我正在尝试创建一个导航抽屉活动,所以我可以扩展该活动,并在所有活动中使用菜单,遵循这个问题
Link中给出的答案,但我的测试应用程序不断崩溃,这是我的代码：
BaseActivity.java
public class BaseActivity extends Activity {
public DrawerLayout drawerLayout;
public ListView drawerList;
public String[] layers;
private ActionBarDrawerToggle drawerToggle;
protected void onCreate(Bundle savedInstanceState) {
// R.id.drawer_layout should be in every activity with exactly the same
// id.
drawerLayout = (DrawerLayout) findViewById(R.id.drawer_layout);
drawerToggle = new ActionBarDrawerToggle((Activity) this,drawerLayout,R.drawable.ic_drawer,0) {
public void onDrawerClosed(View view) {
getActionBar().setTitle(R.string.hello_world);
}
public void onDrawerOpened(View drawerView) {
getActionBar().setTitle(R.string.hello_world);
}
};
drawerLayout.setDrawerListener(drawerToggle);
getActionBar().setDisplayHomeAsUpEnabled(true);
getActionBar().setHomeButtonEnabled(true);
layers = getResources().getStringArray(R.array.planets_array);
drawerList = (ListView) findViewById(R.id.left_drawer);
drawerList.setAdapter(new ArrayAdapter<String>(this,R.layout.drawer_list_item,android.R.id.text1,layers));
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
if (drawerToggle.onOptionsItemSelected(item)) {
return true;
}
return super.onOptionsItemSelected(item);
}
@Override
protected void onPostCreate(Bundle savedInstanceState) {
super.onPostCreate(savedInstanceState);
drawerToggle.syncState();
}
@Override
public void onConfigurationChanged(Configuration newConfig) {
super.onConfigurationChanged(newConfig);
drawerToggle.onConfigurationChanged(newConfig);
}
}
MainActivity.java
public class MainActivity extends BaseActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_profile);
}
}
activity_profile.xml
<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"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context=".ProfileActivity" >
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="@string/hello_world" />
</RelativeLayout>
logcat的
03-03 01:22:18.031: D/AndroidRuntime(27902): Shutting down VM
03-03 01:22:18.031: W/dalvikvm(27902): threadid=1: thread exiting with uncaught exception (group=0x2b542210)
03-03 01:22:18.041: E/AndroidRuntime(27902): FATAL EXCEPTION: main
03-03 01:22:18.041: E/AndroidRuntime(27902): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.slider/com.example.slider.MainActivity}: java.lang.NullPointerException
03-03 01:22:18.041: E/AndroidRuntime(27902): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1967)
03-03 01:22:18.041: E/AndroidRuntime(27902): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1992)
03-03 01:22:18.041: E/AndroidRuntime(27902): at android.app.ActivityThread.access$600(ActivityThread.java:127)
03-03 01:22:18.041: E/AndroidRuntime(27902): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1158)
03-03 01:22:18.041: E/AndroidRuntime(27902): at android.os.Handler.dispatchMessage(Handler.java:99)
03-03 01:22:18.041: E/AndroidRuntime(27902): at android.os.Looper.loop(Looper.java:137)
03-03 01:22:18.041: E/AndroidRuntime(27902): at android.app.ActivityThread.main(ActivityThread.java:4441)
03-03 01:22:18.041: E/AndroidRuntime(27902): at java.lang.reflect.Method.invokeNative(Native Method)
03-03 01:22:18.041: E/AndroidRuntime(27902): at java.lang.reflect.Method.invoke(Method.java:511)
03-03 01:22:18.041: E/AndroidRuntime(27902): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784)
03-03 01:22:18.041: E/AndroidRuntime(27902): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551)
03-03 01:22:18.041: E/AndroidRuntime(27902): at dalvik.system.NativeStart.main(Native Method)
03-03 01:22:18.041: E/AndroidRuntime(27902): Caused by: java.lang.NullPointerException
03-03 01:22:18.041: E/AndroidRuntime(27902): at com.example.slider.BaseActivity.onCreate(BaseActivity.java:35)
03-03 01:22:18.041: E/AndroidRuntime(27902): at com.example.slider.MainActivity.onCreate(MainActivity.java:12)
03-03 01:22:18.041: E/AndroidRuntime(27902): at android.app.Activity.performCreate(Activity.java:4465)
03-03 01:22:18.041: E/AndroidRuntime(27902): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1049)
03-03 01:22:18.041: E/AndroidRuntime(27902): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1931)
03-03 01:22:18.041: E/AndroidRuntime(27902): ... 11 more
解决方法
在主要的活动中,你必须在setContentView()之后调用super.onCreate(savedInstanceState)
