react native 调用原生UI组件 视频播放组件

react native 调用原生UI组件

本文章向大家介绍react native 调用原生UI组件,主要内容包括Java端实现、Js端实现、native层向js发送消息事件、js层向native层发送命令、基本概念、基础应用、原理机制和需要注意的事项等,并结合实例形式分析了其使用技巧,希望通过本文能帮助到大家理解应用这部分内容。

在React Native开发过程中,有时我们想要使用原生的一个UI组件或者是js比较难以实现的功能时,我们可以在react Naitve应用程序中封装和植入已有的原生组件。 本文我们实现一个VideoView的本地调用。 React Native并没有给我们提供VideoView这个组件,那我们要播放视频的话,有两种方法:一种是借助WebView,一种就是使用原生的播放器。

Java端实现
新建VideoViewManager类,并继承SimpleViewManager,SimpleViewManager类需要传入一个泛型,该泛型继承Android的View,也就是说该泛型是要使用android 平台的哪个View就传入该View,比如,我要使用android的VideoView,这个泛型就传入VideoView。相关的代码如下:

public class VideoViewManager extends SimpleViewManager{

    @Override
    public String getName() {//组件名称
        return "VideoView";
    }

    @Override
    protected VideoView createViewInstance(ThemedReactContext reactContext) {
        VideoView video = new VideoView(reactContext);
        return video;
    }
}

getName返回组件名称(可以加前缀RCT),createViewInstance方法返回实例对象,可以在初始化对象时设置一些属性。 其中,可以通过@ReactProp(或@ReactPropGroup)注解来导出属性的设置方法。该方法有两个参数,第一个参数是泛型View的实例对象,第二个参数是要设置的属性值。方法的返回值类型必须为void,而且访问控制必须被声明为public。组件的每一个属性的设置都会调用Java层被对应ReactProp注解的方法。

@ReactProp(name = "source")
public void setSource(RCTVideoView videoView,@Nullable String source){
    if(source != null){
        videoView.setVideoURI(Uri.parse(source));
        videoView.start();
    }
}

@ReactProp注解必须包含一个字符串类型的参数name。这个参数指定了对应属性在JavaScript端的名字。那么现在JS端可以这么设置source属性值。 但是在设置播放地址的时候,我们可能需要同时设置header信息,所以对上面的代码优化如下:

@ReactProp(name = "source")
public void setSource(VideoView videoView,@Nullable ReadableMap source){
    if(source != null){
        if (source.hasKey("url")) {
            String url = source.getString("url");
            FLog.e(VideoViewManager.class,"url = "+url);
            HashMap headerMap = new HashMap<>();
            if (source.hasKey("headers")) {
                ReadableMap headers = source.getMap("headers");
                ReadableMapKeySetIterator iter = headers.keySetIterator();
                while (iter.hasNextKey()) {
                    String key = iter.nextKey();
                    String value = headers.getString(key);
                    FLog.e(VideoViewManager.class,key+" = "+value);
                    headerMap.put(key,value);
                }
            }
            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
                videoView.setVideoURI(Uri.parse(url),headerMap);
            }else{
                try {
                    Method setVideoURIMethod = videoView.getClass().getMethod("setVideoURI", Uri.class, Map.class);
                    setVideoURIMethod.invoke(videoView, Uri.parse(url), headerMap);
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
            videoView.start();
        }
    }
}

VideoViewManager类的完整代码如下:

public class VideoViewManager extends SimpleViewManager{

    @Override
    public String getName() {
        return "VideoView";
    }

    @Override
    protected VideoView createViewInstance(ThemedReactContext reactContext) {
        VideoView video = new VideoView(reactContext);
        return video;
    }

    @Override
    public void onDropViewInstance(VideoView view) {//对象销毁时
        super.onDropViewInstance(view);
         view.stopPlayback();//停止播放
    }

