谷歌官方构建您的第一个应用 Kotlin版-优快云博客

本文介绍了一个简单的Android应用程序，展示了如何在两个活动之间传递消息。通过MainActivity发送消息到DisplayMessageActivity，实现基本的应用内通信。

https://developer.android.google.cn/training/basics/firstapp

MainActivity.kt

package com.example.myfirstapp

import android.support.v7.app.AppCompatActivity
import android.os.Bundle
import android.view.View
import android.content.Intent
import kotlinx.android.synthetic.main.activity_main.*


class MainActivity : AppCompatActivity() {
    companion object {
        val EXTRA_MESSAGE = "com.example.myfirstapp.MESSAGE"
    }
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)
    }
    fun sendMessage(view: View) {
        val message = editText.text.toString()
        val intent = Intent(this, DisplayMessageActivity::class.java)
        intent.putExtra(EXTRA_MESSAGE, message)
        startActivity(intent)
    }
}

DisplayMessageActivity.kt

package com.example.myfirstapp

import android.support.v7.app.AppCompatActivity
import android.os.Bundle
import kotlinx.android.synthetic.main.activity_display_message.*

class DisplayMessageActivity : AppCompatActivity() {

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

        val message = intent.getStringExtra(MainActivity.EXTRA_MESSAGE)
        textView.text=message;
    }
}