Android学习笔记-ContentProvider操作

---恢复内容开始---

之前写了一个用SQlite来实现增删改查的应用，今天又新学了一个用ContentProvider来操作的增删改查

首先ContentProvider是用来共享数据的，那么咱们先来建立一个数据源，之后用其他程序获得共享的ContentProvider，来实现CRUD

  数据源结构，一共三个Java文件

SQLDatabaseHelper.java

package com.example.sqlcz;

import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import android.util.Log;

/**
 * Created by Administrator on 2016/9/22.
 */
public class SQLDatabaseHelper extends SQLiteOpenHelper {
    private static SQLDatabaseHelper sqlDatabaseHelper;
    private static final String DB_NAME = "wxhl.db";
    public static final String TABLE_NAME = "t_person";

    private static final int VERSION = 1;
    private final String TAG = "--main--";

    private SQLDatabaseHelper(Context context, String name, SQLiteDatabase.CursorFactory factory, int version) {
        super(context, name, factory, version);
    }

    public static synchronized SQLDatabaseHelper getInstance(Context context) {
        if (sqlDatabaseHelper == null) {
            sqlDatabaseHelper = new SQLDatabaseHelper(context, DB_NAME, null, VERSION);

        }
        return sqlDatabaseHelper;
    }
    //创建数据表
    @Override
    public void onCreate(SQLiteDatabase db) {
        String sql = "create table if not exists t_person"+
                "(_id integer primary key autoincrement," +
                "name text not null,age int default 18, sex text)";
        db.execSQL(sql);

        Log.e(TAG, "onCreate: 执行---");
    }

    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {

    }
}

SQL文件主要是用来建立数据库，已经数据表，

MyContentProvider.java 核心代码

package com.example.sqlcz;

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.util.Log;

/**
 * Created by Administrator on 2016/9/22.
 */
public class MyContentProvider extends ContentProvider {

    private static final String TAG = "--main--";
    private static UriMatcher uriMatcher = new UriMatcher(UriMatcher.NO_MATCH);
    private static final int SINGLE = 1;//单条数据
    private static final int MULTIPLE = 2;//全部数据

    private SQLDatabaseHelper sqlDatabaseHelper;
    private SQLiteDatabase db;

    static {
        uriMatcher.addURI("com.wuxianedu.provider", "t_person", MULTIPLE);
        uriMatcher.addURI("com.wuxianedu.provider","t_person" + "/#", SINGLE);
    }



    @Override
    public boolean onCreate() {
        //获取数据库实例
        sqlDatabaseHelper = SQLDatabaseHelper.getInstance(getContext());
        db = sqlDatabaseHelper.getWritableDatabase();
        return false;
    }
    //新增数据
    @Override
    public Uri insert(Uri uri, ContentValues values) {
        switch (uriMatcher.match(uri)) {
            case MULTIPLE:
                long id = db.insert("t_person", null, values);
                Uri newUri = ContentUris.withAppendedId(uri, id);
//                db.close();
                return newUri;
        }
//        db.close();
        throw new IllegalArgumentException("无效的 Uri :" + uri);
    }
    //删除数据
    @Override
    public int delete(Uri uri, String selection, String[] selectionArgs) {
//        SQLiteDatabase db = sqlDatabaseHelper.getWritableDatabase();
        int count = 0;
        switch (uriMatcher.match(uri)) {
            case SINGLE:
//                long id = ContentUris.parseId(uri);
//                count = db.delete(SQLDatabaseHelper.TABLE_NAME, "id = ?", new String[]{String.valueOf(id)});
                count = db.delete("t_person", selection, selectionArgs);
//                db.close();
                return count;
            case MULTIPLE:
                count = db.delete("t_person", null, null);
//                db.close();
                return count;
        }
//        db.close();
        throw new IllegalArgumentException("无效的 Uri :" + uri);
    }
    //查询数据
    @Override
    public Cursor query(Uri uri, String[] projection, String selection,
                        String[] selectionArgs, String sortOrder) {
//        SQLiteDatabase db = sqlDatabaseHelper.getWritableDatabase();
        Log.e(TAG, "query: ------");
        Cursor cursor = null;
        switch (uriMatcher.match(uri)) {
            case SINGLE:
//                long id = ContentUris.parseId(uri);
//                cursor = db.query(SQLDatabaseHelper.TABLE_NAME, null, "id = ?", new String[]{String.valueOf(id)}, null, null, null);
                cursor = db.query("t_person", null, selection, selectionArgs, null, null, sortOrder);
//                db.close();
                return cursor;
            case MULTIPLE:
                cursor = db.query("t_person", null, null, null, null, null, sortOrder);
//                db.close();
                return cursor;
        }
//        db.close();
        throw new IllegalArgumentException("无效的 Uri :" + uri);
    }
    //修改数据
    @Override
    public int update(Uri uri, ContentValues values, String selection,
                      String[] selectionArgs) {
//        SQLiteDatabase db = sqlDatabaseHelper.getWritableDatabase();

