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尝试将 facebook sdk 集成到 android 应用程序，但我的应用程序没有启动。有日志。如何修复此运行时异常？

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    ImageView pic = (ImageView) findViewById(R.id.imageView1);
    Button btn = (Button) findViewById(R.id.button1);
    btn.setOnClickListener(this);
}

 08-15 11:48:21.712: E/AndroidRuntime(564): FATAL EXCEPTION: main
08-15 11:48:21.712: E/AndroidRuntime(564): java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.sri.z4globalsoft/com.sri.z4globalsoft.MainActivity}: java.lang.NullPointerException
08-15 11:48:21.712: E/AndroidRuntime(564):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1879)
08-15 11:48:21.712: E/AndroidRuntime(564):  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1980)
08-15 11:48:21.712: E/AndroidRuntime(564):  at android.app.ActivityThread.access$600(ActivityThread.java:122)
08-15 11:48:21.712: E/AndroidRuntime(564):  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1146)
08-15 11:48:21.712: E/AndroidRuntime(564):  at android.os.Handler.dispatchMessage(Handler.java:99)
08-15 11:48:21.712: E/AndroidRuntime(564):  at android.os.Looper.loop(Looper.java:137)
08-15 11:48:21.712: E/AndroidRuntime(564):  at android.app.ActivityThread.main(ActivityThread.java:4340)
08-15 11:48:21.712: E/AndroidRuntime(564):  at java.lang.reflect.Method.invokeNative(Native Method)
08-15 11:48:21.712: E/AndroidRuntime(564):  at java.lang.reflect.Method.invoke(Method.java:511)
08-15 11:48:21.712: E/AndroidRuntime(564):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784)
08-15 11:48:21.712: E/AndroidRuntime(564):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551)
08-15 11:48:21.712: E/AndroidRuntime(564):  at dalvik.system.NativeStart.main(Native Method)
08-15 11:48:21.712: E/AndroidRuntime(564): Caused by: java.lang.NullPointerException
08-15 11:48:21.712: E/AndroidRuntime(564):  at android.content.ContextWrapper.getResources(ContextWrapper.java:81)
08-15 11:48:21.712: E/AndroidRuntime(564):  at com.sri.z4globalsoft.MainActivity.<init>(MainActivity.java:23)
08-15 11:48:21.712: E/AndroidRuntime(564):  at java.lang.Class.newInstanceImpl(Native Method)
08-15 11:48:21.712: E/AndroidRuntime(564):  at java.lang.Class.newInstance(Class.java:1319)
08-15 11:48:21.712: E/AndroidRuntime(564):  at android.app.Instrumentation.newActivity(Instrumentation.java:1023)
08-15 11:48:21.712: E/AndroidRuntime(564):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1870)
08-15 11:48:21.712: E/AndroidRuntime(564):  ... 11 more

尝试根据您在下面给出的答案更改代码应用程序然后也有问题

08-15 12:25:00.800: E/AndroidRuntime(712): FATAL EXCEPTION: main
08-15 12:25:00.800: E/AndroidRuntime(712): java.lang.NoClassDefFoundError: com.facebook.android.Facebook
08-15 12:25:00.800: E/AndroidRuntime(712):  at com.sri.z4globalsoft.MainActivity.<init>(MainActivity.java:25)
08-15 12:25:00.800: E/AndroidRuntime(712):  at java.lang.Class.newInstanceImpl(Native Method)
08-15 12:25:00.800: E/AndroidRuntime(712):  at java.lang.Class.newInstance(Class.java:1319)
08-15 12:25:00.800: E/AndroidRuntime(712):  at android.app.Instrumentation.newActivity(Instrumentation.java:1023)
08-15 12:25:00.800: E/AndroidRuntime(712):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1870)
08-15 12:25:00.800: E/AndroidRuntime(712):  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1980)
08-15 12:25:00.800: E/AndroidRuntime(712):  at android.app.ActivityThread.access$600(ActivityThread.java:122)
08-15 12:25:00.800: E/AndroidRuntime(712):  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1146)
08-15 12:25:00.800: E/AndroidRuntime(712):  at android.os.Handler.dispatchMessage(Handler.java:99)
08-15 12:25:00.800: E/AndroidRuntime(712):  at android.os.Looper.loop(Looper.java:137)
08-15 12:25:00.800: E/AndroidRuntime(712):  at android.app.ActivityThread.main(ActivityThread.java:4340)
08-15 12:25:00.800: E/AndroidRuntime(712):  at java.lang.reflect.Method.invokeNative(Native Method)
08-15 12:25:00.800: E/AndroidRuntime(712):  at java.lang.reflect.Method.invoke(Method.java:511)
08-15 12:25:00.800: E/AndroidRuntime(712):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784)
08-15 12:25:00.800: E/AndroidRuntime(712):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551)
08-15 12:25:00.800: E/AndroidRuntime(712):  at dalvik.system.NativeStart.main(Native Method)
4

2 回答 2

1

听起来您可能会getResources()在技术准备就绪之前尝试使用它们。

如果你有这个：

String APP_ID = getResources().getString(R.string.APP_ID);

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    ...
}

改为这样做：

String APP_ID;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    APP_ID = getResources().getString(R.string.APP_ID);
    ...
}
于 2013-08-15T06:51:57.120 回答
0 
08-15 11:48:21.712: E/AndroidRuntime(564): Caused by: java.lang.NullPointerException
08-15 11:48:21.712: E/AndroidRuntime(564):  at android.content.ContextWrapper.getResources(ContextWrapper.java:81)
08-15 11:48:21.712: E/AndroidRuntime(564):  at com.sri.z4globalsoft.MainActivity.<init>(MainActivity.java:23)

您正在尝试初始化一个成员变量，其中初始化使用thisas Context。在这种情况下，它是getResources()调用。您只能在活动生命周期中或以后使用Activity。ContextonCreate()

具体来说（来自问题评论），改变这个：

String APP_ID = getResources().getString(R.string.APP_ID);

类似于：

String APP_ID;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    APP_ID = getResources().getString(R.string.APP_ID);
    //...
于 2013-08-15T06:47:02.287 回答