初学android时出现的问题

前言
一些自己刚开始学android的时候遇到的问题以及解决方法，记录一下。
1.当android的编译版本和实际的api版本不一致的时候，会报错。

2.需要找到匹配的slf4j和log4j

3.android项目中添加jar包的三种方式

4.点击按钮没反应,解决方法：找到按钮后，btn.setOnClickListener()就可以了

5.报错：java.lang.ClassNotFoundException: Didn’t find class “android.view.View$OnUnhandledKeyEventListener” on path: DexPathList[[zip file "/data/app/com.examp

因为androidx从Android9.0（API 28）开始支持，如果项目使用了androidx但是运行在低于API 28版本的设备上就会出现；

所以把低版本的api改到高版本就可以了。

6. Process: com.example.evprac, PID: 11190
   java.lang.IllegalStateException: WebSocketClient objects are not reuseable
   

   使用webSocket出现了上面的错误。原因是初始化的时候，已经进行了连接。

   switch (v.getId()) {
      case R.id.lg_login:
           if (webSocketClient.isClosed() || webSocketClient.isClosing()) {
               Snackbar.make(v, "Client正在关闭", Snackbar.LENGTH_SHORT).show();
               //webSocketClient.connect();
               webSocketClient.reconnect();
               break;
           }
           System.out.println("发送给后端的信息是"+username.getText().toString().trim());
           webSocketClient.send(username.getText().toString().trim());
           break;
   
       default:
           break;
   
   }
   

解决办法是把 webSocketClient.connect();改为webSocketClient.reconnect();

java.lang.UnsupportedOperationException: Binary XML file line #7: You must supply a layout_width attribute.

这是因为自己的布局文件没有指定layout_width属性，比如我的问题就是在textView中没有指定layout_width属性和layout_height属性，只要指定了问题也就解决了。

8. wrong 2nd argument type found 'android.app.Fragment.' required 'Android.support.v4.app.Fragment'
   

   这是因为导报错误出现的bug，只需要改成需要的包就可以了

   9.android中比较难拼的几个单词（忽略掉，当时不知道为什么要写这一点）

   10.这是我在button想要调用自定义的类的方法的时候出现的错误。目前还没有解决。

   Listener class android.view.View.OnClickListener with method onClick did not match signature of any method onClickUtil::onClickWithMe
   

   Cause: couldn't make a guess for com.example.androidmvvm.utils.onClickUtil
   

   12.设置weight属性的时候，一定要设置width或者height属性为0dp

   13.android项目使用lamda表达式的时候，说版本7不支持lamda表达式

   解决方法：按住alt+enter键，然后选择set language level to 8

   14.之前安装的HAXM突然需要重新安装，打开安装失败的日志文件（在C盘），发现又出现了之前存在的问题，没有将cpu设置为虚拟化，需要重启电脑，设置虚拟化（bios->system options）。

   15.因为之前Android项目应用的是JDK7，然后我换成jdk8之后就出现了这样的错误:app:compileDebugJavaWithJavac，解决方法：在项目结构中，把jdk换成android中内嵌的1.7版本就没问题了。

   16.如果导入依赖后，还是爆红，无法导包，可以点击build→rebuild

   17.下面这段代码在那个activity里面，那个activity就是第一启动项

   <intent-filter>
       <action android:name="android.intent.action.MAIN" />
   
       <category android:name="android.intent.category.LAUNCHER" />
   </intent-filter>
   

18.androidx从API28开始支持，如果项目中使用了androidx，应该注意版本问题。

Didn't find class "android.view.View$OnUnhandledKeyEventListener" on path: DexPathList[[zip file "/data/app/com.example.mvvm-1/base.apk"],nativeLibraryDirectories=[/data/app/com.example.mvvm-1/lib/x86, /system/lib, /vendor/lib]]
        at java.lang.Class dalvik.system.BaseDexClassLoader.findClass(java.lang.String) (BaseDexClassLoader.java:56)

19.在fragment的button中设置点击事件，但是点击按钮后，没有出现该出现的效果，反而报错。

这是因为没有实现点击事件的方法。

E/AndroidRuntime: FATAL EXCEPTION: main
    Process: com.example.cardemo1, PID: 8599
    java.lang.IllegalStateException: Could not find method logoutDialog(View) in a parent or ancestor Context for android:onClick attribute defined on view class androidx.appcompat.widget.AppCompatButton with id 'Logout'
        at androidx.appcompat.app.AppCompatViewInflater$DeclaredOnClickListener.resolveMethod(AppCompatViewInflater.java:424)
        at androidx.appcompat.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:381)
        at android.view.View.performClick(View.java:5610)
        at android.view.View$PerformClick.run(View.java:22265)
        at android.os.Handler.handleCallback(Handler.java:751)
        at android.os.Handler.dispatchMessage(Handler.java:95)
        at android.os.Looper.loop(Looper.java:154)
        at android.app.ActivityThread.main(ActivityThread.java:6077)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:866)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:756)

