Webview Java

https://github.com/webview/webview_java
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A Java port of the webview project that enables building desktop applications with web technologies...
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License:MIT
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### Maven Setup for webview_java

Source: https://context7.com/webview/webview_java/llms.txt

This snippet shows how to add the webview_java core and bridge dependencies to your Maven project. It requires configuring the Jitpack.io repository.

```xml
<repositories>
    <repository>
        <id>jitpack.io</id>
        <url>https://jitpack.io</url>
    </repository>
</repositories>

<dependency>
    <groupId>com.github.webview.webview_java</groupId>
    <artifactId>core</artifactId>
    <version>_VERSION</version>
</dependency>

<!-- Optional: For Bridge bindings -->
<dependency>
    <groupId>com.github.webview.webview_java</groupId>
    <artifactId>bridge</artifactId>
    <version>_VERSION</version>
</dependency>
```

--------------------------------

### Gradle Setup for webview_java

Source: https://context7.com/webview/webview_java/llms.txt

This snippet demonstrates how to include the webview_java core and bridge libraries in your Gradle project. It configures the Jitpack.io repository for dependency resolution.

```gradle
allprojects {
    repositories {
        maven { url 'https://jitpack.io' }
    }
}

dependencies {
    implementation 'com.github.webview.webview_java:core:_VERSION'
    // Optional: For Bridge bindings
    implementation 'com.github.webview.webview_java:bridge:_VERSION'
}
```

--------------------------------

### Serve JAR Resources with ResourceHandler

Source: https://context7.com/webview/webview_java/llms.txt

This example demonstrates how to use the ResourceHandler to serve static files from a JAR's resources directory. It sets up a UIServer to handle requests, mapping URL paths to resources within the specified directory (e.g., '/ui' maps to '/resources/ui/'). This is useful for bundling web assets directly within your Java application.

```java
import dev.webview.webview_java.Webview;
import dev.webview.webview_java.uiserver.UIServer;
import dev.webview.webview_java.uiserver.ResourceHandler;
import java.io.IOException;

public class ResourceHandlerExample {
    public static void main(String[] args) throws IOException {
        Webview wv = new Webview(true);
        UIServer server = new UIServer();

        // Serve files from /resources/ui/ directory in JAR
        // Request to /index.html serves /ui/index.html from resources
        server.setHandler(new ResourceHandler("/ui"));

        server.start();

        wv.setTitle("Resource Server");
        wv.setSize(800, 600);
        wv.loadURL(server.getLocalAddress() + "/index.html");

        wv.run();
        wv.close();
        server.close();
    }
}

// Project structure:
// src/main/resources/ui/
//   index.html
//   styles.css
//   app.js
```

--------------------------------

### Enable Dark Mode Appearance (Windows)

Source: https://context7.com/webview/webview_java/llms.txt

This example shows how to enable dark mode for the application window on Windows. It creates a Webview instance and calls the setDarkAppearance(true) method. This feature is platform-specific to Windows.

```java
import dev.webview.webview_java.Webview;

public class DarkModeExample {
    public static void main(String[] args) {
        Webview wv = new Webview(true);

        // Enable dark window appearance (Windows only)
        wv.setDarkAppearance(true);

        wv.setTitle("Dark Mode App");
        wv.setSize(800, 600);
        wv.loadURL("https://example.com");
        wv.run();
        wv.close();
    }
}
```

--------------------------------

### Get Webview Library Version

Source: https://context7.com/webview/webview_java/llms.txt

This utility method retrieves the version of the webview native library. It's a simple static call to Webview.getVersion() and prints the result to the console. This can be useful for debugging or verifying the installed library version.

```java
import dev.webview.webview_java.Webview;

public class VersionExample {
    public static void main(String[] args) {
        String version = Webview.getVersion();
        System.out.println("Webview native library version: " + version);
    }
}
```

