android.widget.Toolbar 无法转换为 androidx.appcompat.widget.Toolbar

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英文:

android.widget.Toolbar cannot be cast to androidx.appcompat.widget.Toolbar

问题

应用程序在点击按钮时崩溃，并且根据Logcat错误信息中的日志有任何问题。

以下是Logcat中的错误信息：

  1. 2020-07-25 11:58:56.040 11494-11620/com.example.dotchat E/ActivityThread: Failed to find provider info for cn.teddymobile.free.anteater.den.provider
  2. 2020-07-25 11:58:56.903 11494-11569/com.example.dotchat E/Parcel: Reading a NULL string not supported here.
  3. 2020-07-25 11:58:57.356 11494-11494/com.example.dotchat E/Parcel: Reading a NULL string not supported here.
  4. 2020-07-25 11:58:58.761 11494-11494/com.example.dotchat E/AndroidRuntime: FATAL EXCEPTION: main
  5.     Process: com.example.dotchat, PID: 11494
  6.     java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.dotchat/com.example.dotchat.LoginActivity}: java.lang.ClassCastException: android.widget.Toolbar cannot be cast to androidx.appcompat.widget.Toolbar
  7.         at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2955)
  8.         at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3033)
  9.         ...
  10.     Caused by: java.lang.ClassCastException: android.widget.Toolbar cannot be cast to androidx.appcompat.widget.Toolbar
  11.         at com.example.dotchat.LoginActivity.onCreate(LoginActivity.java:35)
  12.         ...

这是您的 LoginActivity.java 文件：

  1. ...
  2. import androidx.appcompat.widget.Toolbar;
  3. ...
  5. public class LoginActivity extends AppCompatActivity {
  6.     ...
  7.     @Override
  8.     protected void onCreate(Bundle savedInstanceState) {
  9.         super.onCreate(savedInstanceState);
  10.         setContentView(R.layout.activity_login);
  12.         Toolbar toolbar = findViewById(R.id.toolbar);
  13.         setSupportActionBar(toolbar);
  14.         ...
  15.     }
  16.     ...
  17. }

根据错误信息，问题似乎出在 LoginActivity.java 文件中的 onCreate 方法中。错误发生在以下行：

  1. Toolbar toolbar = findViewById(R.id.toolbar);
  2. setSupportActionBar(toolbar);

错误消息指出 android.widget.Toolbar 无法转换为 androidx.appcompat.widget.Toolbar。这可能是因为您在布局文件 bar_layout.xml 中定义的 Toolbar 使用了错误的导入。您应该在布局文件的根元素中使用正确的 Toolbar 类导入：

  1. <androidx.appcompat.widget.Toolbar
  2.     xmlns:android="http://schemas.android.com/apk/res/android"
  3.     xmlns:app="http://schemas.android.com/apk/res-auto"
  4.     android:id="@+id/toolbar"
  5.     android:layout_width="match_parent"
  6.     android:layout_height="wrap_content"
  7.     android:background="#79D0D1D0"
  8.     android:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar"
  9.     app:popupTheme="@style/MenuStyle">
  10. </androidx.appcompat.widget.Toolbar>

确保在布局文件 activity_login.xml 和 activity_register.xml 中，以及在 activity_main.xml 中正确使用了 androidx.appcompat.widget.Toolbar。

同时，确保您的项目的 Gradle 配置文件中使用了适当的依赖，以确保使用的库版本是兼容的。

英文:

Applicaton crashes when click on the button and is the any problem in thne gradle file based on the logcat error.

Following is the logcat error

  1. 2020-07-25 11:58:56.040 11494-11620/com.example.dotchat E/ActivityThread: Failed to find provider info for cn.teddymobile.free.anteater.den.provider
  2. 2020-07-25 11:58:56.903 11494-11569/com.example.dotchat E/Parcel: Reading a NULL string not supported here.
  3. 2020-07-25 11:58:57.356 11494-11494/com.example.dotchat E/Parcel: Reading a NULL string not supported here.
  4. 2020-07-25 11:58:58.761 11494-11494/com.example.dotchat E/AndroidRuntime: FATAL EXCEPTION: main
  5.     Process: com.example.dotchat, PID: 11494
  6.     java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.dotchat/com.example.dotchat.LoginActivity}: java.lang.ClassCastException: android.widget.Toolbar cannot be cast to androidx.appcompat.widget.Toolbar
  7.         at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2955)
  8.         at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3033)
  9.         at android.app.ActivityThread.-wrap11(Unknown Source:0)
  10.         at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1747)
  11.         at android.os.Handler.dispatchMessage(Handler.java:106)
  12.         at android.os.Looper.loop(Looper.java:200)
  13.         at android.app.ActivityThread.main(ActivityThread.java:6971)
  14.         at java.lang.reflect.Method.invoke(Native Method)
  15.         at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:524)
  16.         at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:858)
  17.      Caused by: java.lang.ClassCastException: android.widget.Toolbar cannot be cast to androidx.appcompat.widget.Toolbar
  18.         at com.example.dotchat.LoginActivity.onCreate(LoginActivity.java:35)
  19.         at android.app.Activity.performCreate(Activity.java:7225)
  20.         at android.app.Activity.performCreate(Activity.java:7216)
  21.         at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1215)
  22.         at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2908)
  23.         at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3033)&#160;
  24.         at android.app.ActivityThread.-wrap11(Unknown Source:0)&#160;
  25.         at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1747)&#160;
  26.         at android.os.Handler.dispatchMessage(Handler.java:106)&#160;
  27.         at android.os.Looper.loop(Looper.java:200)&#160;
  28.         at android.app.ActivityThread.main(ActivityThread.java:6971)&#160;
  29.         at java.lang.reflect.Method.invoke(Native Method)&#160;
  30.         at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:524)&#160;
  31.         at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:858)&#160;

This is my Registeractivity.java file

  1. package com.example.dotchat;
  3. import android.content.Intent;
  4. import android.os.Bundle;
  5. import android.text.TextUtils;
  6. import android.view.View;
  7. import android.widget.Button;
  8. import android.widget.EditText;
  9. import android.widget.Toast;
  11. import androidx.annotation.NonNull;
  12. import androidx.appcompat.app.AppCompatActivity;
  13. import androidx.appcompat.widget.Toolbar;
  15. import com.google.android.gms.tasks.OnCompleteListener;
  16. import com.google.android.gms.tasks.Task;
  17. import com.google.firebase.auth.AuthResult;
  18. import com.google.firebase.auth.FirebaseAuth;
  19. import com.google.firebase.auth.FirebaseUser;
  20. import com.google.firebase.database.DatabaseReference;
  21. import com.google.firebase.database.FirebaseDatabase;
  23. import java.util.HashMap;
  24. import java.util.Objects;
  26. public class RegisterActivity extends AppCompatActivity {
  28.     EditText username, email, password;
  29.     Button btn_register;
  31.     FirebaseAuth auth;
  32.     DatabaseReference reference;
  34.     @Override
  35.     protected void onCreate(Bundle savedInstanceState) {
  36.         super.onCreate(savedInstanceState);
  37.         setContentView(R.layout.activity_register);
  39.        Toolbar toolbar=findViewById(R.id.toolbar);
  40.         setSupportActionBar(toolbar);
  41.         Objects.requireNonNull(getSupportActionBar()).setDisplayHomeAsUpEnabled(true);
  42.         
  45.         username=findViewById(R.id.username);
  46.         email=findViewById(R.id.email);
  47.         password=findViewById(R.id.password);
  48.         btn_register=findViewById(R.id.btn_register);
  50.         auth=FirebaseAuth.getInstance();
  52.         btn_register.setOnClickListener(new View.OnClickListener() {
  53.             @Override
  54.             public void onClick(View v) {
  55.                 String txt_username =username.getText().toString();
  56.                 String txt_email =email.getText().toString();
  57.                 String txt_password =password.getText().toString();
  59.                 if (TextUtils.isEmpty(txt_username) ||TextUtils.isEmpty(txt_email) ||TextUtils.isEmpty(txt_password)){
  60.                     Toast.makeText(RegisterActivity.this,&quot;All fields are required!&quot;,Toast.LENGTH_SHORT).show();
  61.                 } else if (txt_password.length()&lt;8){
  62.                     Toast.makeText(RegisterActivity.this,&quot;Password must be atleast 8 characters!&quot;,Toast.LENGTH_SHORT).show();
  63.                 } else {
  64.                     register(txt_username,txt_email,txt_password);
  65.                 }
  66.             }
  67.         });
  68.     }
  70.     private void register(final String username, String email, String password){
  72.         auth.createUserWithEmailAndPassword(email,password)
  73.                 .addOnCompleteListener(new OnCompleteListener&lt;AuthResult&gt;() {
  74.                     @Override
  75.                     public void onComplete(@NonNull Task&lt;AuthResult&gt; task) {
  76.                         if (task.isComplete()) {
  77.                             FirebaseUser firebaseUser = auth.getCurrentUser();
  78.                             assert firebaseUser != null;
  79.                             String userid = firebaseUser.getUid();
  81.                             reference = FirebaseDatabase.getInstance().getReference(&quot;Users&quot;).child(userid);
  83.                             HashMap&lt;String,String&gt; hashMap=new HashMap&lt;&gt;();
  84.                             hashMap.put(&quot;id&quot;,userid);
  85.                             hashMap.put(&quot;username&quot;,username);
  86.                             hashMap.put(&quot;imageURL&quot;,&quot;default&quot;);
  88.                             reference.setValue(hashMap).addOnCompleteListener(new OnCompleteListener&lt;Void&gt;() {
  89.                                 @Override
  90.                                 public void onComplete(@NonNull Task&lt;Void&gt; task) {
  91.                                     if (task.isSuccessful()){
  92.                                         Intent intent=new Intent(RegisterActivity.this,MainActivity.class);
  93.                                         intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TASK | Intent.FLAG_ACTIVITY_NEW_TASK);
  94.                                         startActivity(intent);
  95.                                         finish();
  96.                                     }
  98.                                 }
  99.                             });
  100.                         } else {
  101.                             Toast.makeText(RegisterActivity.this,&quot;Sorry! You can&#39;t register with this email or password&quot;,Toast.LENGTH_SHORT).show();
  102.                         }
  103.                     }
  104.                 });
  105.     }
  106. }

This is LoginActivity.java file

  1. package com.example.dotchat;
  3. import android.content.Intent;
  4. import android.os.Bundle;
  5. import android.text.TextUtils;
  6. import android.view.View;
  7. import android.widget.Button;
  8. import android.widget.EditText;
  9. import android.widget.Toast;
  11. import androidx.annotation.NonNull;
  12. import androidx.appcompat.app.AppCompatActivity;
  13. import androidx.appcompat.widget.Toolbar;
  14. import com.google.android.gms.tasks.OnCompleteListener;
  15. import com.google.android.gms.tasks.Task;
  16. import com.google.firebase.auth.AuthResult;
  17. import com.google.firebase.auth.FirebaseAuth;
  19. import java.util.Objects;
  21. //import android.widget.Toolbar
  23. public class LoginActivity extends AppCompatActivity {
  25.     EditText  email,password;
  26.     Button btn_login;
  28.     FirebaseAuth auth;
  30.     @Override protected void onCreate(Bundle savedInstanceState) {
  31.         super.onCreate(savedInstanceState);
  32.         setContentView(R.layout.activity_login);
  35.        Toolbar toolbar=findViewById(R.id.toolbar);
  36.         setSupportActionBar(toolbar);
  37.         Objects.requireNonNull(getSupportActionBar()).setDisplayHomeAsUpEnabled(true);
  39.         auth=FirebaseAuth.getInstance();
  41.         email=findViewById(R.id.email);
  42.         password=findViewById(R.id.password);
  43.         btn_login=findViewById(R.id.btn_login);
  45.         btn_login.setOnClickListener(new View.OnClickListener() {
  46.             @Override
  47.             public void onClick(View v) {
  48.                 String txt_email=email.getText().toString();
  49.                 String txt_password=password.getText().toString();
  51.                 if(TextUtils.isEmpty(txt_email) || TextUtils.isEmpty(txt_password)){
  52.                     Toast.makeText(LoginActivity.this,&quot;All fields are required&quot;,Toast.LENGTH_SHORT).show();
  53.                 } else {
  54.                     auth.signInWithEmailAndPassword(txt_email,txt_password)
  55.                             .addOnCompleteListener(new OnCompleteListener&lt;AuthResult&gt;() {
  56.                                 @Override
  57.                                 public void onComplete(@NonNull Task&lt;AuthResult&gt; task) {
  58.                                     if (task.isSuccessful()){
  59.                                         Intent intent=new Intent(LoginActivity.this,MainActivity.class);
  60.                                         intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TASK | Intent.FLAG_ACTIVITY_NEW_TASK);
  61.                                         startActivity(intent);
  62.                                         finish();
  63.                                     } else {
  64.                                         Toast.makeText(LoginActivity.this,&quot;Authentication failed&quot;,Toast.LENGTH_SHORT).show();
  65.                                     }
  67.                                 }
  68.                             });
  69.                 }
  70.             }
  71.         });
  73.     }
  74. }

