电信电信网站备案系统,专业的集团网站开发开发,淄博著名网站开发方法,网站建设服务器租用目 录PersonCpPersonCp.javainsert()ContentObserver音乐播放器1、添加读写权限1.1、动态权限授予(调用封装好的方法)2、获取音乐文件(MainActivity.java)2、Music.java(实体类)申请访问SD卡的权限设置适配器下拉刷新PersonCpPersonCp.javapackage cn.wangzg.personcp;import a…目 录PersonCpPersonCp.javainsert()ContentObserver音乐播放器1、添加读写权限1.1、动态权限授予(调用封装好的方法)2、获取音乐文件(MainActivity.java)2、Music.java(实体类)申请访问SD卡的权限设置适配器下拉刷新PersonCpPersonCp.javapackage cn.wangzg.personcp;import android.content.ContentProvider;import android.content.ContentUris;import android.content.ContentValues;import android.content.UriMatcher;import android.database.Cursor;import android.database.sqlite.SQLiteDatabase;import android.net.Uri;import java.util.Objects;public class PersonCp extends ContentProvider { //数据库作为数据源将数据保存到数据库中。private MyHelper mHelper;private final static String AUTHORITY cn.wangzg.personprovider;private static UriMatcher mUriMatcher;private static final int PERSON_DIR 0;private static final int PERSON 1;static {mUriMatcher new UriMatcher(UriMatcher.NO_MATCH);// 该URI表示返回所有的person,其中PERSONS为该特定Uri的标识码mUriMatcher.addURI(AUTHORITY, person, PERSON_DIR);// 该URI表示返回某一个person,其中PERSON为该特定Uri的标识码mUriMatcher.addURI(AUTHORITY, person/#, PERSON);}Overridepublic String getType(Uri uri) {switch (mUriMatcher.match(uri)) {case PERSON_DIR:return vnd.android.cursor.dir/ AUTHORITY .persons;case PERSON:return vnd.android.cursor.item/ AUTHORITY .person;default:throw new IllegalArgumentException(unknown uri uri.toString());}}Overridepublic boolean onCreate() {mHelper new MyHelper(getContext());return true;}Overridepublic Uri insert(Uri uri, ContentValues values) {SQLiteDatabase db mHelper.getWritableDatabase();switch (mUriMatcher.match(uri)) {case PERSON_DIR:long newId db.insert(person, name,phone,salary, values);//向外界通知该ContentProvider里的数据发生了变化 ,以便ContentObserver作出相应getContext().getContentResolver().notifyChange(uri, null);return ContentUris.withAppendedId(uri, newId);default:throw new IllegalArgumentException(unknown uri uri.toString());}}Overridepublic int update(Uri uri, ContentValues values, String selection, String[] selectionArgs) {SQLiteDatabase db mHelper.getWritableDatabase();int updatedNum 0;switch (mUriMatcher.match(uri)) {// 更新表case PERSON_DIR:updatedNum db.update(person, values, selection, selectionArgs);break;// 按照id更新某条数据case PERSON:long id ContentUris.parseId(uri);String where id id;if (selection ! null !.equals(selection.trim())) {where selection and where;}updatedNum db.update(person, values, where, selectionArgs);break;default:throw new IllegalArgumentException(unknown uri uri.toString());}//向外界通知该ContentProvider里的数据发生了变化 ,以便ContentObserver作出相应Objects.requireNonNull(getContext()).getContentResolver().notifyChange(uri, null);return updatedNum;}Overridepublic int delete(Uri uri, String selection, String[] selectionArgs) {SQLiteDatabase db mHelper.getWritableDatabase();int deletedNum 0;switch (mUriMatcher.match(uri)) {// 删除表case PERSON_DIR:deletedNum db.delete(person, selection, selectionArgs);break;// 按照id删除某条数据case PERSON:long id ContentUris.parseId(uri);String where id id;if (selection ! null !.equals(selection.trim())) {where selection and where;}deletedNum db.delete(person, where, selectionArgs);break;default:throw new IllegalArgumentException(unknown uri uri.toString());}//向外界通知该ContentProvider里的数据发生了变化 ,以便ContentObserver作出相应Objects.requireNonNull(getContext()).getContentResolver().notifyChange(uri, null);return deletedNum;}Overridepublic Cursor query(Uri uri, String[] projection, String selection, String[] selectionArgs, String sortOrder) {SQLiteDatabase db mHelper.getWritableDatabase();Cursor cursor null;switch (mUriMatcher.match(uri)) {// 查询表case PERSON_DIR:cursor db.query(person, projection, selection, selectionArgs, null, null, sortOrder);break;// 按照id查询某条数据case PERSON:// 第一步:long id ContentUris.parseId(uri);String where id id;// 第二步:if (selection ! null !.equals(selection.trim())) {where selection and where;}cursor db.query(person, projection, where, selectionArgs, null, null, sortOrder);break;default:throw new IllegalArgumentException(unknown uri uri.toString());}return cursor;}}insert()ContentObserver菜鸟教程 【4.4.1 ContentProvider初探】https://www.runoob.com/w3cnote/android-tutorial-contentprovider.html音乐播放器1、添加读写权限1.1、动态权限授予(调用封装好的方法)2、获取音乐文件(MainActivity.java)2、Music.java(实体类)申请访问SD卡的权限设置适配器下拉刷新点个赞吧~ b(▽)d求求了~小本生意不容易啊~
