我正在开发一个项目，该项目由检索和写入
html_data我将之前的
html_dataprev_html_data问题是该变量始终是一个空字符串（我初始化它的方式），这意味着它永远不会被覆盖。
html_data我什至将所有内容分离到一个函数中，这样我就可以从主类中调用它，但它仍然不起作用。
变量始终是一个空字符串，无论我做什么...每次打印它...
我还忘了提及，由于某种原因，我在timerRun()中打印的html_data从未被html_parse()解析，即使我在fetchdata()中调用该函数。
class MainActivity : AppCompatActivity() {
var unique_id = 1000
var html_data = ""
var prev_html_data = ""
lateinit var notificationManager: NotificationManager
lateinit var notificationChannel: NotificationChannel
lateinit var builder: Notification.Builder
private val channelId = "hallomotto"
private val description = "***** alert"
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
enableEdgeToEdge()
setContentView(R.layout.activity_main)
notificationManager = getSystemService(Context.NOTIFICATION_SERVICE) as NotificationManager
fetchdata()
this.prev_html_data = html_data
ViewCompat.setOnApplyWindowInsetsListener(findViewById(R.id.main)) { v, insets ->
val systemBars = insets.getInsets(WindowInsetsCompat.Type.systemBars())
v.setPadding(systemBars.left, systemBars.top, systemBars.right, systemBars.bottom)
insets
}
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
notificationChannel = NotificationChannel(channelId, description, NotificationManager.IMPORTANCE_HIGH)
notificationChannel.enableLights(true)
notificationChannel.lightColor = Color.GREEN
notificationChannel.enableVibration(true)
notificationManager.createNotificationChannel(notificationChannel)
builder = Notification.Builder(this, channelId)
.setContentTitle("Floria alert!!")
.setContentText("A new message has been posted (Floria is here!!!)")
.setSmallIcon(R.drawable.ic_launcher_background)
.setLargeIcon(BitmapFactory.decodeResource(this.resources, R.drawable.ic_launcher_background))
} else {
builder = Notification.Builder(this)
.setContentTitle("Floria alert!!")
.setContentText("A new message has been posted (Floria is here!!!)")
.setSmallIcon(R.drawable.ic_launcher_background)
.setLargeIcon(BitmapFactory.decodeResource(this.resources, R.drawable.ic_launcher_background))
}
val timer = Timer(true)
timer.schedule(object : TimerTask() {
override fun run() {
timerRun()
}
}, 60000, 60000)
}
private fun fetchdata() {
val volleyQueue = Volley.newRequestQueue(this)
val url = "*****"
val jsonRequest = JSONObject()
jsonRequest.put("key", "*****")
val jsonObjectRequest = JsonObjectRequest(
Request.Method.POST,
url,
jsonRequest,
{ response ->
val html_message = response.get("html_data")
html_data = html_message.toString()
display_html()
},
{ error ->
Toast.makeText(this, "Error has occurred when making the request", Toast.LENGTH_LONG).show()
Log.e("MainActivity", "load_error: ${error.localizedMessage}")
}
)
volleyQueue.add(jsonObjectRequest)
Log.v("JSON request", jsonRequest.toString())
}
private fun html_parse() {
html_data = """
<html>
<head>
</head>
<body>
""".trimIndent() + html_data
html_data += """
</body>
</html>
""".trimIndent()
}
private fun display_html() {
html_parse()
Log.v("Output", html_data)
val encoded_data = Base64.encodeToString(html_data.toByteArray(), Base64.NO_PADDING)
val webview = findViewById<WebView>(R.id.webview)
webview.loadData(encoded_data, "text/html", "base64")
}
private fun timerRun(){
fetchdata()
if(html_data != this.prev_html_data){
notificationManager.notify(unique_id, builder.build())
unique_id += 1
Log.e("Match 1", html_data);
Log.e("Match 2", this.prev_html_data)
}
this.prev_html_data = html_data
}
}
Volley 请求是异步的。
volleyQueue.add()因此，当您调用
fetchdata()fetchdata()html_datathis.prev_html_data = html_data相反，您可以根据需要让
fetchdata()prev_html_datahtml_data