--------------------------------

### Implement Reactive Java Properties for JavaScript Updates

Source: https://context7.com/webview/webview_java/llms.txt

This Java example demonstrates how to create reactive properties that automatically update JavaScript when their values change in Java. The `watchForMutate = true` option on the `@JavascriptValue` annotation enables this behavior. The provided JavaScript code then subscribes to these changes using a Svelte-like store mechanism, updating the UI in real-time.

```java
import dev.webview.webview_java.Webview;
import dev.webview.webview_java.bridge.*;

public class ReactiveExample {
    public static void main(String[] args) {
        Webview wv = new Webview(true);
        WebviewBridge bridge = new WebviewBridge(wv);

        bridge.defineObject("Data", new ReactiveDataObject());

        wv.setSize(800, 600);
        wv.setHTML(
            "<!DOCTYPE html><html><body>" +
            "<p>Time: <span id='time'></span></p>" +
            "<script>" +
            "// Subscribe to property changes using Svelte-like stores" +
            "Data.__stores.svelte('currentTime')" +
            "  .subscribe((time) => {" +
            "    document.getElementById('time').innerText = time;" +
            "  });" +
            "</script>" +
            "</body></html>"
        );

        wv.run();
        wv.close();
    }
}

class ReactiveDataObject extends JavascriptObject {

    @JavascriptValue(allowSet = false, watchForMutate = true)
    public long currentTime = 0;

    {
        // Background thread updates the value
        new Thread(() -> {
            while (true) {
                this.currentTime = System.currentTimeMillis();
                try { Thread.sleep(100); } catch (InterruptedException e) { break; }
            }
        }).start();
    }
}

```

--------------------------------

### Create a Local UI Server with UIServer in Java

Source: https://context7.com/webview/webview_java/llms.txt

Illustrates how to create a local HTTP server using the `UIServer` class for serving bundled UI files to a Webview. This allows for dynamic content serving and custom request handling, with the server running on a random available port.

```java
import dev.webview.webview_java.Webview;
import dev.webview.webview_java.uiserver.UIServer;
import co.casterlabs.rhs.protocol.StandardHttpStatus;
import co.casterlabs.rhs.server.HttpResponse;
import java.io.IOException;

public class UIServerExample {
    public static void main(String[] args) throws IOException {
        Webview wv = new Webview(true);
        UIServer server = new UIServer();

        // Set custom request handler
        server.setHandler((session) -> {
            String uri = session.getUri();

            if (uri.equals("/")) {
                return HttpResponse
                    .newFixedLengthResponse(StandardHttpStatus.OK,
                        "<html><body><h1>Welcome!</h1></body></html>")
                    .setMimeType("text/html");
            } else if (uri.equals("/api/data")) {
                return HttpResponse
                    .newFixedLengthResponse(StandardHttpStatus.OK,
                        "{\"status\": \"ok\"}")
                    .setMimeType("application/json");
            }

            return HttpResponse
                .newFixedLengthResponse(StandardHttpStatus.NOT_FOUND, "Not Found");
        });

        server.start();

        System.out.println("Server running at: " + server.getLocalAddress());
        System.out.println("Port: " + server.getPort());

        wv.setTitle("UI Server Example");
        wv.setSize(800, 600);
        wv.loadURL(server.getLocalAddress());

        wv.run();
        wv.close();
        server.close();
    }
}
```

--------------------------------

### Create and Run a Basic Webview in Java

Source: https://context7.com/webview/webview_java/llms.txt

This Java code demonstrates the fundamental usage of the `Webview` class to create a native window, set its properties, load a URL, and run the event loop. It requires the webview_java core library.

```java
import dev.webview.webview_java.Webview;

public class BasicWebviewExample {
    public static void main(String[] args) {
        // Create webview with debug mode enabled (allows DevTools)
        Webview wv = new Webview(true);

        // Alternative: Create with preset dimensions
        // Webview wv = new Webview(true, 1280, 720);

        // Set window properties
        wv.setTitle("My Webview App");
        wv.setSize(800, 600);

        // Load a URL
        wv.loadURL("https://example.com");

        // Or load raw HTML content
        // wv.setHTML("<h1>Hello World!</h1><p>This is a test.</p>");

        // Run the event loop (blocks until window is closed)
        wv.run();

        // Free resources
        wv.close();
    }
}
```

--------------------------------

### Set Initialization Scripts in Java

Source: https://context7.com/webview/webview_java/llms.txt

Injects JavaScript code that runs automatically when any page loads using the `setInitScript()` method. This is useful for setting up global functions or configurations. The `allowNestedAccess` parameter controls script execution in nested iframes.

```java
import dev.webview.webview_java.Webview;

public class InitScriptExample {
    public static void main(String[] args) {
        Webview wv = new Webview(true);

        // Script runs after window.load on each page
        wv.setInitScript(
            "window.appConfig = { version: '1.0', debug: true };" +
            "console.log('App initialized!');"
        );

        // Allow script to run in nested iframes
        wv.setInitScript(
            "window.globalHelper = function() { return 'helper'; };",
            true // allowNestedAccess
        );

        wv.setTitle("Init Script Example");
        wv.loadURL("https://example.com");
        wv.run();
        wv.close();
    }
}
```

