如何从扩展活动覆盖方法？

Question

我有 2 个活动。一是AlertDialogActivity& 二是MainActivity。我AlertDialogActivity在MainActivity.

像这样public class MainActivity extends AlertDialogActivity

现在如何覆盖AlertDialogActivity我的方法MainActivity？

警报对话活动：

package com.jimmytrivedi.alertdialog;

import android.app.AlertDialog;

import android.app.Dialog;

import android.content.Context;

import android.os.Bundle;

import android.widget.EditText;

import android.widget.TextView;

import androidx.appcompat.app.AppCompatActivity;

public class AlertDialogActivity extends AppCompatActivity {

    @Override

    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_alert_dialog);

        showAlertDialog(AlertDialogActivity.this);

    }

    private void showAlertDialog(final Context context) {

        // 1. Instantiate an <code><a href="/reference/android/app/AlertDialog.Builder.html">AlertDialog.Builder</a></code> with its constructor

        AlertDialog.Builder builder = new AlertDialog.Builder(AlertDialogActivity.this);

// 2. Chain together various setter methods to set the dialog characteristics

        builder.setMessage("How are you?")

                .setTitle("Hello");

// 3. Get the <code><a href="/reference/android/app/AlertDialog.html">AlertDialog</a></code> from <code><a href="/reference/android/app/AlertDialog.Builder.html#create()">create()</a></code>

        AlertDialog dialog = builder.create();

        dialog.show();

    }

}

Answer 1

如果您希望其他类能够调用它，请将其showAlertDialog protected改为，甚至公开。privateprotected void showAlertDialog(final Context context) {}私有方法不能被覆盖。

Answer 2

如果你想覆盖一个方法使用 抽象 关键字public abstract class AlertDialogActivity extends AppCompatActivity {@Overrideprotected void onCreate(Bundle savedInstanceState) {&nbsp; &nbsp; super.onCreate(savedInstanceState);&nbsp; &nbsp; setContentView(R.layout.activity_alert_dialog);&nbsp; &nbsp; showAlertDialog(AlertDialogActivity.this);}&nbsp; public abstract void showAlertDialog(final Context context) {&nbsp; &nbsp; // 1. Instantiate an <code><a href="/reference/android/app/AlertDialog.Builder.html">AlertDialog.Builder</a></code> with its constructor&nbsp; &nbsp; AlertDialog.Builder builder = new AlertDialog.Builder(AlertDialogActivity.this);&nbsp; // 2. Chain together various setter methods to set the dialog characteristics&nbsp; &nbsp; builder.setMessage("How are you?")&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; .setTitle("Hello");&nbsp; &nbsp;// 3. Get the <code><a&nbsp;&nbsp; href="/reference/android/app/AlertDialog.html">AlertDialog</a></code> from <code><a&nbsp;&nbsp; href="/reference/android/app/AlertDialog.Builder.html#create()">create()</a></code>&nbsp; &nbsp; AlertDialog dialog = builder.create();&nbsp; &nbsp; dialog.show();}

Answer 3

方法应该具有相同的名称和类型。方法也不应该是私有的。