android - 将android应用程序中布局的背景颜色与kotlin进行比较

Question

我想做一个 if 语句，在其中我将比较我的布局背景颜色的颜色，与 kotlin 类似:

    val viewPaint = (background.getBackground() as PaintDrawable).paint
    val colorARGB = viewPaint.color

    if(colorARGB == Color.GREEN){

        btn_touch.setOnClickListener {


            counter += 1
            textCounter.text = counter.toString()


        }
    }

它不起作用我如何将背景颜色与 kotlin 进行比较？

Answer 1

我回答了your other question ，所以我有更多的上下文 :-) 您应该存储自己的应用程序状态，而不是直接比较背景颜色，这样您就可以控制它在做什么，并让背景做出相应的 react 。

enum class State {
    ON,
    OFF
}

从您的 GitHub 存储库中，更改循环以更新状态:

  when (Random.nextBoolean()) {
       true -> state = State.ON
       false -> state = State.OFF
  }

然后使用该状态更新您的 UI:

private fun updateUI() {
    when (state) {
        State.ON -> {
            background.setBackgroundColor(Color.GREEN)
        }
        State.OFF -> {
            background.setBackgroundColor(Color.RED)
        }
    }
}

因此，您可以再次使用状态来响应按钮单击:

btn_touch.setOnClickListener {
     when (state) {
         State.ON -> reactOnClickWhenOn()
         State.OFF -> reactOnClickWhenOff()
     }
}

private fun reactOnClickWhenOn() {
    counter += 1
}

private fun reactOnClickWhenOff() {
    Toast.makeText(this, "Nope!", Toast.LENGTH_SHORT).show()
}

完整的例子:

import android.graphics.Color
import android.os.Bundle
import android.widget.Toast
import androidx.appcompat.app.AppCompatActivity
import kotlinx.android.synthetic.main.foo.*
import kotlinx.coroutines.*
import java.util.concurrent.TimeUnit
import kotlin.random.Random

class FooActivity : AppCompatActivity() {

    private var state = State.OFF
    private var counter: Int = 0
    private var running = false

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.foo)
        val loop = true
        GlobalScope.launch(Dispatchers.IO) {
            while (loop) {
                while (running) {
                    delay(TimeUnit.SECONDS.toMillis(Random.nextLong(5)))
                    when (Random.nextBoolean()) {
                        true -> state = State.ON
                        false -> state = State.OFF
                    }
                    withContext(Dispatchers.Main) {
                        updateUI()
                    }
                }
            }
        }

        btn_touch.setOnClickListener {
            when (state) {
                State.ON -> reactOnClickWhenOn()
                State.OFF -> reactOnClickWhenOff()
            }
        }

    }

    private fun updateUI() {
        when (state) {
            State.ON -> {
                background.setBackgroundColor(Color.GREEN)
            }
            State.OFF -> {
                background.setBackgroundColor(Color.RED)
            }
        }
    }

    private fun reactOnClickWhenOn() {
        counter += 1
    }

    private fun reactOnClickWhenOff() {
        Toast.makeText(this, "Nope!", Toast.LENGTH_SHORT).show()
    }

    override fun onResume() {
        super.onResume()
        running = true
    }

    override fun onPause() {
        running = false
        super.onPause()
    }

    enum class State {
        ON,
        OFF
    }
}