android实现记事本app

砸漏

发布于 2020-10-28 20:53:26

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发布于 2020-10-28 20:53:26

文章被收录于专栏：恩蓝脚本

自己写的一个简单的记事本app，效果如下：

一、首先是第一个界面的编写，最上面是一个TextView，中间是一个Linearlayout中嵌套一个listview布局，最下面是一个button。下面附上第一个页面的简单布局xml文件。

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" 
 android:layout_width="fill_parent" 
 android:layout_height="fill_parent" 
 android:background="@android:color/darker_gray" 
 android:orientation="vertical"   
 <TextView 
 android:layout_height="wrap_content" 
 android:layout_width="fill_parent" 
 android:text="记事本列表" 
 android:textSize="20sp" 
 android:paddingTop="10dp" 
 android:paddingBottom="5dp" 
 android:background="#039DCF" 
 android:gravity="center"/  
 
 <LinearLayout 
 android:layout_width="fill_parent" 
 android:layout_height="fill_parent" 
 android:layout_weight="1"   
 
 <ListView 
 android:id="@+id/listview" 
 android:layout_margin="5dp" 
 android:background="#81966F" 
 android:layout_width="match_parent" 
 android:layout_height="wrap_content"   
 </ListView  
 </LinearLayout  
 
 <Button 
 android:id="@+id/btn_editnote" 
 android:layout_width="fill_parent" 
 android:layout_height="wrap_content" 
 android:background="@drawable/btn_selctor" 
 android:layout_gravity="center" 
 android:layout_marginBottom="10dp" 
 android:text="添加备忘录" 
 android:textSize="20sp" /  
 
</LinearLayout

至于button的样式btn_selector就是自己定义的button样式。

二、其次就是设置ListView中数据显示的xml文件，代码如下：

<?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:id="@+id/tv_content" 
 android:layout_width="match_parent" 
 android:layout_height="wrap_content" 
 android:layout_marginLeft="10dp" 
 android:singleLine="true" 
 android:text="Large Text" 
 android:textAppearance="?android:attr/textAppearanceLarge" /  
 
 <TextView 
 android:id="@+id/tv_date" 
 android:layout_width="fill_parent" 
 android:layout_height="wrap_content" 
 android:layout_marginLeft="10dp" 
 android:text="TextView" /  
 
</LinearLayout

三、编写第二个界面样式，第二个界面是最上面一个linearlayout，里面包含两个button和一个TextView。代码如下：

<?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:background="#FFAE99" 
 android:orientation="vertical"   
 
 <LinearLayout 
 android:layout_width="match_parent" 
 android:layout_height="wrap_content"   
 
 <Button 
 android:id="@+id/btn_cancel" 
 android:layout_width="wrap_content" 
 android:layout_height="wrap_content" 
 android:background="@drawable/btn_selctor" 
 android:text="取消" /  
 
 <LinearLayout 
 android:layout_width="wrap_content" 
 android:layout_height="wrap_content" 
 android:layout_gravity="center" 
 android:layout_weight="1" 
 android:orientation="vertical"   
 
 <TextView 
 android:layout_width="fill_parent" 
 android:layout_height="wrap_content" 
 android:gravity="center" 
 android:text="编辑备忘录" 
 android:textSize="20sp" /  
 
 <TextView 
 android:id="@+id/tv_date" 
 android:layout_width="fill_parent" 
 android:layout_height="wrap_content" 
 android:gravity="center" 
 android:text="" /  
 </LinearLayout  
 
 <Button 
 android:id="@+id/btn_ok" 
 android:layout_width="wrap_content" 
 android:layout_height="wrap_content" 
 android:background="@drawable/btn_selctor" 
 android:text="保存" /  
 </LinearLayout  
 
 <ScrollView 
 android:layout_width="fill_parent" 
 android:layout_height="fill_parent" 
 android:scrollbars="vertical"   
 
 <LinearLayout 
 android:layout_width="fill_parent" 
 android:layout_height="fill_parent" 
 android:layout_marginLeft="2dp" 
 android:orientation="vertical"   
 
 <EditText 
 android:id="@+id/et_content" 
 android:layout_width="fill_parent" 
 android:layout_height="wrap_content" 
 android:background="#FFAE99" 
 android:textSize="20sp" /  
 </LinearLayout  
 </ScrollView  
 
</LinearLayout

四、将日志的数据保存在数据库中，使用sqlite来创建数据库，数据库中有三个属性，”_id”、”content”、”date”这三个属性，创建一个NoteDB来创建数据库。

package com.example.datenote; 
 
import android.content.Context; 
import android.database.sqlite.SQLiteDatabase; 
import android.database.sqlite.SQLiteOpenHelper; 
import android.util.Log; 
 
public class NotesDB extends SQLiteOpenHelper { 
 
 public static final String TABLE_NAME_NOTES = "note"; 
 public static final String COLUMN_NAME_ID = "_id"; 
 public static final String COLUMN_NAME_NOTE_CONTENT = "content"; 
 public static final String COLUMN_NAME_NOTE_DATE = "date"; 
 
 public NotesDB(Context context) { 
 super(context, "note", null, 1); 
 // TODO Auto-generated constructor stub 
 } 
 
 @Override 
 public void onCreate(SQLiteDatabase db) { 
 String sql = "CREATE TABLE " + TABLE_NAME_NOTES + "(" + COLUMN_NAME_ID 
 + " INTEGER PRIMARY KEY AUTOINCREMENT," 
 + COLUMN_NAME_NOTE_CONTENT + " TEXT NOT NULL DEFAULT\"\"," 
 + COLUMN_NAME_NOTE_DATE + " TEXT NOT NULL DEFAULT\"\"" + ")"; 
 Log.d("SQL", sql); 
 db.execSQL(sql); 
// String sql1="insert into "+TABLE_NAME_NOTES+"values("+"1,"+"'写作业',"+"'晚上要写作业的干活'"+")"; 
// Log.d("SQL1", sql1); 
// db.execSQL(sql1); 
// ContentValues values=new ContentValues(); 
// values.put("id",1); 
// values.put("content","写作业"); 
// values.put("date", "2013-1-2"); 
// db.insert("note", null, values); 
 
 } 
 
 @Override 
 public void onUpgrade(SQLiteDatabase arg0, int arg1, int arg2) { 
 // TODO Auto-generated method stub 
 
 } 
 
}

五、实现点击添加事件的跳转,在第一个页面中点击添加备忘录后会跳转到第二个界面，设置点击事件，由一个activity跳转到另外一个activity，我使用的是intent方式。另外，在ListView中点击每个已记录下来的日志也会跳转到第二个界面，只是显示的不是空白的EditText，而是包含日志的EditText。MainActivity如下：

