Add initial android port (#510)

* Add initial android port

* Add run method

* Add ipc handler

* Cargo fmt

* Update build CI

* Remove used imports

.github/workflows/build.yml

@@ -13,6 +13,7 @@ jobs:
           - { target: x86_64-unknown-linux-gnu, os: ubuntu-latest }
           - { target: x86_64-apple-darwin, os: macos-latest }
           - { target: aarch64-apple-ios, os: macos-latest }
+          - { target: aarch64-linux-android, os: ubuntu-latest }
 
     runs-on: ${{ matrix.platform.os }}
 
@@ -25,13 +26,13 @@ jobs:
           target: ${{ matrix.platform.target }}
 
       - name: install webkit2gtk (ubuntu only)
-        if: matrix.platform.os == 'ubuntu-latest'
+        if: contains(matrix.platform.target, 'gnu') 
         run: |
           sudo apt-get update
           sudo apt-get install -y webkit2gtk-4.0 libgtksourceview-3.0-dev libappindicator3-dev
 
       - name: install webview2 (windows only)
-        if: matrix.platform.os == 'windows-latest'
+        if: contains(matrix.platform.target, 'windows')
         shell: pwsh
         run: |
           Invoke-WebRequest https://go.microsoft.com/fwlink/p/?LinkId=2124703 -OutFile installwebview.exe -UseBasicParsing
@@ -78,8 +79,13 @@ jobs:
 
       - name: build tests and examples
         shell: bash
+        if: (
+          !contains(matrix.platform.target, 'android') &&
+          !contains(matrix.platform.target, 'ios'))
         run: cargo test --no-run --verbose --features tray --target ${{ matrix.platform.target }}
 
       - name: run tests
-        if: (!contains(matrix.platform.target, 'ios'))
+        if: (
+          !contains(matrix.platform.target, 'android') &&
+          !contains(matrix.platform.target, 'ios'))
         run: cargo test --verbose --features tray --target ${{ matrix.platform.target }}

Cargo.toml

@@ -81,3 +81,6 @@ cocoa = "0.24"
 core-graphics = "0.22"
 objc = "0.2"
 objc_id = "0.1"
+
+[target."cfg(target_os = \"android\")".dependencies]
+jni = "0.18.0"

src/application.rs

@@ -9,4 +9,27 @@
 //!
 //! [tao]: https://crates.io/crates/tao
 
+#[cfg(not(target_os = "android"))]
 pub use tao::*;
+
+// TODO Implement actual Window library of Android
+#[cfg(target_os = "android")]
+pub use tao::{dpi, error};
+
+#[cfg(target_os = "android")]
+pub mod window {
+  use tao::dpi::PhysicalSize;
+  pub use tao::window::BadIcon;
+
+  pub struct Window;
+
+  impl Window {
+    pub fn new() -> Self {
+      Self
+    }
+
+    pub fn inner_size(&self) -> PhysicalSize<u32> {
+      todo!()
+    }
+  }
+}

src/lib.rs

@@ -180,4 +180,7 @@ pub enum Error {
   InvalidMethod(#[from] InvalidMethod),
   #[error("Infallible error, something went really wrong: {0}")]
   Infallible(#[from] std::convert::Infallible),
+  #[cfg(target_os = "android")]
+  #[error("JNI error: {0}")]
+  JNIError(#[from] jni::errors::Error),
 }

src/webview/android/mod.rs

@@ -0,0 +1,96 @@
+use std::{ffi::c_void, ptr::null_mut, rc::Rc, sync::RwLock};
+
+use crate::{application::window::Window, Result};
+
+use super::{WebContext, WebViewAttributes};
+
+use jni::{
+  objects::{JClass, JObject},
+  sys::jobject,
+  JNIEnv,
+};
+
+use once_cell::sync::Lazy;
+
+static IPC: Lazy<RwLock<UnsafeIpc>> = Lazy::new(|| RwLock::new(UnsafeIpc(null_mut())));
+
+pub struct InnerWebView {
+  pub window: Rc<Window>,
+  pub attributes: WebViewAttributes,
+}
+
+impl InnerWebView {
+  pub fn new(
+    window: Rc<Window>,
+    attributes: WebViewAttributes,
+    _web_context: Option<&mut WebContext>,
+  ) -> Result<Self> {
+    Ok(Self { window, attributes })
+  }
+
+  pub fn print(&self) {}
+
+  pub fn eval(&self, _js: &str) -> Result<()> {
+    Ok(())
+  }
+
+  pub fn focus(&self) {}
+
+  pub fn devtool(&self) {}
+
+  pub fn run(self, env: JNIEnv, _jclass: JClass, jobject: JObject) -> Result<jobject> {
+    let string_class = env.find_class("java/lang/String")?;
+    // let client = env.call_method(
+    //   jobject,
+    //   "getWebViewClient",
+    //   "()Landroid/webkit/WebViewClient;",
+    //   &[],
+    // )?;
+    let WebViewAttributes {
+      url,
+      initialization_scripts,
+      ipc_handler,
+      ..
+    } = self.attributes;
+
+    // todo
+    // ipc too?
+    if let Some(i) = ipc_handler {
+      let i = UnsafeIpc(Box::into_raw(Box::new(i)) as *mut _);
+      let mut ipc = IPC.write().unwrap();
+      *ipc = i;
+    }
+
+    if let Some(u) = url {
+      let url = env.new_string(u)?;
+      env.call_method(jobject, "loadUrl", "(Ljava/lang/String;)V", &[url.into()])?;
+    }
+
+    // Return initialization scripts
+    let len = initialization_scripts.len();
+    let scripts = env.new_object_array(len as i32, string_class, env.new_string("")?)?;
+    for (idx, s) in initialization_scripts.into_iter().enumerate() {
+      env.set_object_array_element(scripts, idx as i32, env.new_string(s)?)?;
+    }
+    Ok(scripts)
+  }
+
+  pub fn ipc_handler(window: &Window, arg: String) {
+    let function = IPC.read().unwrap();
+    unsafe {
+      let ipc = function.0;
+      if !ipc.is_null() {
+        let ipc = &*(ipc as *mut Box<dyn Fn(&Window, String)>);
+        ipc(window, arg)
+      }
+    }
+  }
+}
+
+pub struct UnsafeIpc(*mut c_void);
+unsafe impl Send for UnsafeIpc {}
+unsafe impl Sync for UnsafeIpc {}
+
+pub fn platform_webview_version() -> Result<String> {
+  todo!()
+}

src/webview/mod.rs

@@ -8,6 +8,10 @@ mod web_context;
 
 pub use web_context::WebContext;
 
+#[cfg(target_os = "android")]
+pub(crate) mod android;
+#[cfg(target_os = "android")]
+use android::*;
 #[cfg(any(
   target_os = "linux",
   target_os = "dragonfly",
@@ -33,6 +37,12 @@ pub(crate) mod webview2;
 #[cfg(target_os = "windows")]
 use self::webview2::*;
 use crate::Result;
+#[cfg(target_os = "android")]
+use jni::{
+  objects::{JClass, JObject},
+  sys::jobject,
+  JNIEnv,
+};
 #[cfg(target_os = "windows")]
 use webview2_com::Microsoft::Web::WebView2::Win32::ICoreWebView2Controller;
 #[cfg(target_os = "windows")]
@@ -324,21 +334,26 @@ pub struct WebView {
 
 // Signal the Window to drop on Linux and Windows. On mac, we need to handle several unsafe code
 // blocks and raw pointer properly.
+#[cfg(any(
+  target_os = "linux",
+  target_os = "dragonfly",
+  target_os = "freebsd",
+  target_os = "netbsd",
+  target_os = "openbsd"
+))]
 impl Drop for WebView {
   fn drop(&mut self) {
-    #[cfg(any(
-      target_os = "linux",
-      target_os = "dragonfly",
-      target_os = "freebsd",
-      target_os = "netbsd",
-      target_os = "openbsd"
-    ))]
     unsafe {
       use crate::application::platform::unix::WindowExtUnix;
       use gtk::prelude::WidgetExtManual;
       self.window().gtk_window().destroy();
     }
-    #[cfg(target_os = "windows")]
+  }
+}
+
+#[cfg(target_os = "windows")]
+impl Drop for WebView {
+  fn drop(&mut self) {
     unsafe {
       DestroyWindow(HWND(self.window.hwnd() as _));
     }
@@ -412,6 +427,16 @@ impl WebView {
     #[cfg(not(target_os = "macos"))]
     self.window.inner_size()
   }
+
+  #[cfg(target_os = "android")]
+  pub fn run(self, env: JNIEnv, jclass: JClass, jobject: JObject) -> jobject {
+    self.webview.run(env, jclass, jobject).unwrap()
+  }
+
+  #[cfg(target_os = "android")]
+  pub fn ipc_handler(window: &Window, arg: String) {
+    InnerWebView::ipc_handler(window, arg)
+  }
 }
 
 /// An event enumeration sent to [`FileDropHandler`].

src/webview/web_context.rs

@@ -76,11 +76,11 @@ impl WebContextData {
   }
 }
 
-#[cfg(target_os = "windows")]
+#[cfg(any(target_os = "windows", target_os = "android"))]
 #[derive(Debug)]
 pub(crate) struct WebContextImpl;
 
-#[cfg(target_os = "windows")]
+#[cfg(any(target_os = "windows", target_os = "android"))]
 impl WebContextImpl {
   fn new(_data: &WebContextData) -> Self {
     Self