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java - 从活动 A 移动到活动 B 并从活动 B 移动到活动 A

问题描述

我对此很陌生，我一直在论坛上寻找我的问题的答案，但我似乎无法得到这个工作，我非常感谢你的专业人士的帮助:)

正如标题所指定的，我想通过单击按钮从活动 A 转到活动 B，然后单击按钮从活动 B 回到活动 A。

我的问题首先是我什至无法从活动 A 转到活动 B，因为当我按下按钮时应用程序崩溃了。为什么？

其次，我想知道我从活动 B 返回到活动 A 的代码是否正确。

我的代码从活动 A 转到活动 B

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

    }

    public void ToCV(View v) {
        Intent intent = new Intent(this, CV.class);
    startActivity(intent);
}
}

现在是从活动 B 返回到活动 A 的代码

public class CV extends AppCompatActivity {
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_cv);
    }
   
    public void GoBack(View v) {
      startActivity(new Intent(CV.this,MainActivity.class));

}
}

这是我运行应用程序时的崩溃日志##

2021-03-03 11:29:46.290 4104-4104/com.example.cvapp D/AndroidRuntime: Shutting down VM
2021-03-03 11:29:46.291 4104-4104/com.example.cvapp W/m.example.cvap: Accessing hidden method Lcom/msic/qarth/PatchStore;->createDisableExceptionQarthFile(Ljava/lang/Throwable;)Z (blacklist, JNI)
2021-03-03 11:29:46.291 4104-4104/com.example.cvapp E/m.example.cvap: [qarth_debug:]  get PatchStore::createDisableExceptionQarthFile method fail.
2021-03-03 11:29:46.296 4104-4104/com.example.cvapp E/AndroidRuntime: FATAL EXCEPTION: main
    Process: com.example.cvapp, PID: 4104
    java.lang.IllegalStateException: Could not execute method for android:onClick
        at androidx.appcompat.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:414)
        at android.view.View.performClick(View.java:6659)
        at com.google.android.material.button.MaterialButton.performClick(MaterialButton.java:992)
        at android.view.View.performClickInternal(View.java:6631)
        at android.view.View.access$3100(View.java:790)
        at android.view.View$PerformClick.run(View.java:26187)
        at android.os.Handler.handleCallback(Handler.java:907)
        at android.os.Handler.dispatchMessage(Handler.java:105)
        at android.os.Looper.loop(Looper.java:216)
        at android.app.ActivityThread.main(ActivityThread.java:7625)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:524)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:987)
     Caused by: java.lang.reflect.InvocationTargetException
        at java.lang.reflect.Method.invoke(Native Method)
        at androidx.appcompat.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:409)
        at android.view.View.performClick(View.java:6659) 
        at com.google.android.material.button.MaterialButton.performClick(MaterialButton.java:992) 
        at android.view.View.performClickInternal(View.java:6631) 
        at android.view.View.access$3100(View.java:790) 
        at android.view.View$PerformClick.run(View.java:26187) 
        at android.os.Handler.handleCallback(Handler.java:907) 
        at android.os.Handler.dispatchMessage(Handler.java:105) 
        at android.os.Looper.loop(Looper.java:216) 
        at android.app.ActivityThread.main(ActivityThread.java:7625) 
        at java.lang.reflect.Method.invoke(Native Method) 
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:524) 
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:987) 
     Caused by: android.content.ActivityNotFoundException: Unable to find explicit activity class {com.example.cvapp/com.example.cvapp.CV}; have you declared this activity in your AndroidManifest.xml?
        at android.app.Instrumentation.checkStartActivityResult(Instrumentation.java:2112)
        at android.app.Instrumentation.execStartActivity(Instrumentation.java:1757)
        at android.app.Activity.startActivityForResult(Activity.java:4803)
        at androidx.fragment.app.FragmentActivity.startActivityForResult(FragmentActivity.java:676)
        at android.app.Activity.startActivityForResult(Activity.java:4743)
        at androidx.fragment.app.FragmentActivity.startActivityForResult(FragmentActivity.java:663)
        at android.app.Activity.startActivity(Activity.java:5164)
        at android.app.Activity.startActivity(Activity.java:5132)
        at com.example.cvapp.MainActivity.ToCV(MainActivity.java:21)
        at java.lang.reflect.Method.invoke(Native Method) 
        at androidx.appcompat.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:409) 
        at android.view.View.performClick(View.java:6659) 
        at com.google.android.material.button.MaterialButton.performClick(MaterialButton.java:992) 
        at android.view.View.performClickInternal(View.java:6631) 
        at android.view.View.access$3100(View.java:790) 
        at android.view.View$PerformClick.run(View.java:26187) 
        at android.os.Handler.handleCallback(Handler.java:907) 
        at android.os.Handler.dispatchMessage(Handler.java:105) 
        at android.os.Looper.loop(Looper.java:216) 
        at android.app.ActivityThread.main(ActivityThread.java:7625) 
        at java.lang.reflect.Method.invoke(Native Method) 
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:524) 
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:987) 

清单

`<?xml version="1.0" encoding="utf-8"?>


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

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

标签： javaandroid

解决方案

在清单文件中注册您的活动 B

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