Android 弹窗浅谈

我们知道 Android 弹窗中，有一类弹窗会在应用之外也显示，这是因为他被申明成了系统弹窗，除此之外还有2类弹窗分别是：子弹窗与应用弹窗。

应用弹窗：就是我们常规使用的 Dialog 之类弹窗，依赖于应用的 Activity；
子弹窗：依赖于父窗口，比如 PopupWindow；
系统弹窗：比如状态栏、Toast等，本文所讲的系统悬浮窗就是系统弹窗。

系统悬浮窗具体实现

权限申请

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

代码设计

下面的包结构截图，简单展示了实现系统悬浮窗的代码结构，更复杂的业务需要可在此基础上进行扩展。

FloatWindowService：系统悬浮窗在此 Service 中弹出；
FloatWindowManager：系统悬浮窗管理类；
FloatLayout：系统悬浮窗布局；
HomeKeyObserverReceiver：监听 Home 键；
FloatWindowUtils：系统悬浮窗工具类。

具体实现

FloatWindowService 类

class FloatWindowService : Service() {
 
    private val TAG = FloatWindowService::class.java.simpleName
    private var mFloatWindowManager: FloatWindowManager? = null
    private var mHomeKeyObserverReceiver: HomeKeyObserverReceiver? = null
 
    override fun onCreate() {
        TLogUtils.i(TAG, "onCreate: ")
        mFloatWindowManager = FloatWindowManager(applicationContext)
        mHomeKeyObserverReceiver = HomeKeyObserverReceiver()
 
        registerReceiver(mHomeKeyObserverReceiver, IntentFilter(Intent.ACTION_CLOSE_SYSTEM_DIALOGS))
        mFloatWindowManager!!.createWindow()
    }
 
    override fun onBind(intent: Intent?): IBinder? {
        return null
    }
 
    override fun onStartCommand(intent: Intent?, flags: Int, startId: Int): Int {
        return START_NOT_STICKY
    }
 
    override fun onDestroy() {
        TLogUtils.i(TAG, "onDestroy: ")
        mFloatWindowManager?.removeWindow()
        if (mHomeKeyObserverReceiver != null) {
            unregisterReceiver(mHomeKeyObserverReceiver)
        }
    }
 
}

FloatWindowManager 类

包括系统悬浮窗的创建、显示、销毁（以及更新）。


public void addView(View view, ViewGroup.LayoutParams params); // 添加 View 到 Window
public void updateViewLayout(View view, ViewGroup.LayoutParams params); //更新 View 在 Window 中的位置
public void removeView(View view); //删除 View

FloatWindowManager 类代码

class FloatWindowManager constructor(context: Context) {
 
    var isShowing = false
    private val TAG = FloatWindowManager::class.java.simpleName
    private var mContext: Context = context
    private var mFloatLayout = FloatLayout(mContext)
    private var mLayoutParams: WindowManager.LayoutParams? = null
    private var mWindowManager: WindowManager = context.getSystemService(Context.WINDOW_SERVICE) as WindowManager
 
    fun createWindow() {
        TLogUtils.i(TAG, "createWindow: start...")
        // 对象配置操作使用apply，额外的处理使用also
        mLayoutParams = WindowManager.LayoutParams().apply {
            type = if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
                // Android 8.0以后需要使用TYPE_APPLICATION_OVERLAY，不允许使用以下窗口类型来在其他应用和窗口上方显示提醒窗口：TYPE_PHONE、TYPE_PRIORITY_PHONE、TYPE_SYSTEM_ALERT、TYPE_SYSTEM_OVERLAY、TYPE_SYSTEM_ERROR。
                WindowManager.LayoutParams.TYPE_APPLICATION_OVERLAY
            } else {
                // 在Android 8.0之前，悬浮窗口设置可以为TYPE_PHONE，这种类型是用于提供用户交互操作的非应用窗口。
                // 在API Level  = 23的时候，需要在Android Manifest.xml文件中声明权限SYSTEM_ALERT_WINDOW才能在其他应用上绘制控件
                WindowManager.LayoutParams.TYPE_PHONE
            }
            // 设置图片格式，效果为背景透明
            format = PixelFormat.RGBA_8888
            // 设置浮动窗口不可聚焦（实现操作除浮动窗口外的其他可见窗口的操作）
            flags = WindowManager.LayoutParams.FLAG_NOT_FOCUSABLE
            // 调整悬浮窗显示的停靠位置为右侧置顶
            gravity = Gravity.TOP or Gravity.END
            width = 800
            height = 200
            x = 20
            y = 40
        }
 
