android ContentProvider 使用实例

创建PeopleProvider.java:

package com.example.ch9;

import com.example.db.DbHelper;

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.text.TextUtils;

public class PeopleProvider extends ContentProvider {
	
	private static final int ITEMS = 1;
	private static final int ITEM_ID = 2;
	public static final String DbName = "Db_People";
	public static final String TableName = "tb_people";
	DbHelper dbhelper ;
	SQLiteDatabase db;
	public static final String CONTENT_ITEMS_TYPE = "vnd.android.cursor.items/com.example.ch94.Db_People";
	public static final String CONTENT_ITEMID_TYPE = "vnd.android.cursor.itemid/com.example.ch94.Db_People";
	public static final Uri CONTENT_URI = Uri.parse("content://com.example.ch94.Db_People/tb_people");
	
	private static final UriMatcher sMatcher;
	static{
		sMatcher = new UriMatcher(UriMatcher.NO_MATCH);
		sMatcher.addURI("com.example.ch94.Db_People", TableName, ITEMS);
		sMatcher.addURI("com.example.ch94.Db_People", TableName+"/#", ITEM_ID);
	}

	@Override
	public int delete(Uri uri, String selection, String[] selectionArgs) {
		db = dbhelper.getWritableDatabase();
		int count = 0;
		switch(sMatcher.match(uri)){
		case ITEMS:
			count = db.delete("tb_people", selection, selectionArgs);
			break;
		case ITEM_ID:
			String id = uri.getPathSegments().get(1);
			count = db.delete("tb_people", "_ID="+id+(!TextUtils.isEmpty("_ID=?")?"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(sMatcher.match(uri)){
		case ITEMS:
			return CONTENT_ITEMS_TYPE;
		case ITEM_ID:
			return CONTENT_ITEMID_TYPE;
		default:
			throw new IllegalArgumentException("Unknown URI"+uri);
			
		}
	}

	@Override
	public Uri insert(Uri uri, ContentValues values) {
		db = dbhelper.getWritableDatabase();
		long rowId ;
		if(sMatcher.match(uri)!=ITEMS){
			throw new IllegalArgumentException("Unknown URI"+uri);
		}
		rowId = db.insert("tb_people", "_ID", values);
		if(rowId>0){
			Uri noteUri = ContentUris.withAppendedId(CONTENT_URI, rowId);
			getContext().getContentResolver().notifyChange(noteUri, null);
			return noteUri;
		}
		throw new IllegalArgumentException("Unknown URI"+uri);
	}

	@Override
	public boolean onCreate() {
		dbhelper = new DbHelper(this.getContext(),"Db_People",null,1);
		return true;
	}

	@Override
	public Cursor query(Uri uri, String[] projection, String selection, String[] selectionArgs,
			String sortOrder) {
		db = dbhelper.getReadableDatabase();
		Cursor c;
		switch(sMatcher.match(uri)){
		case ITEMS:
			c = db.query("tb_people", projection, selection, selectionArgs, null, null, null);
			break;
		case ITEM_ID:
			String id = uri.getPathSegments().get(1);
			c = db.query("tb_people", projection, "_ID="+id+(!TextUtils.isEmpty(selection)?"AND("+selection+')':""), selectionArgs, null, null, sortOrder);
			break;
		default:
			throw new IllegalArgumentException("Unknown URI"+uri);
		}
		c.setNotificationUri(getContext().getContentResolver(), uri);
		return c;
	}

	@Override
	public int update(Uri uri, ContentValues values, String selection, String[] selectionArgs) {
		db = dbhelper.getWritableDatabase();
		int count = 0;
		switch(sMatcher.match(uri)){
		case ITEMS:
			count = db.update("tb_people", values, selection, selectionArgs);
			break;
		case ITEM_ID:
			String id = uri.getPathSegments().get(1);
			count = db.update("tb_people", values, "_ID="+id+(!TextUtils.isEmpty(selection)?"AND("+selection+')':""), selectionArgs);
			break;
		default:
			throw new IllegalArgumentException("Unknown URI"+uri);
		}
		getContext().getContentResolver().notifyChange(uri, null);
		return count;
	}

}

创建主活动类SqlMainActivity.java:

package com.example.ch94;

import com.example.baseexample.R;
import com.example.db.DbHelper;

import android.app.Activity;
import android.content.ContentResolver;
import android.content.Intent;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.net.Uri;
import android.os.Bundle;
import android.view.ContextMenu;
import android.view.ContextMenu.ContextMenuInfo;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.AdapterView.AdapterContextMenuInfo;
import android.widget.ListView;
import android.widget.SimpleCursorAdapter;
import android.widget.TextView;

public class SqlMainActivity extends Activity {
	private ListView list_people;
	private ContentResolver contentResolver;
	private Uri CONTENT_URI = Uri.parse("content://com.example.ch94.Db_People/tb_people");
//	private DbHelper dbhelper;
//	private SQLiteDatabase db;
	
	public void onCreate(Bundle savedInstanceState){
		super.onCreate(savedInstanceState);
		setContentView(R.layout.ch9_sqlmain);
		
		contentResolver = this.getContentResolver();
		
		list_people = (ListView)findViewById(R.id.list_people);
		
//		dbhelper = new DbHelper(this, "Db_People", null, 1);
//		db = dbhelper.getReadableDatabase();
		Cursor c = contentResolver.query(CONTENT_URI, new String[]{"_id","name","phone","mobile","email"}, null, null, null);
		SimpleCursorAdapter adapter = new SimpleCursorAdapter(this, R.layout.ch9_peoplelist, c, new String[]{"_id","name","phone","mobile","email"}, new int[]{R.id.id,R.id.name,R.id.phone,R.id.mobile,R.id.email});
		
		this.list_people.setAdapter(adapter);
		this.registerForContextMenu(list_people);
	}
	
	public boolean onCreateOptionsMenu(Menu menu){
		menu.add(Menu.NONE,Menu.FIRST+1,1,"添加").setIcon(android.R.drawable.ic_menu_add);
		menu.add(Menu.NONE,Menu.FIRST+1,2,"退出").setIcon(android.R.drawable.ic_menu_delete);
		return true;
	}
	
	public boolean onOptionsItemSelected(MenuItem item){
		switch(item.getItemId()){
		case Menu.FIRST+1:
			Intent intent = new Intent();
			intent.setClass(SqlMainActivity.this, AddPeopleActivity.class);
			startActivity(intent);
			break;
		case Menu.FIRST+2:finish();
			break;
		}
		return super.onOptionsItemSelected(item);
	}
	
	public void onCreateContextMenu(ContextMenu menu,View v,ContextMenuInfo menuInfo){
		menu.setHeaderIcon(R.drawable.ic_launcher);
		menu.add(0,3,0,"修改");
		menu.add(0, 4, 0, "删除");
	}
	
	public boolean onContextItemSelected(MenuItem item){
		AdapterContextMenuInfo menuInfo = (AdapterContextMenuInfo)item.getMenuInfo();
		switch(item.getItemId()){
		case 3:
			String name=((TextView)menuInfo.targetView.findViewById(R.id.name)).getText().toString();
			String phone=((TextView)menuInfo.targetView.findViewById(R.id.phone)).getText().toString();
			String mobile=((TextView)menuInfo.targetView.findViewById(R.id.mobile)).getText().toString();
			String email=((TextView)menuInfo.targetView.findViewById(R.id.email)).getText().toString();
			Intent intent = new Intent();
			intent.setClass(SqlMainActivity.this, AddPeopleActivity.class);
			Bundle bundle = new Bundle();
			bundle.putLong("id", menuInfo.id);
			bundle.putString("name", name);
			bundle.putString("phone", phone);
			bundle.putString("mobile", mobile);
			bundle.putString("email", email);
			intent.putExtras(bundle);
			startActivity(intent);
			break;
		case 4:
			contentResolver.delete(CONTENT_URI, "_ID=?", new String[]{menuInfo.id+""});
//			dbhelper = new DbHelper(this,"Db_People",null,1);
//			db = dbhelper.getWritableDatabase();
//			db.delete("tb_people", "_id=?", new String[]{menuInfo.id+""});
			break;
		}
		
		return true;
	}
	
}

创建添加数据的活动类AddPeopleActivity.java：

package com.example.ch94;

import com.example.baseexample.R;
import com.example.db.DbHelper;

import android.app.Activity;
import android.content.ContentResolver;
import android.content.ContentValues;
import android.database.sqlite.SQLiteDatabase;
import android.net.Uri;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;

public class AddPeopleActivity extends Activity {
	private EditText edt_name;
	private EditText edt_phone;
	private EditText edt_mobile;
	private EditText edt_email;
	private Button bt_save;
	private ContentResolver contentResolver;
	private Uri CONTENT_URI = Uri.parse("content://com.example.ch94.Db_People/tb_people");
	String name,phone,mobile,email;
//	DbHelper dbhelper;
//	SQLiteDatabase db;
	Bundle bundle;
	protected void onCreate(Bundle savedInstanceState){
		super.onCreate(savedInstanceState);
		setContentView(R.layout.ch9_addpeople);
		contentResolver = this.getContentResolver();
		
		edt_name=(EditText)findViewById(R.id.edt_name);
		edt_phone=(EditText)findViewById(R.id.edt_phone);
		edt_mobile=(EditText)findViewById(R.id.edt_mobile);
		edt_email=(EditText)findViewById(R.id.edt_email);
		bt_save = (Button)findViewById(R.id.bt_save);
		
		bundle = this.getIntent().getExtras();
		if(bundle!=null){
			edt_name.setText(bundle.getString("name"));
			edt_phone.setText(bundle.getString("phone"));
			edt_mobile.setText(bundle.getString("mobile"));
			edt_email.setText(bundle.getString("email"));
		}
		
		bt_save.setOnClickListener(new Button.OnClickListener(){

			@Override
			public void onClick(View v) {
				name = edt_name.getText().toString();
				phone = edt_phone.getText().toString();
				mobile = edt_mobile.getText().toString();
				email = edt_email.getText().toString();
				
				ContentValues value = new ContentValues();
				value.put("name", name);
				value.put("phone", phone);
				value.put("mobile", mobile);
				value.put("email", email);
				
//				DbHelper dbhelper = new DbHelper(AddPeopleActivity.this,"Db_People",null,1);
//				SQLiteDatabase db = dbhelper.getWritableDatabase();
				long status;
				if(bundle!=null){
					status = contentResolver.update(CONTENT_URI, value, "_ID=?", new String[]{bundle.getLong("id")+""});
				}else{
					Uri uri2 = contentResolver.insert(CONTENT_URI, value);
					if(uri2!=null){
						status =1;
					}else{
						status = -1;
					}
//					status = db.insert("tb_people", null, value);
				}
				if(status!=-1){
					Toast.makeText(AddPeopleActivity.this, "保存成功", Toast.LENGTH_LONG).show();
				}else{
					Toast.makeText(AddPeopleActivity.this, "保存失败", Toast.LENGTH_LONG).show();
				}
			}
			
		});
	}
}

最后,在AndroidManifest.xml增加：

<provider android:name="com.example.ch9.PeopleProvider" android:authorities="com.example.ch94.Db_People"/>