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android – Disable Screen Capture/ScreenShot in React Native App

Posted by: admin June 15, 2020 Leave a comment

Questions:

I have came across few solutions specific for ios and Android to prevent screen-capturing and taking screenshots. But how do i disable screen-capturing in react native?

How to&Answers:

Android

Inside /android/app/src/main/java/com/{Project_Name}/MainActivity.java

you may add the following lines. Prevent capture screen by setFlag FLAG_SECURE, use code below as an example:

import android.os.Bundle;
import android.view.WindowManager;

...

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    getWindow().setFlags(WindowManager.LayoutParams.FLAG_SECURE, WindowManager.LayoutParams.FLAG_SECURE);
}

later when you want to remove secure flag

getWindow().clearFlags(WindowManager.LayoutParams.FLAG_SECURE);

iOS

overlay screen in AppDelegate.m, take this example:

- (void)applicationWillResignActive:(UIApplication *)application {    
    // fill screen with our own colour
    UIView *colourView = [[UIView alloc]initWithFrame:self.window.frame];
    colourView.backgroundColor = [UIColor whiteColor];
    colourView.tag = 1234;
    colourView.alpha = 0;
    [self.window addSubview:colourView];
    [self.window bringSubviewToFront:colourView];
    // fade in the view
    [UIView animateWithDuration:0.5 animations:^{
        colourView.alpha = 1;
    }];
}

- (void)applicationDidBecomeActive:(UIApplication *)application {
    // grab a reference to our coloured view
    UIView *colourView = [self.window viewWithTag:1234];
    // fade away colour view from main view
    [UIView animateWithDuration:0.5 animations:^{
        colourView.alpha = 0;
    } completion:^(BOOL finished) {
        // remove when finished fading
        [colourView removeFromSuperview];
    }];
}

Answer:

Prevent Capture Screen

Android

Prevent capture screen by setFlag secure

getWindow().setFlags(WindowManager.LayoutParams.FLAG_SECURE, WindowManager.LayoutParams.FLAG_SECURE);

If you want to remove flag secure

getWindow().clearFlags(WindowManager.LayoutParams.FLAG_SECURE);

Answer:

In android

/android/app/src/main/java/com/{Project_Name}/MainActivity.java

write some Import Statements

import android.os.Bundle;
import android.view.WindowManager;

Prevent capture screen by setFlag secure use below code inside the MainActivity class

@Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        getWindow().setFlags(WindowManager.LayoutParams.FLAG_SECURE, WindowManager.LayoutParams.FLAG_SECURE);
    }

Answer:

So there is little work for the iOS side build on React Native platform. So be patient with me to read the following approach.

I am using the react-native-video package for playing media. My requirement was to show spinner if user has screen recording enabled.

  1. From https://developer.apple.com/documentation/uikit/uiscreen/2921651-captured?language=objc I understood that captured property is set to YES. I added observer in AppDelegate.m, under didFinishLaunchingWithOptions method.

    [[UIScreen mainScreen] addObserver:self forKeyPath:@"captured" options:NSKeyValueObservingOptionNew context:nil];

  2. Since RN allows communication with Native modules, I decided to add bridge so notify when capture flag is set to YES.

I created two files ScreenRecordingNotification.h and .m

.h

#import <React/RCTBridgeModule.h>
#import <React/RCTEventEmitter.h>
#ifndef ScreenCaptureNotification_h
#define ScreenCaptureNotification_h


@interface ScreenCaptureNotification : RCTEventEmitter <RCTBridgeModule>
-(void) isScreenCaptureEnabled:(BOOL)isCaptured;
@end

#endif /* ScreenCaptureNotification_h */

and .m looks like

#import <Foundation/Foundation.h>
#import "ScreenCaptureNotification.h"
#import <React/RCTLog.h>
@implementation ScreenCaptureNotification

+ (id)allocWithZone:(NSZone *)zone {
  static ScreenCaptureNotification *sharedInstance = nil;
  static dispatch_once_t onceToken;
  dispatch_once(&onceToken, ^{
    sharedInstance = [super allocWithZone:zone];
  });
  return sharedInstance;
}

RCT_EXPORT_MODULE();

- (NSArray<NSString *> *)supportedEvents {
  return @[           
           @"isScreenCaptureEnabled"];
}

-(void) isScreenCaptureEnabled:(BOOL)isCaptured {
  [self sendEventWithName:@"isScreenCaptureEnabled" body:@{@"value": @(isCaptured)}];
}

@end
  1. import #import "ScreenCaptureNotification.h" in AppDelegate and added the following method.

    - (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context {
        if ([keyPath isEqualToString:@"captured"]){
          NSLog(@"Screen Capture is Enabled");
          RCTLog(@"Screen Capture is Enabled");
          if (@available(iOS 11.0, *)) {
            ScreenCaptureNotification *manager = [ScreenCaptureNotification allocWithZone: nil];
            [manager isScreenCaptureEnabled:UIScreen.mainScreen.isCaptured];
          }
        }
    }
    

And also add [[UIScreen mainScreen] addObserver:self forKeyPath:@"captured" options:NSKeyValueObservingOptionNew context:nil]; in didFinishLaunchingWithOptions.
This concludes changes at iOS side.

  1. Now you need to add Listener in .js files for notification which iOS sending. Once you get notification, it’s up to you to decide what to do with it. Roughly it will look like below.
  addListener() {  
    let bridge = new NativeEventEmitter(NativeModules.ScreenCaptureNotification);

    this.screenCaptureEnabled = bridge.addListener("isScreenCaptureEnabled",res => { 
      this.setState({ screenCapture: true })
    })
  }

and

render() {
  if (this.state.screenCapture) {
     //Show spinner
     return <Spinner />
  }
  return (
  <Vido uri ... /> 
  )
}

I am open to suggestions to make changes to this post. Don’t forget to upvote if this post helped you.