在Android的foreach循环打破数据 [英] foreach loop in android for breaking data

问题描述

这是我的SQLBlog类getDataFunc就是我得到的结果数据库功能

this is my SQLBlog class and getDataFunc is the function where i am getting result from database

import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.SQLException;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteDatabase.CursorFactory;
import android.database.sqlite.SQLiteOpenHelper;

public class SQLBlog {

    public static final String KEY_ROWID = "_id";
    public static final String KEY_NAME = "persons_name"; 
    public static final String KEY_BLOG = "persons_blog";

    private static final String DATABASE_NAME = "blog";
    private static final String DATABASE_TABLE = "admin_blog";
    private static final int DATABASE_VERSION = 1;

    private DBhelper ourhelper;
    private final Context ourcontext;
    private SQLiteDatabase ourdatabase;

    private static class DBhelper extends SQLiteOpenHelper{

        public DBhelper(Context context) {
            super(context, DATABASE_NAME, null, DATABASE_VERSION);
            // TODO Auto-generated constructor stub
        }

        @Override
        public void onCreate(SQLiteDatabase db) {
            // TODO Auto-generated method stub
            db.execSQL("Create table "+ DATABASE_TABLE +" (" + KEY_ROWID + " Integer primary key autoincrement, "+
                        KEY_NAME +" text not null, "+
                        KEY_BLOG +" text not null);");

        }

        @Override
        public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
            // TODO Auto-generated method stub
            db.execSQL("drop table if exists "+ DATABASE_TABLE);
            onCreate(db);
        }

        }
    public SQLBlog(Context c){
        ourcontext=c;
    }

    public SQLBlog open() throws SQLException{
        ourhelper= new DBhelper(ourcontext);
        ourdatabase= ourhelper.getWritableDatabase();
        return this;

    }
    public void close(){

        ourhelper.close();
    }

    public long createEntry(String name, String blog) {
        // TODO Auto-generated method stub
        ContentValues cv = new ContentValues();
        cv.put(KEY_NAME, name);
        cv.put(KEY_BLOG, blog);
        return ourdatabase.insert(DATABASE_TABLE, null, cv);

    }

    public String getDataFunc() {
        // TODO Auto-generated method stub
        String columns[]= new String[]{KEY_ROWID, KEY_NAME, KEY_BLOG};
        Cursor c = ourdatabase.query(DATABASE_TABLE, columns, null, null, null, null, null);
        String result= "";
        int iRow = c.getColumnIndex(KEY_ROWID);
        int iName = c.getColumnIndex(KEY_NAME);
        int iBlog = c.getColumnIndex(KEY_BLOG);

        for(c.moveToFirst(); !c.isAfterLast(); c.moveToNext()){
         result = result + c.getString(iRow) + " " + c.getString(iName) + " " + c.getString(iBlog) + "\n";
        }
        return result;
    }


}

下面我使用的结果表明博客，我的用户

Here i am using that result to show blogs to my user

public class SQLLiteView extends Activity{

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        // TODO Auto-generated method stub
        super.onCreate(savedInstanceState);
        setContentView(R.layout.sqlview);
        TextView tv =(TextView)findViewById(R.id.tvSQLinfo);
        SQLBlog getdata = new SQLBlog(this);
        getdata.open();
        String data = getdata.getDataFunc();
        getdata.close();
        tv.setText(data);
    }



}

但问题是我得到的数据作为一个字符串，但我想更多的动态显示数据，如...

But the problem is i am getting data as a string but i want to show the data more dynamically like...

嗨你好：发布者杰克

//注释这里将给出...

//comments will be given here...

如何从我的数据库中获取数据，并把它放在一个ListView是可点击：发布者妮可

How to get data from my database and put it on a ListView that is clickable :Posted By Nicole

//注释放在这里

我如何能实现this..need帮助​​...我想我正在寻找某种类型的foreach循环PHP之类的......它可以打破data..but因为我使用String作为返回类型我不能得到它..

How can i achieve this..need help...i think i am searching for some type foreach loop like php...which can break the data..but as i am using String as return type i cant get it..

推荐答案

您已经有一个的foreach 循环：

    for(c.moveToFirst(); !c.isAfterLast(); c.moveToNext()){
         result = result + c.getString(iRow) + " " + c.getString(iName) + " " + c.getString(iBlog) + "\n";
    }

在这里，您concate你串起来，只是把这个的foreach 循环在你的活动（返回光标，而不是的字符串），或让与有三个字段一个新的类列表和存储您的领域。

Here you concate your string together, just put this foreach loop in your activity (return the cursor, instead of String) or make a list with a new class which has three fields and store your fields.

下面的一类包装您的结果的一个例子 - 这通常是一个不错的主意。但我真的建议阅读有关Java和面向对象编程的一些东西。

Here an example of wrapping your results in a class - which generally is a good idea anyway. But I really recommend to read some stuff about java and objectoriented programming.

如果您不想reutrn光标到活动中，你可以向这样的事情。
首先createa新的类，它保持博客的对象：

If you don't want to reutrn the cursor to the activity you could to something like this. First createa new class which keeps blog-objects:

public class Blog {

    private String author;
    private String content;

    public Blog(String author, String content){
        this.author = author;
        this.content = content;
    }

    public String getAuthor(){
        return author;
    }

    public String getContent(){
        return content;
    }
}

，然后改变你的DB-方法是这样的：

And then change your db-method like this:

public List<Blog> getDataFunc() {
    // TODO Auto-generated method stub
    String columns[]= new String[]{KEY_ROWID, KEY_NAME, KEY_BLOG};
    Cursor c = ourdatabase.query(DATABASE_TABLE, columns, null, null, null, null, null);
    List<Blog> results = new ArrayList<Blog>();
    int iRow = c.getColumnIndex(KEY_ROWID);
    int iName = c.getColumnIndex(KEY_NAME);
    int iBlog = c.getColumnIndex(KEY_BLOG);

    for(c.moveToFirst(); !c.isAfterLast(); c.moveToNext()){
     results.add(new Blog(c.getString(iName),c.getString(iBlog)));
    }
    return results;
}

现在在你的活动，您可以遍历是这样的：

Now in your activity you can iterate like this:

   @Override
protected void onCreate(Bundle savedInstanceState) {
    // TODO Auto-generated method stub
    super.onCreate(savedInstanceState);
    setContentView(R.layout.sqlview);
    TextView tv =(TextView)findViewById(R.id.tvSQLinfo);
    SQLBlog getdata = new SQLBlog(this);
    getdata.open();
    for(Blog blog : getdata.getDataFunc()){
        Log.v("tag",blog.getAuthor());
        Log.v("tag",blog.getContent());
    }
    getdata.close();
    tv.setText(data);
}

这篇关于在Android的foreach循环打破数据的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！