我在flutter应用程序中使用contact_picker来访问从手机通讯录中获取联系人。当我单击电话簿中的联系人姓名时，该应用程序崩溃。
这是代码：
import 'package:flutter/material.dart';
import 'package:contact_picker/contact_picker.dart';
void main() {
runApp(new MyApp());
}
class MyApp extends StatefulWidget {
@override
_MyAppState createState() => new _MyAppState();
}
class _MyAppState extends State<MyApp> {
final ContactPicker _contactPicker = new ContactPicker();
Contact _contact;
@override
Widget build(BuildContext context) {
return new MaterialApp(
home: new Scaffold(
appBar: new AppBar(
title: new Text('Plugin example app'),
),
body: new Center(
child: new Column(
mainAxisSize: MainAxisSize.min,
children: <Widget>[
new MaterialButton(
color: Colors.blue,
child: new Text("CLICK ME"),
onPressed: () async {
Contact contact = await _contactPicker.selectContact();
setState(() {
_contact = contact;
});
},
),
new Text(
_contact == null ? 'No contact selected.' : _contact.toString(),
),
],
),
),
),
);
}
}
以下是显示的错误：
D/AndroidRuntime(14310): Shutting down VM
E/AndroidRuntime(14310): FATAL EXCEPTION: main
E/AndroidRuntime(14310): Process: com.example.kubera_sample, PID: 14310
E/AndroidRuntime(14310): java.lang.RuntimeException: Failure delivering result ResultInfo{who=null, request=2015, result=-1, data=Intent { dat=content://com.android.contacts/data/3 flg=0x1 }} to activity {com.example.kubera_sample/com.example.kubera_sample.MainActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'android.content.ContentResolver android.app.Activity.getContentResolver()' on a null object reference
E/AndroidRuntime(14310): at android.app.ActivityThread.deliverResults(ActivityThread.java:4360)
E/AndroidRuntime(14310): at android.app.ActivityThread.handleSendResult(ActivityThread.java:4402)
E/AndroidRuntime(14310): at android.app.servertransaction.ActivityResultItem.execute(ActivityResultItem.java:49)
E/AndroidRuntime(14310): at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:108)
E/AndroidRuntime(14310): at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:68)
E/AndroidRuntime(14310): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1808)
E/AndroidRuntime(14310): at android.os.Handler.dispatchMessage(Handler.java:106)
E/AndroidRuntime(14310): at android.os.Looper.loop(Looper.java:193)
E/AndroidRuntime(14310): at android.app.ActivityThread.main(ActivityThread.java:6669)
E/AndroidRuntime(14310): at java.lang.reflect.Method.invoke(Native Method)
E/AndroidRuntime(14310): at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493)
E/AndroidRuntime(14310): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:858)
E/AndroidRuntime(14310): Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'android.content.ContentResolver android.app.Activity.getContentResolver()' on a null object reference
E/AndroidRuntime(14310): at net.goderbauer.flutter.contactpicker.ContactPickerPlugin.onActivityResult(ContactPickerPlugin.java:68)
E/AndroidRuntime(14310): at io.flutter.embedding.engine.FlutterEnginePluginRegistry$FlutterEngineActivityPluginBinding.onActivityResult(FlutterEnginePluginRegistry.java:634)
E/AndroidRuntime(14310): at io.flutter.embedding.engine.FlutterEnginePluginRegistry.onActivityResult(FlutterEnginePluginRegistry.java:367)
E/AndroidRuntime(14310): at io.flutter.embedding.android.FlutterActivityAndFragmentDelegate.onActivityResult(FlutterActivityAndFragmentDelegate.java:546)
E/AndroidRuntime(14310): at io.flutter.embedding.android.FlutterActivity.onActivityResult(FlutterActivity.java:594)
E/AndroidRuntime(14310): at android.app.Activity.dispatchActivityResult(Activity.java:7454)
