CDPEventListener

A protocol (or interface) used to receive CDP Event messages sent by DevTool.

Syntax

iOS

LynxBaseInspectorOwner.h

@protocol CDPEventListener <NSObject>

@required
- (void)onEvent:(nonnull NSString *)event;

@end

Android

CDPEventListener.java

public interface CDPEventListener {
  void onEvent(String event);
}

Parameters

event: A JSON string containing the CDP Event content.

Data Format

Field	Type	Description
method	string	Event name, please refer to CDP
params	object	Event parameters, please refer to CDP

For example, the data for Page.screencastFrame is as follows:

{
  "method": "Page.screencastFrame",
  "params": {
    "data": "...",
    "metadata": {
      "deviceHeight": 200.0,
      "deviceWidth": 100.0,
      "offsetTop": 0.0,
      "pageScaleFactor": 1.0,
      "scrollOffsetX": 0.0,
      "scrollOffsetY": 0.0
    }
  }
}

Usage Example

Steps

Implement CDPEventListener.
Get the LynxBaseInspectorOwner instance.
Call the addCDPEventListener method to add the message listener.

Code Example

The following example adds a CDP Event listener named TestListener and sends a Page.startScreencast message via invokeCDPFromSDK to enable screen capture functionality.

As a result, the TestCDPEventListener will receive Page.screencastFrame message.

iOS

TestCDPEventListener.h

#import <Lynx/LynxBaseInspectorOwner.h>

@interface TestCDPEventListener : NSObject <CDPEventListener>

@property(nonatomic, readonly, nonnull) NSString *name;

- (instancetype)initWithName:(NSString * _Nonnull )name;

@end

TestCDPEventListener.m

#import "TestCDPEventListener.h"

@implementation TestCDPEventListener

- (instancetype)initWithName:(NSString *)name {
  if (self = [super init]) {
    _name = name;
  }
  return self;
}

- (void)onEvent:(nonnull NSString *)event {
  NSLog(@"onEvent: %@", event);
}

@end

ViewController.m

#import <Lynx/LynxView.h>
#import <Lynx/LynxBaseInspectorOwner.h>

#import "TestCDPEventListener.h"

@interface LynxViewLifecycleClient : NSObject <LynxViewLifecycle>
@property(nonatomic, weak) LynxView* lynxView;
@end

@implementation LynxViewLifecycleClient {
  TestCDPEventListener* _listener;
}

- (void)lynxView:(LynxView *)view didLoadFinishedWithUrl:(NSString *)url {
  [self addCDPEventListener:@"TestListener"];
  __weak __typeof(self) weakSelf = self;
  dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(10 * NSEC_PER_SEC)),
                 dispatch_get_main_queue(), ^{
                   __strong __typeof(weakSelf) strongSelf = weakSelf;
                   [strongSelf removeCDPEventListener:@"TestListener"];
                 });
}

- (void)addCDPEventListener:(NSString *)name {
  __strong LynxView* view = self.lynxView;
  id<LynxBaseInspectorOwner> owner = [view baseInspectorOwner];
  _listener = [[TestCDPEventListener alloc] initWithName:name];
  [owner addCDPEventListener:name withListener:_listener];
  NSString *method = @"{\"id\":1,\"method\":\"Page.startScreencast\",\"params\":{\"format\":\"jpeg\",\"mode\":\"fullscreen\"}}";
  [owner invokeCDPFromSDK:method withCallback:^(NSString *result){
  }];
}

- (void)removeCDPEventListener:(NSString *)name {
  __strong LynxView* view = self.lynxView;
  id<LynxBaseInspectorOwner> owner = [view baseInspectorOwner];
  [owner removeCDPEventListener:name];
}

@end

@implementation ViewController {
  LynxViewLifecycleClient *_client;
}

- (void)viewDidLoad {
  [super viewDidLoad];

  // ...

  _client = [LynxViewLifecycleClient new];
  _client.lynxView = lynxView;
  [lynxView addLifecycleClient:_client];
}

@end

Android

TestCDPEventListener.java

import android.util.Log;

import com.lynx.devtoolwrapper.CDPEventListener;

public class TestCDPEventListener implements CDPEventListener {
  private final String name;

  public TestCDPEventListener(String name) {
    this.name = name;
  }

  public String getName() {
    return name;
  }

  @Override
  public void onEvent(String event) {
    Log.i("TestCDPEventListener", "onEvent: " + event);
  }
}

MainActivity.java

import android.os.Handler;
import android.os.Looper;

import com.lynx.devtoolwrapper.LynxBaseInspectorOwner;
import com.lynx.tasm.LynxView;
import com.lynx.tasm.LynxViewClient;

import java.lang.ref.WeakReference;

public class MainActivity extends Activity {
  private TestCDPEventListener mTestCDPEventListener = null;

  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    // ...

    lynxView.addLynxViewClient(new LynxViewClient() {
      @Override
      public void onLoadSuccess() {
        addCDPEventListener(lynxView, "TestListener");
      }
    });
  }

  private void addCDPEventListener(LynxView lynxView, String name) {
    LynxBaseInspectorOwner owner = lynxView.getBaseInspectorOwner();
    if (owner == null) {
      return;
    }
    mTestCDPEventListener = new TestCDPEventListener(name);
    owner.addCDPEventListener(name, mTestCDPEventListener);

    String method = "{\"id\":1,\"method\":\"Page.startScreencast\",\"params\":{\"format\":\"jpeg\",\"mode\":\"fullscreen\"}}";
    owner.invokeCDPFromSDK(method, result -> {
    });

    Handler mainHandler = new Handler(Looper.getMainLooper());
    WeakReference<LynxBaseInspectorOwner> weakOwner = new WeakReference<>(owner);
    mainHandler.postDelayed(() -> {
      LynxBaseInspectorOwner strongOwner = weakOwner.get();
      strongOwner.removeCDPEventListener(name);
    }, 10000);
  }
}

Compatibility

LCD tables only load in the browser

#CDPEventListener

#Syntax

#iOS

#Android

#Parameters

#Data Format

#Usage Example

#Steps

#Code Example

#iOS

#Android

#Compatibility

CDPEventListener

Syntax

iOS

Android

Parameters

Data Format

Usage Example

Steps

Code Example

iOS

Android

Compatibility