20.此问题还没有解决

W/oxconn.cardemo: Accessing hidden field Landroid/view/animation/Animation;->mListener:Landroid/view/animation/Animation$AnimationListener; (greylist-max-p, reflection, denied)
E/FragmentManager: No field with the name mListener is found in Animation class
    java.lang.NoSuchFieldException: No field mListener in class Landroid/view/animation/Animation; (declaration of 'android.view.animation.Animation' appears in /system/framework/framework.jar!classes3.dex)
        at java.lang.Class.getDeclaredField(Native Method)
        at androidx.fragment.app.FragmentManagerImpl.getAnimationListener(FragmentManager.java:1301)
        at androidx.fragment.app.FragmentManagerImpl.setHWLayerAnimListenerIfAlpha(FragmentManager.java:1283)
        at androidx.fragment.app.FragmentManagerImpl.moveFragmentToExpectedState(FragmentManager.java:1811)
        at androidx.fragment.app.FragmentManagerImpl.moveToState(FragmentManager.java:1852)
        at androidx.fragment.app.FragmentManagerImpl.executeOpsTogether(FragmentManager.java:2426)
        at androidx.fragment.app.FragmentManagerImpl.removeRedundantOperationsAndExecute(FragmentManager.java:2372)
        at androidx.fragment.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:2273)
        at androidx.fragment.app.FragmentManagerImpl$1.run(FragmentManager.java:733)
        at android.os.Handler.handleCallback(Handler.java:938)
        at android.os.Handler.dispatchMessage(Handler.java:99)
        at android.os.Looper.loop(Looper.java:223)
        at android.app.ActivityThread.main(ActivityThread.java:7656)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:592)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:947)
W/oxconn.cardemo: Accessing hidden field Landroid/view/animation/Animation;->mListener:Landroid/view/animation/Animation$AnimationListener; (greylist-max-p, reflection, denied)
E/FragmentManager: No field with the name mListener is found in Animation class
    java.lang.NoSuchFieldException: No field mListener in class Landroid/view/animation/Animation; (declaration of 'android.view.animation.Animation' appears in /system/framework/framework.jar!classes3.dex)
        at java.lang.Class.getDeclaredField(Native Method)
        at androidx.fragment.app.FragmentManagerImpl.getAnimationListener(FragmentManager.java:1301)
        at androidx.fragment.app.FragmentManagerImpl.animateRemoveFragment(FragmentManager.java:1638)
        at androidx.fragment.app.FragmentManagerImpl.moveToState(FragmentManager.java:1548)
        at androidx.fragment.app.FragmentManagerImpl.moveFragmentToExpectedState(FragmentManager.java:1784)
        at androidx.fragment.app.FragmentManagerImpl.moveToState(FragmentManager.java:1861)
        at androidx.fragment.app.FragmentManagerImpl.executeOpsTogether(FragmentManager.java:2426)
        at androidx.fragment.app.FragmentManagerImpl.removeRedundantOperationsAndExecute(FragmentManager.java:2372)
        at androidx.fragment.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:2273)
        at androidx.fragment.app.FragmentManagerImpl$1.run(FragmentManager.java:733)
        at android.os.Handler.handleCallback(Handler.java:938)
        at android.os.Handler.dispatchMessage(Handler.java:99)
        at android.os.Looper.loop(Looper.java:223)
        at android.app.ActivityThread.main(ActivityThread.java:7656)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:592)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:947)
W/oxconn.cardemo: Accessing hidden field Landroid/view/animation/Animation;->mListener:Landroid/view/animation/Animation$AnimationListener; (greylist-max-p, reflection, denied)
E/FragmentManager: No field with the name mListener is found in Animation class
    java.lang.NoSuchFieldException: No field mListener in class Landroid/view/animation/Animation; (declaration of 'android.view.animation.Animation' appears in /system/framework/framework.jar!classes3.dex)
        at java.lang.Class.getDeclaredField(Native Method)
        at androidx.fragment.app.FragmentManagerImpl.getAnimationListener(FragmentManager.java:1301)
        at androidx.fragment.app.FragmentManagerImpl.setHWLayerAnimListenerIfAlpha(FragmentManager.java:1283)
        at androidx.fragment.app.FragmentManagerImpl.animateRemoveFragment(FragmentManager.java:1659)
        at androidx.fragment.app.FragmentManagerImpl.moveToState(FragmentManager.java:1548)
        at androidx.fragment.app.FragmentManagerImpl.moveFragmentToExpectedState(FragmentManager.java:1784)
        at androidx.fragment.app.FragmentManagerImpl.moveToState(FragmentManager.java:1861)
        at androidx.fragment.app.FragmentManagerImpl.executeOpsTogether(FragmentManager.java:2426)
        at androidx.fragment.app.FragmentManagerImpl.removeRedundantOperationsAndExecute(FragmentManager.java:2372)
        at androidx.fragment.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:2273)
        at androidx.fragment.app.FragmentManagerImpl$1.run(FragmentManager.java:733)
        at android.os.Handler.handleCallback(Handler.java:938)
        at android.os.Handler.dispatchMessage(Handler.java:99)
        at android.os.Looper.loop(Looper.java:223)
        at android.app.ActivityThread.main(ActivityThread.java:7656)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:592)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:947)

21在线JSON校验格式化工具（Be JSON）

22.在使用okhttp的时候出现了这样的问题，这是因为没有联网，所以访问不到

android.system.GaiException: android_getaddrinfo failed: EAI_NODATA (No address associated with hostname)

23. Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.Button

    报空指针异常，原因是我把下面两句话写在了setContentView(R.layout.activity_main);这句话的上面，因此导致了找不到控件。

btn = findViewById(R.id.button);
textView = findViewById(R.id.textview);

正确的写法应该是

super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
btn = findViewById(R.id.button);
textView = findViewById(R.id.textview);

24.这个也不算bug，只是如果在android中重复打印很多次相同的语句的时候，它只会显示两句，中间那句话表示折叠了多少项（比如本例中，循环打印了15遍，所以中间折叠了13次）

25.这是因为在gradle中的依赖的版本不匹配，只需要把版本换成匹配的版本就可以了。

The given artifact contains a string literal with a package reference 'android.support.v4.content' that cannot be safely rewritten. Libraries using reflection such as annotation processors need to be updated manually to add support for androidx.

