运行我的 MainActivty 的一部分在单独的线程中

Question

我正在研究在单独的线程或进程中运行我的 onResume 函数的方法，因此它不会阻止 activity.

的加载

我正在寻找运行单独在 MainActivity 中设置 onResume 函数的方法。 onResume 中的内容是一组例程，可在应用程序启动或恢复时从 sharedPref 加载数据。然而，onResume 进程延迟了 activity 的整个加载，所以我在想是否可以从一个单独的进程运行来不延迟整个 activity 的加载？

package com.taylorworld.tw1

import android.content.Context
import android.content.Context.*
import android.content.Intent
import android.net.Uri
import android.os.Bundle
import android.support.design.widget.FloatingActionButton
import android.support.design.widget.Snackbar
import android.support.v4.view.GravityCompat
import android.support.v7.app.ActionBarDrawerToggle
import android.view.MenuItem
import android.support.v4.widget.DrawerLayout
import android.support.design.widget.NavigationView
import android.support.v7.app.AppCompatActivity
import android.support.v7.widget.Toolbar
import android.view.Menu
import android.view.View
import android.widget.Toast
import com.google.firebase.database.FirebaseDatabase
//import com.google.firebase.firestore.FirebaseFirestore
import kotlinx.android.synthetic.main.content_main.*
import java.sql.Types.NULL

class MainActivity : AppCompatActivity(),     NavigationView.OnNavigationItemSelectedListener {


override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)
    setContentView(R.layout.activity_main)
    val toolbar: Toolbar = findViewById(R.id.toolbar)
    setSupportActionBar(toolbar)

    val fab: FloatingActionButton = findViewById(R.id.fab)
    fab.setOnClickListener { view ->
        val intent = Intent(this, Main2Activity::class.java)
        val sharedPref = this?.getPreferences(Context.MODE_PRIVATE)
        val mystr = sharedPref.getInt(getString(R.string.STR), 0)
        intent.putExtra("data", mystr)
        startActivity(intent)
    }
    val drawerLayout: DrawerLayout = findViewById(R.id.drawer_layout)
    val navView: NavigationView = findViewById(R.id.nav_view)
    val toggle = ActionBarDrawerToggle(
        this, drawerLayout, toolbar, R.string.navigation_drawer_open,     R.string.navigation_drawer_close
    )
    drawerLayout.addDrawerListener(toggle)
    toggle.syncState()

    navView.setNavigationItemSelectedListener(this)

    //val db = FirebaseFirestore.getInstance()
}

override fun onBackPressed() {
    val drawerLayout: DrawerLayout = findViewById(R.id.drawer_layout)
    if (drawerLayout.isDrawerOpen(GravityCompat.START)) {
        drawerLayout.closeDrawer(GravityCompat.START)
    } else {
        super.onBackPressed()
    }
}

override fun onCreateOptionsMenu(menu: Menu): Boolean {
    // Inflate the menu; this adds items to the action bar if it is     present.
    menuInflater.inflate(R.menu.main, menu)
    return true
}

override fun onOptionsItemSelected(item: MenuItem): Boolean {
    // Handle action bar item clicks here. The action bar will
    // automatically handle clicks on the Home/Up button, so long
    // as you specify a parent activity in AndroidManifest.xml.
    return when (item.itemId) {
        R.id.action_settings -> true
        else -> super.onOptionsItemSelected(item)
    }
}

override fun onNavigationItemSelected(item: MenuItem): Boolean {
    // Handle navigation view item clicks here.
    when (item.itemId) {
        R.id.nav_home -> {
            // Handle the camera action
            val i = Intent(Intent.ACTION_VIEW,     Uri.parse("https://www.facebook.com/brobostigon/"))
            startActivity(i)
        }
        R.id.nav_gallery -> {

        }
        R.id.nav_slideshow -> {

        }
        R.id.nav_tools -> {

        }
        R.id.nav_share -> {

        }
        R.id.nav_send -> {

        }
    }
    val drawerLayout: DrawerLayout = findViewById(R.id.drawer_layout)
    drawerLayout.closeDrawer(GravityCompat.START)
    return true
}

public fun saveStr(view: View) {
    var strength = Integer.parseInt(editText2.text.toString())
    // this should be getPreferences
    val sharedPref = this?.getPreferences(Context.MODE_PRIVATE);
    with(sharedPref.edit()) {
        putInt(getString(R.string.STR), strength)
        apply()
    }
    Toast.makeText(this, "Strength Saved", Toast.LENGTH_SHORT).show();

