Question

我想用完全自定义的布局制作AlertDialog。如果用户使用按钮，则只有在我致电AlertDialog时，它才应关闭dialog.cancel()。

我将对话框更改为以下结构：

val builder = AlertDialog.Builder(this, R.style.AlertDialogStyle)
val inflater = this.layoutInflater
val dialogView: View = inflater.inflate(R.layout.alert_dialog_et_layout, null)

builder.apply {
    setMessage(R.string.dialog_msg)
    setPositiveButton(R.string.dialog_accept_label, null)
    setNegativeButton(R.string.dialog_close_label, null)
    setView(dialogView)
}

val alertDialog = builder.create()
val positiveBtn = alertDialog.getButton(AlertDialog.BUTTON_POSITIVE)
val negativeBtn = alertDialog.getButton(AlertDialog.BUTTON_NEGATIVE)
alertDialog.show()

positiveBtn.setOnClickListener {
    //do some stuff with data
}

negativeBtn.setOnClickListener {
    alertDialog.cancel()
}

但这会引发异常：

java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.Button.setOnClickListener(android.view.View$OnClickListener)' on a null object reference

Answer 1

Builder已经为您提供了一个设置onClickListeners的地方。在那里做，您就可以摆脱放在底部的setOnClickListener调用了（这些调用会引起问题）：

builder.apply {
    builder.setMessage(R.string.dialog_msg)
    builder.setPositiveButton(R.string.dialog_accept_label, positiveClickListener)
    builder.setNegativeButton(R.string.dialog_close_label, negativeClickListener)
    builder.setView(dialogView)
}

空对象引用上的AlertDialog按钮侦听器

1 个答案: