Hello World android应用程序启动时崩溃

因此，我尝试使用Android Studio进行一个类项目，但即使只是一个空白的活动，当我尝试启动它时也会出现“HelloWorld”崩溃，我不知道为什么。我也不知道如何让错误控制台显示出来，所以我想我应该试着在这里发布代码，看看它是否因为某种原因出了问题

舱单：

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

    <application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <activity
            android:name=".TestApp"
            android:label="@string/app_name" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

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

</manifest>

<>这就是Android工作室在我用空白活动做了一个新项目时所做的事情。

编辑：得到了stacktrace，在这里

11-03 13:39:30.470    2273-2273/com.example.majeh.myapp E/AndroidRuntime﹕ FATAL EXCEPTION: main
    Process: com.example.majeh.myapp, PID: 2273
    java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.majeh.myapp/com.example.majeh.myapp.TestApp}: java.lang.IllegalStateException: You need to use a Theme.AppCompat theme (or descendant) with this activity.
            at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2298)
            at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2360)
            at android.app.ActivityThread.access$800(ActivityThread.java:144)
            at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1278)
            at android.os.Handler.dispatchMessage(Handler.java:102)
            at android.os.Looper.loop(Looper.java:135)
            at android.app.ActivityThread.main(ActivityThread.java:5221)
            at java.lang.reflect.Method.invoke(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:372)
            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:899)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:694)
     Caused by: java.lang.IllegalStateException: You need to use a Theme.AppCompat theme (or descendant) with this activity.
            at android.support.v7.app.ActionBarActivityDelegate.onCreate(ActionBarActivityDelegate.java:147)
            at android.support.v7.app.ActionBarActivityDelegateBase.onCreate(ActionBarActivityDelegateBase.java:139)
            at android.support.v7.app.ActionBarActivity.onCreate(ActionBarActivity.java:123)
            at com.example.majeh.myapp.TestApp.onCreate(TestApp.java:13)
            at android.app.Activity.performCreate(Activity.java:5933)
            at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1105)
            at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2251)
            at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2360)
            at android.app.ActivityThread.access$800(ActivityThread.java:144)
            at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1278)
            at android.os.Handler.dispatchMessage(Handler.java:102)
            at android.os.Looper.loop(Looper.java:135)
            at android.app.ActivityThread.main(ActivityThread.java:5221)
            at java.lang.reflect.Method.invoke(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:372)
            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:899)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:694)

---

在日志中，您可以看到这一行：

You need to use a Theme.AppCompat theme (or descendant) with this activity.

检查以下对话：

---

你看过日志了吗？你错过了最重要的信息：你的错误跟踪（Stacktrace）是什么。你的构建与目标平台的版本匹配吗？在Android Studio窗口的左下角：有一个小图标：将鼠标放在上面，然后在弹出菜单中选择“Android”：你将看到控制台（在Android上也称为logcat）谢谢，我也注意到了一些api级别的问题，所以我尝试了一个更高的api级别，它立刻就工作了。

11-03 13:39:30.470    2273-2273/com.example.majeh.myapp E/AndroidRuntime﹕ FATAL EXCEPTION: main
    Process: com.example.majeh.myapp, PID: 2273
    java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.majeh.myapp/com.example.majeh.myapp.TestApp}: java.lang.IllegalStateException: You need to use a Theme.AppCompat theme (or descendant) with this activity.
            at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2298)
            at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2360)
            at android.app.ActivityThread.access$800(ActivityThread.java:144)
            at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1278)
            at android.os.Handler.dispatchMessage(Handler.java:102)
            at android.os.Looper.loop(Looper.java:135)
            at android.app.ActivityThread.main(ActivityThread.java:5221)
            at java.lang.reflect.Method.invoke(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:372)
            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:899)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:694)
     Caused by: java.lang.IllegalStateException: You need to use a Theme.AppCompat theme (or descendant) with this activity.
            at android.support.v7.app.ActionBarActivityDelegate.onCreate(ActionBarActivityDelegate.java:147)
            at android.support.v7.app.ActionBarActivityDelegateBase.onCreate(ActionBarActivityDelegateBase.java:139)
            at android.support.v7.app.ActionBarActivity.onCreate(ActionBarActivity.java:123)
            at com.example.majeh.myapp.TestApp.onCreate(TestApp.java:13)
            at android.app.Activity.performCreate(Activity.java:5933)
            at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1105)
            at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2251)
            at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2360)
            at android.app.ActivityThread.access$800(ActivityThread.java:144)
            at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1278)
            at android.os.Handler.dispatchMessage(Handler.java:102)
            at android.os.Looper.loop(Looper.java:135)
            at android.app.ActivityThread.main(ActivityThread.java:5221)
            at java.lang.reflect.Method.invoke(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:372)
            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:899)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:694)

You need to use a Theme.AppCompat theme (or descendant) with this activity.