不明白为什么我的应用程序崩溃

Question

嘿所以我是Android新手，我目前正在创建一个应用程序。到目前为止，我想要做的就是链接我主要活动中的按钮以打开登录活动页面。当我在手机上启动应用程序时，它会运行下面的错误。任何人有任何建议？提前致谢！

11-05 23:24:44.879 14967-14967/com.example.damien.paysafe1_0_a E/AndroidRuntime: FATAL EXCEPTION: main 
11-05 23:24:44.879 14967-14967/com.example.damien.paysafe1_0_a E/AndroidRuntime: Process: com.example.damien.paysafe1_0_a, PID: 14967 
11-05 23:24:44.879 14967-14967/com.example.damien.paysafe1_0_a E/AndroidRuntime: java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.damien.paysafe1_0_a/com.example.damien.paysafe1_0_a.MainActivity}: java.lang.ClassCastException: com.example.damien.paysafe1_0_a.MainActivity cannot be cast to android.view.View$OnClickListener 
11-05 23:24:44.879 14967-14967/com.example.damien.paysafe1_0_a E/AndroidRuntime:  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3119) 
11-05 23:24:44.879 14967-14967/com.example.damien.paysafe1_0_a E/AndroidRuntime:  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3218) 
11-05 23:24:44.879 14967-14967/com.example.damien.paysafe1_0_a E/AndroidRuntime:  at android.app.ActivityThread.access$1000(ActivityThread.java:198) 
11-05 23:24:44.879 14967-14967/com.example.damien.paysafe1_0_a E/AndroidRuntime:  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1676) 
11-05 23:24:44.879 14967-14967/com.example.damien.paysafe1_0_a E/AndroidRuntime:  at android.os.Handler.dispatchMessage(Handler.java:102) 
11-05 23:24:44.879 14967-14967/com.example.damien.paysafe1_0_a E/AndroidRuntime:  at android.os.Looper.loop(Looper.java:145) 
11-05 23:24:44.879 14967-14967/com.example.damien.paysafe1_0_a E/AndroidRuntime:  at android.app.ActivityThread.main(ActivityThread.java:6837) 
11-05 23:24:44.879 14967-14967/com.example.damien.paysafe1_0_a E/AndroidRuntime:  at java.lang.reflect.Method.invoke(Native Method) 
11-05 23:24:44.879 14967-14967/com.example.damien.paysafe1_0_a E/AndroidRuntime:  at java.lang.reflect.Method.invoke(Method.java:372) 
11-05 23:24:44.879 14967-14967/com.example.damien.paysafe1_0_a E/AndroidRuntime:  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1404) 
11-05 23:24:44.879 14967-14967/com.example.damien.paysafe1_0_a E/AndroidRuntime:  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1199) 
11-05 23:24:44.879 14967-14967/com.example.damien.paysafe1_0_a E/AndroidRuntime: Caused by: java.lang.ClassCastException: com.example.damien.paysafe1_0_a.MainActivity cannot be cast to android.view.View$OnClickListener 
11-05 23:24:44.879 14967-14967/com.example.damien.paysafe1_0_a E/AndroidRuntime:  at com.example.damien.paysafe1_0_a.MainActivity.onCreate(MainActivity.java:20) 
11-05 23:24:44.879 14967-14967/com.example.damien.paysafe1_0_a E/AndroidRuntime:  at android.app.Activity.performCreate(Activity.java:6500) 
11-05 23:24:44.879 14967-14967/com.example.damien.paysafe1_0_a E/AndroidRuntime:  at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1120) 
11-05 23:24:44.879 14967-14967/com.example.damien.paysafe1_0_a E/AndroidRuntime:  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3072) 
11-05 23:24:44.879 14967-14967/com.example.damien.paysafe1_0_a E/AndroidRuntime:  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3218)  
11-05 23:24:44.879 14967-14967/com.example.damien.paysafe1_0_a E/AndroidRuntime:  at android.app.ActivityThread.access$1000(ActivityThread.java:198)  
11-05 23:24:44.879 14967-14967/com.example.damien.paysafe1_0_a E/AndroidRuntime:  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1676)  
11-05 23:24:44.879 14967-14967/com.example.damien.paysafe1_0_a E/AndroidRuntime:  at android.os.Handler.dispatchMessage(Handler.java:102)  
11-05 23:24:44.879 14967-14967/com.example.damien.paysafe1_0_a E/AndroidRuntime:  at android.os.Looper.loop(Looper.java:145)  
11-05 23:24:44.879 14967-14967/com.example.damien.paysafe1_0_a E/AndroidRuntime:  at android.app.ActivityThread.main(ActivityThread.java:6837)  
11-05 23:24:44.879 14967-14967/com.example.damien.paysafe1_0_a E/AndroidRuntime:  at java.lang.reflect.Method.invoke(Native Method)  
11-05 23:24:44.879 14967-14967/com.example.damien.paysafe1_0_a E/AndroidRuntime:  at java.lang.reflect.Method.invoke(Method.java:372)  
11-05 23:24:44.879 14967-14967/com.example.damien.paysafe1_0_a E/AndroidRuntime:  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1404)  
11-05 23:24:44.879 14967-14967/com.example.damien.paysafe1_0_a E/AndroidRuntime:  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1199)  

