小白求助:
有两个Acitivity,在FirstActivity里创建数据库后,EditText输入数据,点击button1实现数据写入后清空,输入若干次后,点击button2实现跳转到SecondActivity,在其TextView里显示数据库所有的数据。
请问:SecondActivity要怎么写,如何在SecondActivity里实现读取数据库所有内容,并将其显示再TextView上?
这里附上FirstActivity建立数据库、内部类和点击事件的代码
public class myData extends SQLiteOpenHelper {
public myData(Context context, String str) {
super(context, str, null, 1);
// TODO Auto-generated constructor stub
}
@Override
public void onCreate(SQLiteDatabase db) {
// TODO Auto-generated method stub
String DATABASE_SQL = "CREATE TABLE " + "MYSTUDENTDB" + " ("
+ "_ID" + " INTEGER primary key autoincrement, " + "NAME"
+ " text not null, " + "STUID" + " text not null, "
+ "CLASS" + " text not null, " + "EMAIL"
+ " text not null " + ");";
// "create table mytable (_ID,NAME, STUID, CLASS, EMAIL);"
db.execSQL(DATABASE_SQL);
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
// TODO Auto-generated method stub
}
}
public void onClick(View v) {
// TODO Auto-generated method stub
AlertDialog.Builder builder = new AlertDialog.Builder(
FinalWorkActivity.this);
builder.setIcon(R.drawable.ic_launcher);
myData helper = new myData(FinalWorkActivity.this,
FinalWorkActivity.this.getFilesDir() + "/new_data.db");// 内部类
SQLiteDatabase database = helper.getWritableDatabase();
switch (v.getId()) {
case R.id.bt1:// 添加元素
ContentValues value1 = new ContentValues();
value1.put("NAME", ied1.getText().toString());
value1.put("STUID", ied2.getText().toString());
value1.put("CLASS", ied3.getText().toString());
value1.put("EMAIL", ied4.getText().toString());
long i = database.insert("MYSTUDENTDB", null, value1);
if (i == -1) {
Toast.makeText(this, "添加失败", 0).show();
} else {
Toast.makeText(this, "添加成功", 0).show();
}
database.close();
ied1.setText("");
ied2.setText("");
ied3.setText("");
ied4.setText("");
break;
case R.id.bt2:// 全部条目
Intent it1 = new Intent();
it1.setClassFirstActivity.this, SecondActivity.class);
startActivity(it1);
break;