public class MainActivity extends Activity {
private ListView listview;
private MySQLiteDatabaseUtils dbUtils;// 数据库连接工具类
private TextView empty;
private Cursor cursor;
private SimpleAdapter adapter;
private SimpleCursorAdapter cursorAdapter;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
listview = (ListView) this.findViewById(R.id.listview);
empty = (TextView) this.findViewById(R.id.empty);
dbUtils = new MySQLiteDatabaseUtils();// 创建连接数据库对象
listview.setEmptyView(empty);
registerForContextMenu(listview);
reloadSqlDataListView();
}
public void reloadSqlDataListView() {
// 第一种用SimpleAdapter
String sql = "select * from studentinfo order by sid desc";
List<Map<String, String>> data = dbUtils.selectList(sql, null);
adapter = new SimpleAdapter(this, data, R.layout.listview_item,
new String[] { "sname", "sex", "score" }, new int[] {
R.id.name, R.id.sex, R.id.score });
listview.setAdapter(adapter);
// 第二种：用SimpleCursorAdapter
// 用SimpleCursorAdapter查询语句的主键必须写成如下,相当于 sid as _id,不写as就用空格代替
// 这样写会报如下错误：String sql = "select * from studentinfo";
// Caused by: java.lang.IllegalArgumentException: column '_id' does not
// exist
// String sql =
// "select sid _id,sname,sex,score from studentinfo order by sid desc";
// cursor = dbUtils.selectCursor(sql, null);
// cursorAdapter = new SimpleCursorAdapter(this, R.layout.listview_item,
// cursor, new String[] { "sname", "sex", "score" }, new int[] {
// R.id.name, R.id.sex, R.id.score },
// CursorAdapter.FLAG_REGISTER_CONTENT_OBSERVER); //
// OBSERVER观察者，数据有更新时会自动去更新
// listview.setAdapter(cursorAdapter);
// loader数据加载器
}
// 利用上下文菜单,更新、查找、删除。点中LsitView每个弹出上下文菜单，注意先注册LsitView
@Override
public void onCreateContextMenu(ContextMenu menu, View v,
ContextMenuInfo menuInfo) {
super.onCreateContextMenu(menu, v, menuInfo);
AdapterContextMenuInfo info = (AdapterContextMenuInfo) menuInfo;
// 将选中的该位置的姓名显示在标题上
Map<String, String> mapitem = (Map<String, String>) adapter
.getItem(info.position);
menu.setHeaderTitle(mapitem.get("sname"));
getMenuInflater().inflate(R.menu.contextmenu_listview_main, menu);
}
// 上下文菜单监听
@Override
public boolean onContextItemSelected(MenuItem item) {
// 获取当前记录的ID因为更新删除等都有用到
AdapterContextMenuInfo info = (AdapterContextMenuInfo) item
.getMenuInfo();
Map<String, String> itemMap = (Map<String, String>) adapter
.getItem(info.position);
// 看情况是否要转数据类型：final int sid = Integer.parseInt(itemMap.get("sid"));
final String sid = itemMap.get("sid");
switch (item.getItemId()) {
case R.id.action_delete:
AlertDialog.Builder builder = createDialogBuilder(
R.drawable.ic_launcher, "删除提示：");
builder.setMessage("确认要删除吗？");
builder.setPositiveButton("确定", new OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
String sql = "delete from studentinfo where sid=?";
boolean flag = dbUtils.executeData(sql,
new Object[] { sid });
if (flag) {
Toast.makeText(MainActivity.this, "删除成功！", 100).show();
reloadSqlDataListView();// 删除完更新数据
} else {
Toast.makeText(MainActivity.this, "删除失败！", 100).show();
}
}
});
builder.show();
break;
case R.id.action_update:
AlertDialog.Builder builder2 = createDialogBuilder(
R.drawable.ic_launcher, "更新数据");
View view = getLayoutInflater().inflate(R.layout.dialog_insert,
null);
final EditText edit_name = (EditText) view
.findViewById(R.id.editText_dialog_name);
final EditText edit_sex = (EditText) view
.findViewById(R.id.editText_dialog_sex);
final EditText edit_score = (EditText) view
.findViewById(R.id.editText_dialog_score);
// 将布局给对话框
builder2.setView(view);
// 修改数据首先要查询出数据，根据sid来查找数据,只查找一条所以用游标的那个来查询
String sql = "select*from studentinfo where sid=?";
Cursor cursor2 = dbUtils.selectCursor(sql, new String[] { sid });
cursor2.moveToFirst();// 游标一定要移动
Log.i("MainActivity",
"cursor2.getColumnCount" + cursor2.getColumnCount());
edit_name
.setText(cursor2.getString(cursor2.getColumnIndex("sname")));
edit_sex.setText(cursor2.getString(cursor2.getColumnIndex("sex")));
edit_score.setText(cursor2.getString(cursor2
.getColumnIndex("score")));
cursor2.close();
// 设置一确定按钮给它，到用来确定修改数据
builder2.setPositiveButton("确定", new OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
String sname = edit_name.getText().toString();
String sex = edit_sex.getText().toString();
String score = edit_score.getText().toString();
String sql = "update studentinfo set sname=?,sex=?,score=? where sid=?";
boolean flag = dbUtils.executeData(sql, new Object[] {
sname, sex, score, sid });
if (flag) {
Toast.makeText(MainActivity.this, "更新数据成功！", 100)
.show();
reloadSqlDataListView();// 完更新数据
} else {
Toast.makeText(MainActivity.this, "更新数据添加失败！", 100)
.show();
}
}
});