这里是我的activity_main.xml中

<?xml version="1.0" encoding="utf-8"?> 
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" 
    xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent" 
    android:layout_height="match_parent" 
    tools:context="com.example.damien.paysafe1_0_a.MainActivity" 
    android:orientation="vertical" 
    android:weightSum="1"> 

    <ImageView 
     android:layout_width="wrap_content" 
     android:layout_height="wrap_content" 
     android:layout_marginTop="100dp" 
     android:src="@drawable/paysafe_logo" 
     android:layout_gravity="center_horizontal" /> 

    <Button android:id="@+id/new_user_button" 
     android:layout_width="152dp" 
     android:layout_height="wrap_content" 
     android:layout_marginTop="200dp" 
     android:text="@string/new_user" 
     android:textStyle="bold" 
     android:layout_gravity="center_horizontal" 
     android:backgroundTint="#b5baf6" 
     android:layout_weight="0.08" 
     android:textSize="24sp" 
     android:typeface="normal" /> 

    <LinearLayout 
     android:orientation="vertical" 
     android:layout_width="match_parent" 
     android:layout_height="wrap_content" 
     android:layout_weight="0.85" 
     android:weightSum="1"> 

    </LinearLayout> 

    <TextView 
     android:layout_width="wrap_content" 
     android:layout_height="wrap_content" 
     android:textAppearance="?android:attr/textAppearanceSmall" 
     android:text="@string/copyright" 
     android:id="@+id/textView" 
     android:password="false" 
     android:layout_gravity="center_horizontal" /> 


    <!--Go to register page when pressed--> 

</LinearLayout> 

这里的activity_login.xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" 
    xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent" 
    android:layout_height="match_parent" android:gravity="center_horizontal" 
    android:orientation="vertical" android:paddingBottom="@dimen/activity_vertical_margin" 
    android:paddingLeft="@dimen/activity_horizontal_margin" 
    android:paddingRight="@dimen/activity_horizontal_margin" 
    android:paddingTop="@dimen/activity_vertical_margin" tools:context=".LoginActivity"> 

    <!-- Login progress --> 
    <ProgressBar android:id="@+id/login_progress" style="?android:attr/progressBarStyleLarge" 
     android:layout_width="wrap_content" android:layout_height="wrap_content" 
     android:layout_marginBottom="8dp" android:visibility="gone" /> 

    <ScrollView android:id="@+id/login_form" android:layout_width="match_parent" 
     android:layout_height="match_parent"> 

