为什么在活动之间发送数据不起作用?

问题描述 投票:0回答:2

我目前正在使用Kotlin。我正在尝试通过转到另一个活动即颜色设置活动来更改主活动中框的颜色。我的代码未返回任何错误,但不起作用。我尝试在此页面上阅读不同的结果,但没有一个回答我的问题。谢谢您的帮助。

mainactivity.kt

override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

        val button_box = findViewById<Button>(R.id.button_box)

        button_box.setOnClickListener {
            val intent = Intent(this, boxColor::class.java)
            startActivity(intent)
        }

    }

    override fun onActivityResult(requestCode: Int, resultCode: Int, data: Intent?) {
        super.onActivityResult(requestCode, resultCode, data)

            if (resultCode == RESULT_OK) {

                val returnColor = data!!.getStringExtra("colorName")

                val boxColorChoice = when (returnColor) {
                    "green" -> R.drawable.box_green
                    "grey" -> R.drawable.box_grey
                    "lblue" -> R.drawable.box_lblue
                    "purple" -> R.drawable.box_purple
                    "red" -> R.drawable.box_red
                    "white" -> R.drawable.box_white
                    "yellow" -> R.drawable.box_yellow
                    else -> R.drawable.box_white
                }
                button_box.setBackgroundResource(boxColorChoice)
            }
        }

这里是boxcolor.kt

override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_box_color)

        val green = findViewById<Button>(R.id.green_box)
        val red = findViewById<Button>(R.id.red_box)
        val white = findViewById<Button>(R.id.white_box)
        val yellow = findViewById<Button>(R.id.yellow_box)
        val grey = findViewById<Button>(R.id.grey_box)
        val lblue = findViewById<Button>(R.id.lblue_box)

        green.setOnClickListener {
            val intent = Intent()
            intent.putExtra("colorName", "green")
            setResult(Activity.RESULT_OK, intent)
            finish()
        }

     (and the same onclicklistener for all the other colours)

我也知道这是一个小问题,但非常感谢您的帮助。我是来自拉贾斯坦邦的14岁男孩,我想成为一名程序员并正在学习

android kotlin
2个回答
1
投票

您需要使用startActivityForResult,您的代码必须更改为这些:

mainactivity.kt

...
val mRequestCode = 101  //ADD THIS LINE
...
button_box.setOnClickListener {
            val intent = Intent(this, boxColor::class.java)
            startActivityForResult(intent, mRequestCode) //ADD THIS LINE
        }
...
override fun onActivityResult(requestCode: Int, resultCode: Int, data: Intent?) {
        super.onActivityResult(requestCode, resultCode, data)

            if (resultCode == mRequestCode) { //CHANGE THIS LINE
                ...
            }
        }

并且在您的boxcolor.kt中:

override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_box_color)
        val mRequestCode = 101  //ADD THIS LINE

        ...

        green.setOnClickListener {
            val intent = Intent()
            intent.putExtra("colorName", "green")
            setResult(mRequestCode, intent)  //CHANGE THIS LINE
            finish()
        }

     (and the same onclicklistener for all the other colours)

注意,请不要将Activity.RESULT_OK用作requestCode


0
投票

请使用请求代码startActivityForResult

示例:

私有值RC = 101

val intent = Intent(this,boxColor :: class.java)

startActivityForResult(intent,RC)


0
投票

请使用请求代码startActivityForResult

示例:

私有值RC = 101

val intent = Intent(this,boxColor :: class.java)

startActivityForResult(intent,RC)

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