package com.example.datenote; 
import java.util.ArrayList; 
import java.util.HashMap; 
import java.util.List; 
import java.util.Map; 
import android.app.Activity; 
import android.app.AlertDialog; 
import android.app.AlertDialog.Builder; 
import android.content.Context; 
import android.content.DialogInterface; 
import android.content.Intent; 
import android.database.Cursor; 
import android.database.sqlite.SQLiteDatabase; 
import android.os.Bundle; 
import android.util.Log; 
import android.view.View; 
import android.view.View.OnClickListener; 
import android.view.Window; 
import android.widget.AbsListView; 
import android.widget.AbsListView.OnScrollListener; 
import android.widget.AdapterView; 
import android.widget.AdapterView.OnItemClickListener; 
import android.widget.AdapterView.OnItemLongClickListener; 
import android.widget.Button; 
import android.widget.ListView; 
import android.widget.SimpleAdapter; 
import android.widget.TextView; 
import android.widget.Toast; 
public class MainActivity extends Activity implements OnScrollListener, 
OnItemClickListener, OnItemLongClickListener { 
private Context mContext; 
private ListView listview; 
private SimpleAdapter simp_adapter; 
private List<Map<String, Object   dataList; 
private Button addNote; 
private TextView tv_content; 
private NotesDB DB; 
private SQLiteDatabase dbread; 
@Override 
protected void onCreate(Bundle savedInstanceState) { 
super.onCreate(savedInstanceState); 
requestWindowFeature(Window.FEATURE_NO_TITLE); 
setContentView(R.layout.activity_main); 
tv_content = (TextView) findViewById(R.id.tv_content); 
listview = (ListView) findViewById(R.id.listview); 
dataList = new ArrayList<Map<String, Object  (); 
addNote = (Button) findViewById(R.id.btn_editnote); 
mContext = this; 
addNote.setOnClickListener(new OnClickListener() { 
@Override 
public void onClick(View arg0) { 
noteEdit.ENTER_STATE = 0; 
Intent intent = new Intent(mContext, noteEdit.class); 
Bundle bundle = new Bundle(); 
bundle.putString("info", ""); 
intent.putExtras(bundle); 
startActivityForResult(intent, 1); 
} 
}); 
DB = new NotesDB(this); 
dbread = DB.getReadableDatabase(); 
// 清空数据库中表的内容 
//dbread.execSQL("delete from note"); 
RefreshNotesList(); 
listview.setOnItemClickListener(this); 
listview.setOnItemLongClickListener(this); 
listview.setOnScrollListener(this); 
} 
public void RefreshNotesList() { 
int size = dataList.size(); 
if (size   0) { 
dataList.removeAll(dataList); 
simp_adapter.notifyDataSetChanged(); 
listview.setAdapter(simp_adapter); 
} 
simp_adapter = new SimpleAdapter(this, getData(), R.layout.item, 
new String[] { "tv_content", "tv_date" }, new int[] { 
R.id.tv_content, R.id.tv_date }); 
listview.setAdapter(simp_adapter); 
} 
private List<Map<String, Object   getData() { 
Cursor cursor = dbread.query("note", null, "content!=\"\"", null, null, 
null, null); 
while (cursor.moveToNext()) { 
String name = cursor.getString(cursor.getColumnIndex("content")); 
String date = cursor.getString(cursor.getColumnIndex("date")); 
Map<String, Object  map = new HashMap<String, Object (); 
map.put("tv_content", name); 
map.put("tv_date", date); 
dataList.add(map); 
} 
cursor.close(); 
return dataList; 
} 
@Override 
public void onScroll(AbsListView arg0, int arg1, int arg2, int arg3) { 
// TODO Auto-generated method stub 
} 
// 滑动listview监听事件 
@Override 
public void onScrollStateChanged(AbsListView arg0, int arg1) { 
// TODO Auto-generated method stub 
switch (arg1) { 
case SCROLL_STATE_FLING: 
Log.i("main", "用户在手指离开屏幕之前，由于用力的滑了一下，视图能依靠惯性继续滑动"); 
case SCROLL_STATE_IDLE: 
Log.i("main", "视图已经停止滑动"); 
case SCROLL_STATE_TOUCH_SCROLL: 
Log.i("main", "手指没有离开屏幕，试图正在滑动"); 
} 
} 
// 点击listview中某一项的监听事件 
@Override 
public void onItemClick(AdapterView<?  arg0, View arg1, int arg2, long arg3) { 
noteEdit.ENTER_STATE = 1; 
// Log.d("arg2", arg2 + ""); 
// TextView 
// content=(TextView)listview.getChildAt(arg2).findViewById(R.id.tv_content); 
// String content1=content.toString(); 
String content = listview.getItemAtPosition(arg2) + ""; 
String content1 = content.substring(content.indexOf("=") + 1, 
content.indexOf(",")); 
Log.d("CONTENT", content1); 
Cursor c = dbread.query("note", null, 
"content=" + "'" + content1 + "'", null, null, null, null); 
while (c.moveToNext()) { 
String No = c.getString(c.getColumnIndex("_id")); 
Log.d("TEXT", No); 
// Intent intent = new Intent(mContext, noteEdit.class); 
// intent.putExtra("data", text); 
// setResult(4, intent); 
// // intent.putExtra("data",text); 
// startActivityForResult(intent, 3); 
Intent myIntent = new Intent(); 
Bundle bundle = new Bundle(); 
bundle.putString("info", content1); 
noteEdit.id = Integer.parseInt(No); 
myIntent.putExtras(bundle); 
myIntent.setClass(MainActivity.this, noteEdit.class); 
startActivityForResult(myIntent, 1); 
} 
} 
@Override 
// 接受上一个页面返回的数据，并刷新页面 
protected void onActivityResult(int requestCode, int resultCode, Intent data) { 
// TODO Auto-generated method stub 
super.onActivityResult(requestCode, resultCode, data); 
if (requestCode == 1 && resultCode == 2) { 
RefreshNotesList(); 
} 
} 
// 点击listview中某一项长时间的点击事件 
@Override 
public boolean onItemLongClick(AdapterView<?  arg0, View arg1, int arg2, 
long arg3) { 
final int n=arg2; 
Builder builder = new AlertDialog.Builder(this); 
builder.setTitle("删除该日志"); 
builder.setMessage("确认删除吗？"); 
builder.setPositiveButton("确定", new DialogInterface.OnClickListener() { 
@Override 
public void onClick(DialogInterface dialog, int which) { 
String content = listview.getItemAtPosition(n) + ""; 
String content1 = content.substring(content.indexOf("=") + 1, 
content.indexOf(",")); 
Cursor c = dbread.query("note", null, "content=" + "'" 
+ content1 + "'", null, null, null, null); 
while (c.moveToNext()) { 
String id = c.getString(c.getColumnIndex("_id")); 
String sql_del = "update note set content='' where _id=" 
+ id; 
dbread.execSQL(sql_del); 
RefreshNotesList(); 
} 
} 
}); 
builder.setNegativeButton("取消", new DialogInterface.OnClickListener() { 
@Override 
public void onClick(DialogInterface dialog, int which) { 
} 
}); 
builder.create(); 
builder.show(); 
return true; 
} 
}

