实现回收器视图以显示设备的联系人，使用联系人合同，但存在错误。我涉及下面的gradle错误代码

Question

我已经尝试在回收视图中显示设备联系人。我使用ContactsContract填充列表。我认为错误是没有获取联系人，但我不知道为什么。

你能检查一下我的错误吗?

误差

:

    10-11 17:50:21.550 27076-27076/com.example.anubh.contactsearch D/Proxy: setHttpRequestCheckHandler
    10-11 17:50:21.694 27076-27076/com.example.anubh.contactsearch D/OpenSSLLib: OpensslErr:Module:13(114:155); file:external/openssl/crypto/asn1/asn1_lib.c ;Line:142;Function:ASN1_get_object
    10-11 17:50:22.532 27076-27076/com.example.anubh.contactsearch D/ActivityThread: BIND_APPLICATION handled : 0 / AppBindData{appInfo=ApplicationInfo{14eaff4b com.example.anubh.contactsearch}}
    10-11 17:50:22.533 27076-27076/com.example.anubh.contactsearch V/ActivityThread: Handling launch of ActivityRecord{d9bd28 token=android.os.BinderProxy@2947ea41 {com.example.anubh.contactsearch/com.example.anubh.contactsearch.MainActivity}}
    10-11 17:50:22.803 27076-27076/com.example.anubh.contactsearch V/ActivityThread: ActivityRecord{d9bd28 token=android.os.BinderProxy@2947ea41 {com.example.anubh.contactsearch/com.example.anubh.contactsearch.MainActivity}}: app=android.app.Application@4684527, appName=com.example.anubh.contactsearch, pkg=com.example.anubh.contactsearch, comp={com.example.anubh.contactsearch/com.example.anubh.contactsearch.MainActivity}, dir=/data/app/com.example.anubh.contactsearch-1/base.apk
    10-11 17:50:22.941 27076-27076/com.example.anubh.contactsearch W/art: Before Android 4.1, method android.graphics.PorterDuffColorFilter android.support.graphics.drawable.VectorDrawableCompat.updateTintFilter(android.graphics.PorterDuffColorFilter, android.content.res.ColorStateList, android.graphics.PorterDuff$Mode) would have incorrectly overridden the package-private method in android.graphics.drawable.Drawable
    10-11 17:50:23.147 27076-27076/com.example.anubh.contactsearch I/AppCompatViewInflater: app:theme is now deprecated. Please move to using android:theme instead.
    10-11 17:50:23.440 27076-27076/com.example.anubh.contactsearch D/ActivityThread: hoder:android.app.IActivityManager$ContentProviderHolder@36d02546,provider,holder.Provider:android.content.ContentProviderProxy@1c1f6307
    10-11 17:50:23.482 27076-27076/com.example.anubh.contactsearch I/System.out: Name: Micromax carephone: 18605008286
    10-11 17:50:23.486 27076-27076/com.example.anubh.contactsearch D/AndroidRuntime: Shutting down VM
    10-11 17:50:23.487 27076-27076/com.example.anubh.contactsearch E/AndroidRuntime: FATAL EXCEPTION: main
                                                                                     Process: com.example.anubh.contactsearch, PID: 27076
                                                                                     java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.anubh.contactsearch/com.example.anubh.contactsearch.MainActivity}: java.lang.NullPointerException: Attempt to invoke interface method 'boolean java.util.List.add(java.lang.Object)' on a null object reference
                                                                                         at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2455)
                                                                                         at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2517)
                                                                                         at android.app.ActivityThread.access$800(ActivityThread.java:162)
                                                                                         at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1412)
                                                                                         at android.os.Handler.dispatchMessage(Handler.java:106)
                                                                                         at android.os.Looper.loop(Looper.java:189)
                                                                                         at android.app.ActivityThread.main(ActivityThread.java:5530)
                                                                                         at java.lang.reflect.Method.invoke(Native Method)
                                                                                         at java.lang.reflect.Method.invoke(Method.java:372)
                                                                                         at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:950)
                                                                                         at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:745)
                                                                                      Caused by: java.lang.NullPointerException: Attempt to invoke interface method 'boolean java.util.List.add(java.lang.Object)' on a null object reference
                                                                                         at com.example.anubh.contactsearch.myAdapter.<init>(myAdapter.java:71)
                                                                                         at com.example.anubh.contactsearch.MainActivity.onCreate(MainActivity.java:30)
                                                                                         at android.app.Activity.performCreate(Activity.java:5966)
                                                                                         at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1106)
                                                                                         at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2408)
                                                                                         at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2517) 
                                                                                         at android.app.ActivityThread.access$800(ActivityThread.java:162) 
                                                                                         at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1412) 
                                                                                         at android.os.Handler.dispatchMessage(Handler.java:106) 
                                                                                         at android.os.Looper.loop(Looper.java:189) 
                                                                                         at android.app.ActivityThread.main(ActivityThread.java:5530) 
                                                                                         at java.lang.reflect.Method.invoke(Native Method) 
                                                                                         at java.lang.reflect.Method.invoke(Method.java:372) 
                                                                                         at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:950) 
                                                                                         at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:745) 
    10-11 17:50:29.394 27076-27089/com.example.anubh.contactsearch W/CursorWrapperInner: Cursor finalized without prior close()

MainActivity.java

    package com.example.anubh.contactsearch;
    import android.os.AsyncTask;
    import android.support.v7.app.AppCompatActivity;
    import android.os.Bundle;
    import android.support.v7.widget.RecyclerView;
    import android.support.v7.widget.Toolbar;
    import android.view.Menu;
    import java.util.ArrayList;
    public class MainActivity extends AppCompatActivity {
        Toolbar toolbar;
        RecyclerView recyclerView;
        myAdapter adapter;
        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_main);
            toolbar = (Toolbar) findViewById(R.id.toolbar);
            setSupportActionBar(toolbar);
            //getSupportActionBar().setTitle("Contacts");
            getSupportActionBar().setSubtitle("Search");
            getSupportActionBar().setIcon(R.drawable.ic_action_toolbar);
            recyclerView = (RecyclerView) findViewById(R.id.recyclerview);
            adapter = new myAdapter(this);
            recyclerView.setAdapter(adapter);
        }
        @Override
        public boolean onCreateOptionsMenu(Menu menu) {
            getMenuInflater().inflate(R.menu.menu,menu);
            return super.onCreateOptionsMenu(menu);
        }
    }

myAdapter.java

    package com.example.anubh.contactsearch;
    import android.content.ContentResolver;
    import android.content.Context;
    import android.database.Cursor;
    import android.graphics.Bitmap;
    import android.graphics.BitmapFactory;
    import android.net.Uri;
    import android.provider.ContactsContract;
    import android.support.v7.widget.RecyclerView;
    import android.view.LayoutInflater;
    import android.view.View;
    import android.view.ViewGroup;
    import android.widget.ImageView;
    import android.widget.TextView;
    import java.io.BufferedInputStream;
    import java.io.InputStream;
    import java.util.List;
    public class myAdapter extends RecyclerView.Adapter<ListViewHolder>{
        private List<ListItems> listItemsList;
        private Context mContext;
        private int focusedItem = 0;
        public myAdapter(Context context){
            mContext = context;
            ContentResolver cr = mContext.getContentResolver();
            Cursor cur = cr.query(ContactsContract.Contacts.CONTENT_URI, null, null, null, null);
            String name;
            String phone = null;
            String image_uri = "";
            ListItems listItems;
            int i = 1;
            if (cur.getCount() > 0) {
                while (cur.moveToNext()) {
                    if(i == 1){
                        cur.moveToFirst();
                        i++;
                    }
                    String id = cur.getString(cur
                            .getColumnIndex(ContactsContract.Contacts._ID));
                    name = cur
                            .getString(cur
                                    .getColumnIndex(ContactsContract.Contacts.DISPLAY_NAME));
                    image_uri = cur
                            .getString(cur
                                    .getColumnIndex(ContactsContract.CommonDataKinds.Phone.PHOTO_URI));
                    Cursor pCur = cr.query(
                            ContactsContract.CommonDataKinds.Phone.CONTENT_URI,
                            null,
                            ContactsContract.CommonDataKinds.Phone.CONTACT_ID
                                    + " = ?", new String[]{id}, null);
                    if (pCur.moveToNext()) {
                        phone = pCur
                                .getString(pCur
                                        .getColumnIndex(ContactsContract.CommonDataKinds.Phone.NUMBER));
                        System.out.println("Name: "+ name + "phone: " + phone);
                    }
                    pCur.close();
                    listItems = new ListItems(name,phone,image_uri);
                    listItemsList.add(listItems);
                }
                cur.close();
            }
        }
        @Override
        public ListViewHolder onCreateViewHolder(ViewGroup viewGroup, int position) {
            Context context = viewGroup.getContext();
            LayoutInflater layoutInflater = LayoutInflater.from(context);
            View v = layoutInflater.inflate(R.layout.list_row,null);
            //View v = LayoutInflater.from(viewGroup.getContext()).inflate(R.layout.list_row,null);
            ListViewHolder holder = new ListViewHolder(v);
            holder.relativeLayout.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View view) {
                }
            });
            return holder;
        }
        @Override
        public void onBindViewHolder(ListViewHolder holder, int position) {
            ListItems listItems = listItemsList.get(position);
            TextView contact_name = holder.contactname;
            TextView contact_num = holder.contactnum;
            ImageView contact_image = holder.contactimage;
            contact_name.setText(listItems.getContactname());
            contact_num.setText(listItems.getContactnum());
            Uri myuri = Uri.parse(listItems.getThumbnail());
            InputStream photo_stream = ContactsContract.Contacts.openContactPhotoInputStream(mContext.getContentResolver(),myuri);
            BufferedInputStream buf =new BufferedInputStream(photo_stream);
            Bitmap my_btmp = BitmapFactory.decodeStream(buf);
            contact_image.setImageBitmap(my_btmp);
        }
        @Override
        public int getItemCount() {
            return listItemsList.size();
        }
    }

ListViewHolder.java

    package com.example.anubh.contactsearch;
    import android.support.v7.widget.RecyclerView;
    import android.view.View;
    import android.widget.ImageView;
    import android.widget.RelativeLayout;
    import android.widget.TextView;
    public class ListViewHolder extends RecyclerView.ViewHolder {
        protected ImageView contactimage;
        protected TextView contactname,contactnum;
        protected RelativeLayout relativeLayout;
        public ListViewHolder(View view){
            super(view);
            contactimage = (ImageView)view.findViewById(R.id.contactimage);
            contactname = (TextView) view.findViewById(R.id.contactname);
            contactnum = (TextView) view.findViewById(R.id.contactno);
            relativeLayout = (RelativeLayout) view.findViewById(R.id.relativeLayout);
            view.setClickable(false);
        }
    }

ListItems.java

    package com.example.anubh.contactsearch;
    public class ListItems {
        private String Contactname,contactnum,thumbnail;
        public ListItems(String name,String number,String imageuri){
            this.Contactname = name;
            this.contactnum = number;
            this.thumbnail = imageuri;
        }
        public String getContactname() {
            return Contactname;
        }
        public void setContactname(String contactname) {
            Contactname = contactname;
        }
        public String getContactnum() {
            return contactnum;
        }
        public void setContactnum(String contactnum) {
            this.contactnum = contactnum;
        }
        public String getThumbnail() {
            return thumbnail;
        }
        public void setThumbnail(String thumbnail) {
            this.thumbnail = thumbnail;
        }
    }

Manifest.xml

    <?xml version="1.0" encoding="utf-8"?>
    <manifest xmlns:android="http://schemas.android.com/apk/res/android"
        package="com.example.anubh.contactsearch">
        <uses-permission android:name="android.permission.READ_CONTACTS" />
        <application
            android:allowBackup="true"
            android:icon="@mipmap/ic_launcher"
            android:label="@string/app_name"
            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>
                <meta-data android:name="android.app.searchable"
                    android:resource="@xml/searchable"/>
            </activity>
        </application>
    </manifest>

Answer 1

将这行添加到"myAdapter"构造函数中。

listItemsList = new ArrayList<>();

Answer 2

我知道这是一个旧线程，但我已经检查了你的代码，因为我正在做类似的事情。我看到你的RecyclerView没有显示任何东西的问题，问题可能在于你如何处理你的ListItems对象。

首先，你已经忘记了MainActivity.java中的布局管理器:

recyclerView.setLayoutManager(new LinearLayoutManager(getApplicationContext()));

第二，您没有检查来确定用户是否有图像，因为如果没有，您将收到一个空指针异常错误。当您在thumbnail变量中存储null值时，稍后尝试在适配器

中访问它

Uri myuri = Uri.parse(listItems.getThumbnail());

缺少一个简单的检查，例如

if (listItems.getThumbnail() != null) {
    Uri myuri = Uri.parse(listItems.getThumbnail());
    InputStream photo_stream = ContactsContract.Contacts.openContactPhotoInputStream(mContext.getContentResolver(),myuri);
    BufferedInputStream buf =new BufferedInputStream(photo_stream);
    Bitmap my_btmp = BitmapFactory.decodeStream(buf);
    contact_image.setImageBitmap(my_btmp);
} else {
    // Find an alternative method, like displaying custom ImageView with name initials
}

最后，我想指出一个多余的if语句在适配器的构造函数

if(i == 1){
    cur.moveToFirst();
    i++;
}

不需要另外核对，你只需写上

cur.moveToFirst();