cargo-apk: Print and follow adb logcat output after starting app

.github/workflows/android_test.sh

@@ -10,7 +10,7 @@ adb uninstall rust.example.hello_world || true
 
 if [ -z "$1" ];
 then
-    cargo apk run -p ndk-examples --target x86_64-linux-android --example hello_world
+    cargo apk run -p ndk-examples --target x86_64-linux-android --example hello_world --no-logcat
 else
     adb install -r "$1/hello_world.apk"
     adb shell am start -a android.intent.action.MAIN -n "rust.example.hello_world/android.app.NativeActivity"

cargo-apk/CHANGELOG.md

@@ -3,6 +3,7 @@
 - Upgrade to latest `ndk-build` to deduplicate libraries before packaging them into the APK. ([#333](https://github.com/rust-windowing/android-ndk-rs/pull/333))
 - Support `android:resizeableActivity`. ([#338](https://github.com/rust-windowing/android-ndk-rs/pull/338))
 - Add `--device` argument to select `adb` device by serial (see `adb devices` for connected devices and their serial). ([#329](https://github.com/rust-windowing/android-ndk-rs/pull/329))
+- Print and follow `adb logcat` output after starting app. ([#332](https://github.com/rust-windowing/android-ndk-rs/pull/332))
 
 # 0.9.3 (2022-07-05)
 

cargo-apk/src/apk.rs

@@ -18,12 +18,14 @@ pub struct ApkBuilder<'a> {
     build_dir: PathBuf,
     build_targets: Vec<Target>,
     device_serial: Option<String>,
+    no_logcat: bool,
 }
 
 impl<'a> ApkBuilder<'a> {
     pub fn from_subcommand(
         cmd: &'a Subcommand,
         device_serial: Option<String>,
+        no_logcat: bool,
     ) -> Result<Self, Error> {
         let ndk = Ndk::from_env()?;
         let mut manifest = Manifest::parse_from_toml(cmd.manifest())?;
@@ -100,6 +102,7 @@ impl<'a> ApkBuilder<'a> {
             build_dir,
             build_targets,
             device_serial,
+            no_logcat,
         })
     }
 
@@ -244,7 +247,19 @@ impl<'a> ApkBuilder<'a> {
     pub fn run(&self, artifact: &Artifact) -> Result<(), Error> {
         let apk = self.build(artifact)?;
         apk.install(self.device_serial.as_deref())?;
-        apk.start(self.device_serial.as_deref())?;
+        let pid = apk.start(self.device_serial.as_deref())?;
+
+        if !self.no_logcat {
+            self.ndk
+                .adb(self.device_serial.as_deref())?
+                .arg("logcat")
+                .arg("-v")
+                .arg("color")
+                .arg("--pid")
+                .arg(pid.to_string())
+                .status()?;
+        }
+
         Ok(())
     }
 

cargo-apk/src/main.rs

@@ -6,21 +6,25 @@ fn main() -> anyhow::Result<()> {
     env_logger::init();
     let args = std::env::args();
     let mut device_serial = None;
-    let cmd = Subcommand::new(args, "apk", |name, value| {
-        if name == "--device" {
+    let mut no_logcat = false;
+    let cmd = Subcommand::new(args, "apk", |name, value| match name {
+        "--device" => {
             if let Some(value) = value {
                 println!("Running on {}", value);
                 device_serial = Some(value.to_owned());
                 Ok(true)
             } else {
                 Err(cargo_subcommand::Error::InvalidArgs)
             }
-        } else {
-            Ok(false)
         }
+        "--no-logcat" => {
+            no_logcat = true;
+            Ok(true)
+        }
+        _ => Ok(false),
     })
     .map_err(Error::Subcommand)?;
-    let builder = ApkBuilder::from_subcommand(&cmd, device_serial)?;
+    let builder = ApkBuilder::from_subcommand(&cmd, device_serial, no_logcat)?;
 
     match cmd.cmd() {
         "check" | "c" => builder.check()?,
@@ -79,15 +83,18 @@ USAGE:
     cargo apk [SUBCOMMAND]
 
 SUBCOMMAND:
-    check, c    Checks that the current package builds without creating an apk
-    build, b    Compiles the current package and creates an apk
-    run, r      Run a binary or example of the local package
-    gdb         Start a gdb session attached to an adb device with symbols loaded
-    version     Print the version of cargo-apk
+    check, c            Checks that the current package builds without creating an apk
+    build, b            Compiles the current package and creates an apk
+    run, r              Run a binary or example of the local package
+    gdb                 Start a gdb session attached to an adb device with symbols loaded
+    version             Print the version of cargo-apk
+
+FLAGS:
+    --no-logcat         Don't print and follow `logcat` after running the application.
 
 OPTIONS:
-    --device    Use device with the given serial. See `adb devices` for a list of
-                connected Android devices.
+    --device <serial>   Use device with the given serial. See `adb devices` for a list of
+                        connected Android devices.
 "#
     );
 }

ndk-build/CHANGELOG.md

@@ -3,6 +3,7 @@
 - **Breaking:** Postpone APK library packaging until before zip alignment, to deduplicate possibly overlapping entries. ([#333](https://github.com/rust-windowing/android-ndk-rs/pull/333))
 - Add `adb` device serial parameter to `detect_abi()` and `Apk::{install,start}()`. ([#329](https://github.com/rust-windowing/android-ndk-rs/pull/329))
 - Fix missing `.exe` extension for `adb` on Windows inside `detect_abi()`. ([#339](https://github.com/rust-windowing/android-ndk-rs/pull/339))
+- `start()` now returns the PID of the started app process (useful for passing to `adb logcat --pid`). ([#331](https://github.com/rust-windowing/android-ndk-rs/pull/331))
 
 # 0.7.0 (2022-07-05)