package com.example.shad_fnst.mycontentprovider; import android.app.Activity;
import android.content.ContentResolver;
import android.content.ContentValues;
import android.database.Cursor;
import android.net.Uri;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.EditText;
import android.widget.Toast; public class MainActivity extends Activity{ @Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
} @Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.menu_main, menu);
return true;
} public void onClickAddName(View view){
ContentValues values = new ContentValues(); values.put(StudentsProvider.NAME,
((EditText)findViewById(R.id.txtName)).getText().toString());
values.put(StudentsProvider.GRADE,
((EditText)findViewById(R.id.txtGrade)).getText().toString());
Uri uri = getContentResolver().insert(StudentsProvider.CONTENT_URI, values);
Toast.makeText(getBaseContext(),
uri.toString(), Toast.LENGTH_LONG).show();
} public void onClickRetrieveStudents(View view){
// Retrieve student records
String URL = "content://com.example.provider.College/students";
Uri students = Uri.parse(URL);
//Cursor c = managedQuery(students, null, null, null, "name");
ContentResolver contentResolver = getContentResolver();
Cursor cursor = contentResolver.query(StudentsProvider.CONTENT_URI, null, null, null, "name");
if(cursor.moveToFirst()){
do{
String message = cursor.getString(cursor.getColumnIndex(StudentsProvider._ID)) + ", " +
cursor.getString(cursor.getColumnIndex(StudentsProvider.NAME)) + ", " +
cursor.getString(cursor.getColumnIndex(StudentsProvider.GRADE));
Toast.makeText(this,message, Toast.LENGTH_SHORT).show();
}while(cursor.moveToNext());
}
cursor.close();
}
}
MainActivity.java
package com.example.shad_fnst.mycontentprovider; import android.content.ContentProvider;
import android.content.ContentUris;
import android.content.ContentValues;
import android.content.Context;
import android.content.UriMatcher;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import android.database.sqlite.SQLiteQueryBuilder;
import android.net.Uri;
import android.text.TextUtils; import java.sql.SQLException;
import java.util.HashMap; /**
* Created by shad-fnst on 2015/07/27.
*/
public class StudentsProvider extends ContentProvider{ static final String PROVIDER_NAME = "com.example.provider.College";
static final String URL = "content://" + PROVIDER_NAME + "/students";
static final Uri CONTENT_URI = Uri.parse(URL); static final String _ID = "id";
static final String NAME = "name";
static final String GRADE = "grade"; private static HashMap<String, String> STUDENTS_PROJECTION_MAP; static final int STUDENTS = 1;
static final int STUDENT_ID = 2; static final UriMatcher uriMatcher;
static {
uriMatcher = new UriMatcher(UriMatcher.NO_MATCH);
uriMatcher.addURI(PROVIDER_NAME, "students", STUDENTS);
uriMatcher.addURI(PROVIDER_NAME, "students/#", STUDENT_ID);
} /**
* Database specific constant declarations
*/
private SQLiteDatabase db;
static final String DATABASE_NAME = "College";
static final String STUDENTS_TABLE_NAME = "students";
static final int DATABASE_VERSION = 1;
static final String CREATE_DB_TABLE =
" CREATE TABLE " + STUDENTS_TABLE_NAME +
" ( id INTEGER PRIMARY KEY AUTOINCREMENT, " +
" name TEXT NOT NULL, " +
" grade TEXT NOT NULL);"; /**
* Helper class that actually creates and manages
* the provider's underlying data repository.
* @return
*/
private static class DatabaseHelper extends SQLiteOpenHelper{
DatabaseHelper(Context context){ super(context, DATABASE_NAME, null, DATABASE_VERSION);
} @Override
public void onCreate(SQLiteDatabase db){
db.execSQL(CREATE_DB_TABLE);
} @Override
public void onUpgrade(SQLiteDatabase db, int oldVersion,
int newVersion){
db.execSQL("DROP TABLE IF EXISTS " + STUDENTS_TABLE_NAME);
onCreate(db);
}
} @Override
public boolean onCreate(){
Context context = getContext();
DatabaseHelper dbHelper =new DatabaseHelper(context);
/**
* Create a write able database which will trigger its
* creation if it doesn't already exist.
