前言
在产品经理提需求时候提到，app在接收到报警信息时候能不能弹出一个弹框，告诉用户报警信息，这个弹框要在app的任意界面能够弹出，并且用户点击详情时候，会跳转到报警详情界面，查看具体信息，当用户将app至于后台的时候，接收到报警信息，app发送通知，当用户点击通知时候，跳转到报警详情界面。
功能大体总结如上，在实现弹框与通知在跳转界面时遇到一些问题，在此记录一下。效果图如下：
功能分析
弹框实现，使用DialogFragment。
前后台判断则是，创建一个继承自ActivityLifecycleCallbacks接口和Application的类，继承ActivityLifecycleCallbacks接口是为了前后台判断，继承Application则是方便在基类BaseActivity获取前后台相关数据。
项目原本采用单Activity多Fragment实现，后面因为添加了视频相关功能，改为了多Activity多Fragment。
原单Activity时候，实现比较容易。后面修改为多Activity，就有些头疼，最终用思路是创建基类BaseActivity，后面添加Activity时都要继承基类BaseActivity。使用基类原因是把相同的功能抽取出来，且若每个Activity都自己实现弹框和通知的话太容易出错，也太容易漏下代码了。
代码实现
弹框
在实现继承自DialogFragment的弹框时，需要在onCreateDialog方法内设置dialog的宽高模式以及背景，不然弹框会有默认的边距，导致显示效果与预期不符，未去边距与去掉边距的弹框效果如下：
关于onCreateDialog的代码如下：
override fun onCreateDialog(savedInstanceState: Bundle?): Dialog {
val dialog = Dialog(requireContext())
dialog.setContentView(R.layout.custom_dialog_layout)
dialog.window?.apply {
setLayout(ViewGr0up.LayoutParams.MATCH_PARENT,ViewGr0up.LayoutParams.MATCH_PARENT)
setBackgroundDrawable(ColorDrawable(Color.parseColor("#88000000")))
}
dialog.setCancelable(false)
return dialog
}
此外当弹框出现的时候，弹框背景色还会闪烁。这里采用属性值动画设置弹框背景色控件的透明度变换。完整的Dialog代码如下：
class AlarmDialogFragment: DialogFragment() {
private lateinit var binding:CustomDialogLayoutBinding
private var animator:ObjectAnimator? = null
override fun show(manager: FragmentManager, tag: String?) {
try {
super.show(manager, tag)
}catch (e:Exception){
e.printStackTrace()
}
}
override fun onCreateView(
inflater: LayoutInflater,
container: ViewGr0up?,
savedInstanceState: Bundle?
): View? {
binding = CustomDialogLayoutBinding.inflate(inflater)
return binding.root
}
override fun onStart() {
super.onStart()
binding.viewAlarmDialogBg
startAnimation()
}
override fun onCreateDialog(savedInstanceState: Bundle?): Dialog {
val dialog = Dialog(requireContext())
dialog.setContentView(R.layout.custom_dialog_layout)
dialog.window?.apply {
setLayout(ViewGr0up.LayoutParams.MATCH_PARENT,ViewGr0up.LayoutParams.MATCH_PARENT)
setBackgroundDrawable(ColorDrawable(Color.parseColor("#88000000")))
}
dialog.setCancelable(false)
return dialog
}
override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
super.onViewCreated(view, savedInstanceState)
initView()
}
override fun onDestroy() {
super.onDestroy()
if(animator?.isStarted == true){
animator?.end()
}
}
private fun initView() {
binding.btnCloseDialog.setOnClickListener {
dismiss()
}
binding.btnDialogNav.setOnClickListener {
if(context is MainActivity){
val bundle = Bundle()
bundle.putString("alarmId","1")
findNavController().navigate(R.id.alarmDetailFragment,bundle)
}else{
val intent = Intent(context,MainActivity::class.java)
intent.putExtra("task","toAlarmDetail")
startActivity(intent)
}
dismiss()
}
}
private fun startAnimation() {
animator = ObjectAnimator.ofFloat(binding.viewAlarmDialogBg, "alpha", 0f, 0.6f, 0f, 0.6f, 0f)
animator?.duration = 1200
animator?.interpolator = AccelerateInterpolator()
animator?.start()
}
}
