从 MainActivity 中的 onCreate() 启动另一个 Activity？

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【中文标题】从 MainActivity 中的 onCreate() 启动另一个 Activity？【英文标题】：Start Another Activity from onCreate() in MainActvity? 【发布时间】：2013-11-16 21:40:09 【问题描述】：

我遇到的问题是 MainActivity 中的 onCreate() 方法似乎无法启动另一个活动。

我有代码工作，因此当我单击一个按钮时，我的“AboutActivity”就会启动。但是，我想让它在 MainActivity 中的 onCreate() 完成后立即启动“AboutActivity”。

当我在尝试从 onCreate() 启动“AboutActivity”时运行程序时，程序卡在一个空白屏幕。

发布的代码是问题的简化版本。本质上，这就是我想要做的。

public class MainActivity extends Activity 

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

        // Fire the intent that launches the "About" screen.
        Intent aboutScreen = new Intent(getBaseContext(), AboutActivity.class);
        this.startActivity(aboutScreen);

AboutActivity 类的代码：

public class AboutActivity extends MainActivity 

    @Override
    public void onCreate(Bundle savedInstanceState) 
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_about);
    

    @Override
    public void onPause() 
        super.onPause();
    

    @Override
    public boolean onCreateOptionsMenu(Menu menu) 
        return super.onCreateOptionsMenu(menu);

