java-android error.cannot.find.symbol.variable

Question

我是新来的，执行项目时遇到问题，出现此错误

在此之前，我将“minSdkCompile”从 14 更改为 16，因为我想使用

android:fontFamily 在我的 EditText 中。我不确定这是否是我的错误的原因

找不到符号变量，也找不到解决方案

:app:compileDebugJavaWithJavac

我在 stackoverflow 中搜索过，但没有答案。

• 清理项目并重建项目
• 我已经执行了 gradle 同步
• 使缓存无效并重新启动
• 检查更新
• 检查是否使用嵌入式 SDK

这里的错误:

cannot find symbol variable btnlogin canot find symbol variable logincount

org.gradle.api.tasks.TaskExecutionException: Execution failed for task ':app:compileDebugJavaWithJavac'.
    at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter.executeActions(ExecuteActionsTaskExecuter.java:103)
    at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter.execute(ExecuteActionsTaskExecuter.java:73)
    at org.gradle.api.internal.tasks.execution.OutputDirectoryCreatingTaskExecuter.execute(OutputDirectoryCreatingTaskExecuter.java:51)
    at org.gradle.api.internal.tasks.execution.SkipUpToDateTaskExecuter.execute(SkipUpToDateTaskExecuter.java:59)
    at org.gradle.api.internal.tasks.execution.ResolveTaskOutputCachingStateExecuter.execute(ResolveTaskOutputCachingStateExecuter.java:54)
    at org.gradle.api.internal.tasks.execution.ValidatingTaskExecuter.execute(ValidatingTaskExecuter.java:59)
    at org.gradle.api.internal.tasks.execution.SkipEmptySourceFilesTaskExecuter.execute(SkipEmptySourceFilesTaskExecuter.java:101)
    at org.gradle.api.internal.tasks.execution.FinalizeInputFilePropertiesTaskExecuter.execute(FinalizeInputFilePropertiesTaskExecuter.java:44)
    at org.gradle.api.internal.tasks.execution.CleanupStaleOutputsExecuter.execute(CleanupStaleOutputsExecuter.java:91)
    at org.gradle.api.internal.tasks.execution.ResolveTaskArtifactStateTaskExecuter.execute(ResolveTaskArtifactStateTaskExecuter.java:62)
    at org.gradle.api.internal.tasks.execution.SkipTaskWithNoActionsExecuter.execute(SkipTaskWithNoActionsExecuter.java:59)
    at org.gradle.api.internal.tasks.execution.SkipOnlyIfTaskExecuter.execute(SkipOnlyIfTaskExecuter.java:54)
    at org.gradle.api.internal.tasks.execution.ExecuteAtMostOnceTaskExecuter.execute(ExecuteAtMostOnceTaskExecuter.java:43)
    at org.gradle.api.internal.tasks.execution.CatchExceptionTaskExecuter.execute(CatchExceptionTaskExecuter.java:34)
    at org.gradle.execution.taskgraph.DefaultTaskGraphExecuter$EventFiringTaskWorker$1.run(DefaultTaskGraphExecuter.java:256)
    at org.gradle.internal.progress.DefaultBuildOperationExecutor$RunnableBuildOperationWorker.execute(DefaultBuildOperationExecutor.java:336)
    at org.gradle.internal.progress.DefaultBuildOperationExecutor$RunnableBuildOperationWorker.execute(DefaultBuildOperationExecutor.java:328)
    at org.gradle.internal.progress.DefaultBuildOperationExecutor.execute(DefaultBuildOperationExecutor.java:199)
    at org.gradle.internal.progress.DefaultBuildOperationExecutor.run(DefaultBuildOperationExecutor.java:110)
    at org.gradle.execution.taskgraph.DefaultTaskGraphExecuter$EventFiringTaskWorker.execute(DefaultTaskGraphExecuter.java:249)
    at org.gradle.execution.taskgraph.DefaultTaskGraphExecuter$EventFiringTaskWorker.execute(DefaultTaskGraphExecuter.java:238)
    at org.gradle.execution.taskgraph.DefaultTaskPlanExecutor$TaskExecutorWorker.processTask(DefaultTaskPlanExecutor.java:123)
    at org.gradle.execution.taskgraph.DefaultTaskPlanExecutor$TaskExecutorWorker.access$200(DefaultTaskPlanExecutor.java:79)
    at org.gradle.execution.taskgraph.DefaultTaskPlanExecutor$TaskExecutorWorker$1.execute(DefaultTaskPlanExecutor.java:104)
    at org.gradle.execution.taskgraph.DefaultTaskPlanExecutor$TaskExecutorWorker$1.execute(DefaultTaskPlanExecutor.java:98)
    at org.gradle.execution.taskgraph.DefaultTaskExecutionPlan.execute(DefaultTaskExecutionPlan.java:663)
