私はJava Androidの新機能です。私は私のプロジェクトに助けたいと思っています。私は言っているエラーを解決したい（記号Rと他のものを解決することはできません）

Question

package com.example.abdoanany.sqliteapp; 

import android.app.AlertDialog; 
import android.database.Cursor; 
import android.os.Bundle; 
import android.support.v7.app.AppCompatActivity; 
import android.view.Menu; 
import android.view.MenuItem; 
import android.view.View; 
import android.widget.Button; 
import android.widget.EditText; 
import android.widget.Toast; 

public class MainActivity extends AppCompatActivity { 
    DatabaseHelper myDb; 
    EditText editName,editSurname,editMarks ,editTextId; 
    Button btnAddData; 
    Button btnviewAll; 
    Button btnDelete; 
    Button btnviewUpdate; 

    @Override 
    protected void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     setContentView(R.layout.activity_main); 
     myDb = new DatabaseHelper(this); 
     editName = (EditText)findViewById(R.id.editText_name); 
     editSurname = (EditText)findViewById(R.id.editText_surname); 

     editMarks = (EditText)findViewById(R.id.editText_Marks); 
     editTextId = (EditText)findViewById(R.id.editText_id); 
     btnAddData = (Button)findViewById(R.id.button_add); 
     btnviewAll = (Button)findViewById(R.id.button_viewAll); 
     btnviewUpdate= (Button)findViewById(R.id.button_update); 
     btnDelete= (Button)findViewById(R.id.button_delete); 
     AddData(); 
     viewAll(); 
     UpdateData(); 
     DeleteData(); 
    } 
    public void DeleteData() { 
     btnDelete.setOnClickListener(
       new View.OnClickListener() { 
        @Override 
        public void onClick(View v) { 

         Integer deletedRows = myDb.deleteData(editTextId.getText().toString()); 
         if(deletedRows > 0) 
          Toast.makeText(MainActivity.this,"Data Deleted",Toast.LENGTH_LONG).show(); 
         else 
          Toast.makeText(MainActivity.this,"Data not Deleted", Toast.LENGTH_LONG).show(); 

        } 
       } 
     ); 
    } 
    public void UpdateData() { 
     btnviewUpdate.setOnClickListener(
       new View.OnClickListener() { 
        @Override 
        public void onClick(View v) { 
         boolean isUpdate = myDb.updateData(editTextId.getText().toString(), 
           editName.getText().toString(), 
           editSurname.getText().toString(),editMarks.getText().toString()); 
         if(isUpdate == true) 
          Toast.makeText(MainActivity.this,"Data Update",Toast.LENGTH_LONG).show(); 
         else 
          Toast.makeText(MainActivity.this,"Data not Updated",Toast.LENGTH_LONG).show(); 
        } 
       } 
     ); 
    } 
    public void AddData() { 
     btnAddData.setOnClickListener(
       new View.OnClickListener() { 
        @Override 
        public void onClick(View v) { 
         boolean isInserted = myDb.insertData(editName.getText().toString(), 
           editSurname.getText().toString(), 
           editMarks.getText().toString()); 
         if(isInserted == true) 
          Toast.makeText(MainActivity.this,"Data Inserted",Toast.LENGTH_LONG).show(); 
         else 
          Toast.makeText(MainActivity.this,"Data not Inserted",Toast.LENGTH_LONG).show(); 
        } 
       } 
     ); 
    } 

    public void viewAll() { 
     btnviewAll.setOnClickListener(
       new View.OnClickListener() { 
        @Override 
        public void onClick(View v) { 
         Cursor res = myDb.getAllData(); 
         if(res.getCount() == 0) { 
          // show message 
          showMessage("Error","Nothing found"); 
          return; 
         } 

         StringBuffer buffer = new StringBuffer(); 
         while (res.moveToNext()) { 
          buffer.append("Id :"+ res.getString(0)+"\n"); 
          buffer.append("Name :"+ res.getString(1)+"\n"); 
          buffer.append("Surname :"+ res.getString(2)+"\n"); 
          buffer.append("Marks :"+ res.getString(3)+"\n\n"); 
         } 

         // Show all data 
         showMessage("Data",buffer.toString()); 
        } 
       } 
     ); 
    } 

    public void showMessage(String title,String Message){ 
     AlertDialog.Builder builder = new AlertDialog.Builder(this); 
     builder.setCancelable(true); 
     builder.setTitle(title); 
     builder.setMessage(Message); 
    builder.show(); 

    } 
    @Override 
    public boolean onCreateOptionsMenu(Menu menu) { 
     // Inflate the menu; this adds items to the action bar if it is present. 
     getMenuInflater().inflate(R.menu.menu_main, menu); 
     return true; 
    } 

    @Override 
    public boolean onOptionsItemSelected(MenuItem item) { 
     // Handle action bar item clicks here. The action bar will 
     // automatically handle clicks on the Home/Up button, so long 
     // as you specify a parent activity in AndroidManifest.xml. 
     int id = item.getItemId(); 

     //noinspection SimplifiableIfStatement 
     if (id == R.id.action_settings) { 
      return true; 
     } 

     return `super.onOptionsItemSelected`(item); 
    } 
} 

Answer 1

もしProject - CleanやProject - Rebuildが助けになれないのなら、おそらくxmlファイルでエラーが起きたと考えられます。

この場合、すべてのxmlをチェックしてください。多少のリソースや何かが失われた可能性があります。