This is bar_layout.xml file

  1. &lt;?xml version=&quot;1.0&quot; encoding=&quot;utf-8&quot;?&gt;
  2. &lt;androidx.appcompat.widget.Toolbar xmlns:android=&quot;http://schemas.android.com/apk/res/android&quot;
  3.     android:layout_width=&quot;match_parent&quot;
  4.     android:layout_height=&quot;wrap_content&quot;
  5.     xmlns:app=&quot;http://schemas.android.com/apk/res-auto&quot;
  6.     android:id=&quot;@+id/toolbar&quot;
  7.     android:background=&quot;#79D0D1D0&quot;
  8.     android:theme=&quot;@style/ThemeOverlay.AppCompat.Dark.ActionBar&quot;
  9.     app:popupTheme=&quot;@style/MenuStyle&quot;&gt;
  11. &lt;/androidx.appcompat.widget.Toolbar&gt;

This is gradle file

  1. apply plugin: &#39;com.android.application&#39;
  2. apply plugin: &#39;com.google.gms.google-services&#39;
  4. android {
  5.     compileSdkVersion 29
  6.     buildToolsVersion &quot;29.0.3&quot;
  8.     defaultConfig {
  9.         applicationId &quot;com.example.dotchat&quot;
  10.         minSdkVersion 21
  11.         targetSdkVersion 29
  12.         versionCode 1
  13.         versionName &quot;1.0&quot;
  15.         testInstrumentationRunner &quot;androidx.test.runner.AndroidJUnitRunner&quot;
  16.     }
  18.     buildTypes {
  19.         release {
  20.             minifyEnabled false
  21.             proguardFiles getDefaultProguardFile(&#39;proguard-android-optimize.txt&#39;), &#39;proguard-rules.pro&#39;
  22.         }
  23.     }
  24. }
  26. dependencies {
  27.     implementation fileTree(dir: &quot;libs&quot;, include: [&quot;*.jar&quot;])
  28.     implementation &#39;androidx.appcompat:appcompat:1.1.0&#39;
  29.     implementation &#39;androidx.constraintlayout:constraintlayout:1.1.3&#39;
  30.     implementation &#39;androidx.legacy:legacy-support-v4:1.0.0&#39;
  31.     implementation &#39;com.google.android.material:material:1.1.0&#39;
  32.     implementation &#39;com.google.firebase:firebase-auth:19.3.2&#39;
  33.     implementation &#39;com.google.firebase:firebase-database:19.3.1&#39;
  34.     implementation &#39;com.google.firebase:firebase-core:17.4.4&#39;
  35.     implementation &#39;androidx.cardview:cardview:1.0.0&#39;
  36.     implementation &#39;de.hdodenhof:circleimageview:2.2.0&#39;
  37.     implementation &#39;com.github.bumptech.glide:glide:4.11.0&#39;
  38.     implementation &#39;com.rengwuxian.materialedittext:library:2.1.4&#39;
  39.     testImplementation &#39;junit:junit:4.13&#39;
  40.     androidTestImplementation &#39;androidx.test.ext:junit:1.1.1&#39;
  41.     androidTestImplementation &#39;androidx.test.espresso:espresso-core:3.2.0&#39;
  43. }

