App-Kotlin入门到精通-启动Activity(四)

宁教我负天下人，休教天下人负我!——曹操

 

 

AndroidManifest.xml注册 

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创建布局activity_main.xml

AndroidManifest.xml注册

创建activity_two.xml布局

创建Intent-与TwoActivity建立关联

 /** Called when the user taps the Send button */
    fun sendMessage(view: View) {
        val textView = findViewById(R.id.textView)
        val message = textView.text.toString()
        val intent = Intent(this, TwoActivity::class.java).apply {
            putExtra(EXTRA_MESSAGE, message)
        }
        startActivity(intent)
    }

修改布局activity_main.xml

 接受MainActivity传递的消息 

class TwoActivity : AppCompatActivity() {

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

        // Get the Intent that started this activity and extract the string
        val message = intent.getStringExtra(EXTRA_MESSAGE)

        // Capture the layout's TextView and set the string as its text
        val textView = findViewById(R.id.textView).apply {
            text = message
        }
    }
}

 范型 Class

 fun    comToActivity(t: Class,message : String) {
        val intent=Intent(this, t).apply {
            putExtra(EXTRA_MESSAGE, message)
        };
        startActivity(intent)
    }

class MainActivity : AppCompatActivity() {



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

    /** Called when the user taps the Send button */
    fun sendMessage(view: View) {
        val textView = findViewById(R.id.textView)
        val message = textView.text.toString()
        comToActivity(TwoActivity::class.java,message);
    }

    fun    comToActivity(t: Class,message : String) {
        val intent=Intent(this, t).apply {
            putExtra(EXTRA_MESSAGE, message)
        };
        startActivity(intent)
    }
}

正确使用 android:parentActivityName

 

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下载资源

参考:

Kotlin范型:https://www.kotlincn.net/docs/reference/generics.html

Kotlin 中的泛型介绍:https://zhuanlan.zhihu.com/p/78721880

【码上开学】Kotlin 的泛型:https://www.bilibili.com/video/av66340216/

Kotlin学习笔记：泛型:https://www.jianshu.com/p/ea7e8356a23b