需要注意地方是，由于弹框还负责跳转，而跳转有两种情况，一种是在ActivityA内，fragmentA与fragmentB间的跳转，这种情况使用findNavController().navigate()方法进行跳转，另一种是ActivityB到另一个ActivityA内的指定FragmentB界面。这种采用startActivity(intent)方式跳转，并且在ActivityA的onStart()的方法使用下面方法。
private fun initToAlarmDetail() {
val task = intent.getStringExtra("task")
if (task == "toAlarmDetail"){
val bundle = Bundle()
bundle.putString("alarmId","1")
findNavController(R.id.fragment_main_table).navigate(R.id.alarmDetailFragment,bundle)
}
}
这样从ActivityB到另一个ActivityA时候，在onStart()方法内会触发上面的initToAlarmDetail()方法，获取跳转里面的信息，在决定具体跳转到哪个Fragment。这里解释的可能不太清楚，可以在Github下载源码看看可能更好理解些。
弹框对应的xml文件代码，可以在Github内查看，可以自己写一个，这个xml比较简单，只是xml代码比较占地方这里就不粘贴了。
前后台判断
关于前后台判断，需要创建一个继承ActivityLifecycleCallbacks和Application的类，这里命名为CustomApplication，在类里面实现ActivityLifecycleCallbacks接口相关方法，此外需要创建下面三个变量，分别表示activity数量，当前activity的名称，是否处于后台，代码如下：
private var activityCount = 0
private var nowActivityName:String? = null
private var isInBackground = true
之后需要在onActivityStarted，onActivityResumed，onActivityStopped方法内进行前后台相关处理，代码如下：
override fun onActivityStarted(activity: Activity) {
activityCount++
if (isInBackground){
isInBackground = false
}
nowActivityName = activity.javaClass.name
}
override fun onActivityStopped(activity: Activity) {
activityCount--
if (activityCount == 0 && !isInBackground){
isInBackground = true
}
}
上面代码可以看出，当触发onActivityStarted方法时候，activityCount数量加一，且app处于前台。之后记录当前activity名称，这里记录activity名称是后面有个功能是app置于后台时候弹出通知，而通知相关操作，为了每个activity都能实现就放在基类执行，而弹出通知并不需要每个继承基类的activity都执行，到时候需要根据根据nowActivityName判断哪个继承了基类的activity执行通知操作。
当触发onActivityStopped方法时候，activityCount数量减一，且当activityCount数量为零时，app置于后台。
CustomApplication完整代码如下：
class CustomApplication: Application(),Application.ActivityLifecycleCallbacks {
companion object{
const val TAG = "CustomApplication"
@SuppressLint("CustomContext")
lateinit var context: Context
}
private var activityCount = 0
private var nowActivityName:String? = null
private var isInBackground = true
fun getNowActivityName(): String? {
return nowActivityName
}
fun getIsInBackground():Boolean{
return isInBackground
}
override fun onCreate() {
super.onCreate()
context = applicationContext
registerActivityLifecycleCallbacks(this)
}
override fun onActivityCreated(activity: Activity, p1: Bundle?) {
}
override fun onActivityStarted(activity: Activity) {
activityCount++
if (isInBackground){
isInBackground = false
}
nowActivityName = activity.javaClass.name
}
override fun onActivityResumed(activity: Activity) {
}
override fun onActivityPaused(activity: Activity) {
}
override fun onActivityStopped(activity: Activity) {
activityCount--
if (activityCount == 0 && !isInBackground){
isInBackground = true
}
}
override fun onActivitySaveInstanceState(activity: Activity, p1: Bundle) {
}
override fun onActivityDestroyed(activity: Activity) {
}
}
弹框与通知弹出
开发中弹框与通知弹出的触发条件是，监听Websocket若有信息过来，app处于前台弹框，处于后台弹通知。这里使用Handler来模拟，弹框弹出比较简单，若有继承了DialogFragment的AlarmDialogFragment类。代码如下：
val dialog = AlarmDialogFragment()
dialog.show(supportFragmentManager,"tag")
通知弹出也不难，若只是弹出通知示例代码如下：
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
val channel =
NotificationChannel("normal", "Normal", NotificationManager.IMPORTANCE_DEFAULT)
