设置渐变背景时android studio应用程序崩溃

Question

当我设置渐变背景时，我的应用程序立即崩溃，如果我不这样做，那么一切正常。

我的 activity_main.xml:

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@drawable/gradient_background"
    tools:context="com.example.uytkownik.myapplication.MainActivity">

    <ProgressBar
        android:id="@+id/progressBar2"
        style="?android:attr/progressBarStyle"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerHorizontal="true"
        android:layout_centerVertical="true"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />
</RelativeLayout>

gradient_background.xml:

<?xml version="1.0" encoding="UTF-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
    <item>
        <shape>
            <gradient
                android:startColor="@color/gradientColBeg"
                android:endColor="@color/gradientColEnd"
                android:angle="90"/>
        </shape>
    </item>
</selector>

颜色.xml:

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <color name="colorPrimary">#3F51B5</color>
    <color name="colorPrimaryDark">#303F9F</color>
    <color name="colorAccent">#000000</color>
    <color name="gradientColBeg">#FFF</color>
    <color name="gradientColEnd">#000</color>
</resources>

堆栈跟踪:

12/30 15:39:05: Launching app
$ adb install-multiple -r -t -p com.example.uytkownik.myapplication D:\Projekty\java\nauka\MyApplication\app\build\intermediates\split-apk\debug\slices\slice_0.apk D:\Projekty\java\nauka\MyApplication\app\build\outputs\apk\debug\app-debug.apk 
Split APKs installed
$ adb shell am start -n "com.example.uytkownik.myapplication/com.example.uytkownik.myapplication.MainActivity" -a android.intent.action.MAIN -c android.intent.category.LAUNCHER
Connected to process 16680 on device huawei-huawei_y560_l01-Q6VBBBB5B0520663
Capturing and displaying logcat messages from application. This behavior can be disabled in the "Logcat output" section of the "Debugger" settings page.
I/InstantRun: starting instant run server: is main process
V/HwPolicyFactory: : success to get AllImpl object and return....
V/HwWidgetFactory: : successes to get AllImpl object and return....
E/art: ClassLinker::FindClass not found:Landroid/widget/ViewStub;
E/art: ClassLinker::FindClass not found:Landroid/webkit/ViewStub;
E/art: ClassLinker::FindClass not found:Landroid/app/ViewStub;
W/ResourceType: Failure getting entry for 0x7f020053 (t=1 e=83) (error -75)
D/AndroidRuntime: Shutting down VM
E/AndroidRuntime: FATAL EXCEPTION: main
                  Process: com.example.uytkownik.myapplication, PID: 16680
                  java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.uytkownik.myapplication/com.example.uytkownik.myapplication.MainActivity}: android.view.InflateException: Binary XML file line #2: Error inflating class android.widget.RelativeLayout
                      at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2345)
                      at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2407)
                      at android.app.ActivityThread.access$700(ActivityThread.java:155)
                      at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1317)
                      at android.os.Handler.dispatchMessage(Handler.java:102)
                      at android.os.Looper.loop(Looper.java:135)
                      at android.app.ActivityThread.main(ActivityThread.java:5298)
                      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:911)
                      at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:706)
                   Caused by: android.view.InflateException: Binary XML file line #2: Error inflating class android.widget.RelativeLayout
                      at android.view.LayoutInflater.createView(LayoutInflater.java:633)
                      at com.android.internal.policy.impl.PhoneLayoutInflater.onCreateView(PhoneLayoutInflater.java:55)
                      at com.android.internal.policy.impl.HwPhoneLayoutInflater.onCreateView(HwPhoneLayoutInflater.java:75)
                      at android.view.LayoutInflater.onCreateView(LayoutInflater.java:682)
                      at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:741)
                      at android.view.LayoutInflater.inflate(LayoutInflater.java:482)
                      at android.view.LayoutInflater.inflate(LayoutInflater.java:414)
                      at android.view.LayoutInflater.inflate(LayoutInflater.java:365)
                      at com.android.internal.policy.impl.PhoneWindow.setContentView(PhoneWindow.java:378)
                      at android.app.Activity.setContentView(Activity.java:2160)
                      at com.example.uytkownik.myapplication.MainActivity.onCreate(MainActivity.java:17)
                      at android.app.Activity.performCreate(Activity.java:6039)
                      at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1106)
                      at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2298)
                      at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2407) 
                      at android.app.ActivityThread.access$700(ActivityThread.java:155) 
                      at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1317) 
                      at android.os.Handler.dispatchMessage(Handler.java:102) 
                      at android.os.Looper.loop(Looper.java:135) 
                      at android.app.ActivityThread.main(ActivityThread.java:5298) 
                      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:911) 
                      at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:706) 
                   Caused by: java.lang.reflect.InvocationTargetException
