Android-记事本功能业务（main里面的完整代码）

package cn.itcast.notepad; import android.app.Activity; import android.app.AlertDialog; import android.content.DialogInterface; import android.content.Intent; import android.os.Bundle; import android.view.View; import android.widget.AdapterView; import android.widget.ImageView; import android.widget.ListView; import android.widget.Toast; import java.util.List; import cn.itcast.notepad.adapter.NotepadAdapter; import cn.itcast.notepad.bean.NotepadBean; import cn.itcast.notepad.database.SQLiteHelper; public class NotepadActivity extends Activity { ListView listView; List<NotepadBean> list; SQLiteHelper mSQLiteHelper; NotepadAdapter adapter; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_notepad); //用于显示便签的列表 listView = (ListView) findViewById(R.id.listview); ImageView add = (ImageView) findViewById(R.id.add); add.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { Intent intent = new Intent(NotepadActivity.this, RecordActivity.class); startActivityForResult(intent, 1); } }); initData(); } protected void initData() { mSQLiteHelper= new SQLiteHelper(this); //创建数据库 showQueryData(); listView.setOnItemClickListener(new AdapterView.OnItemClickListener() { @Override public void onItemClick(AdapterView<?> parent,View view,int position,long id){ NotepadBean notepadBean = list.get(position); Intent intent = new Intent(NotepadActivity.this, RecordActivity.class); intent.putExtra("id", notepadBean.getId()); intent.putExtra("time", notepadBean.getNotepadTime()); //记录的时间 intent.putExtra("content", notepadBean.getNotepadContent()); //记录的内容 NotepadActivity.this.startActivityForResult(intent, 1); } }); listView.setOnItemLongClickListener(new AdapterView.OnItemLongClickListener() { @Override public boolean onItemLongClick(AdapterView<?> parent, View view, final int position, long id) { AlertDialog dialog; AlertDialog.Builder builder = new AlertDialog.Builder( NotepadActivity.this) .setMessage("是否删除此事件？") .setPositiveButton("确定", new DialogInterface.OnClickListener() { @Override public void onClick(DialogInterface dialog, int which) { NotepadBean notepadBean = list.get(position); if(mSQLiteHelper.deleteData(notepadBean.getId())){ list.remove(position); adapter.notifyDataSetChanged(); Toast.makeText(NotepadActivity.this,"删除成功", Toast.LENGTH_SHORT).show(); } } }) .setNegativeButton("取消", new DialogInterface.OnClickListener() { @Override public void onClick(DialogInterface dialog, int which) { dialog.dismiss(); } }); dialog = builder.create(); dialog.show(); return true; } }); } private void showQueryData(){ if (list!=null){ list.clear(); } //从数据库中查询数据(保存的标签) list = mSQLiteHelper.query(); adapter = new NotepadAdapter(this, list); listView.setAdapter(adapter); } @Override protected void onActivityResult(int requestCode,int resultCode, Intent data){ super.onActivityResult(requestCode, resultCode, data); if (requestCode==1&&resultCode==2){ showQueryData(); } } }