        mWindowManager.addView(mFloatLayout, mLayoutParams)
        TLogUtils.i(TAG, "createWindow: end...")
        isShowing = true
    }
 
    fun showWindow() {
        TLogUtils.i(TAG, "showWindow: isShowing = $isShowing")
        if (!isShowing) {
            if (mLayoutParams == null) {
                createWindow()
            } else {
                mWindowManager.addView(mFloatLayout, mLayoutParams)
                isShowing = true
            }
        }
    }
 
    fun removeWindow() {
        TLogUtils.i(TAG, "removeWindow: isShowing = $isShowing")
        mWindowManager.removeView(mFloatLayout)
        isShowing = false
    }
 
}

FloatLayout 类及其 Layout

系统悬浮窗自定义View：FloatLayout

class FloatLayout @JvmOverloads constructor(context: Context, attrs: AttributeSet? = null, defStyleAttr: Int = 0, defStyleRes: Int = 0) :
    ConstraintLayout(context, attrs, defStyleAttr, defStyleRes) {
 
    private var mTime: TCLTextView
    private var mDistance: TCLTextView
    private var mSpeed: TCLTextView
    private var mCalories: TCLTextView
 
    init {
        val view = LayoutInflater.from(context).inflate(R.layout.do_exercise_view_float_layout, this, true)
        mTime = view.findViewById(R.id.float_layout_tv_time)
        mDistance = view.findViewById(R.id.float_layout_tv_distance)
        mSpeed = view.findViewById(R.id.float_layout_tv_speed)
        mCalories = view.findViewById(R.id.float_layout_tv_calories)
    }
 
}

布局文件：float_layout_tv_time

HomeKeyObserverReceiver 类

class HomeKeyObserverReceiver : BroadcastReceiver() {
 
    override fun onReceive(context: Context?, intent: Intent?) {
        try {
            val action = intent!!.action
            val reason = intent.getStringExtra("reason")
            TLogUtils.d(TAG, "HomeKeyObserverReceiver: action = $action,reason = $reason")
            if (Intent.ACTION_CLOSE_SYSTEM_DIALOGS == action && "homekey" == reason) {
                val keyCode = intent.getIntExtra("keycode", KeyEvent.KEYCODE_UNKNOWN)
                TLogUtils.d(TAG, "keyCode = $keyCode")
                context?.stopService(Intent(context, FloatWindowService::class.java))
            }
        } catch (ex: Exception) {
            ex.printStackTrace()
        }
    }
 
    companion object {
        private val TAG = HomeKeyObserverReceiver::class.java.simpleName
    }
 
}

FloatWindowUtils 类

object FloatWindowUtils {

    const val REQUEST_FLOAT_CODE = 1000
    private val TAG = FloatWindowUtils::class.java.simpleName

    /**
     * 判断Service是否开启
     */
    fun isServiceRunning(context: Context, ServiceName: String): Boolean {
        if (TextUtils.isEmpty(ServiceName)) {
            return false
        }
        val myManager = context.getSystemService(Context.ACTIVITY_SERVICE) as ActivityManager
        val runningService = myManager.getRunningServices(1000) as ArrayList<ActivityManager.RunningServiceInfo>
        runningService.forEach {
            if (it.service.className == ServiceName) {
                return true
            }
        }
        return false
    }

    /**
     * 检查悬浮窗权限是否开启
     */
    @SuppressLint("NewApi")
    fun checkSuspendedWindowPermission(context: Activity, block: () -> Unit) {
        if (commonROMPermissionCheck(context)) {
            block()
        } else {
            Toast.makeText(context, "请开启悬浮窗权限", Toast.LENGTH_SHORT).show()
            context.startActivityForResult(Intent(Settings.ACTION_MANAGE_OVERLAY_PERMISSION).apply {
                data = Uri.parse("package:${context.packageName}")
            }, REQUEST_FLOAT_CODE)
        }
    }

    /**
     * 判断悬浮窗权限权限
     */
    fun commonROMPermissionCheck(context: Context?): Boolean {
        var result = true
        if (Build.VERSION.SDK_INT >= 23) {
            try {
                val clazz: Class<*> = Settings::class.java
                val canDrawOverlays = clazz.getDeclaredMethod("canDrawOverlays", Context::class.java)
                result = canDrawOverlays.invoke(null, context) as Boolean
            } catch (e: Exception) {
                TLogUtils.e(TAG, e)
            }
        }
        return result
    }

}