26.创建了一个sharedPreference对象，但是没有形成对应的xml文件。

原因可能是项目卡了，关掉项目重新写进一下就可以了。

27.在创建layout文件的时候不能使用大写字母

28.不能再oncreatd()方法外边初始化组件，否则再加载组件的时候无法看到组件。

29.在写通知灯的地方报的错，非法传参错误，原因是我的NotificationManager的notify()的参数传递错误。这里注意：现在的手机为了满足对屏幕的要求，已经把呼吸灯取消了。所以没有办法使用现有的设备对呼吸灯进行调试。

 java.lang.IllegalArgumentException: Invalid notification (no valid small icon): Notification(channel=null pri=0 contentView=null vibrate=null sound=null defaults=0x0 flags=0x1 color=0x00000000 vis=PRIVATE)
        at android.app.NotificationManager.notifyAsUser(NotificationManager.java:393)

30.切换碎片的时候，碎片中的数据丢失。

解决思路：切换Fragment的时候不消毁前一个fragment，再切换回去的时候也不需要重建。

我们不用replace()去切换，而使用add()添加，hide()隐藏。

31.这个问题是service泄露

E/ActivityThread: Service com.foxconn.cardemo1.MqttService has leaked ServiceConnection org.eclipse.paho.android.service.MqttAndroidClient$MyServiceConnection@4b72f7b that was originally bound here
    android.app.ServiceConnectionLeaked: Service com.foxconn.cardemo1.MqttService has leaked ServiceConnection org.eclipse.paho.android.service.MqttAndroidClient$MyServiceConnection@4b72f7b that was originally bound here
        at android.app.LoadedApk$ServiceDispatcher.<init>(LoadedApk.java:1610)
        at android.app.LoadedApk.getServiceDispatcher(LoadedApk.java:1502)
        at android.app.ContextImpl.bindServiceCommon(ContextImpl.java:1659)
        at android.app.ContextImpl.bindService(ContextImpl.java:1612)
        at android.content.ContextWrapper.bindService(ContextWrapper.java:698)
        at org.eclipse.paho.android.service.MqttAndroidClient.connect(MqttAndroidClient.java:425)
        at com.foxconn.cardemo1.MqttService.doClientConnection(MqttService.java:100)
        at com.foxconn.cardemo1.MqttService.init(MqttService.java:82)
        at com.foxconn.cardemo1.MqttService.onCreate(MqttService.java:45)
        at android.app.ActivityThread.handleCreateService(ActivityThread.java:3532)
        at android.app.ActivityThread.access$1300(ActivityThread.java:199)
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1666)
        at android.os.Handler.dispatchMessage(Handler.java:106)
        at android.os.Looper.loop(Looper.java:193)
        at android.app.ActivityThread.main(ActivityThread.java:6669)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:858)
D/EGL_emulation: eglMakeCurrent: 0xde185360: ver 2 0 (tinfo 0xde183650)
Process 5351 terminated.

32.无法连接mqtt服务，原因可能是代理服务器没有转发过来。

W/System.err: MqttException (0) - java.net.SocketTimeoutException: failed to connect to /10.205.57.108 (port 1883) from /192.168.232.2 (port 38204) after 10000ms
W/System.err:     at org.eclipse.paho.client.mqttv3.internal.ExceptionHelper.createMqttException(ExceptionHelper.java:38)
        at org.eclipse.paho.client.mqttv3.internal.ClientComms$ConnectBG.run(ClientComms.java:736)
        at java.lang.Thread.run(Thread.java:764)
W/System.err: Caused by: java.net.SocketTimeoutException: failed to connect to /10.205.57.108 (port 1883) from /192.168.232.2 (port 38204) after 10000ms
        at libcore.io.IoBridge.connectErrno(IoBridge.java:185)
        at libcore.io.IoBridge.connect(IoBridge.java:129)
        at java.net.PlainSocketImpl.socketConnect(PlainSocketImpl.java:137)
        at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:390)
        at java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:230)
        at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:212)
        at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:436)
        at java.net.Socket.connect(Socket.java:621)
        at org.eclipse.paho.client.mqttv3.internal.TCPNetworkModule.start(TCPNetworkModule.java:74)
W/System.err:     at org.eclipse.paho.client.mqttv3.internal.ClientComms$ConnectBG.run(ClientComms.java:722)
    	... 1 more

33.新版本的android放弃了tools，如果想用的话，可以用旧版的tools覆盖。

34.新创建的android项目右边gradle面板没有内容，点击重新构建一下就可以了。

35.如果使用gradlew build构建我们的app的时候第一次构建失败的话，可以重新再执行以下命令，重新构建。

36.运行项目的时候

Installation did not succeed.
The application could not be installed.
Installation failed due to: 'device 'emulator-5554' not found'

解决方法：下面三种方法都可以试试

方法一：

方法二.rebuild一下

方法三.重新安装模拟器

37.android studio检测更新失败解决办法

参考下面链接

http://t.csdn.cn/yI3mL

38.出现下面的问题

解决方法是：把红框里面的对勾去掉，然后同步一下项目

39.新版本中模拟器在studio里面，怎么放外面

把launch in a tool window前面的√去掉。

40.不知道为啥报了空指针异常，后面重新运行了一下就没这个问题了。

java.lang.NullPointerException
	at com.intellij.openapi.wm.impl.ToolWindowDragHelper.getBoundsOnScreen(ToolWindowDragHelper.kt:271)
	at com.intellij.openapi.wm.impl.ToolWindowDragHelper.access$getBoundsOnScreen(ToolWindowDragHelper.kt:32)
	at com.intellij.openapi.wm.impl.ToolWindowDragHelper$relocate$1.run(ToolWindowDragHelper.kt:348)
	at java.desktop/java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:313)
	at java.desktop/java.awt.EventQueue.dispatchEventImpl(EventQueue.java:776)
	at java.desktop/java.awt.EventQueue$4.run(EventQueue.java:727)
	at java.desktop/java.awt.EventQueue$4.run(EventQueue.java:721)
	at java.base/java.security.AccessController.doPrivileged(Native Method)
	at java.base/java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:85)
	at java.desktop/java.awt.EventQueue.dispatchEvent(EventQueue.java:746)
	at com.intellij.ide.IdeEventQueue.defaultDispatchEvent(IdeEventQueue.java:885)
	at com.intellij.ide.IdeEventQueue._dispatchEvent(IdeEventQueue.java:754)
	at com.intellij.ide.IdeEventQueue.lambda$dispatchEvent$6(IdeEventQueue.java:441)
	at com.intellij.openapi.progress.impl.CoreProgressManager.computePrioritized(CoreProgressManager.java:825)
	at com.intellij.ide.IdeEventQueue.lambda$dispatchEvent$7(IdeEventQueue.java:440)
	at com.intellij.openapi.application.impl.ApplicationImpl.runIntendedWriteActionOnCurrentThread(ApplicationImpl.java:794)
	at com.intellij.ide.IdeEventQueue.dispatchEvent(IdeEventQueue.java:492)
	at java.desktop/java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:203)
	at java.desktop/java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:124)
	at java.desktop/java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:113)
	at java.desktop/java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:109)
	at java.desktop/java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:101)
	at java.desktop/java.awt.EventDispatchThread.run(EventDispatchThread.java:90)

41.解决这个问题，看文档

解决Gradle错误：未找到ID为’com.android.application’的插件 - 掘金 (juejin.cn)

42.导入别人的android项目，java代码都会有一个红色的小“J”,解决方法是给模块配置jdk

43.同步项目的时候特别慢，原来是因为没有配置maven，所有在repositories里面添加maven仓库即可。

44.每次创建项目的android项目或者导入android项目的时候，总是会出现重新加载gradle的情况，因为gradle是从外网下载的，所以每次下载都很慢。

解决方法：

第一步.首先，先去这个网站下载需要的gradleGradle Distributions，下载-all.zip格式的压缩包。下载完对应的版本后，不需要解压。

第二步.去android studio中设置代理。这个127.0.0.1就是本机。

第三步.创建一个新的android项目，此时会弹出来一个代理的窗口，先不需要管这个窗口

第四步.进入android项目的目录，把之前下载的压缩包放在这里。

第五步.更改上面的gradle.wrapper.properties文件，把distributionUrl的路径前面的http：XXX去掉，只剩下gradle-x.x.x-bin.zip,然后保存更改。

第六步.回到Android studio，此时还是有那个代理的窗口，点击cancel或者no（不同版本studio不一样），这时候，就开始创建项目了，而且此时，也不会在外网下载gradle了。

注：其实到这里，也就知道设置代理的原因了，就是为了在创建项目的时候，阻止默认从外网下载gradle的过程，由我们自己配置。

45.导入别人的项目后，发现没有gradle文件夹，自己粘贴了gradle文件夹之后，出现了下面这些问题。

46.touch target size too small

我把EditText的textSize设为35dp，然后就出现了上面这个问题，解决方法是添加一个minWidth属性并设置为32dp

47.No speakable text present.

原因是：editText里面刚开始什么内容都没有的时候，需要有提示信息，但是我没有设置，所以就报上面的错误

解决方法：android：hint=”这里是提示内容“

48.在约束布局中，水平约束和垂直约束都需要设置，否则会报错。

49.在android项目中导入依赖的时候，一直提示无法识别依赖，原因是我之前一直写的是implement，解决方法：把implement改成api，就能编译通过了。

50.Failed to resolve: com.scwang.smartrefresh:SmartRefreshLayout:1.1.2

使用的android studio版本是花栗鼠版本的，该版本和之前常用的旧版本的build.gradle不太一样，今天想用smartRefreshLayout实现下拉刷新上拉加载的功能，结果就出现了上面的问题。

解决方法：在settings.gradle中下面这两个位置中添加jcenter(),问题就会解决。

51. Caused by: android.view.InflateException: Binary XML file line #20: Binary XML file line #20: Error inflating class com.scwang.smartrefresh.layout.SmartRefreshLayout

    原因：之前一直以为我的布局文件写的不规范，一点点检查后，发现是规范的，然后又看报错信息，发现是编译的时候没有找到SmartRefreshLayout类

    解决方法：在gradle.properties文件中添加

    android.enableJetifier=true
    

52.Render problem

java.lang.NoClassDefFoundError:androidx/legacy/widget/Space

解决方法：

http://t.csdn.cn/tS28r

53.gradle一直编译错误：No signature of method

检查问题的时候，发现时build.gradle中的repositories出错了。

我在maven那里写了两个allowInsecureProtocol=true

54.android项目出现下面这个问题

Your anti-virus program might be impacting your build performance.
Android Studio checked the following directories:

解决方法：

设置→windows安全中心→病毒和威胁防护→找到病毒和威胁防护设置，点击管理设置→找到排除项，点击添加或删除排除项，然后把想要排除windows安全检查的文件或者文件夹添加到里面即可。