        int count = 0;
        switch (uriMatcher.match(uri)) {
            case SINGLE:
//                long id = ContentUris.parseId(uri);
//                count = db.update(SQLDatabaseHelper.TABLE_NAME, values, "id = ?", new String[]{String.valueOf(id)});
                count = db.update("t_person", values, selection, selectionArgs);
//                db.close();
                return count;
            case MULTIPLE:
                count = db.update("t_person", values, null, null);
//                db.close();
                return count;
        }
//        db.close();
        throw new IllegalArgumentException("无效的 Uri :" + uri);
    }

    @Override
    public String getType(Uri uri) {
        // TODO: Implement this to handle requests for the MIME type of the data
        // at the given URI.
        switch (uriMatcher.match(uri)) {
            case SINGLE:
                return "vnd.android.cursor.item/" + "t_person";
            case MULTIPLE:
                return "vnd.android.cursor.dir/" + "t_person";
        }
        throw new IllegalArgumentException("无效的 Uri :" + uri);
    }
}

下面是共享数据的应用结构

Bean文件

package com.example.zuoye;

import java.io.Serializable;

/**
 * Created by Administrator on 2016/9/22.
 */
public class JavaBean implements Serializable {
    private static final long serialVersionUID = -5689121879237580927L;
    private int id;
    private String name;
    private int age;
    private String sex;

    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 int getAge() {
        return age;
    }
    public void setAge(int age) {
        this.age = age;
    }
    public String getSex() {
        return sex;
    }
    public void setSex(String sex) {
        this.sex = sex;
    }

    @Override
    public String toString() {
        return "Wechat [name=" + name + ", area=" + sex + ", weCode=" + id + "]";
    }
}

MainActivity.java

package com.example.zuoye;

import android.content.ContentResolver;
import android.content.Intent;
import android.database.Cursor;
import android.net.Uri;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.ListView;

import java.util.ArrayList;
import java.util.List;

public class MainActivity extends AppCompatActivity {
    private MainAdapter mainAdapter;//构建数据源
    private List<JavaBean> list;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        ListView listview = (ListView) findViewById(R.id.liebiao);
        list = quyy();
        mainAdapter = new MainAdapter(this,list);
        listview.setAdapter(mainAdapter);
    }
    //查询ContentProvider共享的数据
    public List<JavaBean> quyy(){
        List<JavaBean> list = new ArrayList<JavaBean>();
        ContentResolver resolver = getContentResolver();
        String str = "content://com.wuxianedu.provider/t_person";
        Uri uri = Uri.parse(str);
        Cursor cursor = resolver.query(uri,null,null,null,null);
        while (cursor.moveToNext()){
            JavaBean java = new JavaBean();
            int id = cursor.getInt(cursor.getColumnIndex("_id"));
            int age = cursor.getInt(cursor.getColumnIndex("age"));
            String name = cursor.getString(cursor.getColumnIndex("name"));
            String sex = cursor.getString(cursor.getColumnIndex("sex"));
            Log.e("我是ID",id+"");
            java.setId(id);
            java.setName(name);
            java.setAge(age);
            java.setSex(sex);
            list.add(java);
            Log.e("main---",""+id+"--------------"+age+name+sex);
        }

/*        if(cursor !=null){
            cursor.close();
            cursor = null;
        }*/
        return list;
    }

    @Override //菜单的点击事件
    public boolean onCreateOptionsMenu(Menu menu) {
        getMenuInflater().inflate(R.menu.menu,menu);
        menu.findItem(R.id.add).setOnMenuItemClickListener(new MenuItem.OnMenuItemClickListener() {
            @Override
            public boolean onMenuItemClick(MenuItem item) {
                //点击添加跳转
                Intent intent=new Intent(MainActivity.this,UpdateActivity.class);
                startActivityForResult(intent,5);
                return false;
            }
        });
        return super.onCreateOptionsMenu(menu);

    }
    //利用生命周期
    @Override
    protected void onResume() {
        super.onResume();
        //重新获取list数据
        list = quyy();
        //给list赋值 更新
        mainAdapter.setList(list);
    }
}

