MainActivity Android中的setContentView错误(setContentView Error in MainActivity Android)

 我遇到了一个错误，我很确定与我的代码无关。 我正在使用Android Studio。 
 
 当我重命名一个单独的活动XML文件时出现此错误，它提示我是否希望它使用我允许的新名称自动更新文件。 然后我在MainActivity.java上看到了一个错误。 检查后，我看到错误来自setContentView(R.layout.activity_main);的R setContentView(R.layout.activity_main); 。 
 
package nz.school.app.nb;

import android.content.Intent;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        // Inits the activity
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        setTitle("Home");
    }

    // Timetable button listener
    public void timeTableButtonListener(View view){
        Intent kamarActivity = new Intent(this, TimetableActivity.class);
        startActivity(kamarActivity);
    }

    // Contacts button listener
    public void contactsButtonListener(View view){
        Intent contactsActivity = new Intent(this, ContactActivity.class);
        startActivity(contactsActivity);
    }

    // Links button listener
    public void linksButtonListener(View view){
        Intent linksActivity = new Intent(this, LinksActivity.class);
        startActivity(linksActivity);
    }

    // Notices button listener
    public void noticesButtonListener(View view){
        Intent newsActivity = new Intent(this, NoticesActivity.class);
        startActivity(newsActivity);
    }

    // Events button listener
    public void eventsButtonListener(View view){
        Intent eventActivity = new Intent(this, EventsActivity.class);
        startActivity(eventActivity);
    }
}
 
 然后我在网上快速浏览了一下没有任何帮助。 我决定恢复到我以前的版本没有错误，但同样的事情发生。 然后我删除整个app文件夹并替换为我的朋友（我们都在开发应用程序），因为他的机器上有旧版本。 在那之后问题似乎消失了，这让我很开心。 第二天，我打开MainActivty.java ，一旦文件打开，错误就会恢复。 
 
 我现在对这个问题的来源非常困惑。 

I am experiencing an error which I'm pretty sure has nothing to do with my code. I'm using Android Studio.
 
This error came about when I renamed a separate activity XML file and it prompted me if I wanted it to auto update the file with the new name which I allowed. I then saw an error on my MainActivity.java. After inspection I saw that the error came from the R in setContentView(R.layout.activity_main);.
 
package nz.school.app.nb;

import android.content.Intent;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        // Inits the activity
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        setTitle("Home");
    }

    // Timetable button listener
    public void timeTableButtonListener(View view){
        Intent kamarActivity = new Intent(this, TimetableActivity.class);
        startActivity(kamarActivity);
    }

    // Contacts button listener
    public void contactsButtonListener(View view){
        Intent contactsActivity = new Intent(this, ContactActivity.class);
        startActivity(contactsActivity);
    }

    // Links button listener
    public void linksButtonListener(View view){
        Intent linksActivity = new Intent(this, LinksActivity.class);
        startActivity(linksActivity);
    }

    // Notices button listener
    public void noticesButtonListener(View view){
        Intent newsActivity = new Intent(this, NoticesActivity.class);
        startActivity(newsActivity);
    }

    // Events button listener
    public void eventsButtonListener(View view){
        Intent eventActivity = new Intent(this, EventsActivity.class);
        startActivity(eventActivity);
    }
}
 
I then had a quick look online with nothing that would help. I decide to revert to my previous version with no errors but the same thing happens. I then remove the whole app folder and replace with my friend (We are both developing app) as he has the older version on his machine. After that the problem seemed to disappear which made me very happy. The next day I open the MainActivty.java and as soon as the file was opened the error came back.
 
I am now very confused to what this issue is from.

原文：https://stackoverflow.com/questions/36564450