package com.wangzhu.demo;import android.content.ContentProvider;import android.content.ContentValues;import android.content.Context;import android.database.Cursor;import android.database.sqlite.SQLiteDatabase;import android.net.Uri;public class MyContentProvider extends ContentProvider {    /**     * ContentProvider的数据访问路径     */    public static final Uri URI = Uri.parse("content://com.wangzhu.provider");    private SQLiteDatabase database;    @Override    public int delete(Uri arg0, String arg1, String[] arg2) {        return 0;    }    @Override    public String getType(Uri arg0) {        return null;    }    @Override    public Uri insert(Uri uri, ContentValues values) {        database.insert("tab", "_id", values);        return null;    }    @Override    public boolean onCreate() {        database = getContext().openOrCreateDatabase("myProvider.db3",                Context.MODE_PRIVATE, null);        database.execSQL("create table IF NOT EXISTS tab(_id INTEGER PRIMARY KEY AUTOINCREMENT,name TEXT NOT NULL)");        return true;    }    @Override    public Cursor query(Uri arg0, String[] arg1, String arg2, String[] arg3,            String arg4) {        Cursor cursor = database.query("tab", null, null, null, null, null,                null);        return cursor;    }    @Override    public int update(Uri arg0, ContentValues arg1, String arg2, String[] arg3) {        return 0;    }}

        <!-- android:exported设置为true，表示其他应用可以访问，否则不可以访问 -->        <provider            android:name="MyContentProvider"            android:authorities="com.wangzhu.provider"            android:exported="true" >        </provider>

        final Uri uri = MyContentProvider.URI;    /**     * 往Provider中写入数据     */    protected void write() {        //使用getContentResolver()方法获取ContentResolver对象        ContentResolver resolver = getContentResolver();        ContentValues values = null;        values = new ContentValues();        values.put("name", "Java");        //调用ContentResolver对象的insert方法，插入数据        resolver.insert(uri, values);        values = new ContentValues();        values.put("name", "Swift");        resolver.insert(uri, values);        values = new ContentValues();        values.put("name", "Python");        resolver.insert(uri, values);        values = new ContentValues();        values.put("name", "C#");        resolver.insert(uri, values);    }    /**     * 读取Provider中的内容     */    protected void read() {        StringBuilder accum = new StringBuilder();        //使用getContentResolver()方法获取ContentResolver对象        //调用ContentResolver对象的query方法，查询数据，返回Cursor对象        Cursor cursor = getContentResolver().query(uri, null, null, null, null);        cursor.moveToFirst();        for (int i = 0, count = cursor.getCount(); i < count; i++) {            accum.append(cursor.getString(cursor.getColumnIndex("name")))                    .append("\n");            cursor.moveToNext();        }        System.err.println("read: " + accum);    }