下面是Adapter的代码

package com.example.zuoye;

import android.content.ContentResolver;
import android.content.ContentUris;
import android.content.Context;
import android.content.DialogInterface;
import android.content.Intent;
import android.net.Uri;
import android.support.v7.app.AlertDialog;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.Button;
import android.widget.TextView;
import android.widget.Toast;

import java.util.List;

/**
 * Created by Administrator on 2016/9/22.
 */
public class MainAdapter extends BaseAdapter {
    private Context context;
    private List<JavaBean> list;//接收数据的LIST
    private ContentResolver resolver;

    //适配器
    public MainAdapter(Context context, List<JavaBean> list){
        this.context = context;
        this.list = list;
    }
    //更新集合用
    public void setList(List<JavaBean> list) {
        this.list = list;
        notifyDataSetChanged();
    }

    @Override
    public int getCount() {
        return list.size();
    }

    @Override
    public Object getItem(int position) {
        return list.get(position);
    }

    @Override
    public long getItemId(int position) {
        return position;
    }

    @Override
    public View getView(final int position, View convertView, ViewGroup parent) {
        resolver =context.getContentResolver();
        final HUi hui;
        if(convertView == null){
            hui = new HUi();
            convertView = LayoutInflater.from(context).inflate(R.layout.item_lie, null);
            hui.name = (TextView) convertView.findViewById(R.id.tv_name);
            hui.age = (TextView) convertView.findViewById(R.id.tv_age);
            hui.sex = (TextView) convertView.findViewById(R.id.tv_sex);
            hui.update = (Button) convertView.findViewById(R.id.but_name);
            hui.delete = (Button) convertView.findViewById(R.id.but_delete);
            //修改按钮
            hui.update.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    Intent intent = new Intent(context,UpdateActivity.class);
                    int ooon = (int) hui.update.getTag();
                    Log.e("main---","------Adapterget出来的Id--------"+ooon);
                    JavaBean javabean = list.get(ooon);
                    intent.putExtra("name",javabean);
                    context.startActivity(intent);
                }
            });
            convertView.setTag(hui);
        }else{
            hui = (HUi) convertView.getTag();
        }
        final JavaBean java = list.get(position);
        // hui.update.setTag(position);
        hui.name.setText(java.getName());
        hui.age.setText(String.valueOf(java.getAge()));
        hui.sex.setText(java.getSex());
        hui.delete.setTag(position);
        hui.update.setTag(position);
        //构建删除对话框
        hui.delete.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                AlertDialog.Builder builder = new  AlertDialog.Builder(context);
                builder.setMessage("确定删除吗？");
                builder.setPositiveButton("取消",null);
                builder.setNegativeButton("确定", new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                        //获取下标
                        int on = (int) hui.delete.getTag()+1;
                        String str = "content://com.wuxianedu.provider/t_person/"+java.getId();
                        Uri uri = Uri.parse(str);
                        long id = ContentUris.parseId(uri);
                        int index = resolver.delete(uri,"_id = ? ",new String[]{String.valueOf(id)});
                        list.remove(position);
                        notifyDataSetChanged();
                        Toast.makeText(context,"删除成功",Toast.LENGTH_SHORT).show();
                    }
                }).show();

            }
        });
        return convertView;
    }
    //优化ListView
    class HUi {
        TextView name,age,sex;
        Button update,delete;
    }
}

　　添加数据和修改数据代码

package com.example.zuoye;

import android.content.ContentResolver;
import android.content.ContentUris;
import android.content.ContentValues;
import android.content.Intent;
import android.net.Uri;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;

public class UpdateActivity extends AppCompatActivity implements View.OnClickListener {

    private EditText ed_name,ed_sex,ed_age;
    private JavaBean com;
    private Button xiugai,shanchu;
    private ContentResolver resolver;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_update);
        ed_name= (EditText) findViewById(R.id.ed_name);
        ed_age = (EditText) findViewById(R.id.ed_age);
        ed_sex = (EditText) findViewById(R.id.ed_sex);
        xiugai = (Button) findViewById(R.id.but_tianjia);
        shanchu = (Button) findViewById(R.id.but_queding);
        Intent on = getIntent();
        com = (JavaBean) on.getSerializableExtra("name");
        //这里是取值，是否为空，如果为空就是从添加用户过来的，如果不为空就是从增加数据过来的
        if(com == null){
            shanchu.setVisibility(View.GONE);
        }else{
            xiugai.setVisibility(View.GONE);
            ed_name.setText(com.getName()+"");
            ed_age.setText(String.valueOf(com.getAge())+"");
            ed_sex.setText(com.getSex()+"");
        }
        xiugai.setOnClickListener(this);
        shanchu.setOnClickListener(this);

