我无法检索 android 中的联系人？

Question

我是 android 的初学者。我想在 ListView 中显示联系人列表。我已经在 activity_main.xml 中有一个 ListView，我在 MainActivity.java 中提到了这一点。但是当我运行程序出现错误时

java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.yuvi.contactsex/com.example.yuvi.contactsex.MainActivity}: java.lang.RuntimeException: Your content must have a ListView whose id attribute is 'android.R.id.list'

我从网站上得到了这个代码。我不知道在哪里更改代码。任何人帮助我。

AndroidManifest.xml

<uses-permission android:name="android.permission.READ_CONTACTS"/>

<application
    android:allowBackup="true"
    android:icon="@mipmap/ic_launcher"
    android:label="@string/app_name"
    android:roundIcon="@mipmap/ic_launcher_round"
    android:supportsRtl="true"
    android:theme="@style/AppTheme">
    <activity android:name=".MainActivity">
        <intent-filter>
            <action android:name="android.intent.action.MAIN" />

            <category android:name="android.intent.category.LAUNCHER" />
        </intent-filter>
    </activity>
</application>

activity_main.xml

MainActivity.java

public class MainActivity extends ListActivity {

ListView lv;
Cursor cursor1;

@Override
public int getSelectedItemPosition() {
    return super.getSelectedItemPosition();
}

@Override
public long getSelectedItemId() {
    return super.getSelectedItemId();
}

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

    lv=(ListView)findViewById(R.id.list);
    // create a cursor to query the Contacts on the device to start populating a listview
    cursor1 = getContentResolver().query(ContactsContract.CommonDataKinds.Phone.CONTENT_URI, null, null, null, null);
    startManagingCursor(cursor1);

    String[] from = {ContactsContract.CommonDataKinds.Phone.DISPLAY_NAME, ContactsContract.CommonDataKinds.Phone.NUMBER, ContactsContract.CommonDataKinds.Phone._ID}; // get the list items for the listadapter could be TITLE or URI


    int[] to = {android.R.id.text1, android.R.id.text2}; // sets the items from above string to listview

    // new listadapter, created to use android checked template
    SimpleCursorAdapter listadapter = new SimpleCursorAdapter(this, android.R.layout.simple_list_item_2, cursor1, from, to);


    setListAdapter(listadapter);

    // adds listview so I can get data from it
    lv = getListView();
    lv.setChoiceMode(ListView.CHOICE_MODE_MULTIPLE);


  }
}

Answer 1

java.lang.RuntimeException: Your content must have a ListView whose id attribute is 'android.R.id.list'

当您使用 ListActivity 时，您必须在 xml 的 id 属性中添加 @android:

<ListView 
    android:id="@android:id/list"
    android:layout_width="match_parent"
    android:layout_height="match_parent"/>

希望对您有所帮助。

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