This is the activity_login.xml file

  1. &lt;?xml version=&quot;1.0&quot; encoding=&quot;utf-8&quot;?&gt;
  2. &lt;RelativeLayout xmlns:android=&quot;http://schemas.android.com/apk/res/android&quot;
  3.     xmlns:app=&quot;http://schemas.android.com/apk/res-auto&quot;
  4.     xmlns:tools=&quot;http://schemas.android.com/tools&quot;
  5.     android:orientation=&quot;vertical&quot;
  6.     android:background=&quot;@drawable/appbackground&quot;
  7.     android:layout_width=&quot;match_parent&quot;
  8.     android:layout_height=&quot;match_parent&quot;
  9.     tools:context=&quot;.LoginActivity&quot;&gt;
  12.     &lt;ImageView
  13.         android:layout_width=&quot;145dp&quot;
  14.         android:layout_height=&quot;131dp&quot;
  15.         android:layout_gravity=&quot;center&quot;
  16.         android:layout_marginLeft=&quot;130dp&quot;
  17.         android:layout_marginTop=&quot;50dp&quot;
  18.         android:src=&quot;@drawable/logotblack1&quot; /&gt;
  20.     &lt;TextView
  21.         android:layout_width=&quot;wrap_content&quot;
  22.         android:layout_height=&quot;wrap_content&quot;
  23.         android:paddingBottom=&quot;35dp&quot;
  24.         android:layout_marginLeft=&quot;275dp&quot;
  25.         android:layout_marginTop=&quot;133dp&quot;
  26.         android:text=&quot;C h a t&quot;
  27.         android:textSize=&quot;20dp&quot;
  28.         android:textColor=&quot;#000&quot; /&gt;
  30.     &lt;include
  31.         android:id=&quot;@+id/toolbar&quot;
  32.         layout=&quot;@layout/bar_layout&quot;
  33.         android:layout_width=&quot;match_parent&quot;
  34.         android:layout_height=&quot;37dp&quot; /&gt;
  36.     &lt;LinearLayout
  37.         android:layout_width=&quot;match_parent&quot;
  38.         android:layout_height=&quot;wrap_content&quot;
  39.         android:layout_below=&quot;@id/toolbar&quot;
  40.         android:layout_marginTop=&quot;224dp&quot;
  41.         android:gravity=&quot;center_horizontal&quot;
  42.         android:orientation=&quot;vertical&quot;
  43.         android:padding=&quot;16dp&quot;&gt;
  45.         &lt;TextView
  46.             android:layout_width=&quot;wrap_content&quot;
  47.             android:layout_height=&quot;wrap_content&quot;
  48.             android:paddingBottom=&quot;35dp&quot;
  49.             android:text=&quot;Login into your Account&quot;
  50.             android:textColor=&quot;#000&quot;
  51.             android:textSize=&quot;20dp&quot;
  52.             /&gt;
  54.         &lt;EditText
  55.             android:id=&quot;@+id/email&quot;
  56.             android:layout_width=&quot;378dp&quot;
  57.             android:layout_height=&quot;50dp&quot;
  58.             android:layout_marginTop=&quot;10dp&quot;
  59.             android:background=&quot;@drawable/edit_round&quot;
  60.             android:drawableRight=&quot;@drawable/gmail&quot;
  61.             android:hint=&quot;                                       Email&quot;
  62.             android:textColorHint=&quot;#fff&quot;
  63.             android:inputType=&quot;textEmailAddress&quot; /&gt;
  65.         &lt;EditText
  66.             android:id=&quot;@+id/password&quot;
  67.             android:layout_width=&quot;378dp&quot;
  68.             android:layout_height=&quot;50dp&quot;
  69.             android:layout_marginTop=&quot;10dp&quot;
  70.             android:background=&quot;@drawable/edit_round&quot;
  71.             android:drawableRight=&quot;@drawable/psw&quot;
  72.             android:ems=&quot;10&quot;
  73.             android:hint=&quot;                                    Password&quot;
  74.             android:textColorHint=&quot;#fff&quot;
  75.             android:inputType=&quot;textPassword&quot; /&gt;
  77.         &lt;Button
  78.             android:id=&quot;@+id/btn_login&quot;
  79.             android:layout_width=&quot;125dp&quot;
  80.             android:layout_height=&quot;wrap_content&quot;
  81.             android:layout_marginTop=&quot;25dp&quot;
  82.             android:background=&quot;@drawable/button_roundl&quot;
  83.             android:text=&quot;Login&quot;
  84.             android:textColor=&quot;#000&quot; /&gt;
  86.     &lt;/LinearLayout&gt;
  88. &lt;/RelativeLayout&gt;

