001. Top Activity 当前Activity

第一个应用是 Android 的取最顶部 Activity。

001.TopActivity

分析一下需求。

可以用 AccessibilityService 观察界面跳转
从 AccessibilityEvent 里面取出需要的包名和类名
用 WindowManager 添加移除 View

开发

创建 Android Studio 项目
添加矢量图 play, stop
build.gradle(Module: app) 添加矢量支持

android {
    defaultConfig {
        vectorDrawables.useSupportLibrary = true
    }
}

AndroidManifest.xml 添加顶部窗口权限

<uses-permission android:name="android.permission.SYSTEM_ALERT_WINDOW"/>
<uses-permission android:name="android.permission.SYSTEM_OVERLAY_WINDOW" />

继承 AccessibilityService，当窗口变化时显示或隐藏 TopActivity

override fun onInterrupt() {
}

override fun onAccessibilityEvent(event: AccessibilityEvent?) {
    if (showTopActivityEnabled) {
        show(event!!.packageName.toString() + "\n" + event.className)
    } else {
        dismiss()
    }
}

MainActivity 中控制是否开启显示 TopActivity

override fun onResume() {
    super.onResume()

    updateServiceStatus()
}

private fun updateServiceStatus() {
    val accessibilityManager = getSystemService(Context.ACCESSIBILITY_SERVICE) as AccessibilityManager
    val accessibilityServices = accessibilityManager.getEnabledAccessibilityServiceList(AccessibilityServiceInfo.FEEDBACK_GENERIC)
    serviceEnabled = accessibilityServices.any { it.id == packageName + "/.TopActivityAccessibilityService" }


    if (serviceEnabled) {
        service_textview.setText(R.string.services_on)
        fab.setImageResource(R.drawable.ic_stop_black_24dp)
    } else {
        service_textview.setText(R.string.services_off)
        fab.setImageResource(R.drawable.ic_play_arrow_black_24dp)
        showTopActivityEnabled = false
    }

    service_switch.isEnabled = serviceEnabled
    service_switch.isChecked = showTopActivityEnabled
}