android listView.setAdapter error with SimpleCursorAdapter

Question

我试图将数据库表中的数据显示到listView上，方法是通过光标检索数据，将光标传递给SimpleCursorAdapter，并将适配器设置为listView，如下所示。由于listAdapter.setAdapter（适配器）.上的问题，应用程序崩溃

-我使用确认了聊天表中有数据

-在捕获异常时，ex.getMessage为null，但它指示行号为listAdapter.setAdapter（adapter）代码：

  ChatsActivity.java
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
    Conn connection = new Conn();
    SQLiteDatabase db = connection.getDB(this, "chats", 1);
    //returns readable database
    Cursor result = db.rawQuery("SELECT * FROM chats", null);
    SimpleCursorAdapter adapter = new SimpleCursorAdapter(this,
            R.layout.other,
            result,
            new String[]{"_id", "lastContent"},
            new int[]{R.id.textView1, R.id.textView2});
        ListView listView = (ListView) findViewById(R.id.listView);
        listView.setAdapter(adapter);
        setContentView(listView);
    }
}  

2其他.xml

 <?xml version="1.0" encoding="utf-8"?>
 <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
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_alignParentLeft="true"
    android:layout_alignParentTop="true"
    android:text="Main"
    android:textAppearance="?android:attr/textAppearanceMedium" />
<TextView
    android:id="@+id/textView2"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignLeft="@+id/textView1"
    android:layout_below="@+id/textView1"
    android:text="Sub"
    android:textAppearance="?android:attr/textAppearanceMedium" />  </RelativeLayout>

Activity_chats.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:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
android:paddingBottom="@dimen/activity_vertical_margin" tools:context=".ChatsActivity">

<ListView
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:id="@+id/listView"
    android:layout_alignParentTop="true"
    android:layout_centerHorizontal="true" />  </RelativeLayout>

可能是什么问题？

Answer 1

此处：

setContentView(listView);

在访问layout:中的值之前，不要将listView传递给setContentView，而是将Activity_chats.xml layout id传递为Activity layout

   @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.Activity_chats);
        ....
    }