55.在android项目中，创建了很多个values，但是只能看到一个values文件夹

解决方法是：将视图从project切换到Packages

56.如果安装了一些插件，想要删除的话，可以在Plugin里面找到自己曾经下载过的插件，把前面的√去掉，然后点击ok，android就会卸载了。

57.一个android项目里面有多个activity，然后在manifest文件里面分别注册这几个activity就出现了这个报错。

解决方法：把其他activity的intent-filter去掉，只留下一个主activity的intent-filter，谁有这个intent-filter，谁就是主启动项。

• Exception is:
  org.gradle.api.tasks.TaskExecutionException: Execution failed for task ':app:processDebugMainManifest'.
  at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter.lambda$executeIfValid$1(ExecuteActionsTaskExecuter.java:145)
  at org.gradle.internal.Try$Failure.ifSuccessfulOrElse(Try.java:282)
  at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter.executeIfValid(ExecuteActionsTaskExecuter.java:143)
  at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter.execute(ExecuteActionsTaskExecuter.java:131)
  at org.gradle.api.internal.tasks.execution.CleanupStaleOutputsExecuter.execute(CleanupStaleOutputsExecuter.java:77)
  at org.gradle.api.internal.tasks.execution.FinalizePropertiesTaskExecuter.execute(FinalizePropertiesTaskExecuter.java:46)
  at org.gradle.api.internal.tasks.execution.ResolveTaskExecutionModeExecuter.execute(ResolveTaskExecutionModeExecuter.java:51)
  at org.gradle.api.internal.tasks.execution.SkipTaskWithNoActionsExecuter.execute(SkipTaskWithNoActionsExecuter.java:57)
  at org.gradle.api.internal.tasks.execution.SkipOnlyIfTaskExecuter.execute(SkipOnlyIfTaskExecuter.java:56)
  at org.gradle.api.internal.tasks.execution.CatchExceptionTaskExecuter.execute(CatchExceptionTaskExecuter.java:36)
  at org.gradle.api.internal.tasks.execution.EventFiringTaskExecuter$1.executeTask(EventFiringTaskExecuter.java:77)
  at org.gradle.api.internal.tasks.execution.EventFiringTaskExecuter$1.call(EventFiringTaskExecuter.java:55)
  at org.gradle.api.internal.tasks.execution.EventFiringTaskExecuter$1.call(EventFiringTaskExecuter.java:52)
  at org.gradle.internal.operations.DefaultBuildOperationRunner$CallableBuildOperationWorker.execute(DefaultBuildOperationRunner.java:204)
  at org.gradle.internal.operations.DefaultBuildOperationRunner$CallableBuildOperationWorker.execute(DefaultBuildOperationRunner.java:199)
  at org.gradle.internal.operations.DefaultBuildOperationRunner$2.execute(DefaultBuildOperationRunner.java:66)
  at org.gradle.internal.operations.DefaultBuildOperationRunner$2.execute(DefaultBuildOperationRunner.java:59)
  at org.gradle.internal.operations.DefaultBuildOperationRunner.execute(DefaultBuildOperationRunner.java:157)
  at org.gradle.internal.operations.DefaultBuildOperationRunner.execute(DefaultBuildOperationRunner.java:59)
  at org.gradle.internal.operations.DefaultBuildOperationRunner.call(DefaultBuildOperationRunner.java:53)
  at org.gradle.internal.operations.DefaultBuildOperationExecutor.call(DefaultBuildOperationExecutor.java:73)
  at org.gradle.api.internal.tasks.execution.EventFiringTaskExecuter.execute(EventFiringTaskExecuter.java:52)
  at org.gradle.execution.plan.LocalTaskNodeExecutor.execute(LocalTaskNodeExecutor.java:74)
  at org.gradle.execution.taskgraph.DefaultTaskExecutionGraph$InvokeNodeExecutorsAction.execute(DefaultTaskExecutionGraph.java:402)
  at org.gradle.execution.taskgraph.DefaultTaskExecutionGraph$InvokeNodeExecutorsAction.execute(DefaultTaskExecutionGraph.java:389)
  at org.gradle.execution.taskgraph.DefaultTaskExecutionGraph$BuildOperationAwareExecutionAction.execute(DefaultTaskExecutionGraph.java:382)
  at org.gradle.execution.taskgraph.DefaultTaskExecutionGraph$BuildOperationAwareExecutionAction.execute(DefaultTaskExecutionGraph.java:368)
  at org.gradle.execution.plan.DefaultPlanExecutor$ExecutorWorker.lambda$run$0(DefaultPlanExecutor.java:127)
  at org.gradle.execution.plan.DefaultPlanExecutor$ExecutorWorker.execute(DefaultPlanExecutor.java:191)
  at org.gradle.execution.plan.DefaultPlanExecutor$ExecutorWorker.executeNextNode(DefaultPlanExecutor.java:182)
  at org.gradle.execution.plan.DefaultPlanExecutor$ExecutorWorker.run(DefaultPlanExecutor.java:124)
  at org.gradle.internal.concurrent.ExecutorPolicy$CatchAndRecordFailures.onExecute(ExecutorPolicy.java:64)
  at org.gradle.internal.concurrent.ManagedExecutorImpl$1.run(ManagedExecutorImpl.java:48)
  at org.gradle.internal.concurrent.ThreadFactoryImpl$ManagedThreadRunnable.run(ThreadFactoryImpl.java:61)
  Caused by: java.lang.RuntimeException: Manifest merger failed with multiple errors, see logs
  at com.android.build.gradle.internal.tasks.manifest.ManifestHelperKt.mergeManifests(ManifestHelper.kt:95)
