Android Twitter OAuth上的Java.Lang.NullPointer异常错误
我有一些问题,我想让我的应用程序OAuth与twitter帐户 这是我的Main.xml文件Android Twitter OAuth上的Java.Lang.NullPointer异常错误,android,twitter,oauth,nullpointerexception,Android,Twitter,Oauth,Nullpointerexception,我有一些问题,我想让我的应用程序OAuth与twitter帐户 这是我的Main.xml文件 <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent" android:layout_height="match_p
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent" >
<TextView
android:id="@+id/textView1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerHorizontal="true"
android:layout_centerVertical="true"
android:padding="@dimen/padding_medium"
android:text="@string/hello_world"
tools:context=".MainActivity" />
<ImageButton
android:id="@+id/btnTwitterConnect"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="@+id/textView1"
android:layout_centerHorizontal="true"
android:background="@drawable/standard_twitter"
android:contentDescription="@string/twitter_btn_description"
android:gravity="center" />
</RelativeLayout>
我只是在这里学习了教程:
但是android应用程序总是崩溃
LogCat详细信息:
09-08 19:11:13.754: D/AndroidRuntime(566): Shutting down VM
09-08 19:11:13.754: W/dalvikvm(566): threadid=1: thread exiting with uncaught exception (group=0x4001d800)
09-08 19:11:13.785: E/AndroidRuntime(566): FATAL EXCEPTION: main
09-08 19:11:13.785: E/AndroidRuntime(566): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.test.twitteroauth/com.test.twitteroauth.MainActivity}: java.lang.NullPointerException
09-08 19:11:13.785: E/AndroidRuntime(566): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2663)
09-08 19:11:13.785: E/AndroidRuntime(566): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2679)
09-08 19:11:13.785: E/AndroidRuntime(566): at android.app.ActivityThread.access$2300(ActivityThread.java:125)
09-08 19:11:13.785: E/AndroidRuntime(566): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2033)
09-08 19:11:13.785: E/AndroidRuntime(566): at android.os.Handler.dispatchMessage(Handler.java:99)
09-08 19:11:13.785: E/AndroidRuntime(566): at android.os.Looper.loop(Looper.java:123)
09-08 19:11:13.785: E/AndroidRuntime(566): at android.app.ActivityThread.main(ActivityThread.java:4627)
09-08 19:11:13.785: E/AndroidRuntime(566): at java.lang.reflect.Method.invokeNative(Native Method)
09-08 19:11:13.785: E/AndroidRuntime(566): at java.lang.reflect.Method.invoke(Method.java:521)
09-08 19:11:13.785: E/AndroidRuntime(566): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
09-08 19:11:13.785: E/AndroidRuntime(566): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
09-08 19:11:13.785: E/AndroidRuntime(566): at dalvik.system.NativeStart.main(Native Method)
09-08 19:11:13.785: E/AndroidRuntime(566): Caused by: java.lang.NullPointerException
09-08 19:11:13.785: E/AndroidRuntime(566): at com.test.twitteroauth.MainActivity.onCreate(MainActivity.java:44)
09-08 19:11:13.785: E/AndroidRuntime(566): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
09-08 19:11:13.785: E/AndroidRuntime(566): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2627)
09-08 19:11:13.785: E/AndroidRuntime(566): ... 11 more
我知道这是由java.Lang.NullPointerException引起的,但错误在哪里
多谢各位
(Android 2.2、Eclipse 3.7、Java JDK 1.7)请在
ImageButton btnTwitterConnect=(ImageButton)findViewById(R.id.btnTwitterConnect)之前添加setcontentview(R.layout.main)
行代码>,它将解决您的问题。请在ImageButton btnTwitterConnect=(ImageButton)findViewById(R.id.btnTwitterConnect)之前添加setcontentview(R.layout.main)
行代码>,它将解决您的问题。您需要调用setContentView(layoutID)
并在调用findviewbyd(viewId)
之前传递按钮所属的布局,然后再调用setContentView(layoutID)
并在调用findviewbyd(vieid)之前传递按钮所属的布局
除了setContentView(…)
之外,还应该调用super.onCreate(savedInstanceState)代码>在它上面,否则您将得到一个SuperNotCalledException
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(...);
// ...
}
除了setContentView(…)
,还应该调用super.onCreate(savedInstanceState)代码>在它上面,否则您将得到一个SuperNotCalledException
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(...);
// ...
}
在ImageButton btnTwitterConnect=(ImageButton)findViewById(R.id.btnTwitterConnect)上放置断点;看看这是不是真的null@user1378730我设置了断点,它显示btnTwitterConnect总是空的。如何解决此问题?在ImageButton btnTwitterConnect=(ImageButton)findViewById(R.id.btnTwitterConnect)上设置断点;看看这是不是真的null@user1378730我设置了断点,它显示btnTwitterConnect总是空的。如何解决这个问题?嗨@Keshariya,谢谢你的回答,我会先试试这个。嗨@Keshariya,谢谢你的回答,我会先试试这个。好的接球,不敢相信我错过了那个好的接球,不敢相信我错过了那个