Android学习--------实现增删改查数据库操作以及实现相似微信好友对话管理操作

近期的一个实验用到东西挺多，特地总结一下。

要求功能：

       1、第一个页面加入歌曲名和歌手，跳到第二个页面列表显示全部记录。使用sqlite数据库

       2、对于第二个页面显示的信息能够进行删除和改动操作，并自己主动刷新

最后我做的效果：

 

长按列表项弹出单个管理的菜单，像微信好友对话管理一样。

删除时能够直接删除这一条并在列表中直接显示。更新时弹出对话框更新内容提交后在列表中又一次显示。

做此例遇到的困难：

1、菜单获取上下文

2、获取对话框中的内容

3、对话框button加入监听事件-----注意包不要导错：import android.content.DialogInterface.OnClickListener;

主要代码例如以下：

第一个页面：

package com.example.musiclist;

import android.app.Activity;
import android.content.Intent;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteException;
import android.os.Bundle;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;

public class MainActivity extends Activity {
	SQLiteDatabase db;
	String music;
	String singer;
	Button add;
 	@Override
 	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);
		db = SQLiteDatabase.openOrCreateDatabase(this.getFilesDir().toString()+"/music.db3", null);
		add = (Button)findViewById(R.id.add);
		add.setOnClickListener(new OnClickListener(){
			Cursor cursor = null;
			public void onClick(View sourse){
				music = ((EditText)findViewById(R.id.music)).getText().toString();
				singer = ((EditText)findViewById(R.id.singer)).getText().toString();
				
				try{
					insertData(db,music,singer);
				}catch(SQLiteException se){
					//primary key autoincrement
					db.execSQL("create table musiclist(_id integer primary key autoincrement," 
							+"music varchar(30) ,"
							+"singer varchar(30))");
					insertData(db,music,singer);
				}finally{
					//cursor.close();
					Intent intentSec = new Intent(MainActivity.this,SecondActivity.class);
					startActivity(intentSec);
				}
			}
		});
	}
	private void insertData(SQLiteDatabase db,String name,String weibo){
		//运行插入语句
		db.execSQL("insert into musiclist values(null,?,?
)",new String[]{music,singer});
	}
	public void onDestroy(){
		super.onDestroy();
		if(db!=null&&db.isOpen()){
			db.close();
		}
	}
	@Override
	public boolean onCreateOptionsMenu(Menu menu) {
		// Inflate the menu; this adds items to the action bar if it is present.
		getMenuInflater().inflate(R.menu.main, menu);
		return true;
	}
}

<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:orientation="vertical" >

    <ListView
        android:id="@+id/show"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content" >
    </ListView>

</LinearLayout>

第二个页面:

package com.example.musiclist;

import android.app.Activity;
import android.app.AlertDialog;
import android.content.DialogInterface;
import android.content.DialogInterface.OnClickListener;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteException;
import android.os.Bundle;
import android.support.v4.widget.SimpleCursorAdapter;
import android.view.ContextMenu;
import android.view.ContextMenu.ContextMenuInfo;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.View.OnCreateContextMenuListener;
import android.widget.AdapterView.AdapterContextMenuInfo;
import android.widget.CursorAdapter;
import android.widget.EditText;
import android.widget.ListView;
import android.widget.TableLayout;

public class SecondActivity extends Activity {
	SQLiteDatabase db;
	ListView show;
	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_second);
		show = (ListView)findViewById(R.id.show);
		db = SQLiteDatabase.openOrCreateDatabase(this.getFilesDir().toString()+"/music.db3", null);
		//显示列表
		showlist();
		// 加入长按点击弹出选择菜单
		show.setOnCreateContextMenuListener(new OnCreateContextMenuListener() {
			public void onCreateContextMenu(ContextMenu menu, View v,
					ContextMenuInfo menuInfo) {
				menu.setHeaderTitle("选择操作");
				menu.add(0, 0, 0, "更新该条");
				menu.add(0, 1, 0, "删除该条");
			}
		});
	}
	//给菜单项加入事件
	@Override
	public boolean onContextItemSelected(MenuItem item) {
		AdapterContextMenuInfo info = (AdapterContextMenuInfo) item.getMenuInfo();
		//info.id得到listview中选择的条目绑定的id
		String id = String.valueOf(info.id);
		switch (item.getItemId()) {
		case 0:
			updateDialog(id);
			return true;
		case 1:
			//System.out.println("删除"+info.id);
			deleteData(db,id);
			showlist();
			return true;
		default:
			return super.onContextItemSelected(item);
		}
	}
	//更新对话框
	private void updateDialog(final String id){
		final TableLayout updatemsg = (TableLayout)getLayoutInflater().inflate(R.layout.updatemsg, null);
		new AlertDialog.Builder(this)
		.setTitle("更新该条信息")
		.setView(updatemsg)
		.setPositiveButton("更新",new OnClickListener(){
			@Override
			public void onClick(DialogInterface dialog, int which) {
				// TODO Auto-generated method stub
				String musicN = ((EditText)updatemsg.findViewById(R.id.musicN)).getText().toString();
				String singerN = ((EditText)updatemsg.findViewById(R.id.singerN)).getText().toString();
				updateData(db,id,musicN,singerN);
				showlist();
			}
		})
		.setNegativeButton("取消", new OnClickListener(){
			public void onClick(DialogInterface dialog,int which){
			}
		})
		.create()
		.show();
	}
	private void updateData(SQLiteDatabase db,String id,String musicN,String singerN){
		db.execSQL("update musiclist set music='"+musicN+"',singer='"+singerN+"' where _id=?",new String[]{id});
	}
	//删除列表项
	private void deleteData(SQLiteDatabase db,String id){
		db.execSQL("delete from musiclist where _id=?",new String[]{id});
	}
	//显示列表项
	private void showlist(){
		Cursor cursor = null;
		try{
			cursor = db.rawQuery("select * from musiclist", null);
			inflateList(cursor);
		}catch(SQLiteException se){
			db.execSQL("create table musiclist(_id integer primary key autoincrement," 
					+"music varchar(30) ,"
					+"singer varchar(30))");
			//查询
			cursor = db.rawQuery("select * from musiclist", null);
			inflateList(cursor);
		}finally{
			//cursor.close();
		}
	}
	private void inflateList(Cursor cursor){
		//填充SimpleCursorAdapter
		SimpleCursorAdapter adapter = new SimpleCursorAdapter(SecondActivity.this,R.layout.line,cursor,
				new String[]{"_id","music","singer"},
				new int[]{R.id.idS,R.id.musicS,R.id.singerS},
				CursorAdapter.FLAG_REGISTER_CONTENT_OBSERVER);
		show.setAdapter(adapter);
	}

	public void onDestroy(){
		super.onDestroy();
		if(db!=null&&db.isOpen()){
			db.close();
		}
	}
	@Override
	public boolean onCreateOptionsMenu(Menu menu) {
		// Inflate the menu; this adds items to the action bar if it is present.
		getMenuInflater().inflate(R.menu.main, menu);
		return true;
	}
}

<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:orientation="vertical" >

    <ListView
        android:id="@+id/show"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content" >
    </ListView>

</LinearLayout>

列表 line.xml：

<?
xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="horizontal">
     
    <TextView
        android:id="@+id/idS"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
         />
     <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="     "
         />
    <TextView
        android:id="@+id/musicS"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
         />
    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="     "
         />
    <TextView
        android:id="@+id/singerS"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
         />
    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="     "
         />
</LinearLayout>

对话框：updatemsg.xml

<?xml version="1.0" encoding="utf-8"?>
<TableLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent" >
    <TableRow>
        <TextView
            android:layout_width="100dip"
            android:layout_height="wrap_content"
            android:text="音乐名"
            android:textSize="30px"
            android:textColor="#ffffff" />
        <EditText
            android:id="@+id/musicN"
            android:layout_width="100dip"
            android:layout_height="wrap_content" />
    </TableRow>
    <TableRow>
        <TextView
            android:layout_width="100dip"
            android:layout_height="wrap_content"
            android:text="歌手"
            android:textSize="30px"
            android:textColor="#ffffff" />
        <EditText
            android:id="@+id/singerN"
            android:layout_width="100dip"
            android:layout_height="wrap_content" />
    </TableRow>
</TableLayout>