Question

当我想从android中的Alert框中检索一个值时，它会在我点击OK按钮之前返回。

这是我做的功能：

public String enterSecretCode(){

    AlertDialog.Builder alert = new AlertDialog.Builder(this);

    alert.setTitle("Secret Code");
    alert.setMessage("Enter your 5 digit Secret Code to Encode!");

 // Set an EditText view to get user input
    final EditText input = new EditText(this);
    input.setFilters(new InputFilter[] {new InputFilter.LengthFilter(5)});
    input.setHint("XXXXX");
    input.setInputType(InputType.TYPE_CLASS_NUMBER);
    alert.setView(input);

    alert.setPositiveButton("Ok", new DialogInterface.OnClickListener() {
        public void onClick(DialogInterface dialog, int whichButton) {
            code = input.getText().toString();
            // Do something with value!
        }
    });

    alert.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
        public void onClick(DialogInterface dialog, int whichButton) {
            // Canceled.
        }
    });

    alert.show();

    return code;
}

这是函数调用，我试图在点击按钮时找借口：

String secretCode = enterSecretCode();

Answer 1

show()不是阻止通话。您需要重写代码以将结果作为正按钮onClick()方法的一部分进行处理，而不是让此方法返回一些值。

Answer 2

如果您愿意，可以使用界面：

创建一个名为AlertInterface的新类

public class AlertInterface {

Context context;
Receiver receiver;

public AlertInterface(Context context, Receiver receiver)
{
    this.context=context;
    this.receiver=receiver;
}

public void enterSecretCode()
{
    final AlertDialog.Builder alert = new AlertDialog.Builder(this.context);

    alert.setTitle("Secret Code");
    alert.setMessage("Enter your 5 digit Secret Code to Encode!");

    // Set an EditText view to get user input
    final EditText input = new EditText(this.context);
    input.setFilters(new InputFilter[] {new InputFilter.LengthFilter(5)});
    input.setHint("XXXXX");
    input.setInputType(InputType.TYPE_CLASS_NUMBER);
    alert.setView(input);

    alert.setPositiveButton("Ok", new DialogInterface.OnClickListener() {
        public void onClick(DialogInterface dialog, int whichButton) {
            String code = input.getText().toString();
            receiver.onLoad(code);
        }
    });

    alert.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
        public void onClick(DialogInterface dialog, int whichButton) {
        }
    });
    alert.show();
}

public interface Receiver{
    void onLoad(String code);
}

}

要调用此类，请在您的Activity中添加：

 AlertInterface aux=new AlertInterface(MainActivity.this, new AlertInterface.Receiver() {
        public void onLoad(String code) {
            Toast.makeText(MainActivity.this,"Secret code entered: "+code,Toast.LENGTH_LONG).show();
        }
    });
    aux.enterSecretCode();

结果将在Activity中的onLoad实现方法中接收。

为什么在单击Alert android中的OK按钮之前完成函数执行？

2 个答案: