[英]How to add or find textview outside of the mainactivity in Android Kotlin?
包 com.example.asyntask
导入 android.content.ContentValues.TAG
导入 android.os.AsyncTask
导入 androidx.appcompat.app.AppCompatActivity
导入 android.os.Bundle
导入 android.util.Log
导入 android.widget.Button
导入 android.widget.TextView
导入 kotlinx.android.synthetic.main.activity_main.*
类 MainActivity : AppCompatActivity() {
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
btnStart.setOnClickListener {
val tvCounter=findViewById<TextView>(R.id.tvCounter)
CountTask().execute(5)
}
}
}
类 CountTask() : AsyncTask<Int, Int, Unit>() {
private val tag: String? = "Async"
override fun doInBackground(vararg params: Int?) {
Log.d(tag, "doInBackground: started")
val n: Int = params[0]!!
for (i in 0 until n) {
wait1Sec()
publishProgress(i)
}
}
private fun wait1Sec():Unit{
val start =System.currentTimeMillis()
while(System.currentTimeMillis()<start+1000){}
}
override fun onProgressUpdate(vararg values: Int?) {
super.onProgressUpdate(*values)
//WANT TO WRITE TEXT IN TEXT VIEW BUT HOW TO GET VIEW HERE
}
}
请尝试使用progressupdate从asynchtask到mainactivity创建回调
像:
Interface UpdateListener{
fun onProgressUpdate(progress:Int);
}
class CountTask(val listener:UpdateListener) : AsyncTask<Int, Int, Unit>() {
override fun onProgressUpdate(vararg values: Int?) {
super.onProgressUpdate(*values)
//WANT TO WRITE TEXT IN TEXT VIEW BUT HOW TO GET VIEW HERE
listener.onpreogressupdate(...)
}
}
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
btnStart.setOnClickListener {
val tvCounter=findViewById<TextView>(R.id.tvCounter)
CountTask(object:listener:UpdateListener{
override fun onProgressUpdate(progress:Int){
//TODO update here
}
}).execute(5)
}
}
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