应用程序重新启动，由于 AndroidRuntime 异常而无法运行

Question

Gradle 构建成功 logcat 显示 E/AndroidRuntime: FATAL EXCEPTION: main

--------Logcat 错误------------

07-27 23:04:54.813 21702-21702/? E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.inoalexander.justjava, PID: 21702
java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.example.inoalexander.justjava/com.example.inoalexander.justjava.mainActivity}: java.lang.ClassNotFoundException: Didn't find class "com.example.inoalexander.justjava.mainActivity" on path: DexPathList[[zip file "/data/app/com.example.inoalexander.justjava-2/base.apk", zip file "/data/app/com.example.inoalexander.justjava-2/split_lib_dependencies_apk.apk", zip file "/data/app/com.example.inoalexander.justjava-2/split_lib_slice_0_apk.apk", zip file "/data/app/com.example.inoalexander.justjava-2/split_lib_slice_1_apk.apk", zip file "/data/app/com.example.inoalexander.justjava-2/split_lib_slice_2_apk.apk", zip file "/data/app/com.example.inoalexander.justjava-2/split_lib_slice_3_apk.apk", zip file "/data/app/com.example.inoalexander.justjava-2/split_lib_slice_4_apk.apk", zip file "/data/app/com.example.inoalexander.justjava-2/split_lib_slice_5_apk.apk", zip file "/data/app/com.example.inoalexander.justjava-2/split_lib_slice_6_apk.apk", zip file "/data/app/com.example.inoalexander.justjava-2/split_lib_slice_7_apk.apk", zip file "/data/app/com.example.inoalexander.justjava-2/split_lib_slice_8_apk.apk", zip file "/data/app/com.example.inoalexander.justjava-2/split_lib_slice_9_apk.apk"],nativeLibraryDirectories=[/data/app/com.example.inoalexander.justjava-2/lib/arm64, /system/lib64, /vendor/lib64]]
    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2819)
    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2988)
    at android.app.ActivityThread.-wrap14(ActivityThread.java)
    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1631)
    at android.os.Handler.dispatchMessage(Handler.java:102)
    at android.os.Looper.loop(Looper.java:154)
    at android.app.ActivityThread.main(ActivityThread.java:6682)
    at java.lang.reflect.Method.invoke(Native Method)
    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1534)
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1424)
 Caused by: java.lang.ClassNotFoundException: Didn't find class "com.example.inoalexander.justjava.mainActivity" on path: DexPathList[[zip file "/data/app/com.example.inoalexander.justjava-2/base.apk", zip file "/data/app/com.example.inoalexander.justjava-2/split_lib_dependencies_apk.apk", zip file "/data/app/com.example.inoalexander.justjava-2/split_lib_slice_0_apk.apk", zip file "/data/app/com.example.inoalexander.justjava-2/split_lib_slice_1_apk.apk", zip file "/data/app/com.example.inoalexander.justjava-2/split_lib_slice_2_apk.apk", zip file "/data/app/com.example.inoalexander.justjava-2/split_lib_slice_3_apk.apk", zip file "/data/app/com.example.inoalexander.justjava-2/split_lib_slice_4_apk.apk", zip file "/data/app/com.example.inoalexander.justjava-2/split_lib_slice_5_apk.apk", zip file "/data/app/com.example.inoalexander.justjava-2/split_lib_slice_6_apk.apk", zip file "/data/app/com.example.inoalexander.justjava-2/split_lib_slice_7_apk.apk", zip file "/data/app/com.example.inoalexander.justjava-2/split_lib_slice_8_apk.apk", zip file "/data/app/com.example.inoalexander.justjava-2/split_lib_slice_9_apk.apk"],nativeLibraryDirectories=[/data/app/com.example.inoalexander.justjava-2/lib/arm64, /system/lib64, /vendor/lib64]]
    at dalvik.system.BaseDexClassLoader.findClass(BaseDexClassLoader.java:56)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:380)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:312)
    at android.app.Instrumentation.newActivity(Instrumentation.java:1086)
    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2809)
    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2988) 
    at android.app.ActivityThread.-wrap14(ActivityThread.java) 
    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1631) 
    at android.os.Handler.dispatchMessage(Handler.java:102) 
    at android.os.Looper.loop(Looper.java:154) 
    at android.app.ActivityThread.main(ActivityThread.java:6682) 
    at java.lang.reflect.Method.invoke(Native Method) 
    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1534) 
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1424) 

---------Java 代码从这里开始----------

package com.example.inoalexander.justjava;

import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.TextView;

/**
* This app displays an order form to order coffee.
*/
public class MainActivity extends AppCompatActivity {

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
}

/**
 * This method is called when the order button is clicked.
 */
public void submitOrder(View view) {
    display(1);
}

/**
 * This method displays the given quantity value on the screen.
 */
private void display(int number) {
    TextView quantityTextView = (TextView)            findViewById(R.id.quantity_text_view);
    quantityTextView.setText("" + number);
}

}

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
tools:context=".MainActivity">

---------XML 代码从这里开始-------------

<TextView

    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:textColor="#000000"
    android:textSize="16sp"
    android:layout_marginBottom="16dp"
    android:layout_marginLeft="16dp"
    android:text="Quantity" />
<TextView
    android:id="@+id/quantity_text_view"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:textColor="#000000"
    android:textSize="16sp"
    android:layout_marginLeft="16dp"
    android:layout_marginBottom="16dp"
    android:text="0" />
<Button
    android:id="@+id/button_id"
    android:layout_height="wrap_content"
    android:layout_width="wrap_content"
    android:layout_marginLeft="16dp"
    android:text="Order"
    android:onClick="submitOrder"/>




</LinearLayout>

我不确定，因为这是我构建的第一个不是卡片的应用程序之一。我不确定为什么它没有在我的手机上运行。我正在使用 Galaxy Note 5 来运行我的构建。

Gradle 构建成功并且没有给我任何错误，但是当我尝试在我的设备上运行它时，它一直在尝试重新启动应用程序，直到它最终使应用程序崩溃。我在这里查看了一些答案，并被指示在 android studio 中查看我的Logcat。

老实说，我什至不知道应该从 Logcat 开始，或者它甚至告诉我什么，我已经看到了这个错误的很多变体，但没有一个特定于我的 Logcat 中的每个错误.

Answer 1

将multidex true 设置为应用级别build.gradle 文件，如下所示

android {
    compileSdkVersion 27
    useLibrary 'org.apache.http.legacy'
    defaultConfig {
        applicationId "com.core.######"
        minSdkVersion 16
        targetSdkVersion 27
        versionCode 1
        versionName "1.0"
        multiDexEnabled true // here change
        testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"

    }
}

同时添加依赖

implementation 'com.android.support:multidex:1.0.3'

最后别忘了清理和重建项目。

Answer 2

异常表示它正在尝试查找类 mainActivity，但在您的代码中您有 MainActivity。

确保AndroidManifest.xml 中的活动类名称与您的代码匹配。