    //val database = FirebaseDatabase.getInstance()
    //val myRef = database.getReference("str")
    //myRef.setValue(strength)
}

public fun saveDex(view: View) {
    var dexterity = Integer.parseInt(editText.text.toString())
    // this should be getPreferences
    val sharedPref = this?.getPreferences(Context.MODE_PRIVATE);
    with(sharedPref.edit()) {
        putInt(getString(R.string.DEX), dexterity)
        apply()
    }
    Toast.makeText(this, "Dexterity Saved",     Toast.LENGTH_SHORT).show();
}

public fun saveInt(view: View) {
    var intelligance = Integer.parseInt(editText4.text.toString())
    // this should be getPreferences
    val sharedPref = this?.getPreferences(Context.MODE_PRIVATE);
    with(sharedPref.edit()) {
        putInt(getString(R.string.INT), intelligance)
        apply()
    }
    Toast.makeText(this, "Intelligence Saved", Toast.LENGTH_SHORT).show();
}

public fun saveWis(view: View) {
    var wisdom = Integer.parseInt(editText3.text.toString())
    // this should be getPreferences
    val sharedPref = this?.getPreferences(Context.MODE_PRIVATE);
    with(sharedPref.edit()) {
        putInt(getString(R.string.WIS), wisdom)
        apply()
    }
    Toast.makeText(this, "Wisdom Saved", Toast.LENGTH_SHORT).show();
}

public fun saveCha(view: View) {
    var charisma = Integer.parseInt(editText5.text.toString())
    // this should be getPreferences
    val sharedPref = this?.getPreferences(Context.MODE_PRIVATE);
    with(sharedPref.edit()) {
        putInt(getString(R.string.CHA), charisma)
        apply()
    }
    Toast.makeText(this, "charisma Saved", Toast.LENGTH_SHORT).show();
}

public fun saveCon(view: View) {
    var constitution = Integer.parseInt(editText6.text.toString())
    // this should be getPreferences
    val sharedPref = this?.getPreferences(Context.MODE_PRIVATE);
    with(sharedPref.edit()) {
        putInt(getString(R.string.CON), constitution)
        apply()
    }
    Toast.makeText(this, "Constitution Saved", Toast.LENGTH_SHORT).show();
}

public fun saveChr(view: View) {
    var chrname = editText7.text.toString()
    // this should be getPreferences
    val sharedPref = this?.getPreferences(Context.MODE_PRIVATE);
    with(sharedPref.edit()) {
        putString(getString(R.string.CHR), chrname)
        apply()
    }
    Toast.makeText(this, "Character Name Saved", Toast.LENGTH_SHORT).show();
}

    override fun onResume() {
        super.onResume()

        //public fun readSP(view: View) {

        val sharedPref = this?.getPreferences(Context.MODE_PRIVATE)

        val mystr = sharedPref.getInt(getString(R.string.STR), 0);
        editText2.setText(Integer.toString(mystr))

        val mydex = sharedPref.getInt(getString(R.string.DEX), 0);
        editText.setText(Integer.toString(mydex))

        val myint = sharedPref.getInt(getString(R.string.INT), 0);
        editText4.setText(Integer.toString(myint))

        val mywis = sharedPref.getInt(getString(R.string.WIS), 0);
        editText3.setText(Integer.toString(mywis))

        val mycon = sharedPref.getInt(getString(R.string.CON), 0);
        editText6.setText(Integer.toString(mycon))

        val mycha = sharedPref.getInt(getString(R.string.CHA), 0);
        editText5.setText(Integer.toString(mycha))

        val mychr = sharedPref.getString(getString(R.string.CHR), null);
        editText7.setText(mychr)
    }
}

Answer 1

您可以使用协同程序在后台线程中加载数据，然后切换回 UI 线程来填充您的视图，就像这样（为清楚起见，我只使用 2 个属性）：

data class MyData(
        val myStr: Int,
        val myDex: Int
)

override fun onResume() {
    super.onResume()

    lifecycleScope.launch {
        val data = withContext(Dispatchers.IO) {
            val mystr = sharedPref.getInt(getString(R.string.STR), 0);
            val mydex = sharedPref.getInt(getString(R.string.DEX), 0);
            MyData(mystr, mydex)
        }
        editText2.setText(data.myStr.toString())
        editText.setText(data.myDex.toString())
    }
}

但是请注意，加载首选项非常快，所以我怀疑这是你的瓶颈，你可能需要做一些分析以查看时间花在了哪里。

另请注意，您正在混合 process 和 thread - 您的整个应用程序在 process 中运行，并且您在该过程中有多个 threads - 您可以在您的进程中切换线程，但您的整个应用程序是单个 process.

Answer 2

当您使用 kotlin 时，您还可以使用 Anko 库，它可以让您在后台执行 doAsync{} 和 return 到 UI thread

// Example from Anko documentation
doAsync {
    // Long background task
    uiThread {
        result.text = "Done"
    }
}

检查一下：https://github.com/Kotlin/anko

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