Java Cannot resolve symbol "R"

###前提
はじめてAndroid studioを使っていて、
javaも初心者で、勉強中の身です。
今回、Cannot resolve symbol 'R' のエラーが出て、
・xmlファイルのエラーを取り除くとよいようでしたので注意深く確認して修正したのですが、改善しません。
もし、他のコードや、使用しているものの中で必要な場合追加で記載させていただきます。
何卒よろしくお願いします。

###発生している問題・エラーメッセージ
Cannot resolve symbol 'R'

###該当のソースコード

Java
1
2
3package com.example.eura.myapplication;
4
5import android.os.Bundle;
6import android.support.v7.app.AppCompatActivity;
7import android.view.View;
8import android.widget.Button;
9import android.widget.EditText;
10import android.widget.TextView;
11
12public class MainActivity extends AppCompatActivity {
13
14    TextView textView;
15    EditText editText;
16    Button button;
17
18    View.OnClickListener buttonListener = new View.OnClickListener() {
19        @Override
20        public void onClick(View view) {
21            textView.setText(editText.getText().toString());
22        }
23    };
24
25    @Override
26    protected void onCreate(Bundle savedInstanceState) {
27        super.onCreate(savedInstanceState);
28        setContentView(R.layout.activity_main);
29
30        textView = (TextView) findViewById(R.id.textview);
31        editText = (EditText) findViewById(R.id.edittext);
32        button = (Button) findViewById(R.id.button);
33        button.setOnClickListener(buttonListener);
34
35        findViewById(R.id.button_1).setOnClickListener(buttonNumberListener);
36        findViewById(R.id.button_2).setOnClickListener(buttonNumberListener);
37        findViewById(R.id.button_3).setOnClickListener(buttonNumberListener);
38        findViewById(R.id.button_4).setOnClickListener(buttonNumberListener);
39        findViewById(R.id.button_5).setOnClickListener(buttonNumberListener);
40        findViewById(R.id.button_6).setOnClickListener(buttonNumberListener);
41        findViewById(R.id.button_7).setOnClickListener(buttonNumberListener);
42        findViewById(R.id.button_8).setOnClickListener(buttonNumberListener);
43        findViewById(R.id.button_9).setOnClickListener(buttonNumberListener);
44        findViewById(R.id.button_0).setOnClickListener(buttonNumberListener);
45        findViewById(R.id.button_dot).setOnClickListener(buttonNumberListener);
46
47        findViewById(R.id.button_add).setOnClickListener(buttonOperatorListener);
48        findViewById(R.id.button_subtract).setOnClickListener(buttonOperatorListener);
49        findViewById(R.id.button_multiply).setOnClickListener(buttonOperatorListener);
50        findViewById(R.id.button_divide).setOnClickListener(buttonOperatorListener);
51        findViewById(R.id.button_equal).setOnClickListener(buttonOperatorListener);
52
53    }
54
55    View.OnClickListener buttonNumberListener = new View.OnClickListener() {
56        @Override
57        public void onClick(View view) {
58            Button button = (Button) view;
59
60            if (isOperatorKeyPushed == true) {
61                editText.setText(button.getText());
62            } else {
63                editText.append(button.getText());
64            }
65
66            isOperatorKeyPushed = false;
67        }
68    };
69
70    int recentOperator = R.id.button_equal; // 最近押された計算キー
71    double result;  // 計算結果
72    boolean isOperatorKeyPushed;    // 計算キーが押されたことを記憶
73
74    View.OnClickListener buttonOperatorListener = new View.OnClickListener() {
75        @Override
76        public void onClick(View view) {
77            Button operatorButton = (Button) view;
78            double value = Double.parseDouble(editText.getText().toString());
79            if (recentOperator == R.id.button_equal) {
80                result = value;
81            } else {
82                result = calc(recentOperator, result, value);
83                editText.setText(String.valueOf(result));
84            }
85
86            recentOperator = operatorButton.getId();
87            textView.setText(operatorButton.getText());
88            isOperatorKeyPushed = true;
89        }
90    };
91
92    double calc(int operator, double value1, double value2) {
93        switch (operator) {
94            case R.id.button_add:
95                return value1 + value2;
96            case R.id.button_subtract:
97                return value1 - value2;
98            case R.id.button_multiply:
99                return value1 * value2;
100            case R.id.button_divide:
101                return value1 / value2;
102            default:
103                return value1;
104        }
105    }
106}
107
108

###試したこと
課題に対してアプローチしたことを記載してください

###補足情報(Gradle Console)


Executing tasks: [build]

Configuration on demand is an incubating feature.
NDK is missing a "platforms" directory.
If you are using NDK, verify the ndk.dir is set to a valid NDK directory.  It is currently set to C:\Users\User\AppData\Local\Android\Sdk\ndk-bundle.
If you are not using NDK, unset the NDK variable from ANDROID_NDK_HOME or local.properties to remove this warning.

