Android學習--------實現增刪改查數據庫操作以及實現相似微信好友對話管理操作
近期的一個實驗用到東西挺多。特地總結一下。
要求功能：
?????? 1、第一個頁面加入歌曲名和歌手，跳到第二個頁面列表顯示全部記錄。使用sqlite數據庫
?????? 2、對於第二個頁面顯示的信息能夠進行刪除和改動操作，並自己主動刷新
最後我做的效果：
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長按列表項彈出單個管理的菜單。像微信好友對話管理一樣。
刪除時能夠直接刪除這一條並在列表中直接顯示，更新時彈出對話框更新內容提交後在列表中又一次顯示。
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做此例遇到的困難：
1、菜單獲取上下文
2、獲取對話框中的內容
3、對話框button加入監聽事件-----註意包不要導錯：import android.content.DialogInterface.OnClickListener;
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主要代碼例如以下：
第一個頁面：
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){ //運行插入語句 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; } }
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<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>
第二個頁面:
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);
//顯示列表
showlist();
// 加入長按點擊彈出選擇菜單
show.setOnCreateContextMenuListener(new OnCreateContextMenuListener() {
public void onCreateContextMenu(ContextMenu menu, View v,
ContextMenuInfo menuInfo) {
menu.setHeaderTitle("選擇操作");
menu.add(0, 0, 0, "更新該條");
menu.add(0, 1, 0, "刪除該條");
}
});
}
//給菜單項加入事件
@Override
public boolean onContextItemSelected(MenuItem item) {
AdapterContextMenuInfo info = (AdapterContextMenuInfo) item.getMenuInfo();
//info.id得到listview中選擇的條目綁定的id
String id = String.valueOf(info.id);
switch (item.getItemId()) {
case 0:
updateDialog(id);
return true;
case 1:
//System.out.println("刪除"+info.id);
deleteData(db,id);
showlist();
return true;
default:
return super.onContextItemSelected(item);
}
}
//更新對話框
private void updateDialog(final String id){
final TableLayout updatemsg = (TableLayout)getLayoutInflater().inflate(R.layout.updatemsg, null);
new AlertDialog.Builder(this)
.setTitle("更新該條信息")
.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});
}
//刪除列表項
private void deleteData(SQLiteDatabase db,String id){
db.execSQL("delete from musiclist where _id=?",new String[]{id});
}
//顯示列表項
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))");
//查詢
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>
對話框：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="音樂名"
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>
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Android學習--------實現增刪改查數據庫操作以及實現相似微信好友對話管理操作