3.StudentColumns.java
package cn.gd.pl.lan.providersample;
import android.net.Uri;
import android.provider.BaseColumns;
public class StudentColumns implements BaseColumns{
public static final String AUTHORITY = "cn.gd.pl.lan.provider";
public static final int ALL = 1;
public static final int SINGAL = 2;
public static final Uri CONTENT_URI = Uri.parse("content://" + AUTHORITY + "/students/");
public static final String CONTENT_TYPE = "vnd.android.cursor.dir/vnd.lan.student";
public static final String CONTENT_ITEM_TYPE = "vnd.android.cursor.item/vnd.lan.student";
public static final String DATABASE = "student.db";
public static final int DB_VERSION = 1;
public static final String TABLE = "students";
public static final String ID = "id";
public static final String NAME = "name";
public static final String AGE = "age";
public static final String SEX = "sex";
public static final String GRADE = "grade";
public static final String[] OUTPUT_COLUMNS = {"id","name","age","sex","grade"};
}
4.DBHelper.java
package cn.gd.pl.lan.providersample;
import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
public class DBHelper extends SQLiteOpenHelper {
public DBHelper(Context context) {
super(context, StudentColumns.DATABASE, null, StudentColumns.DB_VERSION);
}
@Override
public void onCreate(SQLiteDatabase db) {
System.out.println("loki: before table create");
String sql = "create table " + StudentColumns.TABLE + "(" +
StudentColumns.ID + " integer primary key," +
StudentColumns.NAME + " text," +
StudentColumns.AGE + " integer," +
StudentColumns.SEX + " text," +
StudentColumns.GRADE + " integer);";
db.execSQL(sql);
System.out.println("loki:table create success :"+StudentColumns.TABLE);
}
@Override
public void onUpgrade(SQLiteDatabase db, int arg1, int arg2) {
String sql = "drop table if exists "+ StudentColumns.TABLE;
db.execSQL(sql);
onCreate(db);
}
}
5.StudentProvider.java
package cn.gd.pl.lan.providersample;
import java.util.HashMap;
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.database.sqlite.SQLiteException;
import android.database.sqlite.SQLiteQueryBuilder;
import android.net.Uri;
import android.text.TextUtils;
public class StudentProvider extends ContentProvider {
private DBHelper helper;
private UriMatcher matcher;
@Override
public int delete(Uri uri, String where, String[] whereArgs) {
SQLiteDatabase db = helper.getWritableDatabase();
int count;
switch(matcher.match(uri)){
case StudentColumns.ALL:
count = db.delete(StudentColumns.TABLE, where, whereArgs);
break;
case StudentColumns.SINGAL:
String rowID = uri.getPathSegments().get(1);
count = db.delete(StudentColumns.TABLE, StudentColumns.ID + "=" + rowID + (!TextUtils.isEmpty(where)?" AND (" + where + ")" :""), whereArgs);
break;
default:
throw new IllegalArgumentException("Unknown Uri :"+uri);
}
getContext().getContentResolver().notifyChange(uri, null);
return count;
}
@Override
public String getType(Uri uri) {
switch(matcher.match(uri)){
case StudentColumns.ALL:
return StudentColumns.CONTENT_TYPE;
case StudentColumns.SINGAL:
return StudentColumns.CONTENT_ITEM_TYPE;
}
throw new IllegalArgumentException("Unknown Uri :"+uri);
}
@Override
public Uri insert(Uri uri, ContentValues cv) {
SQLiteDatabase db = helper.getWritableDatabase();
long rowID = 0;
switch(matcher.match(uri)){
case StudentColumns.ALL:
rowID = db.insert(StudentColumns.TABLE, null, cv);
if(rowID > 0){
System.out.println("loki:insert row success!");
Uri insertedUri = ContentUris.withAppendedId(uri, rowID);
getContext().getContentResolver().notifyChange(insertedUri, null);
return insertedUri;
}
}
throw new SQLiteException();
}
@Override
public boolean onCreate() {
helper = new DBHelper(this.getContext());
matcher = new UriMatcher(UriMatcher.NO_MATCH);
matcher.addURI(StudentColumns.AUTHORITY, StudentColumns.TABLE, StudentColumns.ALL);
