java - 实例化新 Activity 会导致应用程序崩溃

Question

我是 Android 应用程序开发新手，现在正在尝试编写第一个应用程序。当我想显示另一个 Activity 时，应用程序崩溃并显示以下日志(取自 LogCat):

02-01 18:05:50.148: D/HomeScreen(24970): news_button clicked
02-01 18:05:50.203: D/dalvikvm(24970): newInstance failed: p0 i0 [0 a1
02-01 18:05:50.210: D/AndroidRuntime(24970): Shutting down VM
02-01 18:05:50.210: W/dalvikvm(24970): threadid=1: thread exiting with uncaught exception (group=0x40018578)
02-01 18:05:50.218: E/AndroidRuntime(24970): FATAL EXCEPTION: main
02-01 18:05:50.218: E/AndroidRuntime(24970): java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{me.the_Seppi.freakhall/me.the_Seppi.freakhall.NewsScreen}: java.lang.InstantiationException: me.the_Seppi.freakhall.NewsScreen
02-01 18:05:50.218: E/AndroidRuntime(24970):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1573)
02-01 18:05:50.218: E/AndroidRuntime(24970):    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1667)
02-01 18:05:50.218: E/AndroidRuntime(24970):    at android.app.ActivityThread.access$1500(ActivityThread.java:117)
02-01 18:05:50.218: E/AndroidRuntime(24970):    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:935)
02-01 18:05:50.218: E/AndroidRuntime(24970):    at android.os.Handler.dispatchMessage(Handler.java:99)
02-01 18:05:50.218: E/AndroidRuntime(24970):    at android.os.Looper.loop(Looper.java:130)
02-01 18:05:50.218: E/AndroidRuntime(24970):    at android.app.ActivityThread.main(ActivityThread.java:3687)
02-01 18:05:50.218: E/AndroidRuntime(24970):    at java.lang.reflect.Method.invokeNative(Native Method)
02-01 18:05:50.218: E/AndroidRuntime(24970):    at java.lang.reflect.Method.invoke(Method.java:507)
02-01 18:05:50.218: E/AndroidRuntime(24970):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:867)
02-01 18:05:50.218: E/AndroidRuntime(24970):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:625)
02-01 18:05:50.218: E/AndroidRuntime(24970):    at dalvik.system.NativeStart.main(Native Method)
02-01 18:05:50.218: E/AndroidRuntime(24970): Caused by: java.lang.InstantiationException: me.the_Seppi.freakhall.NewsScreen
02-01 18:05:50.218: E/AndroidRuntime(24970):    at java.lang.Class.newInstanceImpl(Native Method)
02-01 18:05:50.218: E/AndroidRuntime(24970):    at java.lang.Class.newInstance(Class.java:1409)
02-01 18:05:50.218: E/AndroidRuntime(24970):    at android.app.Instrumentation.newActivity(Instrumentation.java:1021)
02-01 18:05:50.218: E/AndroidRuntime(24970):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1565)
02-01 18:05:50.218: E/AndroidRuntime(24970):    ... 11 more

执行的代码是:

//HomeScreen.java
//...
public void gotoNews (View view) {
    Log.d(TAG, "news_button clicked");
    Intent news = new Intent(this, NewsScreen.class);
    startActivity(news);
}



//NewsScreen.java
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_news_screen);
    Log.d("NewsScreen", "created");
    AlertDialog.Builder builder = new AlertDialog.Builder(this);
    builder.setMessage(R.string.update_text).setTitle(R.string.update_title).create().show();
    Log.d("NewsScreen", "Started update");  
}

我在代码中找不到错误，因为日志中没有行号。 请帮助我。

Answer 1

您是否已将此 NewScreen Activity 添加到您的 list 文件中？这是崩溃 Activity 中最常见的问题。