--------------------------------

### Expose Nested Objects to JavaScript in Java

Source: https://context7.com/webview/webview_java/llms.txt

Demonstrates how to expose nested Java objects and their properties/methods to JavaScript. These objects are automatically accessible in the JavaScript environment, allowing for seamless interaction between Java and JavaScript.

```java
import dev.webview.webview_java.bridge.*;

public class NestedObjectExample extends JavascriptObject {

    // Nested object accessible as ParentObject.settings
    public final SettingsObject settings = new SettingsObject();

    // Nested object accessible as ParentObject.user
    public final UserObject user = new UserObject();

    @JavascriptFunction
    public void doSomething() {
        System.out.println("Parent function called");
    }
}

class SettingsObject extends JavascriptObject {

    @JavascriptValue
    public boolean darkMode = false;

    @JavascriptValue
    public int fontSize = 14;

    @JavascriptFunction
    public void reset() {
        darkMode = false;
        fontSize = 14;
    }
}

class UserObject extends JavascriptObject {

    @JavascriptValue
    public String username = "guest";

    @JavascriptFunction
    public boolean login(String user, String pass) {
        // Authentication logic
        return true;
    }
}

// JavaScript usage:
// await App.settings.darkMode
// await App.settings.reset()
// await App.user.login("admin", "password")
```

--------------------------------

### Bind Java Functions to JavaScript in webview_java

Source: https://context7.com/webview/webview_java/llms.txt

This Java code illustrates how to use the `bind()` method to expose Java functions to JavaScript. These functions can be called from the webview, and they return Promises that resolve with the Java function's return value. It requires the webview_java core library.

```java
import dev.webview.webview_java.Webview;

public class BindingExample {
    public static void main(String[] args) {
        Webview wv = new Webview(true);

        // Bind a simple echo function
        // JavaScript: await echo(1, 2, 3) returns "[1, 2, 3]"
        wv.bind("echo", (arguments) -> {
            return arguments; // Returns JSON array of arguments
        });

        // Bind a function that performs calculations
        wv.bind("multiply", (arguments) -> {
            // arguments is a JSON string: "[2, 3]"
            // Parse and process as needed
            return "{\"result\": 6}";
        });

        // Bind a function that controls the webview
        wv.bind("setDarkMode", (arguments) -> {
            wv.setDarkAppearance(arguments.contains("true"));
            return null;
        });

        wv.setTitle("Binding Example");
        wv.setSize(800, 600);
        wv.setHTML(
            "<!DOCTYPE html>" +
            "<html><body>" +
            "<button onclick='test()'>Test Echo</button>" +
            "<script>" +
            "async function test() {" +
            "  const result = await echo('hello', 'world');" +
            "  alert('Result: ' + result);" +
            "}" +
            "</script>" +
            "</body></html>"
        );

        wv.run();
        wv.close();
    }
}
```

--------------------------------

### Gradle Dependency for Webview Java Core

Source: https://github.com/webview/webview_java/blob/main/README.md

This snippet demonstrates how to include the webview Java core library in a Gradle project. It involves setting up the Jitpack repository for all projects and then adding the dependency.

```gradle
allprojects {
  repositories {
    maven { url 'https://jitpack.io' }
  }
}

dependencies {
  implementation 'com.github.webview.webview_java:core:_VERSION'
}
```

--------------------------------

### Control Window Size in Java

Source: https://context7.com/webview/webview_java/llms.txt

Manages the dimensions of the webview window using methods like `setSize()`, `setMinSize()`, and `setMaxSize()`. A fixed-size window can also be created using `setFixedSize()`.

```java
import dev.webview.webview_java.Webview;

public class WindowSizeExample {
    public static void main(String[] args) {
        Webview wv = new Webview(true);

        // Set the default window size (resizable)
        wv.setSize(800, 600);

        // Set minimum allowed size
        wv.setMinSize(400, 300);

        // Set maximum allowed size
        wv.setMaxSize(1920, 1080);

        // Or create a fixed-size window that cannot be resized
        // wv.setFixedSize(800, 600);

        wv.setTitle("Window Size Example");
        wv.loadURL("https://example.com");
        wv.run();
        wv.close();
    }
}
```