    @ReactProp(name = "source")
    public void setSource(VideoView videoView,@Nullable ReadableMap source){
        if(source != null){
            if (source.hasKey("url")) {
                String url = source.getString("url");
                System.out.println("url = "+url);
                HashMap headerMap = new HashMap<>();
                if (source.hasKey("headers")) {
                    ReadableMap headers = source.getMap("headers");
                    ReadableMapKeySetIterator iter = headers.keySetIterator();
                    while (iter.hasNextKey()) {
                        String key = iter.nextKey();
                        headerMap.put(key, headers.getString(key));
                    }
                }
                if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
                    videoView.setVideoURI(Uri.parse(url),headerMap);
                }else{
                    try {
                        Method setVideoURIMethod = videoView.getClass().getMethod("setVideoURI", Uri.class, Map.class);
                        setVideoURIMethod.invoke(videoView, Uri.parse(url), headerMap);
                    } catch (Exception e) {
                        e.printStackTrace();
                    }
                }
                videoView.start();
            }
        }
    }
}

接着我们需要将UI组件注册到系统中去。创建VideoViewPackage,并注册到ReactNativeHost。

public class VideoViewPackage implements ReactPackage {
    @Override
    public List createNativeModules(ReactApplicationContext reactContext) {
        return Collections.emptyList();
    }

    @Override
    public List> createJSModules() {
        return Collections.emptyList();
    }

    @Override
    public List createViewManagers(ReactApplicationContext reactContext) {
        return Arrays.asList(
                new VideoViewManager()
        );
    }
}

然后向Application注册,以前的版本是向MainActivity注册。

@Override
protected List getPackages() {
    return Arrays.asList(
            new MainReactPackage(),
            new OrientationPackage(),
            new VideoViewPackage()
    );
}

Js端实现
在项目js/component文件夹下新建VideoView.js。代码如下:

import React,{ PropTypes }from 'react';
import {requireNativeComponent,View} from 'react-native';

var VideoView = {
    name:'VideoView',
    propTypes:{
        style: View.propTypes.style,
        source:PropTypes.shape({
            url:PropTypes.string,
            headers:PropTypes.object,
        }),
        ...View.propTypes,//包含默认的View的属性,如果没有这句会报‘has no propType for native prop’错误
    }
};
var RCTVideoView = requireNativeComponent('VideoView',VideoView);
module.exports = RCTVideoView;

然后我们直接使用即可。调用代码如下:

import React, {Component} from 'react';
import {
    View,
    StyleSheet,
    Text,
    TouchableOpacity
} from 'react-native';
import VideoView from './component/VideoView';

export default class VideoPlayView extends Component {

    constructor(props) {
        super(props);
    }

    render() {
        return (
            

                康熙王朝
                
            
        );
    }
}


const styles = StyleSheet.create({
    videoContainer: {
        flex: 1,
        justifyContent: 'center',
        alignItems: 'center',
    },
    text: {
        fontSize: 20,
        justifyContent: 'center',
    },
    video: {
        marginTop:10,
        height: 250,
        width: 380
    },

});

到此,React Native调用原生组件就基本实现了,不过,native层的一些信息我们还无法获取到,比如:视频的总时长、视频当前播放的时间点等。所以我们希望实现相关的功能。

native层向js发送消息事件
声明一个VideoViewManager的内部类RCTVideoView,它继承VideoView,并实现了一些必要的接口。

private static class RCTVideoView extends VideoView implements LifecycleEventListener,
        MediaPlayer.OnPreparedListener,
        MediaPlayer.OnCompletionListener,
        MediaPlayer.OnErrorListener,
        MediaPlayer.OnInfoListener,MediaPlayer.OnBufferingUpdateListener{

    public RCTVideoView(ThemedReactContext reactContext) {
        super(reactContext);
        reactContext.addLifecycleEventListener(this);
        setOnPreparedListener(this);
        setOnCompletionListener(this);
        setOnErrorListener(this);
    }

    @Override
    public void onHostResume() {
        FLog.e(VideoViewManager.class,"onHostResume");
    }

    @Override
    public void onHostPause() {
        FLog.e(VideoViewManager.class,"onHostPause");
        pause();
    }

