Android 自定义ContentProvider Demo

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ContenProvider：简单查询及修改

1.提供数据来源，在本地创建数据库文件

package util;import android.content.Context;import android.database.sqlite.SQLiteDatabase;import android.database.sqlite.SQLiteOpenHelper;/** * Created by ASUS on 2017/2/7. */public class DbUtil extends SQLiteOpenHelper{    public DbUtil(Context context, String name, SQLiteDatabase.CursorFactory factory, int version) {        super(context, name, factory, version);    }    //创建表的操作    @Override    public void onCreate(SQLiteDatabase db) {        //创建表        db.execSQL("create table person(_id integer primary key autoincrement,name,age)");    }    @Override    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {    }}

2.编写简单布局文件

如图一：

<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"    xmlns:tools="http://schemas.android.com/tools" android:id="@+id/activity_main"    android:layout_width="match_parent" android:layout_height="match_parent"    android:paddingBottom="@dimen/activity_vertical_margin"    android:paddingLeft="@dimen/activity_horizontal_margin"    android:paddingRight="@dimen/activity_horizontal_margin"    android:paddingTop="@dimen/activity_vertical_margin"    android:orientation="vertical"    tools:context="com.asus.android_16_sqlite.MainActivity">    <EditText        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:hint="ID"        android:id="@+id/et_main_id"        />    <EditText        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:hint="用户名"        android:id="@+id/et_main_username"        />    <EditText        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:hint="年龄"        android:id="@+id/et_main_userage"        />    <LinearLayout        android:layout_width="match_parent"        android:layout_height="wrap_content">        <Button            android:layout_width="wrap_content"            android:layout_height="wrap_content"            android:text="保存"            android:onClick="save"            android:layout_weight="1"            />        <Button            android:layout_width="wrap_content"            android:layout_height="wrap_content"            android:text="查询"            android:onClick="query"            android:layout_weight="1"            />    </LinearLayout>    <ListView        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:id="@android:id/list">    </ListView></LinearLayout>