Incremental java compilation is an incubating feature.
:app:preBuild UP-TO-DATE
:app:preDebugBuild UP-TO-DATE
:app:checkDebugManifest
:app:preReleaseBuild UP-TO-DATE
:app:prepareComAndroidSupportAnimatedVectorDrawable2600Alpha1Library
:app:prepareComAndroidSupportAppcompatV72600Alpha1Library
:app:prepareComAndroidSupportConstraintConstraintLayout102Library
:app:prepareComAndroidSupportSupportCompat2600Alpha1Library
:app:prepareComAndroidSupportSupportCoreUi2600Alpha1Library
:app:prepareComAndroidSupportSupportCoreUtils2600Alpha1Library
:app:prepareComAndroidSupportSupportFragment2600Alpha1Library
:app:prepareComAndroidSupportSupportMediaCompat2600Alpha1Library
:app:prepareComAndroidSupportSupportV42600Alpha1Library
:app:prepareComAndroidSupportSupportVectorDrawable2600Alpha1Library
:app:prepareDebugDependencies
:app:compileDebugAidl UP-TO-DATE
:app:compileDebugRenderscript UP-TO-DATE
:app:generateDebugBuildConfig UP-TO-DATE
:app:generateDebugResValues UP-TO-DATE
:app:generateDebugResources UP-TO-DATE
:app:mergeDebugResources
:app:processDebugManifest UP-TO-DATE
:app:processDebugResources
AGPBI: {"kind":"error","text":"String types not allowed (at \u0027activity_horizontal_margin\u0027 with value \u0027\u0027).","sources":[{"file":"C:\\Users\\User\\AndroidStudioProjects\\MyApplication2\\app\\build\\intermediates\\res\\merged\\debug\\values\\values.xml","position":{"startLine":553,"startColumn":68,"startOffset":50632,"endColumn":70,"endOffset":50634}}],"original":"","tool":"AAPT"}
Failed to generate resource table for split ''
C:\Users\User\AndroidStudioProjects\MyApplication2\app\build\intermediates\res\merged\debug\values\values.xml:372: error: Error: String types not allowed (at 'activity_horizontal_margin' with value '').



 FAILED

FAILURE: Build failed with an exception.

* What went wrong:
Execution failed for task ':app:processDebugResources'.
> com.android.ide.common.process.ProcessException: Failed to execute aapt

* Try:
Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output.

BUILD FAILED

Total time: 18.561 secs

行動規範の内容に同意します

回答1件

ベストアンサー

values.xmlの372行目にエラーがあるようです。
activity_horizontal_marginに設定されている値の型がおかしいようです。

投稿2017/08/11 12:01

編集2017/08/11 12:02

yona

総合スコア18155

退会済みユーザー

2017/08/11 13:16

ありがとうございます。新しくやり直しまして、まだRが解決されないのですが、 ``` Executing tasks: [build] Configuration on demand is an incubating feature. NDK is missing a "platforms" directory. If you are using NDK, verify the ndk.dir is set to a valid NDK directory. It is currently set to C:\Users\User\AppData\Local\Android\Sdk\ndk-bundle. If you are not using NDK, unset the NDK variable from ANDROID_NDK_HOME or local.properties to remove this warning. Incremental java compilation is an incubating feature. :app:preBuild UP-TO-DATE :app:preDebugBuild UP-TO-DATE :app:checkDebugManifest :app:preReleaseBuild UP-TO-DATE :app:prepareComAndroidSupportAnimatedVectorDrawable2600Alpha1Library :app:prepareComAndroidSupportAppcompatV72600Alpha1Library :app:prepareComAndroidSupportConstraintConstraintLayout102Library :app:prepareComAndroidSupportDesign2600Alpha1Library :app:prepareComAndroidSupportRecyclerviewV72600Alpha1Library :app:prepareComAndroidSupportSupportCompat2600Alpha1Library :app:prepareComAndroidSupportSupportCoreUi2600Alpha1Library :app:prepareComAndroidSupportSupportCoreUtils2600Alpha1Library :app:prepareComAndroidSupportSupportFragment2600Alpha1Library :app:prepareComAndroidSupportSupportMediaCompat2600Alpha1Library :app:prepareComAndroidSupportSupportV42600Alpha1Library :app:prepareComAndroidSupportSupportVectorDrawable2600Alpha1Library :app:prepareComAndroidSupportTransition2600Alpha1Library :app:prepareDebugDependencies :app:compileDebugAidl :app:compileDebugRenderscript :app:generateDebugBuildConfig :app:generateDebugResValues :app:generateDebugResources :app:mergeDebugResources :app:processDebugManifest :app:processDebugResources AGPBI: {"kind":"error","text":"Error parsing XML: duplicate attribute","sources":[{"file":"C:\\Users\\User\\AndroidStudioProjects\\MyApplication1\\app\\src\\main\\res\\layout\\content_main.xml","position":{"startLine":11}}],"original":"","tool":"AAPT"} AGPBI: {"kind":"error","text":"No resource found that matches the given name (at \u0027title\u0027 with value \u0027@string/action_settings\u0027).","sources":[{"file":"C:\\Users\\User\\AndroidStudioProjects\\MyApplication1\\app\\src\\main\\res\\menu\\menu_main.xml","position":{"startLine":7,"startColumn":23,"startOffset":358,"endColumn":46,"endOffset":381}}],"original":"","tool":"AAPT"} C:\Users\User\AndroidStudioProjects\MyApplication1\app\build\intermediates\res\merged\debug\layout\content_main.xml:12: error: Error parsing XML: duplicate attribute C:\Users\User\AndroidStudioProjects\MyApplication1\app\build\intermediates\res\merged\debug\menu\menu_main.xml:5: error: Error: No resource found that matches the given name (at 'title' with value '@string/action_settings'). ``` と出てきます。おそらく今度の該当エラーは ``` http://schemas.android.com/apk/res/android ``` おそらくこれが未登録であるのが問題であると思います。（違ったらお教えください）不勉強で申し訳ないのですが、解決方法をお教えください。