Android开发教程Kotlin

1.学习内容

2.Activity之间的跳转

MainActivity

package com.example.kotlinstudy
​
import android.content.Intent
import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import android.widget.TextView
​
class MainActivity : AppCompatActivity() {
    var tv_first = findViewById<TextView>(R.id.tv_first)
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)
        tv_first.setOnClickListener{
            val intent = Intent(this,SecondActivity::class.java)
            intent.putExtra("name","测试传参")
            startActivity(intent)
        }
    }
}

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">
​
    <TextView
        android:id="@+id/tv_first"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Click Me!"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toTopOf="parent" />
​
</androidx.constraintlayout.widget.ConstraintLayout>

SecondActivity

package com.example.kotlinstudy
​
import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import android.widget.TextView
​
class SecondActivity : AppCompatActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_second)
        val name = intent.extras?.getString("name")
        var tv_content = findViewById<TextView>(R.id.tv_content)
        tv_content.text = name
    }
}

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".SecondActivity">
​
    <TextView
        android:id="@+id/tv_content"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Second Activity"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintBottom_toBottomOf="parent"
        />
​
</androidx.constraintlayout.widget.ConstraintLayout>

3.Activity之间传参