android - 通过 Intent 向数据库发送一个字符串

Question

晚上好 我需要知道如何通过 Intent 将字符串发送到数据库!

我试过这样做，但没有成功。

这是来自 Activity 的代码。

b1.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            note = (EditText) findViewById(R.id.etNote);
            String notes = note.getText().toString();
            db.insert(notes);


        }
    });

这是数据库中的代码。

public long insert(String message) {
        SQLiteDatabase db = getWritableDatabase();


        ContentValues cv = new ContentValues();
        cv.put(NOTE, message);
        return db.insert(DATABASE_TABLE, null, cv);
    }

但不幸的是它没有用! 有人知道这样做的方法吗？

这是将显示带有数据库的 listView 的 Activity 的全部代码。

import android.database.Cursor;
import android.net.Uri;
import android.os.Bundle;
import android.support.v4.app.FragmentActivity;
import android.support.v4.app.LoaderManager.LoaderCallbacks;
import android.support.v4.content.CursorLoader;
import android.support.v4.content.Loader;
import android.support.v4.widget.SimpleCursorAdapter;
import android.view.Menu;
import android.widget.ListView;

public class show extends FragmentActivity implements LoaderCallbacks<Cursor> {

    SimpleCursorAdapter mAdapter;
    ListView mListView;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_show);

        mListView = (ListView) findViewById(R.id.listview);

        mAdapter = new SimpleCursorAdapter(getBaseContext(),
                R.layout.listview_item_layout,
                null,
                new String[] {  CustomerDB.NOTE},
                new int[] {  R.id.note }, 0);

        mListView.setAdapter(mAdapter);

        /** Creating a loader for populating listview from sqlite database */
        /** This statement, invokes the method onCreatedLoader() */
        getSupportLoaderManager().initLoader(0, null, this);

    }



    /** A callback method invoked by the loader when initLoader() is called */
    @Override
    public Loader<Cursor> onCreateLoader(int arg0, Bundle arg1) {
        Uri uri = Customer.CONTENT_URI;
        return new CursorLoader(this, uri, null, null, null, null);
    }

    /** A callback method, invoked after the requested content provider returned all the data */
    @Override
    public void onLoadFinished(Loader<Cursor> arg0, Cursor arg1) {
        mAdapter.swapCursor(arg1);
    }

    @Override
    public void onLoaderReset(Loader<Cursor> arg0) {
        mAdapter.swapCursor(null);
    }
}

这就是内容提供者。

import android.content.ContentProvider;
import android.content.ContentValues;
import android.content.UriMatcher;
import android.database.Cursor;
import android.net.Uri;

/** A custom Content Provider to do the database operations */
public class Customer extends ContentProvider{

    public static final String PROVIDER_NAME = "in.wptrafficanalyzer.sqllistviewdemo.customer";

    /** A uri to do operations on cust_master table. A content provider is identified by its uri */
    public static final Uri CONTENT_URI = Uri.parse("content://" + PROVIDER_NAME + "/customers" );

    /** Constants to identify the requested operation */
    private static final int CUSTOMERS = 1;

    private static final UriMatcher uriMatcher ;
    static {
        uriMatcher = new UriMatcher(UriMatcher.NO_MATCH);
        uriMatcher.addURI(PROVIDER_NAME, "customers", CUSTOMERS);
    }

    /** This content provider does the database operations by this object */
    CustomerDB mCustomerDB;

    /** A callback method which is invoked when the content provider is starting up */
    @Override
    public boolean onCreate() {
        mCustomerDB = new CustomerDB(getContext());
        return true;
    }

    @Override
    public String getType(Uri uri) {
        return null;
    }

    /** A callback method which is by the default content uri */
    @Override
    public Cursor query(Uri uri, String[] projection, String selection, String[] selectionArgs, String sortOrder) {

        if(uriMatcher.match(uri)==CUSTOMERS){
            return mCustomerDB.getAllCustomers();
        }else{
            return null;
        }
    }

    @Override
    public int delete(Uri uri, String selection, String[] selectionArgs) {
        // TODO Auto-generated method stub
        return 0;
    }

    @Override
    public Uri insert(Uri uri, ContentValues values) {
        // TODO Auto-generated method stub
        return null;
    }

    @Override
    public int update(Uri uri, ContentValues values, String selection,
                      String[] selectionArgs) {
        // TODO Auto-generated method stub
        return 0;
    }
}

