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，想知道为什么它对我真的不起作用.

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

基本上，我只是通过观看在线课程开始学习Android Studio，因此我所做的事情与讲师对视频所做的事情相同，但是结果却从未如此.

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，我想让您知道我没有碰过任何东西.但是Android Studio不显示任何组件，例如textView，当我运行它时，ADB(模拟器)从不运行该应用程序，而仅显示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Android Studio的一些屏幕截图，以向您显示正在发生的事情.

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

从这张图片中可以看到，有一个textView组件，但是它没有出现在中间的屏幕上.

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.

如上所述，我什么都没碰.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，但是如果您查看右上角，会出现一个错误(红色感叹号)，该错误是呈现问题:无法加载具有未知错误的AppCompat ActionBar".

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".

我已经尝试解决了好几个小时的错误，而且也找不到真正的解决方案.

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

当我运行应用程序时(按绿色箭头按钮)，会发生以下情况.

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

它仅停留在此屏幕上.此后什么也没发生.

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

我应该怎么做才能查看我的组件并使它运行该应用程序?我想念什么?我确实完成了与正在观看的在线课程完全相同的操作，而且我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.

有帮助吗?

如果需要它，我也将同时上传两个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gradle文件build.gradle(项目:项目名称)

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

以下是gradle文件build.gradle(模块: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

这是版本28的问题，您应该降级到版本27，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(模块:app)

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

1

更改此行:

compileSdkVersion 28

到

compileSdkVersion 27

2

更改此行:

targetSdkVersion 28

到

targetSdkVersion 27

3

更改此行:

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，方法是单击立即同步

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

请继续学习如何编写代码，很快Android将解决此问题.您可以在此处 a>.

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

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