matcher.addURI(StudentColumns.AUTHORITY, StudentColumns.TABLE+"/#", StudentColumns.SINGAL);
System.out.println("loki:provider onCreate");
return true;
}
@Override
public Cursor query(Uri uri, String[] outputColumns, String where, String[] whereArgs,
String orderBy) {
SQLiteQueryBuilder sqb = new SQLiteQueryBuilder();
SQLiteDatabase db = helper.getReadableDatabase();
Cursor cursor;
System.out.println("loki:"+matcher.match(uri));
HashMap columnMap = new HashMap();
columnMap.put(StudentColumns.ID, StudentColumns.ID);
columnMap.put(StudentColumns.NAME, StudentColumns.NAME);
columnMap.put(StudentColumns.AGE, StudentColumns.AGE);
columnMap.put(StudentColumns.SEX, StudentColumns.SEX);
columnMap.put(StudentColumns.GRADE, StudentColumns.GRADE);
switch(matcher.match(uri)){
case StudentColumns.ALL:
sqb.setTables(StudentColumns.TABLE);
sqb.setProjectionMap(columnMap);
break;
case StudentColumns.SINGAL:
sqb.setTables(StudentColumns.TABLE);
sqb.setProjectionMap(columnMap);
String rowID = uri.getPathSegments().get(1);
sqb.appendWhere(StudentColumns.ID + "=" + rowID);
System.out.println("loki:rowID = " + rowID);
break;
default:
throw new IllegalArgumentException("Unknown Uri :"+uri);
}
if(TextUtils.isEmpty(orderBy))
orderBy = "id DESC";
cursor = sqb.query(db, outputColumns, where, whereArgs, null, null, orderBy);
cursor.setNotificationUri(getContext().getContentResolver(), uri);
return cursor;
}
@Override
public int update(Uri uri, ContentValues cv, String where, String[] whereArgs) {
SQLiteDatabase db = helper.getWritableDatabase();
int count;
switch(matcher.match(uri)){
case StudentColumns.ALL:
count = db.update(StudentColumns.TABLE, cv, where, whereArgs);
break;
case StudentColumns.SINGAL:
String rowID = uri.getPathSegments().get(1);
count = db.update(StudentColumns.TABLE, cv,StudentColumns.ID + "=" + rowID +(!TextUtils.isEmpty(where)? " AND (" + where + ")" :""), whereArgs);
break;
default:
throw new IllegalArgumentException("Unknown Uri :"+uri);
}
getContext().getContentResolver().notifyChange(uri, null);
return count;
}
}
6.activity_main.xml
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:id="@+id/tv"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerHorizontal="true"
android:layout_centerVertical="true"
android:text="@string/hello_world"
tools:context=".MainActivity" />
二、项目【TestProvider】
1.TestActivity.java
package cn.example.testprovider;
import android.net.Uri;
import android.os.Bundle;
import android.app.Activity;
import android.content.ContentResolver;
import android.database.Cursor;
import android.view.Menu;
import android.widget.TextView;
public class TestActivity extends Activity {
private TextView tv;
private ContentResolver cr;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_test);
tv = (TextView) findViewById(R.id.tv);
cr = this.getContentResolver();
String[] projection = {"id","name","age","sex","grade"};
Cursor cursor = cr.query(Uri.parse("content://cn.gd.pl.lan.provider/students/"), projection , null, null, null);
cursor.moveToFirst();
CharSequence rs = "result:";
while(cursor.moveToNext()){
rs = rs + " ,id=" + cursor.getInt(0)+".";
rs = rs + " ,name=" + cursor.getString(1)+".";
rs = rs + " ,age=" + cursor.getInt(2)+".";
rs = rs + " ,sex=" + cursor.getString(3)+".";
rs = rs + " ,grade=" + cursor.getInt(4)+".";
}
System.out.println(rs);
tv.setText(rs);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.activity_test, menu);
return true;
}
}
2.activity_test.xml
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:id="@+id/tv"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerHorizontal="true"
android:layout_centerVertical="true"
android:text="@string/hello_world"
tools:context=".TestActivity" />
--------------------------------华丽分割线-----------------------------------
心得与体会：
细细口味，慢慢研究，cursor.getXxx(int sss);参数（表列数）是从0开始数的，这个要特别注意，其他注意点都加红色了。
