这是log文件
03-16 12:47:02.671: E/AndroidRuntime(1146): at dalvik.system.NativeStart.main(Native Method)
03-16 12:47:02.671: E/AndroidRuntime(1146): Caused by: java.lang.NullPointerException
03-16 12:47:02.671: E/AndroidRuntime(1146): at com.yongxin.adstudyview316.MainActivity.onCreate(MainActivity.java:22)
03-16 12:47:02.671: E/AndroidRuntime(1146): at android.app.Activity.performCreate(Activity.java:5231)
03-16 12:47:02.671: E/AndroidRuntime(1146): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
03-16 12:47:02.671: E/AndroidRuntime(1146): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2159)
代码:
public class MainActivity extends ActionBarActivity {
private TextView textview;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
textview=(TextView)findViewById(R.id.textview);
textview.setText("wohaoyun");
}
布局文件:
<LinearLayout 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"
android:orientation="vertical"
tools:context="com.yongxin.adstudyview316.MainActivity$PlaceholderFragment" >
<TextView
android:id="@+id/textview"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:background="#FF0000"
android:text="@string/hello_world" />
看出来的大神说一下吧,弄了半天了,一点办法都没~~~~~谢谢