    @Override
    public void onHostDestroy() {
        FLog.e(VideoViewManager.class,"onHostDestroy");
    }

    @Override
    public void onPrepared(MediaPlayer mp) {//视频加载成功准备播放
        FLog.e(VideoViewManager.class,"onPrepared duration = "+mp.getDuration());
        mp.setOnInfoListener(this);
        mp.setOnBufferingUpdateListener(this);
    }

    @Override
    public void onCompletion(MediaPlayer mp) {//视频播放结束
        FLog.e(VideoViewManager.class,"onCompletion");
    }

    @Override
    public boolean onError(MediaPlayer mp, int what, int extra) {//视频播放出错
        FLog.e(VideoViewManager.class,"onError what = "+ what+" extra = "+extra);
        return false;
    }

    @Override
    public boolean onInfo(MediaPlayer mp, int what, int extra) {
        FLog.e(VideoViewManager.class,"onInfo");
        switch (what) {
            /**
             * 开始缓冲
             */
            case MediaPlayer.MEDIA_INFO_BUFFERING_START:
                FLog.e(VideoViewManager.class,"开始缓冲");
                break;
            /**
             * 结束缓冲
             */
            case MediaPlayer.MEDIA_INFO_BUFFERING_END:
                FLog.e(VideoViewManager.class,"结束缓冲");
                break;
            /**
             * 开始渲染视频第一帧画面
             */
            case MediaPlayer.MEDIA_INFO_VIDEO_RENDERING_START:
                FLog.e(VideoViewManager.class,"开始渲染视频第一帧画面");
                break;
            default:
                break;
        }
        return false;
    }

    @Override
    public void onBufferingUpdate(MediaPlayer mp, int percent) {//视频缓冲进度
        FLog.e(VideoViewManager.class,"onBufferingUpdate percent = "+percent);
    }
}

接着我们在java层的onPrepared方法中获取视频播放时长,并想js发送事件通知。

@Override
public void onPrepared(MediaPlayer mp) {//视频加载成功准备播放
    int duration = mp.getDuration();
    FLog.e(VideoViewManager.class,"onPrepared duration = "+duration);
    mp.setOnInfoListener(this);
    mp.setOnBufferingUpdateListener(this);
    //向js发送事件
    WritableMap event = Arguments.createMap();
    event.putInt("duration",duration);//key用于js中的nativeEvent
    ReactContext reactContext = (ReactContext) getContext();
    reactContext.getJSModule(RCTEventEmitter.class).receiveEvent(
                    getId(),//native层和js层两个视图会依据getId()而关联在一起
                    "topChange",//事件名称
                    event//事件携带的数据
            );
}

receiveEvent接收三个参数,参数说明如注释所示,这个事件名topChange在JavaScript端映射到onChange回调属性上(这个映射关系在UIManagerModuleConstants.java文件里),这个回调会被原生事件执行。 当Js层收到通知之后,我们对VideoView.js代码进行优化。

class VideoView extends Component{
    constructor(props){
        super(props);
    }

    _onChange(event){
        if(!this.props.onPrepared){
            return;
        }
        this.props.onPrepared(event.nativeEvent.duration);
    }

    render(){
        return ;
    };
}

VideoView.name = "VideoView";
VideoView.propTypes = {
    onPrepared:PropTypes.func,
    style: View.propTypes.style,
    source:PropTypes.shape({
        url:PropTypes.string,
        headers:PropTypes.object,
    }),
    ...View.propTypes,
};
//需要注意下面这两句
var RCTVideoView = requireNativeComponent('VideoView',VideoView,{
    nativeOnly: {onChange: true}
});
module.exports = VideoView;

我们在java中发送的事件中携带的数据WritableMap中,定义的key与在js中event.nativeEvent.duration一致,nativeEvent和key就可以获取到value。

