关于android中自定义contentprovider的使用
在android开发中，有时需要在一个应用中调用操作系统中的另一个应用，而这个操作需要用到contentprovider，今天学习自定义的contentprovider，在android中contentprovider实际上是操作sqlite数据库来增删查改数据的，所以我们需要先写一个继承自SqliteOpenhelper的类，来创建数据库
MysqliteOpenhelper类
public class MySqliteOpenhelper extends SQLiteOpenHelper {
private String dbName = "people.db";
public MySqliteOpenhelper(Context context, String name,
CursorFactory factory, int version) {
super(context, name, null,1);
// TODO Auto-generated constructor stub
}
@Override
public void onCreate(SQLiteDatabase db) {
// TODO Auto-generated method stub
//创建userinfo表的sql语句
String sql = "create table userinfo(id int auto_increate,name varchar(30),age int,phone varchar(50))";
db.execSQL(sql);//创建表
}
@Override
public void onUpgrade(SQLiteDatabase arg0, int arg1, int arg2) {
// TODO Auto-generated method stub
}
}
接下来创建需要操作的UserInfo实体类
public class UserInfo {
private int id;
private String name;
private String phone;
private int age;
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getPhone() {
return phone;
}
public void setPhone(String phone) {
this.phone = phone;
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
public UserInfo(int id, String name, String phone, int age) {
super();
this.id = id;
this.name = name;
this.phone = phone;
this.age = age;
}
public UserInfo(String name, String phone, int age) {
super();
this.name = name;
this.phone = phone;
this.age = age;
}
@Override
public String toString() {
return "UserInfo [id=" + id + ", name=" + name + ", phone=" + phone
+ ", age=" + age + "]";
}
<span style="color:#ff0000;">
}</span> 创建需要向其他应用提供数据操作的contentprovider，MyContentProvider类
public class MyContentProvider extends ContentProvider {
private UriMatcher uriMatcher;//声明需要封装uri的urimatcher
private MySqliteOpenhelper helper;//声明创建数据库的helper
private static final int USERINFO = 1;
private static final int USERINFOS = 2;
@Override
public boolean onCreate() {
// TODO Auto-generated method stub
uriMatcher = new UriMatcher(UriMatcher.NO_MATCH);
//添加uri
uriMatcher.addURI("com.test.self.provider","userinfo/#",USERINFO);//#是一个通配符
uriMatcher.addURI("com.test.self.provider","userinfos",USERINFOS);//整张表
helper = new MySqliteOpenhelper(getContext());
return true;
}
@Override
public int delete(Uri uri, String selection, String[] selectionArgs) {
// TODO Auto-generated method stub
SQLiteDatabase db = helper.getWritableDatabase();
int deleteNumber;
switch (uriMatcher.match(uri)) {
case USERINFOS://删除全部数据
deleteNumber = db.delete("userinfo",selection,selectionArgs);
return deleteNumber;
case USERINFO:
long id = ContentUris.parseId(uri);//解析得到需要删除的行的id
String where = "id="+id;
if (selection != null && !"".equals(selection)) {//如果有其他条件
where = selection +" and "+where;
}
deleteNumber = db.delete("userinfo",where,selectionArgs);
return deleteNumber;
default:
throw new IllegalArgumentException("unknow uri:"+uri);
}
}
@Override
public String getType(Uri arg0) {
// TODO Auto-generated method stub
return null;
}
@Override
public Uri insert(Uri uri, ContentValues values) {
// TODO Auto-generated method stub
SQLiteDatabase db = helper.getWritableDatabase();
long insertId;
switch (uriMatcher.match(uri)) {
case USERINFOS:
insertId = db.insert("userinfo",null,values);//null表示每一列都插入
return ContentUris.withAppendedId(uri, insertId);//更新uri
default:
throw new IllegalArgumentException("unknow uri:"+uri);
}
}
@Override
public Cursor query(Uri uri, String[] projection, String where, String[] whereArgs,
String sortOrder) {
// TODO Auto-generated method stub
Cursor cursor;
SQLiteDatabase db = helper.getWritableDatabase();//得到创建好的db数据库
switch (uriMatcher.match(uri)) {
case USERINFO://content://com.test.self.provider/userinfo/4,,,,对id为4的userinfo查询操作
long id = ContentUris.parseId(uri);//解析得到id，即id=4
String wheres = "id="+id;
if (null != where && !"".equals(where)) {
wheres = where +" and "+wheres;
}
cursor = db.query("userinfo",projection,wheres,whereArgs,null,null,sortOrder);
return cursor;
case USERINFOS://查询所有
cursor = db.query("userinfo",projection,where,whereArgs,null,null,sortOrder);
return cursor;
default:
throw new IllegalArgumentException("unknow uri:"+uri);
}
}
@Override
public int update(Uri uri, ContentValues values, String where, String[] whereArgs) {
// TODO Auto-generated method stub
SQLiteDatabase db = helper.getWritableDatabase();
int updateNumber;
switch (uriMatcher.match(uri)) {
case USERINFOS://更改所有数据
updateNumber = db.update("userinfo",values,where, whereArgs);
return updateNumber;
case USERINFO://更改一条数据
long id = ContentUris.parseId(uri);
String whereClause = "id="+id;
if (where != null && !"".equals(where)) {
whereClause = where + " and "+whereClause;
}
updateNumber= db.update("userinfo", values, whereClause, whereArgs);
return updateNumber;
default:
throw new IllegalArgumentException("unknow uri:"+uri);
}
}
}
需要注意这里需要在清单文件里配置该provider
<provider
android:name="com.example.mycontentprovider.MyContentProvider"
android:authorities="com.test.self.provider"
android:exported="true"
>新建一个应用，调用contentprovider操作数据
public class MainActivity extends Activity {
private Button addone;
private Button addall;
private Button deleteone;
private Button deleteall;
private Button queryone;
private Button queryall;
private Button updateone;
private Button updateall;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
addone = (Button) findViewById(R.id.addone);
addall = (Button) findViewById(R.id.addAll);
deleteone = (Button) findViewById(R.id.deleteone);
deleteall = (Button) findViewById(R.id.deleteall);
queryone = (Button) findViewById(R.id.queryone);
queryall = (Button) findViewById(R.id.queryall);
updateone = (Button) findViewById(R.id.updateone);
updateall = (Button) findViewById(R.id.updateall);
addone.setOnClickListener(new MyClickListener());
addall.setOnClickListener(new MyClickListener());
deleteone.setOnClickListener(new MyClickListener());
deleteall.setOnClickListener(new MyClickListener());
queryone.setOnClickListener(new MyClickListener());
queryall.setOnClickListener(new MyClickListener());
updateone.setOnClickListener(new MyClickListener());
updateall.setOnClickListener(new MyClickListener());
}
public class MyClickListener implements OnClickListener {
Uri uri = null;
Cursor cursor;
@Override
public void onClick(View view) {
// TODO Auto-generated method stub
switch (view.getId()) {
case R.id.addone:
uri = Uri.parse("content://com.test.self.provider/userinfos");
ContentValues values = new ContentValues();
values.put("name","wangwu");
values.put("phone","264546");
values.put("age", 20);
getContentResolver().insert(uri, values);
break;
case R.id.addAll:
uri = Uri.parse("conent://com.test.self.provider/userinfos");
for (int i = 0; i < 5; i++) {
ContentValues values2 = new ContentValues();
values2.put("name","zhangsan");
values2.put("phone","264546");
values2.put("age", 20);
getContentResolver().insert(uri, values2);
}
case R.id.deleteone:
uri = Uri.parse("conent://com.test.self.provider/userinfo/3");//删除第三条数据
getContentResolver().delete(uri, null, null);
case R.id.deleteall:
uri = uri.parse("conent://com.test.self.provider/userinfos");
getContentResolver().delete(uri, null, null);
case R.id.queryone:
uri = Uri.parse("conent://com.test.self.provider/userinfo/6");//查询第六条数据
cursor = getContentResolver().query(uri, null, null, null, null);
if (cursor.moveToNext()) {
int id = cursor.getInt(cursor.getColumnIndex("id"));
String name = cursor.getString(cursor.getColumnIndex("name"));
int age = cursor.getInt(cursor.getColumnIndex("age"));
String phone = cursor.getString(cursor.getColumnIndex("phone"));
System.out.println("id---"+id+"--name--"+name+"--age--"+age+"--phone--"+phone);
}
cursor.close();
case R.id.queryall:
uri = Uri.parse("conent://com.test.self.provider/userinfos");
cursor = getContentResolver().query(uri, null, null, null, null);
while (cursor.moveToNext()) {
int id = cursor.getInt(cursor.getColumnIndex("id"));
String name = cursor.getString(cursor.getColumnIndex("name"));
int age = cursor.getInt(cursor.getColumnIndex("age"));
String phone = cursor.getString(cursor.getColumnIndex("phone"));
System.out.println("id---"+id+"--name--"+name+"--age--"+age+"--phone--"+phone);
}
cursor.close();
case R.id.updateone:
uri = Uri.parse("conent://com.test.self.provider/userinfo/6");
ContentValues values3 = new ContentValues();
values3.put("age",50);
getContentResolver().update(uri, values3, null, null);
case R.id.updateall:
uri = Uri.parse("conent://com.test.self.provider/userinfos");
ContentValues values4 = new ContentValues();
values4.put("name","lisi");
getContentResolver().update(uri, values4, null,null);
default:
break;
}
}
}
}
该mainactivity的布局代码如下：
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
tools:context=".MainActivity" >
<Button
android:id="@+id/addone"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="addone" />
<Button
android:id="@+id/addAll"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="addall" />
<Button
android:id="@+id/deleteone"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="deleteone" />
<Button
android:id="@+id/deleteall"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="deleteall" />
<Button
android:id="@+id/queryone"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="queryone" />
<Button
android:id="@+id/queryall"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="queryall" />
<Button
android:id="@+id/updateone"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="updateone" />
<Button
android:id="@+id/updateall"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="updateall" />
</LinearLayout>