    }
    private void SqlInsert(){
        ContentValues contentValues = new ContentValues();
        contentValues.put("name",ed_name.getText().toString());
        contentValues.put("age",ed_age.getText().toString());
        contentValues.put("sex",ed_sex.getText().toString());
       /* db.insert(contentValues);*/
        resolver = getContentResolver();
        String str = "content://com.wuxianedu.provider/t_person";
        Uri uri = Uri.parse(str);
        // long id = ContentUris.parseId(uri);
        Uri rUri = resolver.insert(uri,contentValues);
        Toast.makeText(UpdateActivity.this,"添加成功",Toast.LENGTH_SHORT).show();
    }
    //修改数据
    private void SqlUpdate(){
        resolver = getContentResolver();
        String str = "content://com.wuxianedu.provider/t_person/"+(com.getId());
        Log.e("main--get出来的ID-",""+com.getId());
        //转换URI
        Uri uri = Uri.parse(str);
        long id = ContentUris.parseId(uri);
        Log.e("main--uri出来的ID-",""+id+"");
        ContentValues values = new ContentValues();
        values.put("name",ed_name.getText().toString());
        values.put("age",ed_age.getText().toString());
        values.put("sex",ed_sex.getText().toString());
        int index =  resolver.update(uri,values,"_id = ?",new String[]{String.valueOf(id)});;
        Toast.makeText(UpdateActivity.this,"修改成功",Toast.LENGTH_SHORT).show();
    }
    //判断
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        if(requestCode != 5){

        }
    }

    @Override
    public void onClick(View v) {
        switch (v.getId()){
            case R.id.but_queding:
                SqlUpdate();
                break;
            case R.id.but_tianjia:
                SqlInsert();
                break;
        }
    }
}

对了，还需要注册，在AndroidManfest.xml中进行注册，代码如下

<provider
    android:name=".MyContentProvider"
    android:authorities="com.wuxianedu.provider"
    android:enabled="true"
    android:exported="true">
</provider>
注：注册时在第一个应用里面注册，第二个不用

下面把布局代码贴一下，
第二个应用activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout 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"
//这里面只有一个ListView,
    tools:context="com.example.zuoye.MainActivity">

    <ListView android:id="@+id/liebiao"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Hello World!" />
</RelativeLayout>

Adapter的布局文件

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="horizontal" android:layout_width="match_parent"
    android:layout_height="match_parent">
    <LinearLayout   android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_weight="5">
        <TextView android:id="@+id/tv_name"
            android:layout_width="0dp" android:layout_gravity="center_vertical"
            android:layout_height="wrap_content"
            android:text="aaa" android:layout_weight="1"
            android:gravity="center"/>

        <TextView android:id="@+id/tv_age"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content" android:layout_gravity="center_vertical"
            android:text="aaa" android:layout_weight="1"
            android:gravity="center"/>
        <TextView android:id="@+id/tv_sex"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content" android:layout_gravity="center_vertical"
            android:text="aaa" android:layout_weight="1"
            android:gravity="center"/>
    </LinearLayout>
    <Button android:id="@+id/but_name"
        android:layout_width="0dp"
        android:layout_height="40dp"
        android:layout_marginTop="2dp"
        android:text="修改" android:layout_weight="1"
        android:gravity="center"  android:background="#3F51B5"
        android:textColor="#FFFFFF"  android:padding="10dp"
        android:layout_marginRight="10dp"/>

    <Button android:id="@+id/but_delete"
        android:layout_width="0dp"
        android:layout_height="40dp"
        android:layout_marginTop="2dp"
        android:text="删除" android:layout_weight="1"
        android:gravity="center" android:background="#3F51B5"

        android:textColor="#FFFFFF" android:layout_marginRight="10dp"/>
</LinearLayout>

修改和添加用户的界面

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout 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:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="com.example.zuoye.UpdateActivity">
    <EditText android:id="@+id/ed_name"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:hint="请输入姓名"/>

    <EditText android:id="@+id/ed_age"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:hint="请输入年龄"
        android:layout_below="@+id/ed_name"/>

    <EditText android:id="@+id/ed_sex"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:hint="请输入性别"
        android:layout_below="@+id/ed_age"/>

    <Button android:id="@+id/but_queding"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:hint="修改用户"
        android:layout_below="@+id/ed_sex"/>

    <Button android:id="@+id/but_tianjia"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:hint="添加用户"
        android:layout_below="@+id/ed_sex"/>
</RelativeLayout>

好了，到这里就全部完成了，最后时限效果是这样的

---恢复内容结束---