Android开发笔记(五十四)数据共享接口ContentProvider

ContentProvider

前面几节介绍了进程间通信的几种方式,包括消息包级别的Messenger、接口调用级别的AIDL、启动页面/服务级别的Notification,还有就是本节这个数据库级别的ContentProvider。
ContentProvider为存取数据提供统一的接口,它让不同APP之间得以共享数据。ContentProvider类本身是个服务端的数据存取接口,主要操作类似SQLite,也都提供了如下常见的数据库管理API:
query : 查询数据。
insert : 插入数据。
update : 更新数据。
delete : 删除数据。
getType : 获取数据类型。
实际开发中,APP很少会开放数据接口给其他应用,所以ContentProvider类作为服务端接口反而基本用不到。Content组件中能够用到的场合,基本上是APP想要使用系统的手机通讯数据,比如查看联系人/短信/彩信/通话记录,以及对这些通讯信息进行增删改。


ContentResolver

使用说明

ContentResolver是客户端APP用来操作服务端数据的接口,相对应的ContentProvider是服务端的接口。获取一个ContentResolver对象,调用Context.getContentResolver()即可。
与ContentProvider一样,客户端的ContentResolver也提供了query、insert、update、delete、getType等等方法。其中最常用的是query函数,调用该函数返回一个Cursor对象,有关Cursor的操作参见《 Android开发笔记(三十一)SQLite游标及其数据结构》。下面是query的具体参数说明:
uri : Uri类型,可以理解为本次操作的数据表路径
projection : String[]类型,指定将要查询的字段名列表
selection : String类型,指定查询条件
selectionArgs : String[]类型,指定查询条件中的参数取值列表
sortOrder : String类型,指定排序条件


下面是ContentResolver在查看通讯信息中的具体运用:


读取联系人

代码示例如下:
	private static Uri mContactUri = ContactsContract.CommonDataKinds.Phone.CONTENT_URI;
	private static String[] mContactColumn = new String[] {
		ContactsContract.CommonDataKinds.Phone.NUMBER,
		ContactsContract.CommonDataKinds.Phone.DISPLAY_NAME };

	public static int readPhoneContacts(ContentResolver resolver) {
		ArrayList<Contact> contactArray = new ArrayList<Contact>();
		Cursor cursor = resolver.query(mContactUri, mContactColumn, null, null, null);
		if (cursor.moveToFirst()) {
			for (;; cursor.moveToNext()) {
				Contact contact = new Contact();
				contact.phone = cursor.getString(0).replace("+86", "").replace(" ", "");
				contact.name = cursor.getString(1);
				Log.d(TAG, contact.name+" "+contact.phone);
				contactArray.add(contact);
				if (cursor.isLast() == true) {
					break;
				}
			}
		}
		cursor.close();
		return contactArray.size();
	}

上面代码获取的是手机里的联系人。获取SIM卡上的联系人与之类似,不同之处要把Uri换成“content://icc/adn”。



读取短信

代码示例如下:
	private static Uri mSmsUri;
	private static String[] mSmsColumn;
	
	@TargetApi(Build.VERSION_CODES.KITKAT)
	public static int readSms(ContentResolver resolver, String phone, int gaps) {
		if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT) {
			mSmsUri = Telephony.Sms.Inbox.CONTENT_URI;
			mSmsColumn = new String[] { 
					Telephony.Sms.ADDRESS, Telephony.Sms.PERSON,
					Telephony.Sms.BODY, Telephony.Sms.DATE,
					Telephony.Sms.TYPE};
		} else {
			mSmsUri = Uri.parse("content://sms/inbox");
			mSmsColumn = new String[] { "address","person","body","date","type" };
		}
		ArrayList<SmsContent> smsArray = new ArrayList<SmsContent>();
		String selection = "";
		if (phone!=null && phone.length()>0) {
			selection = String.format("address='%s'", phone);
		}
		if (gaps > 0) {
			selection = String.format("%s%sdate>%d", selection, 
					(selection.length()>0)?" and ":"", System.currentTimeMillis()-gaps*1000);
		}
		Cursor cursor = resolver.query(mSmsUri, mSmsColumn, selection, null, "date desc");
		if (cursor.moveToFirst()) {
			for (;; cursor.moveToNext()) {
				SmsContent sms = new SmsContent();
				sms.address = cursor.getString(0);
				sms.person = cursor.getString(1);
				sms.body = cursor.getString(2);
				sms.date = formatDate(cursor.getLong(3));
				sms.type = cursor.getInt(4);  //type=1表示收到的短信,type=2表示发送的短信
				Log.d(TAG, sms.address+" "+sms.person+" "+sms.date+" "+sms.type+" "+sms.body);
				smsArray.add(sms);
				if (cursor.isLast() == true) {
					break;
				}
			}
		}
		cursor.close();
		return smsArray.size();
	}



读取彩信

代码示例如下:
	private static Uri mMmsUri;
	private static String[] mMmsColumn;
	
	@TargetApi(Build.VERSION_CODES.KITKAT)
	public static int readMms(ContentResolver resolver, int gaps) {
		if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT) {
			mMmsUri = Telephony.Mms.Inbox.CONTENT_URI;
			mMmsColumn = new String[] { 
					Telephony.Mms.DATE, Telephony.Mms.READ,
					Telephony.Mms.SUBJECT, Telephony.Mms.EXPIRY,
					Telephony.Mms.STATUS, Telephony.Mms.MESSAGE_SIZE};
		} else {
			mMmsUri = Uri.parse("content://mms/inbox");
			mMmsColumn = new String[] { "date","read","sub","exp","st","m_size" };
		}
		ArrayList<MmsContent> mmsArray = new ArrayList<MmsContent>();
		String selection = String.format("date>%d", System.currentTimeMillis()-gaps*1000);
		Cursor cursor = resolver.query(mMmsUri, mMmsColumn, selection, null, "date desc");
		if (cursor.moveToFirst()) {
			for (;; cursor.moveToNext()) {
				MmsContent mms = new MmsContent();
				mms.date = formatDate(cursor.getLong(0));
				mms.read = cursor.getString(1);
				mms.subject = cursor.getString(2);
				mms.expire = cursor.getString(3);
				mms.status = cursor.getString(4);
				mms.message_size = cursor.getString(5);
				Log.d(TAG, mms.date+" "+mms.read+" "+mms.subject+" "+mms.expire+" "+mms.status+" "+mms.message_size);
				mmsArray.add(mms);
				if (cursor.isLast() == true) {
					break;
				}
			}
		}
		cursor.close();
		return mmsArray.size();
	}



读取通话记录

代码示例如下:
	private static Uri mRecordUri = CallLog.Calls.CONTENT_URI;
	private static String[] mRecordColumn = new String[] { 
		CallLog.Calls.CACHED_NAME, CallLog.Calls.NUMBER, CallLog.Calls.TYPE,
		CallLog.Calls.DATE, CallLog.Calls.DURATION, CallLog.Calls.NEW };
	
	public static int readCallRecord(ContentResolver resolver, int gaps) {
		ArrayList<CallRecord> recordArray = new ArrayList<CallRecord>();
		String selection = String.format("date>%d", System.currentTimeMillis()-gaps*1000);
		Cursor cursor = resolver.query(mRecordUri, mRecordColumn, selection, null, "date desc");
		if (cursor.moveToFirst()) {
			for (;; cursor.moveToNext()) {
				CallRecord record = new CallRecord();
				record.name = cursor.getString(0);
				record.phone = cursor.getString(1);
				record.type = cursor.getInt(2);  //type=1表示接听,2表示拨出,3表示未接
				record.date = formatDate(cursor.getLong(3));
				record.duration = cursor.getLong(4);
				record._new = cursor.getInt(5);
				Log.d(TAG, record.name+" "+record.phone+" "+record.type+" "+record.date+" "+record.duration);
				recordArray.add(record);
				if (cursor.isLast() == true) {
					break;
				}
			}
		}
		cursor.close();
		return recordArray.size();
	}




ContentProviderOperation

使用说明

前面说过,ContentResolver可以由客户端用来给服务端添加数据,不过有时候某种数据在服务端对应的是多张表,比如说联系人信息在服务端实际有联系人姓名表、联系人电话表(因为有家庭电话、工作电话之分)、联系人电子邮箱表。对于这种情况,使用ContentResolver固然可以通过多次插入来实现,可是多次插入就对应多个事务,一旦某次插入失败,那我们还得手工进行回滚操作,非常麻烦。
针对上面的问题,Android提供了ContentProviderOperation类,用于在一个事务中批量插入多条记录,这样即使出现失败,也会由ContentProviderOperation统一处理回滚事宜,避免了开发者关注内部事务的麻烦。


下面是两种插入方式在添加联系人信息中的具体运用:


ContentResolver方式

代码示例如下:
public static void addContacts(ContentResolver resolver) {
	//往 raw_contacts 中添加数据,并获取添加的id号
	Uri raw_uri = Uri.parse("content://com.android.contacts/raw_contacts");
	ContentValues values = new ContentValues();
	long contactId = ContentUris.parseId(resolver.insert(raw_uri, values));
		
	//往 data 中添加数据(要根据前面获取的id号)
	Uri uri = Uri.parse("content://com.android.contacts/data");
        ContentValues name = new ContentValues();
        name.put("raw_contact_id", contactId);
        name.put("mimetype", "vnd.android.cursor.item/name");
        name.put("data2", "阿四");
        resolver.insert(uri, name);
          
        ContentValues phone = new ContentValues();
        phone.put("raw_contact_id", contactId);
        phone.put("mimetype", "vnd.android.cursor.item/phone_v2");
        phone.put("data2", "2");
        phone.put("data1", "15960238696");
        resolver.insert(uri, phone);

        ContentValues email = new ContentValues();
        email.put("raw_contact_id", contactId);
        email.put("mimetype", "vnd.android.cursor.item/email_v2");
        email.put("data2", "2");
        email.put("data1", "[email protected]");
        resolver.insert(uri, email);
}



ContentProviderOperation方式

代码示例如下:
public static void addFullContacts(ContentResolver resolver) {
	Uri raw_uri = Uri.parse("content://com.android.contacts/raw_contacts");
	Uri uri = Uri.parse("content://com.android.contacts/data");
        
        ContentProviderOperation op_main = ContentProviderOperation.newInsert(raw_uri)
                .withValue("account_name", null).build();
        ContentProviderOperation op_name = ContentProviderOperation.newInsert(uri)
                .withValueBackReference("raw_contact_id", 0)
                .withValue("mimetype", "vnd.android.cursor.item/name")
                .withValue("data2", "阿三").build();
        ContentProviderOperation op_phone = ContentProviderOperation.newInsert(uri)
                .withValueBackReference("raw_contact_id", 0)
                .withValue("mimetype", "vnd.android.cursor.item/phone_v2")
                .withValue("data2", "2")
                .withValue("data1", "15960238696").build();
        ContentProviderOperation op_email = ContentProviderOperation
                .newInsert(uri).withValueBackReference("raw_contact_id", 0)
                .withValue("mimetype", "vnd.android.cursor.item/email_v2")
                .withValue("data2", "2")
                .withValue("data1", "[email protected]").build();  
        
        ArrayList<ContentProviderOperation> operations = new ArrayList<ContentProviderOperation>();
        operations.add(op_main);
        operations.add(op_name);
        operations.add(op_phone);
        operations.add(op_email);
        try {
            resolver.applyBatch("com.android.contacts", operations);
        } catch (Exception e) {
            e.printStackTrace();
        }
}




ContentObserver

使用说明

有时我们不但要获取以往的数据,还要实时获取新增的数据,最常见的业务场景便是短信验证码。电商APP中常常在用户注册或者付款时下发验证码短信,这时为提高用户体验,APP就得自动获取手机刚收到的短信验证码。类似的场景在系统APP中也存在,比如流量监控APP向运营商发送流量校准短信,此时APP也得自动拦截短信来获取流量信息。
由于系统在接收短信后会同时发出一个广播“android.provider.Telephony.SMS_RECEIVED”,所以我们可以使用广播接收器来监听短信的接收动作。然而不是所有的系统数据变更都会触发广播(比如添加联系人),所以Android又提供了ContentObserver类,该类可协助处理Content数据变化的监听事件。
下面是在ContentResolver对象中使用ContentObserver的相关方法:
registerContentObserver : 注册内容观察者。
unregisterContentObserver : 注销内容观察者。
notifyChange : 通知内容观察者发生了数据变化。


下面是两种监听方式在监听短信接收中的具体运用,监听结果消息使用了Notification推送到消息栏,有关Notification的使用说明参见《 Android开发笔记(五十二)通知推送Notification》。


广播方式

广播类的代码示例如下:
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.os.Bundle;
import android.telephony.SmsMessage;
import android.util.Log;

public class SmsGetReceiver extends BroadcastReceiver {
    private static final String TAG = "SmsGetReceiver";

    @Override
    public void onReceive(Context context, Intent intent) {
        Log.d(TAG, "onReceive");
        Bundle bundle = intent.getExtras();
        SmsMessage[] smsMessages = null;
        Object[] pdus = null;

        if (bundle != null) {
            pdus = (Object[]) bundle.get("pdus");
        }
        if (pdus !=null){
            smsMessages = new SmsMessage[pdus.length];
            String sender = "";
            String content = "";
            for (int i=0; i<pdus.length; i++){
                smsMessages[i] = SmsMessage.createFromPdu((byte[]) pdus[i]);
                sender = smsMessages[i].getOriginatingAddress();
                content = smsMessages[i].getMessageBody();
                Log.d(TAG, "SMS:"+sender+content);
            }
            NotificationUtil.sendSmsNotify(context, "广播来源:"+sender, content);
        }
    }
}


配置文件需要注册该广播
		<receiver android:name=".content.util.SmsGetReceiver">
				<intent-filter>
						<action android:name="android.provider.Telephony.SMS_RECEIVED" />
				</intent-filter>
		</receiver>



观察者方式

观察者类的代码示例如下:
import android.annotation.TargetApi;
import android.content.Context;
import android.database.ContentObserver;
import android.database.Cursor;
import android.net.Uri;
import android.os.Build;
import android.os.Handler;
import android.provider.Telephony;

@TargetApi(Build.VERSION_CODES.KITKAT)
public class SmsGetObserver extends ContentObserver {

	private static final String TAG = "SmsGetObserver";
	private Context mContext;
	private static Uri mSmsUri;
	private static String[] mSmsColumn;
	
	public SmsGetObserver(Context context, Handler handler) {
		super(handler);
		mContext = context;
		if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT) {
			mSmsUri = Telephony.Sms.Inbox.CONTENT_URI;
			mSmsColumn = new String[] { 
					Telephony.Sms.ADDRESS, Telephony.Sms.BODY, Telephony.Sms.DATE };
		} else {
			mSmsUri = Uri.parse("content://sms/inbox");
			mSmsColumn = new String[] { "address","body","date" };
		}
	}

	@Override
	public void onChange(boolean selfChange) {
        String sender = "";
        String content = "";
		String selection = String.format("date>%d", System.currentTimeMillis()-2*1000);
		Cursor cursor = mContext.getContentResolver().query(
				mSmsUri, mSmsColumn, selection, null, null);
		while(cursor.moveToNext()){
			sender = cursor.getString(0);
			content = cursor.getString(1);
		}
		cursor.close();
        NotificationUtil.sendSmsNotify(mContext, "观察者来源:"+sender, content);
		super.onChange(selfChange);
	}
}


主页面中对观察者类的调用代码如下:
		SmsGetObserver observer = new SmsGetObserver(this, new Handler());
		getContentResolver().registerContentObserver(
				Uri.parse("content://sms"), true, observer);



常用的Uri

总结下在Content组件中使用过程中遇到的几个Uri常量:
联系人信息(不包含手机号与电子邮箱):
ContactsContract.Contacts.CONTENT_URI   content://com.android.contacts/contacts
联系人电话信息:
ContactsContract.CommonDataKinds.Phone.CONTENT_URI   content://com.android.contacts/data/phones
联系人邮箱信息:
ContactsContract.CommonDataKinds.Email.CONTENT_URI   content://com.android.contacts/data/emails
SIM卡联系人信息:
content://icc/adn
短信信息:
Telephony.Sms.CONTENT_URI   content://sms
彩信信息:
Telephony.Mms.CONTENT_URI   content://mms
通话记录信息:
CallLog.Calls.CONTENT_URI   content://call_log/calls


下面是与短信有关的Uri分类说明:
收件箱:
Telephony.Sms.Inbox.CONTENT_URI   content://sms/inbox
已发送:
Telephony.Sms.Sent.CONTENT_URI   content://sms/sent
草稿箱:
Telephony.Sms.Draft.CONTENT_URI   content://sms/draft
发件箱(正在发送的信息):
Telephony.Sms.Outbox.CONTENT_URI   content://sms/outbox
发送失败:
content://sms/failed         
待发送列表(比如开启飞行模式后,该短信就在待发送列表里):
content://sms/queued    
 




点此查看Android开发笔记的完整目录

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