java - AlertDialog - 试图理解这种语法

Question

这是本书示例中的代码:

new AlertDialog.Builder(this)
    .setTitle(getResources().getString(R.string.alert_label))
    .setMessage(validationText.toString())
    .setPositiveButton("Continue", new DialogInterface.OnClickListener() {
        public void onClick(DialogInterface dialog, int arg1) {
           // in this case, don't need to do anything other than close alert
        }
    })
.show();

我想看懂这段代码，请分几条语句改写，使每条语句恰好做一次操作。谢谢!

Answer 1

// Create a builder
AlertDialog.Builder adb = new AlertDialog.Builder(this);

// Set a title
adb.setTitle(getResources().getString(R.string.alert_label));

// Set the dialogs message
adb.setMessage(validationText.toString());

// Set label and even handling of the "positive button"
// 
// NOTE: If you don't want to do anything here except to close the dlg 
// use the next line instead (you don't have to specifiy an event handler)
// adb.setPositiveButton("Continue", null);

adb.setPositiveButton("Continue",
    new android.content.DialogInterface.OnClickListener() {
    public void onClick(DialogInterface dialog, int arg1) {
       // in this case, don't need to do anything other than close alert
    }
    });

// Show the dialog
adb.show();

单独的语句，每个语句都在一个普通的构建器对象上执行。

或者，您可以链接构建器方法以保存一些字符(如您的原始来源)，但您可以将其编写得更具可读性。为此，请删除每行开头的分号和对象引用。每个构建器方法都会返回原始构建器对象，您可以使用该对象在其上运行下一条语句。

这里有一个小的、可读性更好的例子:

new AlertDialog.Builder(this)
.setTitle("Title")
.setMessage("42 is the answer")
.show();