E/AndroidRuntime(14310): at android.app.ActivityThread.deliverResults(ActivityThread.java:4353)
E/AndroidRuntime(14310): ... 11 more
I/Process (14310): Sending signal. PID: 14310 SIG: 9
Lost connection to device
知道为什么会这样吗？ 我正在使用contact_picker 0.0.2
电话簿出现，但单击联系人后，应用程序崩溃。
答案 0 :(得分：2)
您需要编辑以下文件 C：\您的发布缓存目录\ contact_picker-0.0.1 + 2 \ android \ src \ main \ java \ net \ goderbauer \ flutter \ contactpicker \ ContactPickerPlugin.java < / strong>，并替换为以下代码。
// Copyright 2017 Michael Goderbauer. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
package net.goderbauer.flutter.contactpicker;
import android.app.Activity;
import android.content.Intent;
import android.database.Cursor;
import android.net.Uri;
import android.provider.ContactsContract;
import java.util.HashMap;
import io.flutter.plugin.common.MethodChannel;
import io.flutter.plugin.common.MethodChannel.MethodCallHandler;
import io.flutter.plugin.common.MethodChannel.Result;
import io.flutter.plugin.common.MethodCall;
import io.flutter.plugin.common.PluginRegistry;
import io.flutter.plugin.common.PluginRegistry.Registrar;
import static android.app.Activity.RESULT_OK;
public class ContactPickerPlugin implements MethodCallHandler, PluginRegistry.ActivityResultListener {
public static void registerWith(Registrar registrar) {
final MethodChannel channel = new MethodChannel(registrar.messenger(), "contact_picker");
ContactPickerPlugin instance = new ContactPickerPlugin(registrar.activity());
registrar.addActivityResultListener(instance);
channel.setMethodCallHandler(instance);
}
private ContactPickerPlugin(Activity activity) {
this.activity = activity;
}
private static int PICK_CONTACT = 2015;
private Activity activity;
private Result pendingResult = null;
@Override
public void onMethodCall(MethodCall call, Result result) {
if (call.method.equals("selectContact")) {
if (pendingResult != null) {
pendingResult.error("multiple_requests", "Cancelled by a second request.", null);
pendingResult = null;
}
pendingResult = result;
Intent i = new Intent(Intent.ACTION_PICK, ContactsContract.CommonDataKinds.Phone.CONTENT_URI);
activity.startActivityForResult(i, PICK_CONTACT);
} else {
//result.notImplemented();
pendingResult = null;
}
}
@Override
public boolean onActivityResult(int requestCode, int resultCode, Intent data) {
if (requestCode != PICK_CONTACT) {
return false;
}
if (resultCode != RESULT_OK) {
pendingResult.success(null);
pendingResult = null;
}
if(pendingResult != null){
Uri contactUri = data.getData();
Cursor cursor = activity.getContentResolver().query(contactUri, null, null, null, null);
cursor.moveToFirst();
int phoneType = cursor.getInt(cursor.getColumnIndex(ContactsContract.CommonDataKinds.Phone.TYPE));
String customLabel = cursor.getString(cursor.getColumnIndex(ContactsContract.CommonDataKinds.Phone.LABEL));
String label = (String) ContactsContract.CommonDataKinds.Email.getTypeLabel(activity.getResources(), phoneType, customLabel);
String number = cursor.getString(cursor.getColumnIndex(ContactsContract.CommonDataKinds.Phone.NUMBER));
String fullName = cursor.getString(cursor.getColumnIndex(ContactsContract.CommonDataKinds.Phone.DISPLAY_NAME));
HashMap phoneNumber = new HashMap();
phoneNumber.put("number", number);
phoneNumber.put("label", label);
HashMap contact = new HashMap();
contact.put("fullName", fullName);
contact.put("phoneNumber", phoneNumber);
pendingResult.success(contact);
pendingResult = null;
return true;
}
else{
pendingResult = null;
return false;
}
}
}
干杯！