LogCat 消息是：

11-16 16:33:47.335: D/dalvikvm(1702): GC_FOR_ALLOC freed 65K, 7% free 2692K/2876K, paused 70ms, total 72ms
11-16 16:33:47.335: I/dalvikvm-heap(1702): Grow heap (frag case) to 3.347MB for 635812-byte allocation
11-16 16:33:47.435: D/dalvikvm(1702): GC_FOR_ALLOC freed 2K, 6% free 3310K/3500K, paused 98ms, total 98ms
11-16 16:33:47.715: D/dalvikvm(1702): GC_FOR_ALLOC freed 20K, 4% free 3469K/3608K, paused 28ms, total 29ms
11-16 16:33:47.735: I/dalvikvm-heap(1702): Grow heap (frag case) to 5.478MB for 2073616-byte allocation
11-16 16:33:47.845: D/dalvikvm(1702): GC_FOR_ALLOC freed 1K, 3% free 5493K/5636K, paused 112ms, total 112ms
11-16 16:33:48.175: I/Choreographer(1702): Skipped 36 frames!  The application may be doing too much work on its main thread.
11-16 16:33:48.465: D/libEGL(1702): loaded /system/lib/egl/libEGL_emulation.so
11-16 16:33:48.555: D/(1702): HostConnection::get() New Host Connection established 0x2a210280, tid 1702
11-16 16:33:48.604: D/libEGL(1702): loaded /system/lib/egl/libGLESv1_CM_emulation.so
11-16 16:33:48.615: D/libEGL(1702): loaded /system/lib/egl/libGLESv2_emulation.so
11-16 16:33:48.715: W/EGL_emulation(1702): eglSurfaceAttrib not implemented
11-16 16:33:48.725: D/OpenGLRenderer(1702): Enabling debug mode 0
11-16 16:33:51.794: D/dalvikvm(1702): GC_FOR_ALLOC freed 139K, 4% free 6352K/6608K, paused 38ms, total 46ms
11-16 16:33:53.135: D/dalvikvm(1702): GREF has increased to 201
11-16 16:33:55.315: D/dalvikvm(1702): GC_FOR_ALLOC freed 219K, 5% free 7420K/7756K, paused 58ms, total 64ms
11-16 16:34:00.825: D/dalvikvm(1702): GC_FOR_ALLOC freed 281K, 5% free 8778K/9176K, paused 131ms, total 133ms
11-16 16:34:00.955: W/EGL_emulation(1702): eglSurfaceAttrib not implemented
11-16 16:34:01.405: I/Choreographer(1702): Skipped 31 frames!  The application may be doing too much work on its main thread.
11-16 16:34:01.635: W/EGL_emulation(1702): eglSurfaceAttrib not implemented
11-16 16:34:02.295: W/EGL_emulation(1702): eglSurfaceAttrib not implemented
11-16 16:34:03.026: W/EGL_emulation(1702): eglSurfaceAttrib not implemented
11-16 16:34:03.625: W/EGL_emulation(1702): eglSurfaceAttrib not implemented
11-16 16:34:04.246: W/EGL_emulation(1702): eglSurfaceAttrib not implemented
11-16 16:34:04.875: W/EGL_emulation(1702): eglSurfaceAttrib not implemented
11-16 16:34:05.557: W/EGL_emulation(1702): eglSurfaceAttrib not implemented
11-16 16:34:06.206: W/EGL_emulation(1702): eglSurfaceAttrib not implemented
11-16 16:34:06.675: D/dalvikvm(1702): GREF has increased to 301
11-16 16:34:06.816: W/EGL_emulation(1702): eglSurfaceAttrib not implemented
11-16 16:34:07.458: W/EGL_emulation(1702): eglSurfaceAttrib not implemented
11-16 16:34:07.978: I/Choreographer(1702): Skipped 30 frames!  The application may be doing too much work on its main thread.
11-16 16:34:08.296: W/EGL_emulation(1702): eglSurfaceAttrib not implemented
11-16 16:34:08.975: W/EGL_emulation(1702): eglSurfaceAttrib not implemented
11-16 16:34:09.686: W/EGL_emulation(1702): eglSurfaceAttrib not implemented
11-16 16:34:10.315: W/EGL_emulation(1702): eglSurfaceAttrib not implemented
11-16 16:34:10.945: W/EGL_emulation(1702): eglSurfaceAttrib not implemented
11-16 16:34:13.094: D/dalvikvm(1702): GC_FOR_ALLOC freed 367K, 5% free 10460K/10944K, paused 124ms, total 128ms
11-16 16:34:16.446: W/EGL_emulation(1702): eglSurfaceAttrib not implemented
11-16 16:34:16.965: I/Choreographer(1702): Skipped 30 frames!  The application may be doing too much work on its main thread.
11-16 16:34:17.125: W/EGL_emulation(1702): eglSurfaceAttrib not implemented
11-16 16:34:17.625: I/Choreographer(1702): Skipped 30 frames!  The application may be doing too much work on its main thread.
11-16 16:34:17.827: W/EGL_emulation(1702): eglSurfaceAttrib not implemented
11-16 16:34:18.355: I/Choreographer(1702): Skipped 32 frames!  The application may be doing too much work on its main thread.
11-16 16:34:18.555: W/EGL_emulation(1702): eglSurfaceAttrib not implemented
11-16 16:34:19.145: I/Choreographer(1702): Skipped 34 frames!  The application may be doing too much work on its main thread.
11-16 16:34:19.358: W/EGL_emulation(1702): eglSurfaceAttrib not implemented
11-16 16:34:20.103: W/EGL_emulation(1702): eglSurfaceAttrib not implemented
11-16 16:34:20.615: I/Choreographer(1702): Skipped 34 frames!  The application may be doing too much work on its main thread.
11-16 16:34:20.880: W/EGL_emulation(1702): eglSurfaceAttrib not implemented
11-16 16:34:22.825: W/EGL_emulation(1702): eglSurfaceAttrib not implemented
11-16 16:34:23.445: I/Choreographer(1702): Skipped 35 frames!  The application may be doing too much work on its main thread.
11-16 16:34:23.675: W/EGL_emulation(1702): eglSurfaceAttrib not implemented
11-16 16:34:24.195: D/dalvikvm(1702): GC_FOR_ALLOC freed 381K, 4% free 12129K/12628K, paused 289ms, total 291ms
11-16 16:34:24.355: I/Choreographer(1702): Skipped 40 frames!  The application may be doing too much work on its main thread.
11-16 16:34:24.585: W/EGL_emulation(1702): eglSurfaceAttrib not implemented
11-16 16:34:25.215: I/Choreographer(1702): Skipped 36 frames!  The application may be doing too much work on its main thread.
11-16 16:34:25.496: W/EGL_emulation(1702): eglSurfaceAttrib not implemented
11-16 16:34:26.025: I/Choreographer(1702): Skipped 30 frames!  The application may be doing too much work on its main thread.
11-16 16:34:26.235: W/EGL_emulation(1702): eglSurfaceAttrib not implemented
11-16 16:34:26.735: D/dalvikvm(1702): GREF has increased to 401
11-16 16:34:26.795: I/Choreographer(1702): Skipped 32 frames!  The application may be doing too much work on its main thread.
11-16 16:34:27.006: W/EGL_emulation(1702): eglSurfaceAttrib not implemented
11-16 16:34:29.516: W/EGL_emulation(1702): eglSurfaceAttrib not implemented
11-16 16:34:30.075: I/Choreographer(1702): Skipped 37 frames!  The application may be doing too much work on its main thread.
11-16 16:34:30.305: W/EGL_emulation(1702): eglSurfaceAttrib not implemented
11-16 16:34:30.825: I/Choreographer(1702): Skipped 31 frames!  The application may be doing too much work on its main thread.
11-16 16:34:31.046: W/EGL_emulation(1702): eglSurfaceAttrib not implemented
11-16 16:34:31.595: I/Choreographer(1702): Skipped 32 frames!  The application may be doing too much work on its main thread.
11-16 16:34:31.816: W/EGL_emulation(1702): eglSurfaceAttrib not implemented
11-16 16:34:32.385: I/Choreographer(1702): Skipped 34 frames!  The application may be doing too much work on its main thread.
11-16 16:34:32.615: W/EGL_emulation(1702): eglSurfaceAttrib not implemented
11-16 16:34:33.145: I/Choreographer(1702): Skipped 31 frames!  The application may be doing too much work on its main thread.
11-16 16:34:33.365: W/EGL_emulation(1702): eglSurfaceAttrib not implemented
11-16 16:34:37.115: D/dalvikvm(1702): GC_FOR_ALLOC freed 392K, 4% free 13787K/14296K, paused 164ms, total 167ms
11-16 16:34:38.345: W/EGL_emulation(1702): eglSurfaceAttrib not implemented
11-16 16:34:45.285: W/EGL_emulation(1702): eglSurfaceAttrib not implemented
11-16 16:34:49.475: I/Choreographer(1702): Skipped 67 frames!  The application may be doing too much work on its main thread.