                      at java.lang.reflect.Constructor.newInstance(Native Method)
                      at java.lang.reflect.Constructor.newInstance(Constructor.java:288)
                      at android.view.LayoutInflater.createView(LayoutInflater.java:607)
                      at com.android.internal.policy.impl.PhoneLayoutInflater.onCreateView(PhoneLayoutInflater.java:55) 
                      at com.android.internal.policy.impl.HwPhoneLayoutInflater.onCreateView(HwPhoneLayoutInflater.java:75) 
                      at android.view.LayoutInflater.onCreateView(LayoutInflater.java:682) 
                      at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:741) 
                      at android.view.LayoutInflater.inflate(LayoutInflater.java:482) 
                      at android.view.LayoutInflater.inflate(LayoutInflater.java:414) 
                      at android.view.LayoutInflater.inflate(LayoutInflater.java:365) 
                      at com.android.internal.policy.impl.PhoneWindow.setContentView(PhoneWindow.java:378) 
                      at android.app.Activity.setContentView(Activity.java:2160) 
                      at com.example.uytkownik.myapplication.MainActivity.onCreate(MainActivity.java:17) 
                      at android.app.Activity.performCreate(Activity.java:6039) 
                      at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1106) 
                      at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2298) 
                      at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2407) 
                      at android.app.ActivityThread.access$700(ActivityThread.java:155) 
                      at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1317) 
                      at android.os.Handler.dispatchMessage(Handler.java:102) 
                      at android.os.Looper.loop(Looper.java:135) 
                      at android.app.ActivityThread.main(ActivityThread.java:5298) 
                      at java.lang.reflect.Method.invoke(Native Method) 
                      at java.lang.reflect.Method.invoke(Method.java:372) 
                      at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:911) 
                      at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:706) 
                   Caused by: android.content.res.Resources$NotFoundException: Resource "com.example.uytkownik.myapplication:drawable/gradient_background" (7f020053)  is not a Drawable (color or path): TypedValue{t=0x1/d=0x7f020053 a=-1 r=0x7f020053}
                      at android.content.res.Resources.loadDrawableForCookie(Resources.java:2462)
                      at android.content.res.Resources.loadDrawable(Resources.java:2400)
                      at android.content.res.HwResources.loadDrawable(HwResources.java:609)
                      at android.content.res.TypedArray.getDrawable(TypedArray.java:785)
                      at android.view.View.<init>(View.java:3747)
                      at android.view.ViewGroup.<init>(ViewGroup.java:498)
                      at android.widget.RelativeLayout.<init>(RelativeLayout.java:249)
                      at android.widget.RelativeLayout.<init>(RelativeLayout.java:245)
                      at android.widget.RelativeLayout.<init>(RelativeLayout.java:241)
                      at java.lang.reflect.Constructor.newInstance(Native Method) 
                      at java.lang.reflect.Constructor.newInstance(Constructor.java:288) 
                      at android.view.LayoutInflater.createView(LayoutInflater.java:607) 
                      at com.android.internal.policy.impl.PhoneLayoutInflater.onCreateView(PhoneLayoutInflater.java:55) 
                      at com.android.internal.policy.impl.HwPhoneLayoutInflater.onCreateView(HwPhoneLayoutInflater.java:75) 
                      at android.view.LayoutInflater.onCreateView(LayoutInflater.java:682) 
                      at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:741) 
                      at android.view.LayoutInflater.inflate(LayoutInflater.java:482) 
                      at android.view.LayoutInflater.inflate(LayoutInflater.java:414) 
                      at android.view.LayoutInflater.inflate(LayoutInflater.java:365) 
                      at com.android.internal.policy.impl.PhoneWindow.setContentView(PhoneWindow.java:378) 
                      at android.app.Activity.setContentView(Activity.java:2160) 
                      at com.example.uytkownik.myapplication.MainActivity.onCreate(MainActivity.java:17) 
                      at android.app.Activity.performCreate(Activity.java:6039) 
                      at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1106) 
                      at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2298) 
                      at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2407) 
                      at android.app.ActivityThread.access$700(ActivityThread.java:155) 
                      at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1317) 
                      at android.os.Handler.dispatchMessage(Handler.java:102) 
                      at android.os.Looper.loop(Looper.java:135) 
                      at android.app.ActivityThread.main(ActivityThread.java:5298) 
                      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:911) 
                      at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:706) 
I/Process: Sending signal. PID: 16680 SIG: 9
Application terminated.

我是 android studio 的新手，我不知道什么会导致该异常。我将不胜感激任何帮助，非常感谢!

Answer 1

我已经测试了你的可绘制代码，它工作正常所以您必须确保您没有执行以下可能导致应用程序崩溃的操作。

1. 您没有将 gradient_background 放在 drawable-v21 文件夹中，而只是将 drawable 放在旧版本设备中。

2. 您不会将主题更改为其他内容并在样式或 list 中应用其他内容。