Android 保存界面状态

方法一：

android:configChanges="orientation|screenSize"

方法二：

SaveActivity

class SaveActivity : AppCompatActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_save)
        //取数据
        if (savedInstanceState != null) {
            textView4.text = savedInstanceState.getString("textView4")
        }

        button12.setOnClickListener {
            textView4.text = editText2.text
        }
    }

    //转场时保存数据
    override fun onSaveInstanceState(outState: Bundle) {
        super.onSaveInstanceState(outState)
        outState.putString("textView4", textView4.text.toString())
    }
}