如果我让应用程序在我的 AVD 上运行，LogCat 只会不断循环这部分日志：

11-16 16:34:31.046: W/EGL_emulation(1702): eglSurfaceAttrib not implemented
    11-16 16:34:31.595: I/Choreographer(1702): Skipped 32 frames!  The application may be doing too much work on its main thread.

我不知道如何解决这个问题。请帮忙！

【问题讨论】：

暂时忘记代码和 onCreate 以及所有这些东西。 你想做什么？ 如果我的 SharedPreferences 中的布尔值设置为 true，我会尝试弹出一个屏幕。也可以通过 MainActivity UI 中的按钮访问同一屏幕。最终，我试图实现类似闪屏的效果。 什么是MainActivity？你能发布它的代码吗？ 您的 AboutActivity 是否必须扩展 MainActivity，还是只能扩展 Activity？我还没有测试过，但这可能会导致一些问题。 【参考方案1】：

你的 AboutActivity 类...

public class AboutActivity extends MainActivity

请改成：

public class AboutActivity extends Activity

正如其他人所说，在构建您的意图时，请使用 this 或 MainActivity.this。

【讨论】：

【参考方案2】：

试试这个：

Intent aboutScreen = new Intent(MainActivity.this, AboutActivity.class);
this.startActivity(aboutScreen);

【讨论】：

那么您的问题可能出在其他地方。你能发布整个代码。您似乎正在做一些内存密集型工作。 我认为您的问题出在主要活动中，我认为甚至没有达到对“关于”屏幕的调用。您可以通过在通话前添加日志来检查它是否已打印。 我已经完成了整个应用程序的断点。我可以向你保证，它确实达到了“this.startActivity(aboutScreen);” Hmm.. 然后检查它是否到达 about 活动的 setContentView。也许您的布局在膨胀时未能膨胀或导致问题？【参考方案3】：

尝试将 this 而不是 getBaseContext() 传递给意图。

公共类 MainActivity 扩展 Activity 

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

    // Fire the intent that launches the "About" screen.
    Intent aboutScreen = new Intent(this, AboutActivity.class);
    this.startActivity(aboutScreen);

【讨论】：

这似乎无法解决我的问题。 :// 能分享一下 AboutActivity 类的实现吗？ AboutActivity 现在在原始帖子中可见。 你还做了什么？ 最初，我在 MainActivity 的 onCreate() 方法中运行了一些其他代码。但是，为了简单起见，我将问题归结为您在 onCreate() 方法中看到的所有内容。它是完全复制的。【参考方案4】：

我才意识到问题出在哪里。

问题是 AboutActivity 导致意图反复触发。 AboutActivity 的 onCreate() 中的第一行是 super.onCreate(savedInstanceState)。这意味着应用程序控制将返回到 MainActivity 的 onCreate()，然后将再次触发 Intent。因此，我似乎造成了intent调用的无限循环。

如果我找到解决方案，我会发布。

【讨论】：

@Melquiades 用我自己的解决方案击败了我。 为什么你的 AboutActivity 会扩展 MainActivity？真的，它应该只是扩展普通的旧 Activity。 @Lethal Left Eye: 很高兴你自己发现了问题 :) 事实上，因为 AboutActivity 扩展了 MainActivity，并调用它的 super()，你在 Main 的 onCreate 中一遍又一遍地创建一个意图。 【参考方案5】： 
@Override
protected void onCreate(Bundle savedInstanceState) 
super.onCreate(savedInstanceState);    
setContentView(R.layout.activity_main);

// Fire the intent that launches the "About" screen.
Intent i= new Intent(this, AboutActivity.class);
startActivity(i);

【讨论】：

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