    at org.gradle.execution.taskgraph.DefaultTaskExecutionPlan.executeWithTask(DefaultTaskExecutionPlan.java:597)
    at org.gradle.execution.taskgraph.DefaultTaskPlanExecutor$TaskExecutorWorker.run(DefaultTaskPlanExecutor.java:98)
    at org.gradle.internal.concurrent.ExecutorPolicy$CatchAndRecordFailures.onExecute(ExecutorPolicy.java:63)
    at org.gradle.internal.concurrent.ManagedExecutorImpl$1.run(ManagedExecutorImpl.java:46)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
    at org.gradle.internal.concurrent.ThreadFactoryImpl$ManagedThreadRunnable.run(ThreadFactoryImpl.java:55)
    at java.lang.Thread.run(Thread.java:745)
Caused by: org.gradle.api.internal.tasks.compile.CompilationFailedException: Compilation failed; see the compiler error output for details.
    at org.gradle.api.internal.tasks.compile.JdkJavaCompiler.execute(JdkJavaCompiler.java:52)
    at org.gradle.api.internal.tasks.compile.JdkJavaCompiler.execute(JdkJavaCompiler.java:37)
    at org.gradle.api.internal.tasks.compile.NormalizingJavaCompiler.delegateAndHandleErrors(NormalizingJavaCompiler.java:98)
    at org.gradle.api.internal.tasks.compile.NormalizingJavaCompiler.execute(NormalizingJavaCompiler.java:51)
    at org.gradle.api.internal.tasks.compile.NormalizingJavaCompiler.execute(NormalizingJavaCompiler.java:37)
    at org.gradle.api.internal.tasks.compile.CleaningJavaCompilerSupport.execute(CleaningJavaCompilerSupport.java:35)
    at org.gradle.api.internal.tasks.compile.CleaningJavaCompilerSupport.execute(CleaningJavaCompilerSupport.java:25)
    at org.gradle.api.internal.tasks.compile.incremental.IncrementalResultStoringDecorator.execute(IncrementalResultStoringDecorator.java:41)
    at org.gradle.api.internal.tasks.compile.incremental.IncrementalResultStoringDecorator.execute(IncrementalResultStoringDecorator.java:27)
    at org.gradle.api.internal.tasks.compile.incremental.IncrementalAnnotationProcessingCompiler.execute(IncrementalAnnotationProcessingCompiler.java:50)
    at org.gradle.api.internal.tasks.compile.incremental.IncrementalAnnotationProcessingCompiler.execute(IncrementalAnnotationProcessingCompiler.java:36)
    at org.gradle.api.tasks.compile.JavaCompile.performCompilation(JavaCompile.java:156)
    at org.gradle.api.tasks.compile.JavaCompile.compile(JavaCompile.java:126)
    at com.android.build.gradle.tasks.factory.AndroidJavaCompile.compile(AndroidJavaCompile.java:92)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at org.gradle.internal.reflect.JavaMethod.invoke(JavaMethod.java:73)
    at org.gradle.api.internal.project.taskfactory.IncrementalTaskAction.doExecute(IncrementalTaskAction.java:50)
    at org.gradle.api.internal.project.taskfactory.StandardTaskAction.execute(StandardTaskAction.java:39)
    at org.gradle.api.internal.project.taskfactory.StandardTaskAction.execute(StandardTaskAction.java:26)
    at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter$1.run(ExecuteActionsTaskExecuter.java:124)
    at org.gradle.internal.progress.DefaultBuildOperationExecutor$RunnableBuildOperationWorker.execute(DefaultBuildOperationExecutor.java:336)
    at org.gradle.internal.progress.DefaultBuildOperationExecutor$RunnableBuildOperationWorker.execute(DefaultBuildOperationExecutor.java:328)
    at org.gradle.internal.progress.DefaultBuildOperationExecutor.execute(DefaultBuildOperationExecutor.java:199)
    at org.gradle.internal.progress.DefaultBuildOperationExecutor.run(DefaultBuildOperationExecutor.java:110)
    at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter.executeAction(ExecuteActionsTaskExecuter.java:113)
    at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter.executeActions(ExecuteActionsTaskExecuter.java:95)
    ... 33 more

这是我的代码:

MainActivity.java

    package com.example.ndarecuy.myapp;
    import android.content.Intent;
    import android.graphics.Color;
    import android.os.Bundle;
    import android.support.v7.app.AppCompatActivity;
    import android.view.View;
    import android.widget.Button;
    import android.widget.EditText;
    import android.widget.TextView;
    import android.widget.Toast;

public class MainActivity extends AppCompatActivity {
    Button b1;
    EditText ed1,ed2;
    TextView tx1;
    private int counter = 3;


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Button b2 = findViewById(R.id.btnMhs);
        final Button b1 = findViewById(R.id.btnlogin);
        final TextView tx1 = findViewById(R.id.logincount);

        tx1.setVisibility(View.GONE);

        final EditText ed1= findViewById(R.id.txtpassword);
        final EditText ed2 = findViewById(R.id.txtusername);


        b2.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent i = new   Intent(getApplicationContext(),Main2Activity.class);
                startActivity(i);
            }
        });

        b1.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

                Intent i = new Intent(getApplicationContext(),MenuProgram.class);
                startActivity(i);
                if(ed1.getText().toString().equals("admin")&&
                        ed2.getText().toString().equals("admin")){
                    Toast.makeText(getApplicationContext(),"berhasil",Toast.LENGTH_SHORT).show();
                }
                else {
                    Toast.makeText(getApplicationContext(),"Gagal Login",Toast.LENGTH_SHORT).show();
                            tx1.setVisibility(View.VISIBLE);
                            tx1.setBackgroundColor(Color.RED);
                            counter--;
                    tx1.setText(Integer.toString(counter));
                            if (counter==0){
                                b1.setEnabled(false);
                            }
                }
            }
        });

    }
    }



activitymain.xml

    <?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity"
    android:background="@drawable/gradient_animation">

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="vertical"
        android:padding="10dp"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        >
    <TextView
        android:id="@+id/atas"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="LOGIN"
        android:textColor="@color/colorWhite"
        android:layout_gravity="center_horizontal"
        android:textSize="30sp"

        />

    <TextView
        android:id="@+id/bawah"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/stmik_mercusuar"
        android:layout_gravity="center_horizontal"
        android:textSize="25sp"
        android:textColor="@color/colorWhite"
        />

    <ImageView
        android:id="@+id/imageView"
        android:layout_width="143dp"
        android:layout_height="210dp"
        app:srcCompat="@mipmap/logo_mercusuar"
        android:layout_gravity="center_horizontal"
        android:contentDescription="@string/stmik_mercusuar"/>

        <EditText
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:textColor="@color/colorAccent"
            android:id="@+id/txtusername"
            android:hint="@string/username"
            android:textColorHint="@color/colorAccent"
            android:focusable="true"
            android:textColorHighlight="#ff7eff15"
            android:fontFamily="sans-serif"
            android:inputType="text"
            />

        <EditText
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:hint="@string/password"
            android:id="@+id/txtpassword"
            android:textColor="@color/colorAccent"
            android:textColorHint="@color/colorAccent"
            android:focusable="true"
            android:inputType="textPassword"
            />

        <TextView

            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="@string/kesempatan_anda_3x"
            android:textSize="17sp"
            android:id="@+id/logincount"
            />

    <Button
        android:id="@+id/btnlogin"
        android:layout_width="350dp"
        android:layout_height="wrap_content"
        android:layout_marginTop="0dp"
        android:text="@string/login" />
    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/btnMhs"
        android:text="@string/profil"/>
    </LinearLayout>
</android.support.constraint.ConstraintLayout>

my build

<pre>    apply plugin: 'com.android.application'

android {

    compileSdkVersion 28
    buildToolsVersion '28.0.3'
    defaultConfig {
        applicationId "com.example.ndarecuy.myapp"
        minSdkVersion 16
        targetSdkVersion 28
        versionCode 1
        versionName "1.0"
        testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
    }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }

}

dependencies {

    implementation fileTree(dir: 'libs', include: ['*.jar'])
    implementation 'com.android.support:appcompat-v7:28.0.0'
    implementation 'com.android.support.constraint:constraint-layout:1.1.3'
    implementation 'com.android.support:design:28.0.0'
    implementation 'com.android.support:support-v4:28.0.0'
    testImplementation 'junit:junit:4.12'
    androidTestImplementation 'com.android.support.test:runner:1.0.2'
    androidTestImplementation 'com.android.support.test.espresso:espresso-core:3.0.2'

}

我被困在这里..任何建议/帮助都会非常感谢..

Answer 1

您的 MainActivity Java 类返回 xml 值

setContentView(R.layout.activity_main)

但是你的 xml 被命名为

activitymain.xml