This is activity_main.xml file

  1. &lt;?xml version=&quot;1.0&quot; encoding=&quot;utf-8&quot;?&gt;
  2. &lt;LinearLayout xmlns:android=&quot;http://schemas.android.com/apk/res/android&quot;
  3.     xmlns:app=&quot;http://schemas.android.com/apk/res-auto&quot;
  4.     xmlns:tools=&quot;http://schemas.android.com/tools&quot;
  5.     android:layout_width=&quot;match_parent&quot;
  6.     android:layout_height=&quot;wrap_content&quot;
  7.     android:orientation=&quot;vertical&quot;
  8.     tools:context=&quot;.MainActivity&quot;&gt;
  10.     &lt;com.google.android.material.appbar.AppBarLayout
  11.         android:layout_width=&quot;match_parent&quot;
  12.         android:layout_height=&quot;wrap_content&quot;&gt;
  14.         &lt;androidx.appcompat.widget.Toolbar
  15.             android:id=&quot;@+id/toolbar&quot;
  16.             android:layout_width=&quot;match_parent&quot;
  17.             android:layout_height=&quot;wrap_content&quot;
  18.             android:background=&quot;#fff&quot;
  19.             android:theme=&quot;@style/Base.ThemeOverlay.AppCompat.Dark.ActionBar&quot;
  20.             app:popupTheme=&quot;@style/MenuStyle&quot;&gt;
  22.             &lt;de.hdodenhof.circleimageview.CircleImageView
  23.                 android:layout_width=&quot;30dp&quot;
  24.                 android:layout_height=&quot;30dp&quot;
  25.                 android:id=&quot;@+id/profile_image&quot;
  26.                 /&gt;
  27.             &lt;TextView
  28.                 android:layout_width=&quot;wrap_content&quot;
  29.                 android:layout_height=&quot;wrap_content&quot;
  30.                 android:layout_marginLeft=&quot;20dp&quot;
  31.                 android:text=&quot;Username&quot;
  32.                 android:textColor=&quot;#000&quot;
  33.                 android:textStyle=&quot;bold&quot;
  34.                 android:layout_marginStart=&quot;25dp&quot;/&gt;
  36.         &lt;/androidx.appcompat.widget.Toolbar&gt;
  37.     &lt;/com.google.android.material.appbar.AppBarLayout&gt;
  39. &lt;/LinearLayout&gt;

This is activity_register.xml file

  1. &lt;?xml version=&quot;1.0&quot; encoding=&quot;utf-8&quot;?&gt;
  2. &lt;RelativeLayout xmlns:android=&quot;http://schemas.android.com/apk/res/android&quot;
  3.     xmlns:app=&quot;http://schemas.android.com/apk/res-auto&quot;
  4.     xmlns:tools=&quot;http://schemas.android.com/tools&quot;
  5.     android:orientation=&quot;vertical&quot;
  6.     android:background=&quot;@drawable/appbackground&quot;
  7.     android:layout_width=&quot;match_parent&quot;
  8.     android:layout_height=&quot;match_parent&quot;
  9.     tools:context=&quot;.RegisterActivity&quot;&gt;
  12.     &lt;ImageView
  13.         android:layout_width=&quot;115dp&quot;
  14.         android:layout_height=&quot;110dp&quot;
  15.         android:layout_gravity=&quot;center&quot;
  16.         android:layout_marginLeft=&quot;90dp&quot;
  17.         android:layout_marginTop=&quot;100dp&quot;
  18.         android:src=&quot;@drawable/logotblack1&quot; /&gt;
  20.     &lt;TextView
  21.         android:layout_width=&quot;wrap_content&quot;
  22.         android:layout_height=&quot;wrap_content&quot;
  23.         android:layout_marginLeft=&quot;200dp&quot;
  24.         android:layout_marginTop=&quot;153dp&quot;
  25.         android:paddingBottom=&quot;35dp&quot;
  26.         android:text=&quot;C h a t&quot;
  27.         android:textColor=&quot;#000&quot;
  28.         android:textSize=&quot;30dp&quot; /&gt;
  30.     &lt;include
  31.         android:id=&quot;@+id/toolbar&quot;
  32.         layout=&quot;@layout/bar_layout&quot;
  33.         android:layout_width=&quot;match_parent&quot;
  34.         android:layout_height=&quot;37dp&quot; /&gt;
  36.     &lt;LinearLayout
  37.         android:layout_width=&quot;match_parent&quot;
  38.         android:layout_height=&quot;wrap_content&quot;
  39.         android:layout_below=&quot;@id/toolbar&quot;
  40.         android:layout_marginTop=&quot;278dp&quot;
  41.         android:gravity=&quot;center_horizontal&quot;
  42.         android:orientation=&quot;vertical&quot;
  43.         android:padding=&quot;16dp&quot;&gt;
  45.         &lt;TextView
  46.             android:layout_width=&quot;wrap_content&quot;
  47.             android:layout_height=&quot;wrap_content&quot;
  48.             android:paddingBottom=&quot;35dp&quot;
  49.             android:text=&quot;Create a New Account&quot;
  50.             android:textColor=&quot;#000&quot;
  51.             android:textSize=&quot;25dp&quot;
  52.             android:textStyle=&quot;bold&quot; /&gt;
  54.         &lt;EditText
  56.             android:id=&quot;@+id/username&quot;
  57.             android:layout_width=&quot;279dp&quot;
  58.             android:layout_height=&quot;50dp&quot;
  59.             android:layout_marginTop=&quot;10dp&quot;
  60.             android:background=&quot;@drawable/edit_round&quot;
  61.             android:drawableRight=&quot;@drawable/usericon&quot;
  62.             android:hint=&quot;                      Username&quot;
  63.             android:textColorHint=&quot;#fff&quot;/&gt;
  65.         &lt;EditText
  66.             android:id=&quot;@+id/email&quot;
  67.             android:layout_width=&quot;278dp&quot;
  68.             android:layout_height=&quot;50dp&quot;
  69.             android:layout_marginTop=&quot;10dp&quot;
  70.             android:background=&quot;@drawable/edit_round&quot;
  71.             android:drawableRight=&quot;@drawable/gmail&quot;
  72.             android:hint=&quot;                          Email&quot;
  73.             android:inputType=&quot;textEmailAddress&quot;
  74.             android:textColorHint=&quot;#fff&quot;/&gt;
  76.         &lt;EditText
  77.             android:id=&quot;@+id/password&quot;
  78.             android:layout_width=&quot;278dp&quot;
  79.             android:layout_height=&quot;50dp&quot;
  80.             android:layout_marginTop=&quot;10dp&quot;
  81.             android:background=&quot;@drawable/edit_round&quot;
  82.             android:drawableRight=&quot;@drawable/psw&quot;
  83.             android:ems=&quot;10&quot;
  84.             android:hint=&quot;                       Password&quot;
  85.             android:inputType=&quot;textPassword&quot;
  86.             android:textColorHint=&quot;#fff&quot;/&gt;
  88.         &lt;Button
  89.             android:layout_width=&quot;176dp&quot;
  90.             android:layout_height=&quot;wrap_content&quot;
  91.             android:id=&quot;@+id/btn_register&quot;
  92.             android:layout_marginTop=&quot;25dp&quot;
  93.             android:background=&quot;@drawable/button_round&quot;
  94.             android:text=&quot;register now&quot;
  95.             android:textColor=&quot;#000&quot; /&gt;
  97.     &lt;/LinearLayout&gt;
  99. &lt;/RelativeLayout&gt;

