Android Studio APP 构建成功但无法运行答案

【问题标题】：Android Studio APP builds successfully but it doesn't runAndroid Studio APP 构建成功但无法运行
【发布时间】：2020-12-01 02:37:09
【问题描述】：

我是 android studio 的新手，我刚刚完成了我的第一个应用程序，遵循（复制）此视频中的代码：https://www.youtube.com/watch?v=gTy13ioTddg&t=594s

应用程序构建没有问题，但当我尝试运行它时，它突然关闭。

Android Manifest.xml：

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.pokedex">

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/Theme.Pokedex">
        <activity android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

</manifest>

主活动

package com.example.pokedex;

import androidx.appcompat.app.AppCompatActivity;
import android.os.Bundle;

import androidx.recyclerview.widget.LinearLayoutManager;
import androidx.recyclerview.widget.RecyclerView;

public class MainActivity extends AppCompatActivity {

    private RecyclerView recyclerView;
    private RecyclerView.Adapter adapter;
    private RecyclerView.LayoutManager layoutManager;


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

        recyclerView=findViewById(R.id.recycler_view);
        adapter=new PokedexAdapter();
        layoutManager=new LinearLayoutManager(this);

        recyclerView.setAdapter(adapter);
        recyclerView.setLayoutManager(layoutManager);

    }
}

PokedexAdapter：

package com.example.pokedex;

import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.LinearLayout;
import android.widget.TextView;

import androidx.annotation.NonNull;
import androidx.recyclerview.widget.RecyclerView;

import java.lang.reflect.Array;
import java.util.Arrays;
import java.util.List;

public class PokedexAdapter extends RecyclerView.Adapter<PokedexAdapter.PokedexViewHolder>{

    public static class PokedexViewHolder extends RecyclerView.ViewHolder{
        public LinearLayout containerView;
        public TextView textView;
        PokedexViewHolder(View view){
            super(view);
            containerView=view.findViewById(R.id.pokedex_row);
            textView=view.findViewById(R.id.pokedex_row_text_view);

        }
    }

    private List<Pokemon> pokemon = Arrays.asList(
            new Pokemon("bulbasaur",1),
            new Pokemon("Ivisaur",2),
            new Pokemon ("Venasaur",3));

    @NonNull
    @Override
    public PokedexViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
        View view= LayoutInflater.from(parent.getContext()).inflate(R.layout.pokedex_row,parent,false);
        return new PokedexViewHolder(view);
    }

    @Override
    public void onBindViewHolder(@NonNull PokedexViewHolder holder, int position) {

        Pokemon current= pokemon.get(position);
        holder.textView.setText(current.getName());
    }

    @Override
    public int getItemCount() {
        return pokemon.size();
    }
}

构建.gradle

plugins {
    id 'com.android.application'
}

android {
    compileSdkVersion 30
    buildToolsVersion "30.0.2"

    defaultConfig {
        applicationId "com.example.pokedex"
        minSdkVersion 21
        targetSdkVersion 30
        versionCode 1
        versionName "1.0"

        testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
    }

    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
        }
    }
    compileOptions {
        sourceCompatibility JavaVersion.VERSION_1_8
        targetCompatibility JavaVersion.VERSION_1_8
    }
}

dependencies {


    implementation 'com.android.support:appcompat-v7:+'
    implementation 'com.android.support.constraint:constraint-layout:2.0.4'
    implementation "androidx.recyclerview:recyclerview:1.1.0"
    testImplementation 'junit:junit:4.+'
    androidTestImplementation 'com.android.support.test:runner:1.0.2'
    androidTestImplementation 'com.android.support.test.espresso:espresso-core:3.0.2'
}

Gradle.properties：

# Project-wide Gradle settings.
# IDE (e.g. Android Studio) users:
# Gradle settings configured through the IDE *will override*
# any settings specified in this file.
# For more details on how to configure your build environment visit
# http://www.gradle.org/docs/current/userguide/build_environment.html
# Specifies the JVM arguments used for the daemon process.
# The setting is particularly useful for tweaking memory settings.
org.gradle.jvmargs=-Xmx2048m -Dfile.encoding=UTF-8
# When configured, Gradle will run in incubating parallel mode.
# This option should only be used with decoupled projects. More details, visit
# http://www.gradle.org/docs/current/userguide/multi_project_builds.html#sec:decoupled_projects
# org.gradle.parallel=true
android.useAndroidX=true
android.enableJetifier=true

如果有人能帮助我，我将非常感激！

【问题讨论】：

我认为你没有完成签署应用程序的过程。这是正在安装的未签名应用程序。
查看android logcat的原因。
按 Alt + 6 打开 logcat。您应该会看到崩溃时崩溃的确切原因的日志。你能发布这些信息吗？
如何查看 logcat？
在 CMD 中运行 logcat。您将获得所有日志。

标签： java android android-studio kotlin cs50

【解决方案1】：

如果您的应用在启动时立即崩溃，请检查您的 AndroidManifest.xml。我在开始 android 开发时遇到了同样的问题，我认为它 90% 是你的 AndroidManifest.xml，也许你错过了那里的东西。

【讨论】：