建立一个音乐列表，添加音乐能够用ListView显示出来。
添加音乐界面代码：
import android.app.Activity;
import android.content.ContentValues;
import android.content.Intent;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;
public class MainActivity extends Activity {
TextView tet1,tet2;
EditText edt1,edt2;
Button btn;
int verson=2;//数据库版本
String dbname="sql_db";//表名
Cursor cr;
ContentValues values=new ContentValues();
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
tet1=(TextView)findViewById(R.id.tet1);
tet2=(TextView)findViewById(R.id.tet2);
edt1=(EditText)findViewById(R.id.edt1);
edt2=(EditText)findViewById(R.id.edt2);
btn=(Button)findViewById(R.id.btn);
DatebaseHelper dbh=new DatebaseHelper(this, dbname,null,verson);
final SQLiteDatabase sqldb=dbh.getWritableDatabase();
btn.setOnClickListener(new OnClickListener() {
public void onClick(View arg0) {
cr=sqldb.query("musiclist", null, null, null, null, null, null);
int count=1;
while(cr.moveToNext()){count++;
System.out.println(count);
}
values.put("num", count);
values.put("name", " "+edt1.getText().toString());
values.put("singer", " "+edt2.getText().toString());
long res=sqldb.insert("musiclist", null, values);//添加到数据库
//int res=sqldb.delete("musicList", null, null);//删除数据库中的信息
if(res==-1){
Toast.makeText(MainActivity.this, "添加失败",Toast.LENGTH_SHORT).show();
}else{
Toast.makeText(MainActivity.this, "添加成功",Toast.LENGTH_SHORT).show();
}
Intent intent=new Intent(MainActivity.this,SecondActivity.class);
startActivity(intent);
}
});
}
}
布局：
<RelativeLayout 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:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context=".MainActivity" >
<TextView
android:id="@+id/tet1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="音乐名"
/>
<EditText
android:id="@+id/edt1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="@+id/tet1"
android:layout_alignLeft="@+id/tet1"
/>
<TextView
android:id="@+id/tet2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="@+id/edt1"
android:layout_alignLeft="@+id/tet1"
android:text="歌手"
/>
<EditText
android:id="@+id/edt2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="@+id/tet2"
android:layout_alignLeft="@+id/tet1"
/>
<Button
android:id="@+id/btn"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="@+id/edt2"
android:layout_alignLeft="@+id/tet1"
android:text="添加"
/>
</RelativeLayout>
显示列表界面代码：
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import android.app.Activity;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.os.Bundle;
import android.widget.ListView;
import android.widget.SimpleAdapter;
public class SecondActivity extends Activity{
SQLiteDatabase sdb;
int verson=2;//数据库版本
String name="sql_db";//表名
ListView lv;
List<Map<String,Object>>list;
Cursor cr;
Database db;
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_second);
lv=(ListView)findViewById(R.id.lv);
list=new ArrayList<Map<String,Object>>();
db=new Database(this, name,null,verson);
sdb=db.getReadableDatabase();
cr=sdb.query("musiclist", null, null, null, null, null, null);//查询表
while(cr.moveToNext()){
Map<String, Object>mp=new HashMap<String, Object>();
mp.put("num", cr.getInt(0));
mp.put("name", cr.getString(1));
mp.put("singer", cr.getString(2));
list.add(mp);
SimpleAdapter adapter=new SimpleAdapter(this, list, R.layout.layout_listview, new String[]{"num","name","singer"},new int[]{R.id.num,R.id.name,R.id.singer}); //显示到list上
lv.setAdapter(adapter);
}
}
}
布局：
<?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="vertical" >
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="浏览音乐信息" />
<ListView
android:id="@+id/lv"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
</LinearLayout>
ListView布局：
<?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/num"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
<TextView
android:id="@+id/name"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
<TextView
android:id="@+id/singer"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
</LinearLayout>
连接数据库部分1：
import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteDatabase.CursorFactory;
import android.database.sqlite.SQLiteOpenHelper;
public class DatebaseHelper extends SQLiteOpenHelper{
public static final int i=2;
public DatebaseHelper(Context context, String name,
CursorFactory factory, int version) {
super(context, name, factory, version);
}
public DatebaseHelper(Context context,String name,int version){
this(context,name,null,version);
}
public DatebaseHelper(Context context,String name){
this(context,name,i);
}
public void onCreate(SQLiteDatabase db) {
System.out.print("Create a Database");
db.execSQL("create table musicList(num int,name verchar(20),singer verchar(10))");
}
public void onUpgrade(SQLiteDatabase arg0, int arg1, int arg2) {
}
}
连接数据库部分2：
import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteDatabase.CursorFactory;
import android.database.sqlite.SQLiteOpenHelper;
public class Database extends SQLiteOpenHelper{
static int i=2;
public Database(Context context, String name, CursorFactory factory,
int version) {
super(context, name, factory, version);
}
public Database(Context context,String name,int version){
this(context,name,null,version);
}
public Database(Context context,String name){
this(context,name,i);
}
@Override
public void onCreate(SQLiteDatabase db) {
// TODO Auto-generated method stub
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
// TODO Auto-generated method stub
}
}