*/
db = dbHelper.getWritableDatabase();
return (db == null) ? false:true;
} @Override
public Uri insert(Uri uri, ContentValues values){
/**
* Add a new student record
*/
long rowID = db.insert(STUDENTS_TABLE_NAME, "", values);
/**
* If record is added successfully
*/
if(rowID > 0){
Uri _uri = ContentUris.withAppendedId(CONTENT_URI, rowID);
getContext().getContentResolver().notifyChange(_uri, null); //通知其他ContentObserver数据改变
return uri;
}
//throw new SQLException("Failed to add a record into " + uri);
return uri;
} @Override
public Cursor query(Uri uri, String[] projection, String selection,
String[] selectionArgs, String sortOrder){
SQLiteQueryBuilder qb = new SQLiteQueryBuilder();
qb.setTables(STUDENTS_TABLE_NAME); switch (uriMatcher.match(uri)){
case STUDENTS:
qb.setProjectionMap(STUDENTS_PROJECTION_MAP);
break;
case STUDENT_ID:
qb.appendWhere( _ID + "=" + uri.getPathSegments().get(1));
break;
default:
throw new IllegalArgumentException("Unknown URI " + uri);
}
if(sortOrder == null || sortOrder == ""){
sortOrder =NAME;
}
Cursor c = qb.query(db, projection, selection, selectionArgs,
null, null, sortOrder);
c.setNotificationUri(getContext().getContentResolver(), uri); return c;
} /*
@Override
public Cursor query(Uri uri, String[] projection, String selection,
String[] selectionArgs, String sortOrder){
//SQLiteQueryBuilder qb = new SQLiteQueryBuilder();
//qb.setTables(STUDENTS_TABLE_NAME); Cursor cursor = null;
switch (uriMatcher.match(uri)){
case STUDENTS:
cursor = db.query(STUDENTS_TABLE_NAME, projection, selection, selectionArgs, null, null, null);
break;
case STUDENT_ID:
//qb.appendWhere( _ID + "=" + uri.getPathSegments().get(1));
break;
} return cursor;
}
*/ @Override
public int delete(Uri uri, String selection, String[] selectionArgs){
int count = 0; switch (uriMatcher.match(uri)){
case STUDENTS:
count = db.delete(STUDENTS_TABLE_NAME, selection, selectionArgs);
break;
case STUDENT_ID:
String id = uri.getPathSegments().get(1);
count = db.delete(STUDENTS_TABLE_NAME, _ID + " = " + id +
(!TextUtils.isEmpty(selection) ? " AND (" +
selection + ')' : ""), selectionArgs);
break;
default:
throw new IllegalArgumentException("Unknown URI " + uri);
} getContext().getContentResolver().notifyChange(uri, null);
return count;
} @Override
public int update(Uri uri, ContentValues values, String selection,
String[] selectionArgs){
int count = 0; switch (uriMatcher.match(uri)){
case STUDENTS:
count = db.update(STUDENTS_TABLE_NAME, values, selection, selectionArgs);
break;
case STUDENT_ID:
count = db.update(STUDENTS_TABLE_NAME, values, _ID +
" = " +uri.getPathSegments().get(1) +
(!TextUtils.isEmpty(selection) ? " AND (" +
selection + ')' : ""), selectionArgs);
break;
default:
throw new IllegalArgumentException("Unknown URI " + uri);
}
getContext().getContentResolver().notifyChange(uri, null);
return count;
} @Override
public String getType(Uri uri){
switch (uriMatcher.match(uri)){
/**
* Get all students records
*/
case STUDENTS:
return "vnd.android.cursor.dir/vnd.example.students";
/**
* Get a particular student
*/
case STUDENT_ID:
return "vnd.android.cursor.item/vnd.example.students";
default:
throw new IllegalArgumentException("Unsupported URI: " + uri); }
}
}
StudentsProvider.java
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.shad_fnst.mycontentprovider"
android:versionCode="1"
android:versionName="1.0" > <uses-sdk
android:minSdkVersion="8"
android:targetSdkVersion="17" >
</uses-sdk> <application
android:allowBackup="true"
android:icon="@mipmap/ic_launcher"
android:label="@string/app_name"
android:theme="@style/AppTheme" >
<activity
android:name="com.example.shad_fnst.mycontentprovider.MainActivity"
android:label="@string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" /> <category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity> <provider
android:authorities="com.example.provider.College"
android:name=".StudentsProvider">
</provider> </application> </manifest>
AndroidMainfest.xml
<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:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
android:paddingBottom="@dimen/activity_vertical_margin"
android:orientation="vertical"
tools:context=".MainActivity"> <TextView
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="Name" />
<EditText
android:id="@+id/txtName"
android:layout_width="fill_parent"
android:layout_height="wrap_content" /> <TextView
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="Grade" />
<EditText
android:id="@+id/txtGrade"
android:layout_width="fill_parent"
android:layout_height="wrap_content" /> <Button
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="Add Name"
android:id="@+id/btnAdd"
android:onClick="onClickAddName" /> <Button
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="Retrieve Students"
android:id="@+id/btnRetrieve"
android:onClick="onClickRetrieveStudents" /> </LinearLayout>
activity_main.xml
