Android Studio 组件未显示且应用程序未运行 [英] Android Studio components aren't displaying and app does not run

问题描述

我是 Android Studio 的新手，想知道它为什么对我不起作用.

I am new to Android Studio and want to know why it does not really work for me.

基本上，我刚刚开始学习 Android Studio，观看在线课程，所以我只是在做讲师在视频中所做的相同的事情，但结果永远不会相同.

Basically, I just started learning Android Studio watching an online course, so I am just doing the same thing what the lecturer does on the videos, but the result never turns out the same.

首先我想让你知道我没有碰任何东西.但是Android Studio 没有显示任何组件，例如textView，当我运行它时，ADB(模拟器)从不运行该应用程序，而只显示Android 手机的默认屏幕.

Firstly I want to let you know that I have not touched anything. But Android Studio does not show any of components, such as textView, and when I run it, the ADB(the Emulator) never runs the app but only shows the default screen of an Android phone.

我最好附上我的 Android Studio 的一些屏幕截图，以向您展示发生了什么.

I better attach some screenshots of my Android Studio to show you what is going on.

从这张图中可以看出，有一个textView组件，但是它没有出现在屏幕中央.

As you can see from this picture, there is a textView component but it does not appear on the screen that is in the center.

正如我上面写的，我没有碰任何东西.在我创建一个新项目之后就可以了.无论我添加什么组件，它都不会显示.

As I wrote above, I did not touch anything. It is just right after I create a new project. No matter what component I add, it never shows up.

我不知道这是否重要，但如果您查看右上角，会出现一个错误(红色感叹号)，内容为渲染问题:无法加载 AppCompat ActionBar，出现未知错误".

I have no idea if it would matter but if you look at the top right, an error occurs (red exclamation mark) that is saying "Render Problem: Failed to load AppCompat ActionBar with unknown error".

我已经尝试解决这个错误几个小时了，但也没有真正找到解决方案.

I have tried to solve this error for several hours and could not really find a solution to this too.

当我运行应用程序(按绿色箭头按钮)时，会发生以下情况.

And when I run the app (by pressing green arrow button), here's what happens.

它只是停留在这个屏幕上.在这之后什么都没有发生.

It just stays on this screen. Nothing really happens after this.

我应该怎么做才能看到我的组件并让它运行应用程序?我错过了什么?我确实做了与我正在观看的在线课程完全相同的事情，而且我发现没有人遇到我现在面临的问题.

What should I do to see my components and to make it run the app? What am I missing? I really have done exactly the same as the online course I am watching and I see no one is having the problem I am facing now.

有什么帮助吗?

如果需要，我也会上传我的两个 gradle 文件:

In case of it will be needed, I am uploading both of my gradle files too:

// Top-level build file where you can add configuration options common to all sub-projects/modules.

buildscript {

    repositories {
        google()
        jcenter()
    }
    dependencies {
        classpath 'com.android.tools.build:gradle:3.1.4'


        // NOTE: Do not place your application dependencies here; they belong
        // in the individual module build.gradle files
    }
}

allprojects {
    repositories {
        google()
        jcenter()
    }
}

task clean(type: Delete) {
    delete rootProject.buildDir
}

这是一个gradle文件build.gradle(项目:项目名称)

This is a gradle file build.gradle (Project: project name)

而下面是一个gradle文件build.gradle(Module: app)

And the following is a gradle file build.gradle (Module: app)

apply plugin: 'com.android.application'

android {
    compileSdkVersion 28
    defaultConfig {
        applicationId "com.example.auclo.exampleapp"
        minSdkVersion 15
        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-rc02'
    implementation 'com.android.support.constraint:constraint-layout:1.1.3'
    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'
}

和styles.xml

And styles.xml

谢谢.

推荐答案

这是 28 版的问题，请降级到 27 版，直到问题解决.

This is an issue of version 28, you should downgrade to version 27 until the problem is solved.

转到您的应用程序/Gradle Scripts/build.gradle (Module:app)

Go to your app/Gradle Scripts/build.gradle (Module:app)

1

改变这一行:

compileSdkVersion 28

到

compileSdkVersion 27

2

改变这一行:

targetSdkVersion 28

到

targetSdkVersion 27

3

改变这一行:

implementation 'com.android.support:appcompat-v7:28.0.0-rc02'

到

implementation 'com.android.support:appcompat-v7:27.1.1'

然后 Android Studio 会要求您同步文件，您可以点击立即同步

Then Android Studio will ask you to Sync the files, and you do so by clicking in Sync Now

继续学习如何编码，很快 Android 就会解决这个问题.您可以在此处查看有关此讨论的更多信息一>.

Keep learning how to code, and soon Android will solve this problem. You can see more about this discussion here.

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