我想在左側創建一個抽屜。在此期間,當我嘗試執行則給出了這樣的錯誤和應用程序崩潰:Android:null對象在onCreate方法返回列表視圖
造成的:顯示java.lang.NullPointerException:試圖調用虛擬方法無效android.widget.ListView.setAdapter(機器人。上的空對象引用
這裏widget.ListAdapter)」是我的代碼: MainActivity.java
import android.os.Bundle;
import android.support.v4.widget.DrawerLayout;
import android.support.v7.app.ActionBarActivity;
import android.widget.ArrayAdapter;
import android.widget.ListView;
public class MainActivity extends ActionBarActivity {
private String items[];//={"Home","Profile","Requests","Notifications","Search","Track My Tifin","Settings"};
private DrawerLayout dl;
private ListView listView;
//ArrayAdapter<String> adapter;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
dl=(DrawerLayout)findViewById(R.id.drawerOnleft);
listView=(ListView) findViewById(R.id.list);
items=getResources().getStringArray(R.array.list_items);
//Set adapter for this list
listView.setAdapter(new ArrayAdapter<>(this,android.R.layout.simple_list_item_1,items));
setContentView(R.layout.drawer_ex);
}
}
drawer_ex.xml
<?xml version="1.0" encoding="utf-8"?>
<android.support.v4.widget.DrawerLayout
android:id="@+id/drawerOnleft"
android:layout_height="match_parent"
android:layout_width="match_parent"
xmlns:android="http://schemas.android.com/apk/res/android">
<FrameLayout
android:id="@+id/mainView"
android:layout_width="match_parent"
android:layout_height="match_parent"></FrameLayout>
<ListView
android:id="@+id/list"
android:layout_width="240dp"
android:layout_height="match_parent"
android:layout_gravity="left"
android:choiceMode="singleChoice"
android:divider="@android:color/transparent"
android:background="#33CCFF"
android:dividerHeight="0dp"
></ListView>
的strings.xml
<resources>
<string name="app_name">MyDrawer</string>
<string name="hello_world">Hello world!</string>
<string name="action_settings">Settings</string>
<string-array name="list_items">
<item>Home</item>
<item>Profile</item>
<item>Requests</item>
<item>Notifications</item>
<item>Search</item>
<item>Track My Tifin</item>
<item>Settings</item>
</string-array>
提前感謝!
Whoilaaa..thank you so much much @savepopulation。它演變得像魅力。但是我有一個問題,爲什麼當我最終設置了「setContentView(R.layout.drawer_ex)」時,它會拋出異常。你能解釋一下嗎?謝謝! – pritesh 2015-04-06 09:25:12