notificationManager?.createNotificationChannel(channel)
}
val notification = NotificationCompat.Builder(this.applicationContext, "normal")
.setContentTitle("标题")
.setContentText("通知次数:${++alarmCount}")
.setSmallIcon(R.drawable.ic_launcher_background)
.setTimeoutAfter(5000)
.setAutoCancel(true)
.build()
notificationManager?.notify(notificationId,notification)
弹框与通知的特殊要求是，能在界面任意地方弹出且跳转到指定界面。弹框跳转相关代码在上面'弹框'部分，下面来说下通知的跳转，点击通知跳转是通过创建PendingIntent后在设置进NotificationCompat的setContentIntent方法内，不过通知跳转与弹框跳转一样需要分两种情况考虑，第一种同一Activity内Fragment与Fragment跳转，这种情况下PendingIntent如下代码所示：
var pendingIntent:PendingIntent? = null
val bundle = Bundle()
bundle.putString("alarmId","1")
pendingIntent = NavDeepLinkBuilder(this)
.setGraph(R.navigation.main_navigation)
.setDestination(R.id.alarmDetailFragment)
.setArguments(bundle)
.createPendingIntent()
上面代码中使用NavDeepLinkBuilder创建了一个PendingIntent，并且使用setGraph()指向使用的导航图，setDestination()则指向目标Fragment。
另一种情况则是ActivityB到另一个ActivityA内的指定FragmentB界面，这种情况下PendingIntent设置代码如下：
val intent = Intent(this@BaseActivity,MainActivity::class.java)
intent.putExtra("task","toAlarmDetail")
intent.flags = Intent.FLAG_ACTIVITY_NEW_TASK or Intent.FLAG_ACTIVITY_CLEAR_TASK
pendingIntent = TaskStackBuilder.create(this@BaseActivity)
.addNextIntentWithParentStack(intent)
.getPendingIntent(0,PendingIntent.FLAG_UPDATE_CURRENT)
这种是创建一个跳转到MainActivity的Intent，并添加传递的参数task，接着设置Intent的启动方式，其中Intent.FLAG_ACTIVITY_NEW_TASK，表示启动Activity作为新任务启动，Intent.FLAG_ACTIVITY_CLEAR_TASK，表示清除任务栈中所有现有的Activity。之后调用TaskStackBuilder创建PendingIntent。
上面两种方式创建的PendingIntent可以通过NotificationCompat.setContentIntent(pendingIntent)添加进去，关于通知创建的代码如下：
private fun useNotificationPI() {
var pendingIntent:PendingIntent? = null
if(javaClass.simpleName == "MainActivity"){
val bundle = Bundle()
bundle.putString("alarmId","1")
pendingIntent = NavDeepLinkBuilder(this)
.setGraph(R.navigation.main_navigation)
.setDestination(R.id.alarmDetailFragment)
.setArguments(bundle)
.createPendingIntent()
}else {
val intent = Intent(this@BaseActivity,MainActivity::class.java)
intent.putExtra("task","toAlarmDetail")
intent.flags = Intent.FLAG_ACTIVITY_NEW_TASK or Intent.FLAG_ACTIVITY_CLEAR_TASK
pendingIntent = TaskStackBuilder.create(this@BaseActivity)
.addNextIntentWithParentStack(intent)
.getPendingIntent(0,PendingIntent.FLAG_UPDATE_CURRENT)
}
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
val channel =
NotificationChannel("normal", "Normal", NotificationManager.IMPORTANCE_DEFAULT)
notificationManager?.createNotificationChannel(channel)
}
val notification = NotificationCompat.Builder(this.applicationContext, "normal")
.setContentTitle("标题")
.setContentText("通知次数:${++alarmCount}")
.setSmallIcon(R.drawable.ic_launcher_background)
.setTimeoutAfter(5000)
.setAutoCancel(true)
.setContentIntent(pendingIntent)
.build()
notificationManager?.notify(notificationId,notification)
}
上面代码中if(javaClass.simpleName == "MainActivity"),及第四行代码，该代码用处是当app置于后台时候，pp界面是MainActivity时，pendingIntent使用NavDeepLinkBuilder生成，当是其他Activity时使用TaskStackBuilder生成。之所以这样是因为，在MainActivity的xml，使用了FragmentContainerView用于fragment间跳转，其他的Activity没有FragmentContainerView，因此在生成pendingIntent需要采用不同的方式生成。