  at com.android.build.gradle.tasks.ProcessApplicationManifest.doTaskAction(ProcessApplicationManifest.kt:149)
  at com.android.build.gradle.internal.tasks.NonIncrementalTask$taskAction$$inlined$recordTaskAction$1.invoke(BaseTask.kt:66)
  at com.android.build.gradle.internal.tasks.Blocks.recordSpan(Blocks.java:51)
  at com.android.build.gradle.internal.tasks.NonIncrementalTask.taskAction(NonIncrementalTask.kt:97)
  at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
  at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
  at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
  at org.gradle.internal.reflect.JavaMethod.invoke(JavaMethod.java:104)
  at org.gradle.api.internal.project.taskfactory.StandardTaskAction.doExecute(StandardTaskAction.java:58)
  at org.gradle.api.internal.project.taskfactory.StandardTaskAction.execute(StandardTaskAction.java:51)
  at org.gradle.api.internal.project.taskfactory.StandardTaskAction.execute(StandardTaskAction.java:29)
  at org.gradle.api.internal.tasks.execution.TaskExecution$2.run(TaskExecution.java:239)
  at org.gradle.internal.operations.DefaultBuildOperationRunner$1.execute(DefaultBuildOperationRunner.java:29)
  at org.gradle.internal.operations.DefaultBuildOperationRunner$1.execute(DefaultBuildOperationRunner.java:26)
  at org.gradle.internal.operations.DefaultBuildOperationRunner$2.execute(DefaultBuildOperationRunner.java:66)
  at org.gradle.internal.operations.DefaultBuildOperationRunner$2.execute(DefaultBuildOperationRunner.java:59)
  at org.gradle.internal.operations.DefaultBuildOperationRunner.execute(DefaultBuildOperationRunner.java:157)
  at org.gradle.internal.operations.DefaultBuildOperationRunner.execute(DefaultBuildOperationRunner.java:59)
  at org.gradle.internal.operations.DefaultBuildOperationRunner.run(DefaultBuildOperationRunner.java:47)
  at org.gradle.internal.operations.DefaultBuildOperationExecutor.run(DefaultBuildOperationExecutor.java:68)
  at org.gradle.api.internal.tasks.execution.TaskExecution.executeAction(TaskExecution.java:224)
  at org.gradle.api.internal.tasks.execution.TaskExecution.executeActions(TaskExecution.java:207)
  at org.gradle.api.internal.tasks.execution.TaskExecution.executeWithPreviousOutputFiles(TaskExecution.java:190)
  at org.gradle.api.internal.tasks.execution.TaskExecution.execute(TaskExecution.java:168)
  at org.gradle.internal.execution.steps.ExecuteStep.executeInternal(ExecuteStep.java:89)
  at org.gradle.internal.execution.steps.ExecuteStep.access$000(ExecuteStep.java:40)
  at org.gradle.internal.execution.steps.ExecuteStep$1.call(ExecuteStep.java:53)
  at org.gradle.internal.execution.steps.ExecuteStep$1.call(ExecuteStep.java:50)
  at org.gradle.internal.operations.DefaultBuildOperationRunner$CallableBuildOperationWorker.execute(DefaultBuildOperationRunner.java:204)
  at org.gradle.internal.operations.DefaultBuildOperationRunner$CallableBuildOperationWorker.execute(DefaultBuildOperationRunner.java:199)
  at org.gradle.internal.operations.DefaultBuildOperationRunner$2.execute(DefaultBuildOperationRunner.java:66)
  at org.gradle.internal.operations.DefaultBuildOperationRunner$2.execute(DefaultBuildOperationRunner.java:59)
  at org.gradle.internal.operations.DefaultBuildOperationRunner.execute(DefaultBuildOperationRunner.java:157)
  at org.gradle.internal.operations.DefaultBuildOperationRunner.execute(DefaultBuildOperationRunner.java:59)
  at org.gradle.internal.operations.DefaultBuildOperationRunner.call(DefaultBuildOperationRunner.java:53)
  at org.gradle.internal.operations.DefaultBuildOperationExecutor.call(DefaultBuildOperationExecutor.java:73)
  at org.gradle.internal.execution.steps.ExecuteStep.execute(ExecuteStep.java:50)
  at org.gradle.internal.execution.steps.ExecuteStep.execute(ExecuteStep.java:40)
  at org.gradle.internal.execution.steps.RemovePreviousOutputsStep.execute(RemovePreviousOutputsStep.java:68)
  at org.gradle.internal.execution.steps.RemovePreviousOutputsStep.execute(RemovePreviousOutputsStep.java:38)
  at org.gradle.internal.execution.steps.ResolveInputChangesStep.execute(ResolveInputChangesStep.java:48)
  at org.gradle.internal.execution.steps.ResolveInputChangesStep.execute(ResolveInputChangesStep.java:36)
  at org.gradle.internal.execution.steps.CancelExecutionStep.execute(CancelExecutionStep.java:41)
  at org.gradle.internal.execution.steps.TimeoutStep.executeWithoutTimeout(TimeoutStep.java:74)
  at org.gradle.internal.execution.steps.TimeoutStep.execute(TimeoutStep.java:55)