有时候有一些特殊的属性,想从原生组件中导出,但是又不希望它们成为对应React封装组件的属性,可以使用nativeOnly来声明。如果没有什么特殊属性需要设置的话,requireNativeComponent第三个参数可以不用。 需要注意的是,之前VideoView.js以下两句是这样:

var RCTVideoView = requireNativeComponent('VideoView',VideoView);
module.exports = RCTVideoView;

我们需要将它改为下面的这样:

var RCTVideoView = requireNativeComponent('VideoView',VideoView,{
    nativeOnly: {onChange: true}
});
module.exports = VideoView;

如果你不小心还是使用之前exports RCTVideoView 的那样,那么会一直接收不到onChange事件的回调! VideoView增加了onPrepared回调方法,运行程序后,可以看到打印了duration信息。但是如果native层需要发送的事件比较多的情况下,那么如果我们使用单一的topChange事件,就会导致回调的onChange不是单一职责。那么,我们是否可以自定义该事件的名称呢,使每一个事件对应各自的回调方法呢?下面我们就讲讲如何自定义事件名称。

自定义事件名称
首先,在VideoViewManager类中重写getExportedCustomDirectEventTypeConstants方法,然后自定义事件名称。

@Override
public Map getExportedCustomDirectEventTypeConstants() {
    return MapBuilder.of(
            "onCompletion", MapBuilder.of("registrationName", "onCompletion"));
}

第一个onCompletion字符串是java端发送事件是的名称,即receiveEvent方法的第二个参数值;第二个onCompletion字符串是定义在js端的回调方法;registrationName字符串的值是固定的,不能修改。对比一下topChange事件就知道了。

@Override
public Map getExportedCustomDirectEventTypeConstants() {
    return MapBuilder.of(
            "topChange", MapBuilder.of("registrationName", "onChange"));
}

接着,在内部类RCTVideoView的onCompletion方法发送事件。相关代码如下:

@Override
public void onCompletion(MediaPlayer mp) {//视频播放结束
    FLog.e(VideoViewManager.class,"onCompletion");
    ReactContext reactContext = (ReactContext) getContext();
    reactContext.getJSModule(RCTEventEmitter.class).receiveEvent(
            getId(),//native和js两个视图会依据getId()而关联在一起
            "onCompletion",//事件名称
            null
    );
}

由于只是通知js端,告诉它播放结束,不用携带任何数据,所以receiveEvent的第三个参数为null即可。然后在VideoView.js增加propTypes属性。

VideoView.propTypes = {
    onCompletion:PropTypes.func,
    //省略其它代码
};

最后在VideoPlayScene.js中使用VideoView时,增加onCompletion属性即可。相关的逻辑如下:

{
        console.log("JS onCompletion");
    }}
/>

当我们运行时,在浏览器就可以看到相关的打印日志。

其他的事件的定义流程都一样,比如获取当前进度信息、缓存进度、错误回调等。然后,我们看看VideoViewManager的完整实现。

public class VideoViewManager extends SimpleViewManager{

    private enum VideoEvent{
        EVENT_PREPARE("onPrepared"),
        EVENT_PROGRESS("onProgress"),
        EVENT_UPDATE("onBufferUpdate"),
        EVENT_ERROR("onError"),
        EVENT_COMPLETION("onCompletion");

        private String mName;
        VideoEvent(String name) {
            this.mName = name;
        }

        @Override
        public String toString() {
            return mName;
        }
    }

    @Override
    public String getName() {
        return "VideoView";
    }

    @Override
    protected VideoView createViewInstance(ThemedReactContext reactContext) {
        RCTVideoView video = new RCTVideoView(reactContext);
        return video;
    }

    @Nullable
    @Override
    public Map getCommandsMap() {
        return super.getCommandsMap();
    }

    @Override
    public void receiveCommand(VideoView root, int commandId, @Nullable ReadableArray args) {
        super.receiveCommand(root, commandId, args);
    }

    @Nullable
    @Override
    public Map getExportedCustomDirectEventTypeConstants() {
        MapBuilder.Builder builder = MapBuilder.builder();
        for (VideoEvent event:VideoEvent.values()){
            builder.put(event.toString(),MapBuilder.of("registrationName", event.toString()));
        }
        return builder.build();
    }