这示例代码中，主要涉及到的Avtivity有MainActivity与VideoActivity，MainActivity使用FragmentContainerView，而VideoActivity没有。弹框与通知跳转的界面是AlarmDetailFragment，这个fragment在MainActivity通过Navigation实现导航。
因此在MainActivity界面进入后台时，pendingIntent使用NavDeepLinkBuilder生成，NavDeepLinkBuilder则可以使用导航图中fragment生成深度链接URI，这个URI则可以导航到指定的fragment（关于NavDeepLinkBuilder了解不深入，这里说的可能有错误地方，欢迎大佬指正）。
而VideoActivity界面进入后台时，就需要使用TaskStackBuilder生成一个启动MainActivity的Intent。而在MainActivity的onStart方法内有下面initToAlarmDetail方法，判断跳转时携带参数决定是否跳转到AlarmDetailFragment界面。
private fun initToAlarmDetail() {
val task = intent.getStringExtra("task")
if (task == "toAlarmDetail"){
val bundle = Bundle()
bundle.putString("alarmId","1")
findNavController(R.id.fragment_main_table).navigate(R.id.alarmDetailFragment,bundle)
}
}
至此弹框与通知的功能基本实现，完整的BaseActivity代码如下：
open class BaseActivity: AppCompatActivity() {
companion object{
const val TAG = "BaseActivity"
}
private var alarmCount = 0
private val handler = Handler(Looper.myLooper()!!)
private val notificationId = 1
private var alarmDialogFragment: AlarmDialogFragment? = null
private var notificationManager:NotificationManager? = null
private var bgServiceIntent:Intent? = null
private var nowClassName = ""
private val dialogRunnable = object : Runnable {
override fun run() {
if (nowClassName == "VideoActivity"){
CustomLog.d(TAG,"不使用弹框 ${nowClassName}")
}else{
CustomLog.d(TAG,"使用弹框 ${nowClassName}")
useDialog()
handler.postDelayed(this, 10000)
}
}
}
private val notificationRunnable = object :Runnable{
override fun run() {
useNotificationPI()
handler.postDelayed(this,10000)
}
}
override fun onCreateView(name: String, context: Context, attrs: AttributeSet): View? {
initWindow()
return super.onCreateView(name, context, attrs)
}
override fun onCreate(savedInstanceState: Bundle?, persistentState: PersistableBundle?) {
super.onCreate(savedInstanceState, persistentState)
CustomLog.d(TAG,"onCreate(savedInstanceState: Bundle?, persistentState: PersistableBundle?) 当前类:${javaClass.simpleName}")
}
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
CustomLog.d(TAG,"onCreate(savedInstanceState: Bundle?) 当前类:${javaClass.simpleName}")
initData()
}
override fun onStart() {
super.onStart()
CustomLog.d(TAG,"onStart 当前类:${javaClass.simpleName}")
nowClassName = javaClass.simpleName
handler.postDelayed(dialogRunnable, 3000)
initService()
}
override fun onResume() {
super.onResume()
CustomLog.d(TAG,"onResume 当前类:${javaClass.simpleName}")
}
override fun onRestart() {
super.onRestart()
CustomLog.d(TAG,"onRestart 当前类:${javaClass.simpleName}")
}
override fun onPause() {
super.onPause()
CustomLog.d(TAG,"onPause 当前类:${javaClass.simpleName}")
}
override fun onStop() {
super.onStop()
CustomLog.d(TAG,"onStop 当前类:${javaClass.simpleName}")
val customApplication = applicationContext as CustomApplication
val nowActivityName = customApplication.getNowActivityName()
val activitySimpleName = nowActivityName?.substringAfterLast(".")