  at org.gradle.internal.execution.steps.CreateOutputsStep.execute(CreateOutputsStep.java:51)
  at org.gradle.internal.execution.steps.CreateOutputsStep.execute(CreateOutputsStep.java:29)
  at org.gradle.internal.execution.steps.CaptureStateAfterExecutionStep.execute(CaptureStateAfterExecutionStep.java:61)
  at org.gradle.internal.execution.steps.CaptureStateAfterExecutionStep.execute(CaptureStateAfterExecutionStep.java:42)
  at org.gradle.internal.execution.steps.BroadcastChangingOutputsStep.execute(BroadcastChangingOutputsStep.java:60)
  at org.gradle.internal.execution.steps.BroadcastChangingOutputsStep.execute(BroadcastChangingOutputsStep.java:27)
  at org.gradle.internal.execution.steps.BuildCacheStep.executeWithoutCache(BuildCacheStep.java:188)
  at org.gradle.internal.execution.steps.BuildCacheStep.lambda$execute$1(BuildCacheStep.java:75)
  at org.gradle.internal.Either$Right.fold(Either.java:175)
  at org.gradle.internal.execution.caching.CachingState.fold(CachingState.java:59)
  at org.gradle.internal.execution.steps.BuildCacheStep.execute(BuildCacheStep.java:73)
  at org.gradle.internal.execution.steps.BuildCacheStep.execute(BuildCacheStep.java:48)
  at org.gradle.internal.execution.steps.StoreExecutionStateStep.execute(StoreExecutionStateStep.java:38)
  at org.gradle.internal.execution.steps.StoreExecutionStateStep.execute(StoreExecutionStateStep.java:27)
  at org.gradle.internal.execution.steps.RecordOutputsStep.execute(RecordOutputsStep.java:36)
  at org.gradle.internal.execution.steps.RecordOutputsStep.execute(RecordOutputsStep.java:22)
  at org.gradle.internal.execution.steps.SkipUpToDateStep.executeBecause(SkipUpToDateStep.java:109)
  at org.gradle.internal.execution.steps.SkipUpToDateStep.lambda$execute$2(SkipUpToDateStep.java:56)
  at org.gradle.internal.execution.steps.SkipUpToDateStep.execute(SkipUpToDateStep.java:56)
  at org.gradle.internal.execution.steps.SkipUpToDateStep.execute(SkipUpToDateStep.java:38)
  at org.gradle.internal.execution.steps.ResolveChangesStep.execute(ResolveChangesStep.java:73)
  at org.gradle.internal.execution.steps.ResolveChangesStep.execute(ResolveChangesStep.java:44)
  at org.gradle.internal.execution.steps.legacy.MarkSnapshottingInputsFinishedStep.execute(MarkSnapshottingInputsFinishedStep.java:37)
  at org.gradle.internal.execution.steps.legacy.MarkSnapshottingInputsFinishedStep.execute(MarkSnapshottingInputsFinishedStep.java:27)
  at org.gradle.internal.execution.steps.ResolveCachingStateStep.execute(ResolveCachingStateStep.java:89)
  at org.gradle.internal.execution.steps.ResolveCachingStateStep.execute(ResolveCachingStateStep.java:50)
  at org.gradle.internal.execution.steps.ValidateStep.execute(ValidateStep.java:114)
  at org.gradle.internal.execution.steps.ValidateStep.execute(ValidateStep.java:57)
  at org.gradle.internal.execution.steps.CaptureStateBeforeExecutionStep.execute(CaptureStateBeforeExecutionStep.java:76)
  at org.gradle.internal.execution.steps.CaptureStateBeforeExecutionStep.execute(CaptureStateBeforeExecutionStep.java:50)
  at org.gradle.internal.execution.steps.SkipEmptyWorkStep.lambda$execute$2(SkipEmptyWorkStep.java:93)
  at org.gradle.internal.execution.steps.SkipEmptyWorkStep.execute(SkipEmptyWorkStep.java:93)
  at org.gradle.internal.execution.steps.SkipEmptyWorkStep.execute(SkipEmptyWorkStep.java:34)
  at org.gradle.internal.execution.steps.legacy.MarkSnapshottingInputsStartedStep.execute(MarkSnapshottingInputsStartedStep.java:38)
  at org.gradle.internal.execution.steps.LoadPreviousExecutionStateStep.execute(LoadPreviousExecutionStateStep.java:43)
  at org.gradle.internal.execution.steps.LoadPreviousExecutionStateStep.execute(LoadPreviousExecutionStateStep.java:31)
  at org.gradle.internal.execution.steps.AssignWorkspaceStep.lambda$execute$0(AssignWorkspaceStep.java:40)
  at org.gradle.api.internal.tasks.execution.TaskExecution$3.withWorkspace(TaskExecution.java:284)
  at org.gradle.internal.execution.steps.AssignWorkspaceStep.execute(AssignWorkspaceStep.java:40)
  at org.gradle.internal.execution.steps.AssignWorkspaceStep.execute(AssignWorkspaceStep.java:30)
  at org.gradle.internal.execution.steps.IdentityCacheStep.execute(IdentityCacheStep.java:37)
  at org.gradle.internal.execution.steps.IdentityCacheStep.execute(IdentityCacheStep.java:27)
  at org.gradle.internal.execution.steps.IdentifyStep.execute(IdentifyStep.java:44)
  at org.gradle.internal.execution.steps.IdentifyStep.execute(IdentifyStep.java:33)
