRAWER:
root.openDrawer();
break;
case CLOSE_DRAWER:
root.closeDrawer();
break;
}
}
@Override
public @Nullable Map getExportedViewConstants() {
return MapBuilder.of(
"DrawerPosition",
MapBuilder.of("Left", Gravity.START, "Right", Gravity.END));
}
@Override
public @Nullable Map getExportedCustomDirectEventTypeConstants() {
return MapBuilder.of(
DrawerSlideEvent.EVENT_NAME, MapBuilder.of("registrationName", "onDrawerSlide"),
DrawerOpenedEvent.EVENT_NAME, MapBuilder.of("registrationName", "onDrawerOpen"),
DrawerClosedEvent.EVENT_NAME, MapBuilder.of("registrationName", "onDrawerClose"),
DrawerStateChangedEvent.EVENT_NAME, MapBuilder.of(
"registrationName", "onDrawerStateChanged"));
}
/**
* This method is overridden because of two reasons:
* 1. A drawer must have exactly two children
* 2. The second child that is added, is the navigationView, which gets panned from the side.
*/
@Override
public void addView(ReactDrawerLayout parent, View child, int index) {
if (getChildCount(parent) >= 2) {
throw new
JSApplicationIllegalArgumentException("The Drawer cannot have more than two children");
}
if (index != 0 && index != 1) {
throw new JSApplicationIllegalArgumentException(
"The only valid indices for drawer's child are 0 or 1. Got " + index + " instead.");
}
parent.addView(child, index);
parent.setDrawerProperties();
}
public static class DrawerEventEmitter implements DrawerLayout.DrawerListener {
private final DrawerLayout mDrawerLayout;
private final EventDispatcher mEventDispatcher;
public DrawerEventEmitter(DrawerLayout drawerLayout, EventDispatcher eventDispatcher) {
mDrawerLayout = drawerLayout;
mEventDispatcher = eventDispatcher;
}
@Override
public void onDrawerSlide(View view, float v) {
mEventDispatcher.dispatchEvent(
new DrawerSlideEvent(mDrawerLayout.getId(), SystemClock.uptimeMillis(), v));
}
@Override
public void onDrawerOpened(View view) {
mEventDispatcher.dispatchEvent(
new DrawerOpenedEvent(mDrawerLayout.getId(), SystemClock.uptimeMillis()));
}
@Override
public void onDrawerClosed(View view) {
mEventDispatcher.dispatchEvent(
new DrawerClosedEvent(mDrawerLayout.getId(), SystemClock.uptimeMillis()));
}
@Override
public void onDrawerStateChanged(int i) {
mEventDispatcher.dispatchEvent(
new DrawerStateChangedEvent(mDrawerLayout.getId(), SystemClock.uptimeMillis(), i));
}
}
}
原生控件的实现步骤、方法、例子等其实在源码中都有了，想实现什么组件就照着源码开发，绝不会出错啦。
到此只是完成了android端的java代码，那么组件如何与js代码联系起来，并且供js代码调用呢，我们来看看工程中的react-navie文件夹吧，秘密都在它里面。
react-navie文件结构：
QQ20151218-1@2x.png
打开react-native文件夹，我一眼就注意到了ReactAndroid目录（因为做Android嘛，对含有Android的词比较敏感>_<）， 翻遍了其下所有的目录文件，终于找到一个有用点的文件package.json，在其中找到关键的一句话
【"main": "Libraries/react-native/react-native.js"】图上用红框标注了。
下一步就该看看Libraries目录了，Libraries目录结构：
QQ20151218-0@2x.png
图上我用红框标注了几个我们熟悉的控件命名的文件家，我们重点关注两个文件夹
Components与CustomComponents 我们看看里面有什么：
QQ20151218-2@2x.png
红线标注的控件是不是很熟悉，我们随便找一个控件进去看看，就看DrawerAndroid吧，截图如下：
QQ20151218-4@2x.png
QQ20151218-3@2x.png
大家遇到的各种不解之处，其实大部分都可以在源码中得到解答，我也在继续学习中，我只是和大家分享我学习的过程，我也只是顺藤摸瓜了解了如何方便的去自定义组件。其实里面的好多ES6语法我也不是特别理解，只是照猫画虎。欢迎大家来吐槽>_<。
1.如何自定义react-native的android组件（一）
3.react-native-0.16.1 自定义Android组件部分的源码初探
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