This is activity_start.xml file

  1. &lt;?xml version=&quot;1.0&quot; encoding=&quot;utf-8&quot;?&gt;
  2. &lt;RelativeLayout xmlns:android=&quot;http://schemas.android.com/apk/res/android&quot;
  3.     xmlns:app=&quot;http://schemas.android.com/apk/res-auto&quot;
  4.     xmlns:tools=&quot;http://schemas.android.com/tools&quot;
  5.     android:layout_width=&quot;match_parent&quot;
  6.     android:layout_height=&quot;match_parent&quot;
  7.     android:background=&quot;@drawable/appbackground&quot;
  8.     tools:context=&quot;.StartActivity&quot;&gt;
  9.     &lt;ImageView
  10.         android:layout_width=&quot;131dp&quot;
  11.         android:layout_height=&quot;110dp&quot;
  12.         android:layout_marginLeft=&quot;75dp&quot;
  13.         android:layout_marginTop=&quot;295dp&quot;
  14.         android:src=&quot;@drawable/logotblack1&quot; /&gt;
  16.     &lt;ImageView
  17.         android:layout_width=&quot;181dp&quot;
  18.         android:layout_height=&quot;147dp&quot;
  19.         android:layout_marginLeft=&quot;200dp&quot;
  20.         android:layout_marginRight=&quot;75dp&quot;
  21.         android:layout_marginTop=&quot;299dp&quot;
  22.         android:src=&quot;@drawable/chatblack&quot; /&gt;
  27.         &lt;Button
  28.             android:id=&quot;@+id/login&quot;
  29.             android:layout_width=&quot;125dp&quot;
  30.             android:layout_height=&quot;wrap_content&quot;
  31.             android:layout_marginTop=&quot;650dp&quot;
  32.             android:layout_marginLeft=&quot;20dp&quot;
  33.             android:background=&quot;@drawable/llogin&quot;
  34.             android:text=&quot;Login&quot;
  35.             android:textColor=&quot;#000&quot; /&gt;
  37.         &lt;Button
  38.             android:id=&quot;@+id/register&quot;
  39.             android:layout_width=&quot;176dp&quot;
  40.             android:layout_height=&quot;wrap_content&quot;
  41.             android:layout_marginTop=&quot;650dp&quot;
  42.             android:layout_marginLeft=&quot;193dp&quot;
  43.             android:background=&quot;@drawable/llogin&quot;
  44.             android:text=&quot;register now&quot;
  45.             android:textColor=&quot;#000&quot; /&gt;
  47. &lt;/RelativeLayout&gt;