    @Override
    public void onDropViewInstance(VideoView view) {//销毁对象时释放一些资源
        super.onDropViewInstance(view);
        ((ThemedReactContext) view.getContext()).removeLifecycleEventListener((RCTVideoView) view);
         view.stopPlayback();
    }


    @ReactProp(name = "source")
    public void setSource(RCTVideoView videoView,@Nullable ReadableMap source){
        if(source != null){
            if (source.hasKey("url")) {
                String url = source.getString("url");
                FLog.e(VideoViewManager.class,"url = "+url);
                HashMap headerMap = new HashMap<>();
                if (source.hasKey("headers")) {
                    ReadableMap headers = source.getMap("headers");
                    ReadableMapKeySetIterator iter = headers.keySetIterator();
                    while (iter.hasNextKey()) {
                        String key = iter.nextKey();
                        String value = headers.getString(key);
                        FLog.e(VideoViewManager.class,key+" = "+value);
                        headerMap.put(key,value);
                    }
                }
                if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
                    videoView.setVideoURI(Uri.parse(url),headerMap);
                }else{
                    try {
                        Method setVideoURIMethod = videoView.getClass().getMethod("setVideoURI", Uri.class, Map.class);
                        setVideoURIMethod.invoke(videoView, Uri.parse(url), headerMap);
                    } catch (Exception e) {
                        e.printStackTrace();
                    }
                }
                videoView.start();
            }
        }
    }

    private static class RCTVideoView extends VideoView implements LifecycleEventListener,
            MediaPlayer.OnPreparedListener,
            MediaPlayer.OnCompletionListener,
            MediaPlayer.OnErrorListener,
            MediaPlayer.OnInfoListener,
            MediaPlayer.OnBufferingUpdateListener,
            Runnable{

        private Handler mHandler;

        public RCTVideoView(ThemedReactContext reactContext) {
            super(reactContext);
            reactContext.addLifecycleEventListener(this);
            setOnPreparedListener(this);
            setOnCompletionListener(this);
            setOnErrorListener(this);
            mHandler = new Handler();
        }

        @Override
        public void onHostResume() {
            FLog.e(VideoViewManager.class,"onHostResume");
        }

        @Override
        public void onHostPause() {
            FLog.e(VideoViewManager.class,"onHostPause");
            pause();
        }

        @Override
        public void onHostDestroy() {
            FLog.e(VideoViewManager.class,"onHostDestroy");
            mHandler.removeCallbacks(this);
        }

        @Override
        public void onPrepared(MediaPlayer mp) {//视频加载成功准备播放
            int duration = mp.getDuration();
            FLog.e(VideoViewManager.class,"onPrepared duration = "+duration);
            mp.setOnInfoListener(this);
            mp.setOnBufferingUpdateListener(this);
            WritableMap event = Arguments.createMap();
            event.putInt("duration",duration);//key用于js中的nativeEvent
            dispatchEvent(VideoEvent.EVENT_PREPARE.toString(),event);
            mHandler.post(this);
        }

        @Override
        public void onCompletion(MediaPlayer mp) {//视频播放结束
            FLog.e(VideoViewManager.class,"onCompletion");
            dispatchEvent(VideoEvent.EVENT_COMPLETION.toString(),null);
            mHandler.removeCallbacks(this);
            int progress = getDuration();
            WritableMap event = Arguments.createMap();
            event.putInt("progress",progress);
            dispatchEvent(VideoEvent.EVENT_PROGRESS.toString(),event);
        }

        @Override
        public boolean onError(MediaPlayer mp, int what, int extra) {//视频播放出错
            FLog.e(VideoViewManager.class,"onError what = "+ what+" extra = "+extra);
            mHandler.removeCallbacks(this);
            WritableMap event = Arguments.createMap();
            event.putInt("what",what);
            event.putInt("extra",what);
            dispatchEvent(VideoEvent.EVENT_ERROR.toString(),event);
            return true;
        }