builder2.show();
break;
case R.id.action_none:
break;
}
return super.onContextItemSelected(item);
}
// 添加数据用的是OptionMenu,即按菜单键添加
@Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.main, menu);
return super.onCreateOptionsMenu(menu);
}
// 点中菜单后添加数据的监听事件
@Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
case R.id.action_insert:
// 创建自定义对话框
AlertDialog.Builder builder = createDialogBuilder(
R.drawable.ic_launcher, "添加数据!");
// 生成对话框的一个自定义布局,返回View,因为还要查找里面的控件
View view = getLayoutInflater().inflate(R.layout.dialog_insert,
null);
final EditText edit_name = (EditText) view
.findViewById(R.id.editText_dialog_name);
final EditText edit_sex = (EditText) view
.findViewById(R.id.editText_dialog_sex);
final EditText edit_score = (EditText) view
.findViewById(R.id.editText_dialog_score);
// 将布局给对话框
builder.setView(view);
// 设置一确定按钮给它，到用来添加数据
builder.setPositiveButton("确定", new OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
String sname = edit_name.getText().toString();
String sex = edit_sex.getText().toString();
String score = edit_score.getText().toString();
String sql = "insert into studentinfo(sname,sex,score)values(?,?,?)";
boolean flag = dbUtils.executeData(sql, new Object[] {
sname, sex, score });
if (flag) {
Toast.makeText(MainActivity.this, "添加成功！", 100).show();
reloadSqlDataListView();// 添加完更新数据
} else {
Toast.makeText(MainActivity.this, "添加失败！", 100).show();
}
}
});
// 显示对话框
builder.show();
break;
}
return super.onOptionsItemSelected(item);
}
public Builder createDialogBuilder(int icLauncher, String title) {
AlertDialog.Builder builder = new AlertDialog.Builder(this);
builder.setTitle(title);
builder.setIcon(icLauncher);
builder.setNegativeButton("取消", null);
return builder;
}
@Override
protected void onDestroy() {
super.onDestroy();
cursor.close();
dbUtils.destroy();
}
}
//主程序中用到的数据库操作类
public class MySQLiteDatabaseUtils {
private static final String dbPtah = Environment
.getExternalStorageDirectory() + File.separator + "student.db";
private SQLiteDatabase db;
/**
* 建立数据库连接的构造方法
*/
public MySQLiteDatabaseUtils() {
db = SQLiteDatabase.openDatabase(dbPtah, null,
SQLiteDatabase.OPEN_READWRITE);
}
/**
* 查询方法一：返回的是游标
*
* @param sql
* @param selectionArgs
* @return
*/
public Cursor selectCursor(String sql, String[] selectionArgs) {
Cursor cursor = db.rawQuery(sql, selectionArgs);
return cursor;
}
/**
* 查询方法二：返回的是lsit集合
*
* @param sql
* @param selectionArgs
* @return
*/
public List<Map<String, String>> selectList(String sql,
String[] selectionArgs) {
Cursor cursor = db.rawQuery(sql, selectionArgs);
return cursorToList(cursor);
}
/**
* 封装游标数据到List
*
* @param cursor
* @return
*/
public List<Map<String, String>> cursorToList(Cursor cursor) {
List<Map<String, String>> list = new ArrayList<Map<String, String>>();
while (cursor.moveToNext()) {// 循环的是每一行数据
Map<String, String> map = new HashMap<String, String>();
for (int i = 0; i < cursor.getColumnCount(); i++) {// 这个循环的是每一行的列数
map.put(cursor.getColumnName(i), cursor.getString(i));// 键：key:存储每一行的字段，value:值就是内容
}
list.add(map);
}
cursor.close();
return list;
}
/**
* 增删查的方法
*
* @param sql
* @param bindArgs
* ：是 sql语句中要绑定(占位符)的参数值
* @return
*/
public boolean executeData(String sql, Object[] bindArgs) {
try {
if (bindArgs == null) {
db.execSQL(sql);
} else {
db.execSQL(sql, bindArgs);
}
return true;
} catch (SQLException e) {
e.printStackTrace();
Log.i("MainActivity", "数据错误！！");
return false;
}
}
// 关闭时销毁db
public void destroy() {
if (db != null) {
db.close();
}
}
}
//主布局
<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"
tools:context="${relativePackage}.${activityClass}" >
<ListView
android:id="@+id/listview"
android:layout_width="match_parent"
android:layout_height="wrap_content" />
<TextView
android:id="@+id/empty"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="@+id/listview"
android:text="没有数据！" />
</RelativeLayout>
//自定义适配器ListView的布局
<TextView
android:id="@+id/name"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:textSize="20sp" />
<TextView
android:id="@+id/sex"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:textSize="20sp" />
<TextView
android:id="@+id/score"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:textSize="20sp" />
//修改添加数据的三个输入框
<EditText
android:id="@+id/editText_dialog_name"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="请输入姓名" >
</EditText>
<EditText
android:id="@+id/editText_dialog_sex"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="输入性别" />
<EditText
android:id="@+id/editText_dialog_score"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="输入分数" />
//上写文菜单分别是：删除、修改、不操作
//选项菜单：添加