这就是数据库。

import android.content.ContentValues;
import android.content.Context;
import android.content.Intent;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import android.os.Bundle;

public class CustomerDB extends SQLiteOpenHelper{

    /** Database name */
    private static String DBNAME = "sqllistviewdemo";

    /** Version number of the database */
    private static int VERSION = 1;

    /** Field 1 of the table cust_master, which is the primary key */
    public static final String KEY_ROW_ID = "_id";


    public static final String NOTE="OK";

    /** A constant, stores the the table name */
    private static final String DATABASE_TABLE = "cust_master";

    /** An instance variable for SQLiteDatabase */
    private SQLiteDatabase mDB;

    /** Constructor */
    public CustomerDB(Context context) {
        super(context, DBNAME, null, VERSION);
        this.mDB = getWritableDatabase();
    }

    /** This is a callback method, invoked when the method
     * getReadableDatabase() / getWritableDatabase() is called
     * provided the database does not exists
     * */


     @Override
    public void onCreate(SQLiteDatabase db) {
        String sql =     "create table "+ DATABASE_TABLE + " ( "
                + KEY_ROW_ID + " integer primary key autoincrement , "
                + NOTE + "  text  ) " ;

        db.execSQL(sql);

    }

    public long insert(String message) {
        SQLiteDatabase db = getWritableDatabase();


        ContentValues cv = new ContentValues();
        cv.put(NOTE, message);
        return db.insert(DATABASE_TABLE, null, cv);
    }

    /** Returns all the customers in the table */
    public Cursor getAllCustomers(){
        return mDB.query(DATABASE_TABLE, new String[] { KEY_ROW_ID,  NOTE  } ,
                null, null, null, null,null
                );
    }

    @Override
    public void onUpgrade(SQLiteDatabase arg0, int arg1, int arg2) {
        // TODO Auto-generated method stub
    }
}

Answer 1

 /** SQLiteDatabase IMPLEMENTATION */
 public final class SQLiteDatabase extends SQLiteClosable {

 /**
 * Convenience method for inserting a row into the database.
 *
 * @param table the table to insert the row into
 * @param nullColumnHack optional; may be <code>null</code>.
 *            SQL doesn't allow inserting a completely empty row without
 *            naming at least one column name.  If your provided <code>values</code> is
 *            empty, no column names are known and an empty row can't be inserted.
 *            If not set to null, the <code>nullColumnHack</code> parameter
 *            provides the name of nullable column name to explicitly insert a NULL into
 *            in the case where your <code>values</code> is empty.
 * @param values this map contains the initial column values for the
 *            row. The keys should be the column names and the values the
 *            column values
 * @return the row ID of the newly inserted row, or -1 if an error occurred
 */
public long insert(String table, String nullColumnHack, ContentValues values)

• 检查内容值中的必填列(标记为 REQUIRED NOT NULL)

• 顺便说一下，你把所有的东西都混合了

如果您决定使用内容提供商 - 它应该与您的应用分开

• 在内容提供商中
  您将数据库例程插入/更新/删除用于相应的内容提供者方法

• 在应用程序中( Activity 等) 你使用加载器(回调)或内容解析器

  getContentResolver().insert(...);/。询问(..); .删除(..);

如何使用内容解析器的示例:

/**
 * update user by id with USERS table info
 * returns  row (should be the same as prev
 */
public int updateUserPassword(User user) {

    // Define the updated row content.
    ContentValues updatedValues = new ContentValues();

    // Assign values for each row.
    updatedValues.put(UserTable.USER_PASSWORD, user.getPassword());

    // get where for insert/update 
    String query = " " + UserTable.USER_ID + "=?";
    String rowId = String.valueOf(user.getID());

    /** insert record via content provider */
    App.log.debug("Sending uri via content resolver to content provider...");

    // construct URI
    Uri uri = Uri.parse(ContentProvider.USERS_CONTENT_URI + "/" + rowId);

    // involve content resolver
    int updatedRouCount = getContext().getContentResolver().update(uri,
            updatedValues,
            query,
            new String[]{rowId});

    /** return count of updated rows  should be 1 if all ok */
    return updatedRouCount;
}

实现内容提供者先读

EXCELENT HOW TO

ANDROID API - CONTENT PROVIDER