Question

我正在尝试在自定义列表视图中填充我的联系人列表但我正面临这个问题

activity_main.xml中

<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=".MainActivity">

<ListView
    android:layout_width="wrap_content"
    android:layout_height="match_parent"
    android:id="@+id/listView"
    android:layout_centerHorizontal="true"
    android:layout_alignParentBottom="true" />

listview_item.xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="horizontal" android:layout_width="match_parent"
android:layout_height="match_parent">

<LinearLayout
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:layout_gravity="right"
    android:layout_marginTop="50dp"
    android:layout_marginLeft="20dp"
    android:paddingTop="30dp">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textAppearance="?android:attr/textAppearanceLarge"
        android:text="Large Text"
        android:id="@+id/name" />

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textAppearance="?android:attr/textAppearanceMedium"
        android:text="Medium Text"
        android:id="@+id/num" />
</LinearLayout>

我的主要活动课

公共类MainActivity扩展了ActionBarActivity {

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

    ListView lv = (ListView) findViewById(R.id.listView);

    Uri uri = ContactsContract.Contacts.CONTENT_URI;
     String [] cols = {ContactsContract.Contacts._ID
             , ContactsContract.Contacts.DISPLAY_NAME
             , ContactsContract.Contacts.LOOKUP_KEY
             ,ContactsContract.Contacts.HAS_PHONE_NUMBER};

    String selections = ContactsContract.Contacts.HAS_PHONE_NUMBER + " = ? ";

    Cursor cursor = getContentResolver().query(uri,cols,selections,new String [] {"1"},null);

    Adapter adapter = new Adapter(MainActivity.this , cursor);
    lv.setAdapter(adapter);

}

扩展CursorAdapter的适配器类

类Adapter扩展了CursorAdapter {

    Context context;
    Cursor c;

    public Adapter(Context context , Cursor c ) {
        super(context, c, 0);
        this.context = context;
        this.c = c;
    }

    @Override
    public View newView(Context context, Cursor cursor, ViewGroup viewGroup) {
        View v = getLayoutInflater().inflate(R.layout.listview_item, viewGroup, false);

        return v;
    }

    @Override
    public void bindView(View view, Context context, Cursor cursor) {


            TextView name = (TextView) findViewById(R.id.name);
            name.setText(cursor.getString(cursor.getColumnIndex(ContactsContract.Contacts.DISPLAY_NAME)));
            TextView num = (TextView) findViewById(R.id.num);
            num.setText(cursor.getString(cursor.getColumnIndex(ContactsContract.Contacts.HAS_PHONE_NUMBER)));

        }
    }
}

这是LogCat异常

03-26 20:56:55.450    1847-1847/com.examples.anabil.contentproviderex E/AndroidRuntime﹕ FATAL EXCEPTION: main
java.lang.NullPointerException
        at com.examples.anabil.contentproviderex.MainActivity$Adapter.bindView(MainActivity.java:79)
        at android.widget.CursorAdapter.getView(CursorAdapter.java:250)
        at android.widget.AbsListView.obtainView(AbsListView.java:2177)
        at android.widget.ListView.measureHeightOfChildren(ListView.java:1247)
        at android.widget.ListView.onMeasure(ListView.java:1159)
        at android.view.View.measure(View.java:15848)
        at android.widget.RelativeLayout.measureChildHorizontal(RelativeLayout.java:728)
        at android.widget.RelativeLayout.onMeasure(RelativeLayout.java:477)
        at android.view.View.measure(View.java:15848)
        at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5012)
        at android.widget.FrameLayout.onMeasure(FrameLayout.java:310)
        at android.view.View.measure(View.java:15848)
        at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5012)
        at android.support.v7.internal.widget.ActionBarOverlayLayout.onMeasure(ActionBarOverlayLayout.java:453)
        at android.view.View.measure(View.java:15848)
        at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5012)
        at android.widget.FrameLayout.onMeasure(FrameLayout.java:310)
        at android.view.View.measure(View.java:15848)
        at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5012)
        at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1404)
        at android.widget.LinearLayout.measureVertical(LinearLayout.java:695)
        at android.widget.LinearLayout.onMeasure(LinearLayout.java:588)
        at android.view.View.measure(View.java:15848)
        at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5012)
        at android.widget.FrameLayout.onMeasure(FrameLayout.java:310)
        at com.android.internal.policy.impl.PhoneWindow$DecorView.onMeasure(PhoneWindow.java:2189)
        at android.view.View.measure(View.java:15848)
        at android.view.ViewRootImpl.performMeasure(ViewRootImpl.java:1905)
        at android.view.ViewRootImpl.measureHierarchy(ViewRootImpl.java:1104)
        at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1284)
        at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1004)
        at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:5481)
        at android.view.Choreographer$CallbackRecord.run(Choreographer.java:749)
        at android.view.Choreographer.doCallbacks(Choreographer.java:562)
        at android.view.Choreographer.doFrame(Choreographer.java:532)
        at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:735)
        at android.os.Handler.handleCallback(Handler.java:730)
        at android.os.Handler.dispatchMessage(Handler.java:92)
        at android.os.Looper.loop(Looper.java:137)
        at android.app.ActivityThread.main(ActivityThread.java:5103)
        at java.lang.reflect.Method.invokeNative(Native Method)
        at java.lang.reflect.Method.invoke(Method.java:525)
        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
        at dalvik.system.NativeStart.main(Native Method)

Answer 1

VadymVL答案将修复您的空指针错误。

访问原始联系人表（ContactsContract.Contacts）的速度很慢。尝试使用ContactsContract.CommonDataKinds.Phone：

public Uri uri = ContactsContract.CommonDataKinds.Phone.CONTENT_URI;
String [] cols = {ContactsContract.CommonDataKinds.Phone.CONTACT_ID
         , ContactsContract.CommonDataKinds.Phone.DISPLAY_NAME
         , ContactsContract.CommonDataKinds.Phone.NUMBER}; 

String selections =  ContactsContract.CommonDataKinds.Phone.HAS_PHONE_NUMBER + " = '1'";

Cursor Cursor = contentResolver.query(uri, cols, selections, null, null);

在bindView中：

@Override
public void bindView(View view, Context context, Cursor cursor) {

        TextView name = (TextView) view.findViewById(R.id.name);
        name.setText(cursor.getString(cursor.getColumnIndex(ContactsContract.CommonDataKinds.Phone.DISPLAY_NAME)));
        TextView num = (TextView) view.findViewById(R.id.num);
        num.setText(cursor.getString(cursor.getColumnIndex(ContactsContract.CommonDataKinds.Phone.NUMBER)));
    }
}

在列表视图中填充手机联系人时出错

1 个答案: