ContentProvider和ContentResolver应用

主要是调用现成的ContentProvider...

ContentResolver是通过URI来查询ContentProvider中提供的数据.
在android中，每个应用程序是可以实现数据共享的，都拥有一个contentprovider实例，而contentresolver用于管理程序的contentprovider实例.
首先需要获得一个ContentResolver的实例，可通过Activity的成员方法getContentResovler（）方法：ContentResolver contentResolver = getContentResolver();

ContentResolver实例带的方法可实现找到指定的Contentprovider并获取到Contentprovider的数据。

When you want to access data in a content provider, you use the ContentResolver object in your application's Context to communicate with the provider as a client. The ContentResolver object communicates with the provider object, an instance of a class that implements ContentProvider. The provider object receives data requests from clients, performs the requested action, and returns the results.

在配置文件中要加上权限
<uses-permission android:name="android.permission.READ_CONTACTS"/>



step1:建立android工程,命名为ContentProviderTest.
step2:设置配置文件
main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical" >

    <TextView
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="@string/hello" />

    <Button
        android:id="@+id/button01"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="@string/read" />

</LinearLayout>

strings.xml

<?xml version="1.0" encoding="utf-8"?>
<resources>

    <string name="hello">Hello World, ContentProviderTest!</string>
    <string name="app_name">ContentProviderTest</string>
    <string name="read">读取联系人</string>
</resources>

AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.cb.contentprovider"
    android:versionCode="1"
    android:versionName="1.0" >

    <uses-sdk android:minSdkVersion="10" />

    <application
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name" >
        <activity
            android:label="@string/app_name"
            android:name=".ContentProviderTest" >
            <intent-filter >
                <action android:name="android.intent.action.MAIN" />

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

    <!-- 必须加入访问权限,官方文档中解释:Allows an application to read the user's contacts data. -->
    <uses-permission android:name="android.permission.READ_CONTACTS" />

</manifest>

step3:ContentProviderTest.java

package com.cb.contentprovider;

import android.app.Activity;
import android.content.ContentResolver;
import android.database.Cursor;
import android.os.Bundle;
import android.provider.ContactsContract;
import android.view.View;
import android.widget.Button;
import android.widget.Toast;

//使用现成的Content Provider

public class ContentProviderTest extends Activity {
    private Button mButton;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        mButton = (Button) findViewById(R.id.button01);

        mButton.setOnClickListener(new Button.OnClickListener() {

            @Override
            public void onClick(View v) {

                /*
                 * 官方文档对ContentReceiver的解释: This class provides applications
                 * access to the content model
                 */
                ContentResolver mContentResolver = getContentResolver();

                // 读取所有联系人记录
                Cursor cursor = mContentResolver.query(
                        ContactsContract.Contacts.CONTENT_URI, null, null,
                        null, null);
                if (cursor.moveToFirst()) { // 当记录不为空时

                    /*
                     * 根据getColumnIndex(string name)中的
                     * 参数name的名称获得它的列索引，
                     * 因为getString，getInt这些方法需要的是列索引,而不是列名称。!!!!!提醒自己
                     */
                    int idColumn = cursor
                            .getColumnIndex(ContactsContract.Contacts._ID);
                    int nameColumn = cursor
                            .getColumnIndex(ContactsContract.Contacts.DISPLAY_NAME);
                    do {
                        // 获得联系人的id号
                        String contactId = cursor.getString(idColumn);
                        // 获得联系人的姓名
                        String contactName = cursor.getString(nameColumn);

                        Toast.makeText(ContentProviderTest.this,
                                "id号:" + contactId + ", 联系人姓名:" + contactName,
                                Toast.LENGTH_SHORT).show();

                        // 查看该联系人有多少个电话号码
                        int phoneCount = cursor.getInt(cursor
                                .getColumnIndex(ContactsContract.Contacts.HAS_PHONE_NUMBER));
                        if (phoneCount > 0) {
                            // 获得联系人的电话号码列表
                            Cursor phonesCursor = mContentResolver
                                    .query(ContactsContract.CommonDataKinds.Phone.CONTENT_URI,
                                            null,
                                            ContactsContract.CommonDataKinds.Phone.CONTACT_ID
                                                    + " = " + contactId, null,
                                            null);
                            if (phonesCursor.moveToFirst()) {
                                do {
                                    // 遍历所有的电话号码
                                    String phoneNumber = phonesCursor.getString(phonesCursor
                                            .getColumnIndex(ContactsContract.CommonDataKinds.Phone.NUMBER));
                                    Toast.makeText(ContentProviderTest.this,
                                            "联系人电话：" + phoneNumber,
                                            Toast.LENGTH_LONG).show();
                                } while (phonesCursor.moveToNext());
                            }

                        }

                    } while (cursor.moveToNext());
                }
            }
        });

    }
}

step4:图示