        @Override
        public boolean onInfo(MediaPlayer mp, int what, int extra) {
            FLog.e(VideoViewManager.class,"onInfo");
            switch (what) {
                /**
                 * 开始缓冲
                 */
                case MediaPlayer.MEDIA_INFO_BUFFERING_START:
                    FLog.e(VideoViewManager.class,"开始缓冲");
                    break;
                /**
                 * 结束缓冲
                 */
                case MediaPlayer.MEDIA_INFO_BUFFERING_END:
                    FLog.e(VideoViewManager.class,"结束缓冲");
                    break;
                /**
                 * 开始渲染视频第一帧画面
                 */
                case MediaPlayer.MEDIA_INFO_VIDEO_RENDERING_START:
                    FLog.e(VideoViewManager.class,"开始渲染视频第一帧画面");
                    break;
                default:
                    break;
            }
            return false;
        }

        @Override
        public void onBufferingUpdate(MediaPlayer mp, int percent) {//视频缓冲进度
            FLog.e(VideoViewManager.class,"onBufferingUpdate percent = "+percent);
            int buffer = (int) Math.round((double) (mp.getDuration() * percent) / 100.0);
            WritableMap event = Arguments.createMap();
            event.putInt("buffer",buffer);
            dispatchEvent(VideoEvent.EVENT_UPDATE.toString(),event);
        }

        @Override
        public void run() {
            int progress = getCurrentPosition();
            WritableMap event = Arguments.createMap();
            event.putInt("progress",progress);
            dispatchEvent(VideoEvent.EVENT_PROGRESS.toString(),event);
            mHandler.postDelayed(this,1000);
        }

        private void dispatchEvent(String eventName,WritableMap eventData){
            ReactContext reactContext = (ReactContext) getContext();
            reactContext.getJSModule(RCTEventEmitter.class).receiveEvent(
                    getId(),//native和js两个视图会依据getId()而关联在一起
                    eventName,//事件名称
                    eventData
            );
        }
    }
}

对于VideoView.js我们改造如下:

class VideoView extends Component{
    constructor(props){
        super(props);
    }

    /*_onChange(event){
        if(!this.props.onPrepared){
            return;
        }
        this.props.onPrepared(event.nativeEvent.duration);
    }*/

    _onPrepared(event){
        if(!this.props.onPrepared){
            return;
        }
        this.props.onPrepared(event.nativeEvent.duration);
    }

    _onError(event){
        if(!this.props.onError){
            return;
        }
        this.props.onError(event.nativeEvent);
    }

    _onBufferUpdate(event){
        if(!this.props.onBufferUpdate){
            return;
        }
        this.props.onBufferUpdate(event.nativeEvent.buffer);
    }

    _onProgress(event){
        if(!this.props.onProgress){
            return;
        }
        this.props.onProgress(event.nativeEvent.progress);
    }

    render(){
        //return ;
        return ;
    };
}

VideoView.name = "VideoView";
VideoView.propTypes = {
    onPrepared:PropTypes.func,
    onCompletion:PropTypes.func,
    onError:PropTypes.func,
    onBufferUpdate:PropTypes.func,
    onProgress:PropTypes.func,
    style: View.propTypes.style,
    source:PropTypes.shape({
        url:PropTypes.string,
        headers:PropTypes.object,
    }),
    ...View.propTypes,
};

var RCTVideoView = requireNativeComponent('VideoView',VideoView,{
    nativeOnly: {onChange: true}
});
module.exports = VideoView;

VideoView的使用(省略其它代码),VideoPlayScene.js

{
        console.log("JS onCompletion");
    }}
    onError={(e)=>{
        console.log("what="+e.what+" extra="+e.extra);
    }}
    onBufferUpdate={(buffer)=>{
        console.log("JS buffer = "+buffer);
    }}
    onProgress={(progress)=>{
        console.log("JS progress = "+progress);
    }}
/>

js层向native层发送命令
讲完native层向js发送事件后,那么js如何向native命令呢?继续往下看。比如在js端我想通过点击某个按钮,来控制视频暂停,那么就需要native层来响应这个操作,因为native掌握着VideoView的所有权,暂停可以通过调用VideoView对象的pause方法。首先,我们需要在native层定义这些命令,并在接收到命令时处理相关操作。 在VideoViewManager重写getCommandsMap方法。

private static final int COMMAND_PAUSE_ID = 1;
private static final String COMMAND_PAUSE_NAME = "pause";

@Override
public Map getCommandsMap() {
    return MapBuilder.of(
            COMMAND_PAUSE_NAME,COMMAND_PAUSE_ID
    );
}

getCommandsMap接收多组命令,每组命令需要包括名称(js端调用的方法名)和命令id,如上面的COMMAND_PAUSE_NAME 和 COMMAND_PAUSE_ID。 然后重写receiveCommand方法,处理相应的命令。

@Override
public void receiveCommand(VideoView root, int commandId, @Nullable ReadableArray args) {
    switch (commandId){
        case COMMAND_PAUSE_ID:
            root.pause();
            break;
        default:
            break;
    }
}

Native端在接收到COMMAND_PAUSE_ID 命令时,调用了VideoView的pause方法进行暂停播放。 接下来就是js端如何发起该命令了,打开VideoView.js,添加如下代码:

import {
    requireNativeComponent,
    View,
    UIManager,
    findNodeHandle,
} from 'react-native';

var RCT_VIDEO_REF = 'VideoView';

class VideoView extends Component{
    //省略其它代码
    pause(){
        //向native层发送命令
        UIManager.dispatchViewManagerCommand(
            findNodeHandle(this.refs[RCT_VIDEO_REF]),
            UIManager.VideoView.Commands.pause,//Commands.pause与native层定义的COMMAND_PAUSE_NAME一致
            null//命令携带的参数数据
        );
    }
    render(){
        return ;
    };
}

主要是定义了一个pause函数,该函数内使用UIManager.dispatchViewManagerCommand向native层发送命令,该方法接收三个参数:第一个参数是组件的实例对象;第二个是发送的命令名称,与native层定义的command name一致;第三个是命令携带的参数数据。 打开VideoPlayScene.js,给视频播放添加暂停功能。

export default class VideoPlayScene extends Component {
    //暂停播放
    _onPressPause(){
        this.video.pause();
    }

    render() {
        return (
            
                {this.video = video}}
                    //省略其它代码
                />
                
                    {this.state.time}/{this.state.totalTime}
                    
                        暂停
                    
                
            
        );
    }
}

运行程序,你发现已经可以暂停播放了。同样的流程,我们再给播放器添加‘开始播放’的功能。开发VideoViewManager.java,添加开始播放功能。

private static final int COMMAND_START_ID = 2;
private static final String COMMAND_START_NAME = "start";
@Override
public Map getCommandsMap() {
    return MapBuilder.of(
            COMMAND_PAUSE_NAME,COMMAND_PAUSE_ID,
            COMMAND_START_NAME,COMMAND_START_ID);
}

@Override
public void receiveCommand(VideoView root, int commandId, @Nullable ReadableArray args) {
    FLog.e(VideoViewManager.class,"receiveCommand id = "+commandId);
    switch (commandId){
        case COMMAND_PAUSE_ID:
            root.pause();
            break;
        case COMMAND_START_ID:
            root.start();
            break;
        default:
            break;
    }
}

VideoView.js 添加开始播放的代码

start(){
    UIManager.dispatchViewManagerCommand(
        findNodeHandle(this.refs[RCT_VIDEO_REF]),
        UIManager.VideoView.Commands.start,
        null
    );
}

在VideoPlayScene.js添加开始播放的功能。

_onPressPause(){
    this.video.pause();
}

_onPressStart(){
    this.video.start();
}

render() {
    return (
        
            {this.video = video}}
                //省略其它代码
            />
            
                {this.state.time}/{this.state.totalTime}
                
                    暂停
                
                
                    开始
                
            

        
    );
}

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