答案1

得分: 2

在您的 XML 文件中定义了错误的 Toolbar 类。请将其从以下内容进行更改：

从
&lt;Toolbar .../&gt;

改为

&lt;androidx.appcompat.widget.Toolbar .../&gt;

在您的 XML 中，您可能仅使用了&lt;Toolbar&gt;&lt;/Toolbar&gt;来声明工具栏，在这种情况下，工具栏将从android.widget包中创建。因此，如果您尝试通过将其强制转换为androidx.appcompat.widget.Toolbar并调用findViewById，肯定会抛出RuntimeException。

如果您正在使用应该使用的 AndroidX，那么您必须将工具栏的 XML 声明更改为&lt;androidx.appcompat.widget.Toolbar&gt;&lt;/androidx.appcompat.widget.Toolbar&gt;。

然后，您可以继续调用（androidx.appcompat.widget.Toolbar）的findViewById(..)，这应该会成功。

英文:

Wrong Toolbar class defined in your xml file. Change it from

&lt;Toolbar .../&gt;

to

&lt;androidx.appcompat.widget.Toolbar .../&gt;

In your XML, you probably declared your toolbar using just <Toolbar></Toolbar> in that case, the toolbar will be created from the package android.widget. So if you try to call findViewById by casting it to androidx.appcompat.widget.Toolbar it will surely throw you a RuntimeException.

If you are using AndroidX, which you should, then you have to change the xml declaration of your toolbar to <androidx.appcompat.widget.Toolbar></androidx.appcompat.widget.Toolbar>

You can then proceed to call your (androidx.appcompat.widget.Toolbar) findViewByid(..) which should succeed

答案2

得分: 0

在bar_layout文件中，我认为您放入了在Android中未定义的错误弹出菜单样式。

为此，您需要在样式文件夹中创建一个名为"MenuStyle"的属性，然后您的代码将可以正常运行。

  1. <style name="MenuStyle" parent="ThemeOverlay.AppCompat.Dark.ActionBar">
  2.     <!-- 在这里编写您的属性 -->
  3. </style>

或者，您可以选择使用Android中预定义的其他样式属性。

希望对您有所帮助 : )。

英文:

In the bar_layout file, I think you have put the wrong popup menu style that is not defined in android.

For this, you have to create a MenuStyle attribute in style folder, then you code run perfectly.

  1. &lt;style name=&quot;MenuStyle&quot; parent=&quot;ThemeOverlay.AppCompat.Dark.ActionBar&quot;&gt;
  2.     &lt;!--  Write your attributes here --&gt;
  3. &lt;/style&gt;

or you can prefer other style attributes that are pre-defined in android.

Hope it helps ).

答案3

得分: 0

刚刚遇到了相同的问题。
除了按照Moaz Ragab的回答进行操作外，我还建议检查AndroidManifest.xml文件，确保对应的活动（在您的情况下是LoginActivity）具有android:theme="style/AppTheme.NoActionBar"。

例如：

  1. <?xml version="1.0" encoding="utf-8"?>
  2. <manifest xmlns:android="http://schemas.android.com/apk/res/android"
  3.     package="com.example.dotchat">
  4.     <application>
  5.         <activity
  6.             android:name=".LoginActivity"
  7.             android:label="@string/activity_login"
  8.             android:theme="@style/AppTheme.NoActionBar" />
  9.     </application>
  10. </manifest>
英文:

Just came across the same issue.
Besides following Moaz Ragab answer, I'd also suggest to check AndroidManifest.xml file and make sure you have android:theme="@style/AppTheme.NoActionBar" for the corresponding activity, which, in your case, is LoginActivity.

For example:

  1. &lt;?xml version=&quot;1.0&quot; encoding=&quot;utf-8&quot;?&gt;
  2. &lt;manifest xmlns:android=&quot;http://schemas.android.com/apk/res/android&quot;
  3.     package=&quot;com.example.dotchat&quot;&gt;
  4.     &lt;application&gt;
  5.         &lt;activity
  6.             android:name=&quot;.LoginActivity&quot;
  7.             android:label=&quot;@string/activity_login&quot;
  8.             android:theme=&quot;@style/AppTheme.NoActionBar&quot; /&gt;
  9.     &lt;/application&gt;
  10. &lt;/manifest&gt;

huangapple
  • 本文由 发表于 2020年7月25日 14:50:30
  • 转载请务必保留本文链接：https://java.coder-hub.com/63085289.html
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