3.ContentProvider内容提供者，内容来源：数据库

首先写一个类，继承ContentProvider

他会重写6个方法，

如下：

package provider;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 android.support.annotation.Nullable;import android.util.Log;import util.DbUtil;/** * Created by ASUS on 2017/2/8. */public class MyContentProvider extends ContentProvider{    private SQLiteDatabase db;    private UriMatcher uriMatcher;    @Override    public boolean onCreate() {        Log.i("test","onCreate");        DbUtil dbUtil=new DbUtil(getContext(),"person.db",null,2);        db = dbUtil.getReadableDatabase();        //实例化URI匹配器        uriMatcher = new UriMatcher(UriMatcher.NO_MATCH);        //添加规则        //1.查询所有        uriMatcher.addURI("com.asus.android_16_sqlite.PERSON","person",1);        //2.查询单个        uriMatcher.addURI("com.asus.android_16_sqlite.PERSON","person/#",2);//        uriMatcher.addURI("com.asus.android_16_sqlite.PERSON","person/#/#/#",3);        return false;    }    @Nullable    @Override    public Cursor query(Uri uri, String[] projection, String selection, String[] selectionArgs, String sortOrder) {        //根据URI匹配器开始匹配uri        int code=uriMatcher.match(uri);        switch (code) {            case 1 :                //查询所有                Log.i("test","query所有");                //获取数据库中所有的数据                return db.query(false,"person",projection,selection,selectionArgs,null,null,sortOrder,null);            case 2 :                //查询单个                //获取#的值                long id=ContentUris.parseId(uri);                Log.i("test","query单个");                return db.rawQuery("select * from person where _id=?",new String[]{id+""});        }        return null;    }    @Nullable    @Override    public String getType(Uri uri) {        Log.i("test","getType");        return null;    }    @Nullable    @Override    public Uri insert(Uri uri, ContentValues values) {        Log.i("test","insert");        return null;    }    @Override    public int delete(Uri uri, String selection, String[] selectionArgs) {        Log.i("test","delete");        return 0;    }    @Override    public int update(Uri uri, ContentValues values, String selection, String[] selectionArgs) {        Log.i("test","update");//        db.execSQL(" update person set name=?,age=? where _id=? ",new String[]{""+2,""+2,""+2});//        String str=""+uriMatcher.match(uri);//        Log.i("text",str);        return db.update("person",values,selection,selectionArgs);    }}
4.MainActivity:
package com.asus.android_24_contentprovider;import android.content.ContentResolver;import android.content.ContentValues;import android.database.Cursor;import android.net.Uri;import android.support.v7.app.AlertDialog;import android.support.v7.app.AppCompatActivity;import android.os.Bundle;import android.text.TextUtils;import android.util.Log;import android.view.View;import android.widget.AdapterView;import android.widget.Button;import android.widget.EditText;import android.widget.LinearLayout;import android.widget.ListView;import android.widget.SimpleCursorAdapter;import android.widget.TextView;public class MainActivity extends AppCompatActivity {    private ContentResolver contentResolver;    private EditText et_main_id;    private Uri uri;    private ListView listview_main_person;    private Cursor cursor;    private SimpleCursorAdapter simpleCursorAdapter;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        contentResolver = getContentResolver();        et_main_id = (EditText) findViewById(R.id.et_main_id);        listview_main_person = (ListView) findViewById(R.id.listview_main_person);    }    public void getData(View view){        //判断输入框的值是否为空        if (TextUtils.isEmpty(et_main_id.getText().toString())){            //为空，查询所有            uri = Uri.parse("content://com.asus.android_16_sqlite.PERSON/person");        }else{            //不为空，查询单个            String id=et_main_id.getText().toString();            uri = Uri.parse("content://com.asus.android_16_sqlite.PERSON/person/"+id);        }        cursor = contentResolver.query(uri,null,null,null,null);        simpleCursorAdapter = new SimpleCursorAdapter(this, R.layout.items_listview,cursor,new String[]{"_id","name","age"},new int[]{R.id.tv_items_id,R.id.tv_items_name,R.id.tv_items_age});        //给ListView设置适配器        listview_main_person.setAdapter(simpleCursorAdapter);        //给ListView设置长按事件        listview_main_person.setOnItemLongClickListener(new AdapterView.OnItemLongClickListener() {            private TextView tv_dialog_id;            private EditText et_dialog_age;            private EditText et_dialog_name;            @Override            public boolean onItemLongClick(AdapterView<?> parent, View view, int position, long id) {                LinearLayout root= (LinearLayout) view;                String _id=((TextView) root.findViewById(R.id.tv_items_id)).getText().toString();                String name=((TextView) root.findViewById(R.id.tv_items_name)).getText().toString();                String age=((TextView) root.findViewById(R.id.tv_items_age)).getText().toString();                final AlertDialog.Builder builder=new AlertDialog.Builder(MainActivity.this);                final AlertDialog alertDialog=builder.create();                //点击空白处，不取消对话框                alertDialog.setCancelable(false);//                View v= LayoutInflater.from(MainActivity.this).inflate(R.layout.activity_dialog,null);                View v=View.inflate(MainActivity.this,R.layout.activity_dialog,null);                tv_dialog_id = (TextView) v.findViewById(R.id.tv_dialog_id);                et_dialog_name = (EditText) v.findViewById(R.id.et_dialog_name);                et_dialog_age = (EditText) v.findViewById(R.id.et_dialog_age);                tv_dialog_id.setText(_id);                et_dialog_name.setText(name);                et_dialog_age.setText(age);                ((Button)v.findViewById(R.id.bt_dialog_ok)).setOnClickListener(new View.OnClickListener() {                    @Override                    public void onClick(View v) {                        String id=tv_dialog_id.getText().toString();                        String name=et_dialog_name.getText().toString();                        String age=et_dialog_age.getText().toString();//                        Toast.makeText(MainActivity.this, ""+ et_dialog_name.getText().toString(), Toast.LENGTH_SHORT).show();                        uri = Uri.parse("content://com.asus.android_16_sqlite.PERSON/person/");                        ContentValues values=new ContentValues();                        values.put("name",""+et_dialog_name.getText().toString());                        values.put("age",""+et_dialog_age.getText().toString());                        contentResolver.update(uri,values,"_id=?",new String[]{id});                        //重新查询，刷新                        cursor = contentResolver.query(uri,null,null,null,null);                        //通知适配器发生该变                        simpleCursorAdapter.changeCursor(cursor);                        //关闭当前的对话框                        alertDialog.dismiss();                    }                });                ((Button)v.findViewById(R.id.bt_dialog_no)).setOnClickListener(new View.OnClickListener() {                    @Override                    public void onClick(View v) {                        //关闭当前的对话框                        alertDialog.dismiss();                    }                });                alertDialog.setView(v);                alertDialog.show();                return true;            }        });        while (cursor.moveToNext()){            int id=cursor.getInt(cursor.getColumnIndex("_id"));            String name=cursor.getString(cursor.getColumnIndex("name"));            int age=cursor.getInt(cursor.getColumnIndex("age"));            Log.i("test",id+"  "+name+"  "+age);        }    }}
5.记得要注册内容提供者
在AndroidManifest.xml中
<!--配置内容提供者--><provider    android:authorities="com.asus.android_16_sqlite.PERSON"    android:name="provider.MyContentProvider"    android:exported="true"    ></provider>
提示，本DemoListView设置长按功能，布局文件自己写即可。
这样，自定义内容提供者就写好了。
ContentResolver：简单查询及修改
然后，我们写内容访问者：
步骤差不多：
1.写布局文件
如图二
<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"    xmlns:tools="http://schemas.android.com/tools" android:id="@+id/activity_main"    android:layout_width="match_parent" android:layout_height="match_parent"    android:paddingBottom="@dimen/activity_vertical_margin"    android:paddingLeft="@dimen/activity_horizontal_margin"    android:paddingRight="@dimen/activity_horizontal_margin"    android:paddingTop="@dimen/activity_vertical_margin"    android:orientation="vertical"    tools:context="com.asus.android_24_contentprovider.MainActivity">    <EditText        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:id="@+id/et_main_id"        android:hint="请输入ID"        />    <Button        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:text="获取数据"        android:onClick="getData"        />    <ListView        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:id="@+id/listview_main_person"        >    </ListView></LinearLayout>