     <LinearLayout android:id="@+id/email_login_form" android:layout_width="match_parent" 
      android:layout_height="wrap_content" android:orientation="vertical"> 

      <android.support.design.widget.TextInputLayout android:layout_width="match_parent" 
       android:layout_height="wrap_content"> 

       <AutoCompleteTextView android:id="@+id/email" android:layout_width="match_parent" 
        android:layout_height="wrap_content" android:hint="@string/prompt_email" 
        android:inputType="textEmailAddress" android:maxLines="1" 
        android:singleLine="true" /> 

      </android.support.design.widget.TextInputLayout> 

      <android.support.design.widget.TextInputLayout android:layout_width="match_parent" 
       android:layout_height="wrap_content"> 

       <EditText android:id="@+id/password" android:layout_width="match_parent" 
        android:layout_height="wrap_content" android:hint="@string/prompt_password" 
        android:imeActionId="@+id/login" 
        android:imeActionLabel="@string/action_sign_in_short" 
        android:imeOptions="actionUnspecified" android:inputType="textPassword" 
        android:maxLines="1" android:singleLine="true" /> 

      </android.support.design.widget.TextInputLayout> 

      <Button android:id="@+id/email_sign_in_button" style="?android:textAppearanceSmall" 
       android:layout_width="match_parent" android:layout_height="wrap_content" 
       android:layout_marginTop="16dp" android:text="@string/action_sign_in" 
       android:textStyle="bold" /> 

     </LinearLayout> 
    </ScrollView> 
</LinearLayout> 

这里是我的Android清单，以防万一：

<?xml version="1.0" encoding="utf-8"?> 
<manifest xmlns:android="http://schemas.android.com/apk/res/android" 
    package="com.example.damien.paysafe1_0_a" > 

    <!-- To auto-complete the email text field in the login form with the user's emails --> 
    <uses-permission android:name="android.permission.GET_ACCOUNTS" /> 
    <uses-permission android:name="android.permission.READ_PROFILE" /> 
    <uses-permission android:name="android.permission.READ_CONTACTS" /> 

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

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


</manifest> 

编辑：代码主要活动：

package com.example.damien.paysafe1_0_a; 

import android.content.Intent; 
import android.support.v7.app.AppCompatActivity; 
import android.os.Bundle; 
import android.util.Log; 
import android.view.Menu; 
import android.view.View; 
import android.widget.Button; 
import android.view.View.OnClickListener; 

public class MainActivity extends AppCompatActivity { 

    @Override 
    protected void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     setContentView(R.layout.activity_main); 

     Button new_user_button = (Button) findViewById(R.id.new_user_button); 
     new_user_button.setOnClickListener((OnClickListener) this); 
    } 

    public void onClick(View v) { 
     Log.i("clicks", "You Clicked New User"); 
     Intent i=new Intent(MainActivity.this, LoginActivity.class); 
     startActivity(i); 
    } 

} 

Answer 1

您必须在您的活动上实施onClickListener。即

public class MainActivity extends AppCompatActivity implements View.OnClickListener{ 

@Override 
protected void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.activity_main); 

    Button new_user_button = (Button) findViewById(R.id.new_user_button); 
    new_user_button.setOnClickListener(this); 
} 

@Override 
public void onClick(View v) { 
    Log.i("clicks", "You Clicked New User"); 
    Intent i=new Intent(MainActivity.this, LoginActivity.class); 
    startActivity(i); 
} 

} 

Answer 2

，您可以尝试：

new_user_button.setOnClickListener(new View.OnClickListener() { 
     @Override 
     public void onClick(View v) { 

      Log.i("clicks", "You Clicked New User"); 
      Intent i=new Intent(MainActivity.this, LoginActivity.class); 
      startActivity(i); 
     } 
    }); 

Answer 3

您的活动没有实现OnClickListener，但你施放活动为OnClickListener，所以这情况下，类转换异常