frame counter example

Author: AleksRychkov

Diff for: examples/android-gradle-kts/build.gradle.kts

@@ -48,6 +48,7 @@ androidMethodHook {
             addConfig("./methodhook/descriptor.conf")
             addConfig("./methodhook/okhttp.conf")
             addConfig("./methodhook/auto_trace.conf")
+            addConfig("./methodhook/frame_counter.conf")
         }
     }
 }

Diff for: examples/android-gradle-kts/methodhook/frame_counter.conf

@@ -0,0 +1,10 @@
+frameCounterContext {
+    type = "descriptor"
+    package = "androidx.appcompat.app"
+    superClass = "*"
+    interfaces = []
+    class = "androidx.appcompat.app.AppCompatActivity"
+    methods = [ "attachBaseContext" ]
+    descriptor = "(Landroid/content/Context;)V"
+    enter = "io.github.aleksrychkov.methodhook.FrameCounterHook.attachBaseContext"
+}

Diff for: examples/android-gradle-kts/src/main/AndroidManifest.xml

@@ -25,7 +25,6 @@
 
         <service android:name="io.github.aleksrychkov.example.MainService" />
 
-        <activity android:name="io.github.aleksrychkov.example2.MainActivity2" />
     </application>
 
 </manifest>

Diff for: examples/android-gradle-kts/src/main/kotlin/io/github/aleksrychkov/example/FrameCounter.kt

@@ -0,0 +1,103 @@
+package io.github.aleksrychkov.example
+
+import android.annotation.SuppressLint
+import android.app.Activity
+import android.app.Application
+import android.content.Context
+import android.os.Bundle
+import android.view.Choreographer
+import android.view.Gravity
+import android.view.View
+import android.view.ViewGroup
+import android.view.WindowManager
+import android.widget.FrameLayout
+import android.widget.TextView
+import androidx.core.view.ViewCompat
+import androidx.core.view.setPadding
+import java.lang.ref.WeakReference
+
+object FrameCounter : Application.ActivityLifecycleCallbacks {
+
+    private val tvId = ViewCompat.generateViewId()
+    private val callbacksMap = mutableMapOf<String, FrameCallback>()
+    private var frameCounter: Int = 0
+
+    private fun attach(container: Activity) {
+        val counterView = buildCounterView(container)
+        val rootView = container.findViewById<ViewGroup>(android.R.id.content)
+        if (rootView.findViewById<View?>(tvId) == null) {
+            rootView.addView(counterView, 0)
+        }
+        FrameCallback(WeakReference(counterView)).also {
+            val identityHash = Integer.toHexString(System.identityHashCode(container))
+            callbacksMap[identityHash] = it
+            Choreographer.getInstance().postFrameCallback(it)
+        }
+    }
+
+    private fun detach(container: Activity) {
+        val identityHash = Integer.toHexString(System.identityHashCode(container))
+        callbacksMap[identityHash]?.let { Choreographer.getInstance().removeFrameCallback(it) }
+        callbacksMap.remove(identityHash)
+        val rootView = container.findViewById<ViewGroup>(android.R.id.content)
+        val counterView = rootView.findViewById<View?>(tvId)
+        rootView.removeView(counterView)
+    }
+
+    private fun buildCounterView(context: Context): TextView =
+        TextView(context).apply {
+            layoutParams = FrameLayout.LayoutParams(
+                WindowManager.LayoutParams.WRAP_CONTENT,
+                WindowManager.LayoutParams.WRAP_CONTENT,
+            ).apply {
+                gravity = Gravity.TOP or Gravity.END
+                setPadding(10)
+            }
+            setBackgroundColor(0x88000000.toInt())
+            setTextColor(0xFFFFFFFF.toInt())
+            textSize = 14f
+            id = tvId
+        }
+
+    private class FrameCallback(
+        private val tvCounter: WeakReference<TextView>,
+    ) : Choreographer.FrameCallback {
+
+        @SuppressLint("SetTextI18n")
+        override fun doFrame(frameTimeNanos: Long) {
+            val counterView = tvCounter.get() ?: return
+            frameCounter++
+            counterView.text = "Frame# $frameCounter"
+            logTrace()
+            Choreographer.getInstance().postFrameCallback(this)
+        }
+
+        private fun logTrace() {
+            android.os.Trace.beginSection("=>Frame# $frameCounter")
+            android.os.Trace.endSection()
+        }
+    }
+
+    override fun onActivityCreated(activity: Activity, savedInstanceState: Bundle?) {
+    }
+
+    override fun onActivityStarted(activity: Activity) {
+    }
+
+    override fun onActivityResumed(activity: Activity) {
+        attach(activity)
+    }
+
+    override fun onActivityPaused(activity: Activity) {
+        detach(activity)
+    }
+
+    override fun onActivityStopped(activity: Activity) {
+    }
+
+    override fun onActivitySaveInstanceState(activity: Activity, outState: Bundle) {
+    }
+
+    override fun onActivityDestroyed(activity: Activity) {
+    }
+}

Diff for: examples/android-gradle-kts/src/main/kotlin/io/github/aleksrychkov/methodhook/FrameCounterHook.kt

@@ -0,0 +1,18 @@
+package io.github.aleksrychkov.methodhook
+
+import android.app.Application
+import android.content.Context
+import io.github.aleksrychkov.example.FrameCounter
+
+@Suppress("unused")
+object FrameCounterHook {
+
+    private var isRegistered = false
+
+    @JvmStatic
+    fun attachBaseContext(context: Context) {
+        if (isRegistered) return
+        isRegistered = true
+        (context.applicationContext as Application).registerActivityLifecycleCallbacks(FrameCounter)
+    }
+}

Diff for: methodhook/src/main/kotlin/io/github/aleksrychkov/methodhook/injects/InjectorContext.kt

@@ -5,7 +5,8 @@ package io.github.aleksrychkov.methodhook.injects
  *
  * @property className The name of the class that contains the method being injected.
  * @property methodName The name of the method being injected.
- * @property methodDescriptor The descriptor of the method being injected, providing information about the method's parameter and return types.
+ * @property methodDescriptor The descriptor of the method being injected,
+ *           providing information about the method's parameter and return types.
  * @property access The access modifiers of the method, represented as an integer (e.g., public, private).
  */
 class InjectorContext(