2.MainActvity
package com.asus.android_24_contentprovider;import android.content.ContentResolver;import android.content.ContentValues;import android.database.Cursor;import android.net.Uri;import android.support.v7.app.AlertDialog;import android.support.v7.app.AppCompatActivity;import android.os.Bundle;import android.text.TextUtils;import android.util.Log;import android.view.View;import android.widget.AdapterView;import android.widget.Button;import android.widget.EditText;import android.widget.LinearLayout;import android.widget.ListView;import android.widget.SimpleCursorAdapter;import android.widget.TextView;public class MainActivity extends AppCompatActivity {    private ContentResolver contentResolver;    private EditText et_main_id;    private Uri uri;    private ListView listview_main_person;    private Cursor cursor;    private SimpleCursorAdapter simpleCursorAdapter;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        contentResolver = getContentResolver();        et_main_id = (EditText) findViewById(R.id.et_main_id);        listview_main_person = (ListView) findViewById(R.id.listview_main_person);    }    public void getData(View view){        //判断输入框的值是否为空        if (TextUtils.isEmpty(et_main_id.getText().toString())){            //为空，查询所有            uri = Uri.parse("content://com.asus.android_16_sqlite.PERSON/person");        }else{            //不为空，查询单个            String id=et_main_id.getText().toString();            uri = Uri.parse("content://com.asus.android_16_sqlite.PERSON/person/"+id);        }        cursor = contentResolver.query(uri,null,null,null,null);        simpleCursorAdapter = new SimpleCursorAdapter(this, R.layout.items_listview,cursor,new String[]{"_id","name","age"},new int[]{R.id.tv_items_id,R.id.tv_items_name,R.id.tv_items_age});        //给ListView设置适配器        listview_main_person.setAdapter(simpleCursorAdapter);        //给ListView设置长按事件        listview_main_person.setOnItemLongClickListener(new AdapterView.OnItemLongClickListener() {            private TextView tv_dialog_id;            private EditText et_dialog_age;            private EditText et_dialog_name;            @Override            public boolean onItemLongClick(AdapterView<?> parent, View view, int position, long id) {                LinearLayout root= (LinearLayout) view;                String _id=((TextView) root.findViewById(R.id.tv_items_id)).getText().toString();                String name=((TextView) root.findViewById(R.id.tv_items_name)).getText().toString();                String age=((TextView) root.findViewById(R.id.tv_items_age)).getText().toString();                final AlertDialog.Builder builder=new AlertDialog.Builder(MainActivity.this);                final AlertDialog alertDialog=builder.create();                //点击空白处，不取消对话框                alertDialog.setCancelable(false);//                View v= LayoutInflater.from(MainActivity.this).inflate(R.layout.activity_dialog,null);                View v=View.inflate(MainActivity.this,R.layout.activity_dialog,null);                tv_dialog_id = (TextView) v.findViewById(R.id.tv_dialog_id);                et_dialog_name = (EditText) v.findViewById(R.id.et_dialog_name);                et_dialog_age = (EditText) v.findViewById(R.id.et_dialog_age);                tv_dialog_id.setText(_id);                et_dialog_name.setText(name);                et_dialog_age.setText(age);                ((Button)v.findViewById(R.id.bt_dialog_ok)).setOnClickListener(new View.OnClickListener() {                    @Override                    public void onClick(View v) {                        String id=tv_dialog_id.getText().toString();                        String name=et_dialog_name.getText().toString();                        String age=et_dialog_age.getText().toString();//                        Toast.makeText(MainActivity.this, ""+ et_dialog_name.getText().toString(), Toast.LENGTH_SHORT).show();                        uri = Uri.parse("content://com.asus.android_16_sqlite.PERSON/person/");                        ContentValues values=new ContentValues();                        values.put("name",""+et_dialog_name.getText().toString());                        values.put("age",""+et_dialog_age.getText().toString());                        contentResolver.update(uri,values,"_id=?",new String[]{id});                        //重新查询，刷新                        cursor = contentResolver.query(uri,null,null,null,null);                        //通知适配器发生该变                        simpleCursorAdapter.changeCursor(cursor);                        //关闭当前的对话框                        alertDialog.dismiss();                    }                });                ((Button)v.findViewById(R.id.bt_dialog_no)).setOnClickListener(new View.OnClickListener() {                    @Override                    public void onClick(View v) {                        //关闭当前的对话框                        alertDialog.dismiss();                    }                });                alertDialog.setView(v);                alertDialog.show();                return true;            }        });        while (cursor.moveToNext()){            int id=cursor.getInt(cursor.getColumnIndex("_id"));            String name=cursor.getString(cursor.getColumnIndex("name"));            int age=cursor.getInt(cursor.getColumnIndex("age"));            Log.i("test",id+"  "+name+"  "+age);        }    }}

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