CustomLog.d(TAG,"activitySimpleName:$activitySimpleName")
val isInBackground = (this@BaseActivity.applicationContext as CustomApplication).getIsInBackground()
if (isInBackground && activitySimpleName.equals(javaClass.simpleName)){
handler.postDelayed(notificationRunnable,3000)
CustomLog.d(TAG,"使用通知 $nowClassName")
}else{
CustomLog.d(TAG,"关闭所有定时任务 $nowClassName")
closeAllTask()
}
}
override fun onDestroy() {
super.onDestroy()
CustomLog.d(TAG,"onDestroy 当前类:${javaClass.simpleName}")
closeAllTask()
this.stopService(bgServiceIntent)
}
private fun closeAllTask() {
handler.removeCallbacks(dialogRunnable)
handler.removeCallbacks(notificationRunnable)
}
private fun initData() {
notificationManager = notificationManager ?: this.getSystemService(Context.NOTIFICATION_SERVICE) as NotificationManager
alarmDialogFragment = alarmDialogFragment ?: AlarmDialogFragment()
}
private fun useNotificationPI() {
var pendingIntent:PendingIntent? = null
if(javaClass.simpleName == "MainActivity"){
CustomLog.d(TAG,">>>通知：MainActivity")
val bundle = Bundle()
bundle.putString("alarmId","1")
pendingIntent = NavDeepLinkBuilder(this)
.setGraph(R.navigation.main_navigation)
.setDestination(R.id.alarmDetailFragment)
.setArguments(bundle)
.createPendingIntent()
}else {
CustomLog.d(TAG,">>>通知：else")
val intent = Intent(this@BaseActivity,MainActivity::class.java)
intent.putExtra("task","toAlarmDetail")
intent.flags = Intent.FLAG_ACTIVITY_NEW_TASK or Intent.FLAG_ACTIVITY_CLEAR_TASK
pendingIntent = TaskStackBuilder.create(this@BaseActivity)
.addNextIntentWithParentStack(intent)
.getPendingIntent(0,PendingIntent.FLAG_UPDATE_CURRENT)
}
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
val channel =
NotificationChannel("normal", "Normal", NotificationManager.IMPORTANCE_DEFAULT)
notificationManager?.createNotificationChannel(channel)
}
val notification = NotificationCompat.Builder(this.applicationContext, "normal")
.setContentTitle("标题")
.setContentText("通知次数:${++alarmCount}")
.setSmallIcon(R.drawable.ic_launcher_background)
.setTimeoutAfter(5000)
.setAutoCancel(true)
.setContentIntent(pendingIntent)
.build()
notificationManager?.notify(notificationId,notification)
}
private fun useDialog() {
if (alarmDialogFragment?.isVisible == false){
alarmDialogFragment?.show(supportFragmentManager,"testDialog")
}else{
}
}
private fun closeAlarmDialog() {
if (alarmDialogFragment?.isVisible == true) {
alarmDialogFragment?.dismiss()
}
}
private fun initWindow() {
window.statusBarColor = Color.TRANSPARENT
window.decorView.systemUiVisibility = View.SYSTEM_UI_FLAG_LAYOUT_HIDE_NAVIGATION
}
private fun initService() {
CustomLog.d(TAG,"开启前台服务")
bgServiceIntent = bgServiceIntent ?: Intent(this, BackgroundService::class.java)
this.startService(bgServiceIntent)
}
}
总结
只是弹出弹框和通知的话，实现很好实现，中间麻烦地方在于当app使用多个Activity，该怎么实现跳转到指定的界面。当然这里麻烦是，从ActivityB跳转到ActivityA的Fragment，如果是只有一个Activity应该会好办些。个人感觉fragment跳转应该有更好的方式实现希望能和大佬们交流下这种情况下，用什么技术实现。
PS：感觉原生Android在写界面和跳转方面写起来不太方便。不知道大家有便捷的方式吗。
代码地址
GitHub：github.com/SmallCrispy…
作者：卤肉拌面
来源：juejin.cn/post/7260808821659779129
，原图本身是长方形的，通过Modifier修饰符修饰后，很容易变成圆角图片。想一下如果用XML方式来写，是不是要写好多代码呢。