--------------------------------

### Expose Java Fields and Methods to JavaScript using Annotations

Source: https://context7.com/webview/webview_java/llms.txt

This Java code illustrates how to use annotations from the `dev.webview.webview_java.bridge` package to control the exposure of Java fields and methods to JavaScript. Annotations like `@JavascriptValue`, `@JavascriptFunction`, `@JavascriptGetter`, and `@JavascriptSetter` allow fine-grained control over property accessibility (read-only, read-write, write-only), custom naming, and mutation watching.

```java
import dev.webview.webview_java.bridge.*;

// @JavascriptValue - Exposes a field to JavaScript
// @JavascriptFunction - Exposes a method to JavaScript
// @JavascriptGetter - Custom getter method for a property
// @JavascriptSetter - Custom setter method for a property

public class AnnotatedObject extends JavascriptObject {

    // Read-only property with mutation watching
    // JavaScript: await MyObject.timestamp
    @JavascriptValue(allowSet = false, watchForMutate = true)
    public long timestamp = System.currentTimeMillis();

    // Read-write property
    // JavaScript: await MyObject.name or MyObject.name = "value"
    @JavascriptValue(allowSet = true, allowGet = true)
    public String name = "Default";

    // Write-only property
    @JavascriptValue(allowGet = false, allowSet = true)
    public String secretKey;

    // Custom property name
    @JavascriptValue(value = "displayName")
    public String internalName = "Test";

    // Exposed function
    // JavaScript: await MyObject.calculateSum(1, 2, 3)
    @JavascriptFunction
    public int calculateSum(int a, int b, int c) {
        return a + b + c;
    }

    // Function with custom JavaScript name
    @JavascriptFunction(value = "greet")
    public String sayHello(String name) {
        return "Hello, " + name + "!";
    }
}

```

--------------------------------

### Leiningen Dependency for Webview Java Core

Source: https://github.com/webview/webview_java/blob/main/README.md

This snippet shows how to add the webview Java core library as a dependency in a Leiningen project. It involves configuring the Jitpack repository and then listing the dependency.

```clojure
:repositories [["jitpack" "https://jitpack.io"]]

:dependencies [[com.github.webview.webview_java/core "_VERSION"]]
```

--------------------------------

### Execute JavaScript from Java

Source: https://context7.com/webview/webview_java/llms.txt

Executes JavaScript code immediately in the current page context using the `eval()` method. This allows Java code to interact with the web page, such as modifying its appearance or logging messages.

```java
import dev.webview.webview_java.Webview;

public class EvalExample {
    public static void main(String[] args) {
        Webview wv = new Webview(true);

        wv.bind("triggerUpdate", (arguments) -> {
            // Execute JavaScript from Java
            wv.eval("document.body.style.backgroundColor = 'lightblue';");
            wv.eval("console.log('Background updated from Java!');");
            return null;
        });

        wv.setSize(800, 600);
        wv.setHTML(
            "<html><body>" +
            "<h1>Eval Example</h1>" +
            "<button onclick='triggerUpdate()'>Change Background</button>" +
            "</body></html>"
        );

        wv.run();
        wv.close();
    }
}
```

--------------------------------

### SBT Dependency for Webview Java Core

Source: https://github.com/webview/webview_java/blob/main/README.md

This snippet illustrates how to add the webview Java core library as a dependency in an SBT project. It requires adding the Jitpack resolver and then specifying the library dependency.

```sbt
resolvers += "jitpack" at "https://jitpack.io"

libraryDependencies += "com.github.webview.webview_java" % "core" % "_VERSION"
```

--------------------------------

### Create Java-JavaScript Object Bridge in Java

Source: https://context7.com/webview/webview_java/llms.txt

This snippet demonstrates how to create a bridge between Java and JavaScript using the WebviewBridge module. It exposes a Java object ('MyAppObject') to JavaScript, allowing JavaScript to call its methods ('increment', 'showMessage') and access its properties ('counter'). The 'MyAppObject' class extends 'JavascriptObject' and uses annotations like '@JavascriptValue' and '@JavascriptFunction' to define accessible members.

```java
import dev.webview.webview_java.Webview;
import dev.webview.webview_java.bridge.*;

public class BridgeBasicExample {
    public static void main(String[] args) {
        Webview wv = new Webview(true);
        WebviewBridge bridge = new WebviewBridge(wv);

        // Define a Java object accessible from JavaScript
        bridge.defineObject("MyApp", new MyAppObject());

        wv.setTitle("Bridge Example");
        wv.setSize(800, 600);
        wv.setHTML(
            "<!DOCTYPE html><html><body>" +
            "<p>Counter: <span id='counter'></span></p>" +
            "<button onclick='MyApp.increment()'>Increment</button>" +
            "<button onclick='MyApp.showMessage(\"Hello!\")'>Show Message</button>" +
            "<script>" +
            "async function updateCounter() {" +
            "  document.getElementById('counter').innerText = await MyApp.counter;" +
            "}" +
            "setInterval(updateCounter, 100);" +
            "</script>" +
            "</body></html>"
        );

        wv.run();
        wv.close();
    }
}

class MyAppObject extends JavascriptObject {

    @JavascriptValue(allowSet = true)
    public int counter = 0;

    @JavascriptFunction
    public void increment() {
        counter++;
    }

    @JavascriptFunction
    public String showMessage(String message) {
        System.out.println("Message from JS: " + message);
        return "Received: " + message;
    }
}

```

--------------------------------

### Maven Dependency for Webview Java Core

Source: https://github.com/webview/webview_java/blob/main/README.md

This snippet shows how to add the core webview Java library as a dependency in a Maven project. It requires configuring the Jitpack repository and specifying the version.

```xml
<repositories>
    <repository>
        <id>jitpack.io</id>
        <url>https://jitpack.io</url>
    </repository>
</repositories>

<dependency>
    <groupId>com.github.webview.webview_java</groupId>
    <artifactId>core</artifactId>
    <version>_VERSION</version>
</dependency>
```

--------------------------------

### Emit Events from Java to JavaScript using Webview

Source: https://context7.com/webview/webview_java/llms.txt

Shows how to emit events from Java code to JavaScript listeners within a Webview. This is achieved using the `emit()` method of `WebviewBridge`, allowing for real-time communication and updates from the backend to the frontend.

```java
import dev.webview.webview_java.Webview;
import dev.webview.webview_java.bridge.*;
import co.casterlabs.rakurai.json.element.*;

public class EventEmitterExample {
    public static void main(String[] args) {
        Webview wv = new Webview(true);
        WebviewBridge bridge = new WebviewBridge(wv);

        // Emit events from Java to JavaScript
        wv.bind("startNotifications", (arguments) -> {
            new Thread(() -> {
                for (int i = 0; i < 10; i++) {
                    JsonObject data = new JsonObject();
                    data.put("count", i);
                    data.put("message", "Notification #" + i);
                    bridge.emit("notification", data);
                    try { Thread.sleep(1000); } catch (InterruptedException e) { break; }
                }
            }).start();
            return null;
        });

        wv.setSize(800, 600);
        wv.setHTML(
            "<!DOCTYPE html><html><body>" +
            "<button onclick='startNotifications()'>Start</button>" +
            "<ul id='notifications'></ul>" +
            "<script>" +
            "Bridge.on('notification', (data) => {" +
            "  const li = document.createElement('li');" +
            "  li.textContent = data.message;" +
            "  document.getElementById('notifications').appendChild(li);" +
            "});" +
            "</script>" +
            "</body></html>"
        );

        wv.run();
        wv.close();
    }
}
```

--------------------------------

### Embed Webview in Swing Applications using AWTWebview

Source: https://context7.com/webview/webview_java/llms.txt

Integrates a webview into Swing applications using the `AWTWebview` class, which is an AWT Canvas component. This class automatically initializes a webview when rendered. Note: This functionality may not work on macOS due to first-thread UI requirements.

```java
import dev.webview.webview_java.AWTWebview;
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;

public class SwingIntegrationExample {
    public static void main(String[] args) {
        JFrame frame = new JFrame();

        // Create AWTWebview with debug mode
        AWTWebview component = new AWTWebview(true);

        // Set callback for when webview is ready
        component.setOnInitialized((wv) -> {
            // Bind functions
            wv.bind("echo", (arguments) -> arguments);

            // Load content
            wv.loadURL("https://example.com");

            // Handle window close
            frame.addWindowListener(new WindowAdapter() {
                @Override
                public void windowClosing(WindowEvent e) {
                    component.close();
                    frame.dispose();
                    System.exit(0);
                }
            });
        });

        // Add to frame
        frame.getContentPane().add(component, BorderLayout.CENTER);
        frame.setTitle("Swing Webview App");
        frame.setSize(800, 600);
        frame.setVisible(true);
    }
}
```

--------------------------------

### Run Webview Asynchronously in Java

Source: https://context7.com/webview/webview_java/llms.txt

Executes the webview event loop in a separate thread using `runAsync()`, allowing the main thread to continue execution. This is useful for non-blocking operations and background processing.

```java
import dev.webview.webview_java.Webview;

public class AsyncExample {
    public static void main(String[] args) {
        Webview wv = new Webview(true);

        wv.setTitle("Async Webview");
        wv.setSize(800, 600);
        wv.loadURL("https://example.com");

        // Run event loop asynchronously
        wv.runAsync();

        // Main thread continues here
        System.out.println("Webview started in background");

        // Do other work...
        try {
            Thread.sleep(5000);
        } catch (InterruptedException e) {}

        // Close the webview programmatically
        wv.close();
    }
}
```
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