【ContentWriter】

package com.jikexueyuan.contentwriter;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 Myprovider extends ContentProvider {    public static final Uri URI = Uri.parse("content://com.jikexueyuan.cp");    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 arg0, ContentValues arg1) {        database.insert("tab", "_id", arg1);//        database.close();        return null;    }    @Override    public boolean onCreate() {        database = getContext().openOrCreateDatabase("mycp.db3", Context.MODE_PRIVATE, null);        database.execSQL("create table 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;    }}

public class MainActivity extends Activity {    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        findViewById(R.id.button1).setOnClickListener(new View.OnClickListener() {                        @Override            public void onClick(View arg0) {                write();            }        });    }        public void write() {        ContentValues values;        values = new ContentValues();        values.put("name", "Java");        getContentResolver().insert(Myprovider.URI, values);                values = new ContentValues();        values.put("name", "Swift");        getContentResolver().insert(Myprovider.URI, values);                values = new ContentValues();        values.put("name", "Python");        getContentResolver().insert(Myprovider.URI, values);                values = new ContentValues();        values.put("name", "C#");        getContentResolver().insert(Myprovider.URI, values);    }}

 

【ContentReader】

public class MainActivity extends Activity {      Uri URI = Uri.parse("content://com.jikexueyuan.cp");    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);                Cursor cursor = getContentResolver().query(URI, null, null, null, null);        cursor.moveToFirst();        for (int i = 0; i < cursor.getCount(); i++) {            String value = cursor.getString(cursor.getColumnIndex("name"));            Toast.makeText(getApplicationContext(), value, Toast.LENGTH_SHORT).show();            cursor.moveToNext();        }    }}