重複類：MainActivity

Question

我有一個簡單的問題，我確信有人理解一點點Java的基礎知識可以幫助我。

我正在使用React-Native，並獲得了iOS的一切工作，但是當試圖爲android編譯時，我得到一個名爲「duplicate class：com.myApp.MainActivity」的錯誤。

我知道它可能MainActivity在下面的代碼中定義了2次，但由於某種原因，我嘗試了我所知道的一切，並且我無法將這兩個MainActivity合併爲一個。

有人能指出我正確的方向嗎？謝謝！

package com.myApp; 

    import com.facebook.react.ReactActivity; 
    import com.oblador.vectoricons.VectorIconsPackage; 
    import com.tuanpm.RCTSmartconfig.RCTSmartconfigPackage; 
    import com.pusherman.networkinfo.RNNetworkInfoPackage; 
    import com.tuanpm.RCTMqtt.*; 

    public class MainActivity extends ReactActivity { 

     /** 
     * Returns the name of the main component registered from JavaScript. 
     * This is used to schedule rendering of the component. 
     */ 
     @Override 
     protected String getMainComponentName() { 
      return "myApp"; 
     } 
    } 

    public class MainActivity extends Activity implements DefaultHardwareBackBtnHandler { 
     @Override 
     protected void onCreate(Bundle savedInstanceState) { 
      super.onCreate(savedInstanceState); 
      mReactRootView = new ReactRootView(this); 

      mReactInstanceManager = ReactInstanceManager.builder() 
        .setApplication(getApplication()) 
        .setBundleAssetName("index.android.bundle") 
        .setJSMainModuleName("index.android") 
        .addPackage(new MainReactPackage(), 
       new VectorIconsPackage(), 
       new RCTSmartconfigPackage(), 
       new RCTMqttPackage()) 
        .addPackage(new RNNetworkInfoPackage())  // <- ADD HERE 
        .setUseDeveloperSupport(BuildConfig.DEBUG) 
        .setInitialLifecycleState(LifecycleState.RESUMED) 
        .build(); 

      mReactRootView.startReactApplication(mReactInstanceManager, "myApp", null); 

      setContentView(mReactRootView); 
     } 
    } 

更新1

以下@cybersam解決方案後，我得到這個：

:app:compileDebugJavaWithJavac 
/Users/nicolasferro/Desktop/myApp/android/app/src/main/java/com/myApp/MainActivity.java:9: error: cannot find symbol 
public class MainActivity extends ReactActivity implements DefaultHardwareBackBtnHandler { 
                 ^
    symbol: class DefaultHardwareBackBtnHandler 
/Users/nicolasferro/Desktop/myApp/android/app/src/main/java/com/myApp/MainActivity.java:12: error: cannot find symbol 
    protected void onCreate(Bundle savedInstanceState) { 
          ^
    symbol: class Bundle 
    location: class MainActivity 
/Users/nicolasferro/Desktop/myApp/android/app/src/main/java/com/myApp/MainActivity.java:14: error: mReactRootView has private access in ReactActivity 
     mReactRootView = new ReactRootView(this); 
     ^
/Users/nicolasferro/Desktop/myApp/android/app/src/main/java/com/myApp/MainActivity.java:14: error: cannot find symbol 
     mReactRootView = new ReactRootView(this); 
          ^
    symbol: class ReactRootView 
    location: class MainActivity 
/Users/nicolasferro/Desktop/myApp/android/app/src/main/java/com/myApp/MainActivity.java:16: error: mReactInstanceManager has private access in ReactActivity 
     mReactInstanceManager = ReactInstanceManager.builder() 
     ^
/Users/nicolasferro/Desktop/myApp/android/app/src/main/java/com/myApp/MainActivity.java:26: error: cannot find symbol 
       .setInitialLifecycleState(LifecycleState.RESUMED) 
             ^
    symbol: variable LifecycleState 
    location: class MainActivity 
/Users/nicolasferro/Desktop/myApp/android/app/src/main/java/com/myApp/MainActivity.java:20: error: cannot find symbol 
       .addPackage(new MainReactPackage(), 
           ^
    symbol: class MainReactPackage 
    location: class MainActivity 
/Users/nicolasferro/Desktop/myApp/android/app/src/main/java/com/myApp/MainActivity.java:16: error: cannot find symbol 
     mReactInstanceManager = ReactInstanceManager.builder() 
           ^
    symbol: variable ReactInstanceManager 
    location: class MainActivity 
/Users/nicolasferro/Desktop/myApp/android/app/src/main/java/com/myApp/MainActivity.java:29: error: mReactInstanceManager has private access in ReactActivity 
     mReactRootView.startReactApplication(mReactInstanceManager, "myApp", null); 
              ^
/Users/nicolasferro/Desktop/myApp/android/app/src/main/java/com/myApp/MainActivity.java:29: error: mReactRootView has private access in ReactActivity 
     mReactRootView.startReactApplication(mReactInstanceManager, "myApp", null); 
     ^
/Users/nicolasferro/Desktop/myApp/android/app/src/main/java/com/myApp/MainActivity.java:31: error: mReactRootView has private access in ReactActivity 
     setContentView(mReactRootView); 
        ^
11 errors 
:app:compileDebugJavaWithJavac FAILED 

Answer 1

你有兩個類具有完全相同的類名MainActivity。如果您繼承了您聲明的兩個類中的兩個行爲，則可以將第一個類重命名爲類似BaseActivity的類，然後獲取您聲明的第二個MainActivity類以擴展BaseActivity。

Answer 2

由於ReactActivity已經擴展Activity，可以合併2個公共課（不允許）使用相同的全名（也不允許）爲一個：

package com.myApp; 

import com.facebook.react.ReactActivity; 
import com.oblador.vectoricons.VectorIconsPackage; 
import com.tuanpm.RCTSmartconfig.RCTSmartconfigPackage; 
import com.pusherman.networkinfo.RNNetworkInfoPackage; 
import com.tuanpm.RCTMqtt.*; 

public class MainActivity extends ReactActivity implements DefaultHardwareBackBtnHandler { 

    @Override 
    protected void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     mReactRootView = new ReactRootView(this); 

     mReactInstanceManager = ReactInstanceManager.builder() 
       .setApplication(getApplication()) 
       .setBundleAssetName("index.android.bundle") 
       .setJSMainModuleName("index.android") 
       .addPackage(new MainReactPackage(), 
      new VectorIconsPackage(), 
      new RCTSmartconfigPackage(), 
      new RCTMqttPackage()) 
       .addPackage(new RNNetworkInfoPackage())  // <- ADD HERE 
       .setUseDeveloperSupport(BuildConfig.DEBUG) 
       .setInitialLifecycleState(LifecycleState.RESUMED) 
       .build(); 

     mReactRootView.startReactApplication(mReactInstanceManager, "myApp", null); 

     setContentView(mReactRootView); 
    } 

    /** 
    * Returns the name of the main component registered from JavaScript. 
    * This is used to schedule rendering of the component. 
    */ 
    @Override 
    protected String getMainComponentName() { 
     return "myApp"; 
    } 
} 

Answer 3

您不僅有2類具有相同名稱，但是，您在同一文件中有兩個公用類，它們不能用java編譯。