  at org.gradle.internal.execution.impl.DefaultExecutionEngine$1.execute(DefaultExecutionEngine.java:76)
  at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter.executeIfValid(ExecuteActionsTaskExecuter.java:142)
  at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter.execute(ExecuteActionsTaskExecuter.java:131)
  at org.gradle.api.internal.tasks.execution.CleanupStaleOutputsExecuter.execute(CleanupStaleOutputsExecuter.java:77)
  at org.gradle.api.internal.tasks.execution.FinalizePropertiesTaskExecuter.execute(FinalizePropertiesTaskExecuter.java:46)
  at org.gradle.api.internal.tasks.execution.ResolveTaskExecutionModeExecuter.execute(ResolveTaskExecutionModeExecuter.java:51)
  at org.gradle.api.internal.tasks.execution.SkipTaskWithNoActionsExecuter.execute(SkipTaskWithNoActionsExecuter.java:57)
  at org.gradle.api.internal.tasks.execution.SkipOnlyIfTaskExecuter.execute(SkipOnlyIfTaskExecuter.java:56)
  at org.gradle.api.internal.tasks.execution.CatchExceptionTaskExecuter.execute(CatchExceptionTaskExecuter.java:36)
  at org.gradle.api.internal.tasks.execution.EventFiringTaskExecuter$1.executeTask(EventFiringTaskExecuter.java:77)
  at org.gradle.api.internal.tasks.execution.EventFiringTaskExecuter$1.call(EventFiringTaskExecuter.java:55)
  at org.gradle.api.internal.tasks.execution.EventFiringTaskExecuter$1.call(EventFiringTaskExecuter.java:52)
  at org.gradle.internal.operations.DefaultBuildOperationRunner$CallableBuildOperationWorker.execute(DefaultBuildOperationRunner.java:204)
  at org.gradle.internal.operations.DefaultBuildOperationRunner$CallableBuildOperationWorker.execute(DefaultBuildOperationRunner.java:199)
  at org.gradle.internal.operations.DefaultBuildOperationRunner$2.execute(DefaultBuildOperationRunner.java:66)
  at org.gradle.internal.operations.DefaultBuildOperationRunner$2.execute(DefaultBuildOperationRunner.java:59)
  at org.gradle.internal.operations.DefaultBuildOperationRunner.execute(DefaultBuildOperationRunner.java:157)
  at org.gradle.internal.operations.DefaultBuildOperationRunner.execute(DefaultBuildOperationRunner.java:59)
  at org.gradle.internal.operations.DefaultBuildOperationRunner.call(DefaultBuildOperationRunner.java:53)
  at org.gradle.internal.operations.DefaultBuildOperationExecutor.call(DefaultBuildOperationExecutor.java:73)
  at org.gradle.api.internal.tasks.execution.EventFiringTaskExecuter.execute(EventFiringTaskExecuter.java:52)
  at org.gradle.execution.plan.LocalTaskNodeExecutor.execute(LocalTaskNodeExecutor.java:74)
  at org.gradle.execution.taskgraph.DefaultTaskExecutionGraph$InvokeNodeExecutorsAction.execute(DefaultTaskExecutionGraph.java:402)
  at org.gradle.execution.taskgraph.DefaultTaskExecutionGraph$InvokeNodeExecutorsAction.execute(DefaultTaskExecutionGraph.java:389)
  at org.gradle.execution.taskgraph.DefaultTaskExecutionGraph$BuildOperationAwareExecutionAction.execute(DefaultTaskExecutionGraph.java:382)
  at org.gradle.execution.taskgraph.DefaultTaskExecutionGraph$BuildOperationAwareExecutionAction.execute(DefaultTaskExecutionGraph.java:368)
  at org.gradle.execution.plan.DefaultPlanExecutor$ExecutorWorker.lambda$run$0(DefaultPlanExecutor.java:127)
  at org.gradle.execution.plan.DefaultPlanExecutor$ExecutorWorker.execute(DefaultPlanExecutor.java:191)
  at org.gradle.execution.plan.DefaultPlanExecutor$ExecutorWorker.executeNextNode(DefaultPlanExecutor.java:182)
  at org.gradle.execution.plan.DefaultPlanExecutor$ExecutorWorker.run(DefaultPlanExecutor.java:124)
  at org.gradle.internal.concurrent.ExecutorPolicy$CatchAndRecordFailures.onExecute(ExecutorPolicy.java:64)
  at org.gradle.internal.concurrent.ManagedExecutorImpl$1.run(ManagedExecutorImpl.java:48)
  at org.gradle.internal.concurrent.ThreadFactoryImpl$ManagedThreadRunnable.run(ThreadFactoryImpl.java:61)
  

  58.写了一个程序，切换app语言（简体中文、繁体中文、英文），但是简体中文和繁体中文出现了问题。

  出现的问题就是：如果strings.xml里面是英文，那么无法切换；如果是简体中文，那么可以切换简体中文和英文；如果是繁体中文，那么可以切换繁体中文和英文。
  原因是我没真正理解Locale类
  解决方法是：设置Locale.CHINA、Local.TAIWAN、Local.US就能切换语言了。

  59.Connection timed out: connect. If you are behind an HTTP proxy, please configure the proxy settings either in IDE or Gradle.

  原因：一直连接超时，当时用的是手机热点，手机休眠后，热点关闭，所以才导致一直连接失败，修改了手机的休眠时间我的问题就解决了。

  60.启动android项目时，是不能直接加载fragment的。
  61.cannot resolve system “Theme.MaterialComponents.DayNight.DarkActionBar”
  clean一下项目，在rebuild一下就可以了。
  62.android studio中出现大面积的乱码该如何解决？
  进入到以下目录，

  C:Users用户名.AndroidStudio4.0system

将该目录下面的cache文件夹删掉，然后重启androidstudio，工程重新载入后问题解决。