如何在Android应用程序中将数据从一项活动传递到另一项活动

Question

I'm trying to create simple app where you type your data in one activity by editText and it's shown in another in TextView. But i really don't know how to make it work. As you can see this is simple code but right now when i click submit nothing happens on another activity. this is first activty

class MainActivity : AppCompatActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)
    }
    fun switchToActivity (view: View){
        val myIntent = Intent(this, Main2Activity::class.java)
        startActivity(myIntent)
    }
    override fun onActivityResult(requestCode: Int,
                                  resultCode: Int,
                                  myInten: Intent?) {
        var text2 = myInten?.getStringExtra("text")
        textView.setText(text2)
    }
}

And this is second

class Main2Activity : AppCompatActivity() {

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main2)
    }
    fun buttonListener (view: View){
        var text = editText.text.toString()

        val myIntent = Intent()
        myIntent.putExtra("textView", text)
        setResult(Activity.RESULT_OK, myIntent)
        finish()
    }
}

Answer 1

There are 2 issues with your code.

First, to receive result from another activity, you must use startActivityForResult() instead.

fun switchToActivity (view: View){
    val myIntent = Intent(this, Main2Activity::class.java)
    startActivityForResult(myIntent)
}

Second, you must use the same key when saving and retrieving result.

var text2 = myInten?.getStringExtra("textView")

Put it together.

class MainActivity : AppCompatActivity() {

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

    fun switchToActivity (view: View){
        val myIntent = Intent(this, Main2Activity::class.java)
        startActivityForResult(myIntent)
    }

    override fun onActivityResult(requestCode: Int,
                                  resultCode: Int,
                                  myInten: Intent?) {
        var text2 = myInten?.getStringExtra("textView")
        textView.setText(text2)
    }
}

Answer 2

您应该使用： startActivityForResult(myIntent)而不是： startActivity(myIntent)