六、编写第二个跳转后界面的Activity，如下：

package com.example.datenote; 
import java.text.SimpleDateFormat; 
import java.util.Date; 
import android.app.Activity; 
import android.content.Context; 
import android.content.Intent; 
import android.database.sqlite.SQLiteDatabase; 
import android.database.sqlite.SQLiteStatement; 
import android.os.Bundle; 
import android.util.Log; 
import android.view.View; 
import android.view.View.OnClickListener; 
import android.view.Window; 
import android.view.WindowManager; 
import android.view.inputmethod.InputMethodManager; 
import android.widget.Button; 
import android.widget.EditText; 
import android.widget.TextView; 
public class noteEdit extends Activity { 
private TextView tv_date; 
private EditText et_content; 
private Button btn_ok; 
private Button btn_cancel; 
private NotesDB DB; 
private SQLiteDatabase dbread; 
public static int ENTER_STATE = 0; 
public static String last_content; 
public static int id; 
@Override 
protected void onCreate(Bundle savedInstanceState) { 
// TODO Auto-generated method stub 
super.onCreate(savedInstanceState); 
// 设置无标题 
requestWindowFeature(Window.FEATURE_NO_TITLE); 
setContentView(R.layout.edit); 
tv_date = (TextView) findViewById(R.id.tv_date); 
Date date = new Date(); 
SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm"); 
String dateString = sdf.format(date); 
tv_date.setText(dateString); 
et_content = (EditText) findViewById(R.id.et_content); 
// 设置软键盘自动弹出 
getWindow().setSoftInputMode( 
WindowManager.LayoutParams.SOFT_INPUT_STATE_ALWAYS_VISIBLE); 
DB = new NotesDB(this); 
dbread = DB.getReadableDatabase(); 
Bundle myBundle = this.getIntent().getExtras(); 
last_content = myBundle.getString("info"); 
Log.d("LAST_CONTENT", last_content); 
et_content.setText(last_content); 
// 确认按钮的点击事件 
btn_ok = (Button) findViewById(R.id.btn_ok); 
btn_ok.setOnClickListener(new OnClickListener() { 
public void onClick(View arg0) { 
// 获取日志内容 
String content = et_content.getText().toString(); 
Log.d("LOG1", content); 
// 获取写日志时间 
Date date = new Date(); 
SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd"); 
String dateNum = sdf.format(date); 
String sql; 
String sql_count = "SELECT COUNT(*) FROM note"; 
SQLiteStatement statement = dbread.compileStatement(sql_count); 
long count = statement.simpleQueryForLong(); 
Log.d("COUNT", count + ""); 
Log.d("ENTER_STATE", ENTER_STATE + ""); 
// 添加一个新的日志 
if (ENTER_STATE == 0) { 
if (!content.equals("")) { 
sql = "insert into " + NotesDB.TABLE_NAME_NOTES 
+ " values(" + count + "," + "'" + content 
+ "'" + "," + "'" + dateNum + "')"; 
Log.d("LOG", sql); 
dbread.execSQL(sql); 
} 
} 
// 查看并修改一个已有的日志 
else { 
Log.d("执行命令", "执行了该函数"); 
String updatesql = "update note set content='" 
+ content + "' where _id=" + id; 
dbread.execSQL(updatesql); 
// et_content.setText(last_content); 
} 
Intent data = new Intent(); 
setResult(2, data); 
finish(); 
} 
}); 
btn_cancel = (Button) findViewById(R.id.btn_cancel); 
btn_cancel.setOnClickListener(new OnClickListener() { 
public void onClick(View arg0) { 
finish(); 
} 
}); 
} 
@Override 
protected void onActivityResult(int requestCode, int resultCode, Intent data) { 
// TODO Auto-generated method stub 
super.onActivityResult(requestCode, resultCode, data); 
// if (requestCode == 3 && resultCode == 4) { 
// last_content=data.getStringExtra("data"); 
// Log.d("LAST_STRAING", last_content+"gvg"); 
// } 
} 
}

七、其中，对ListView添加OnItemLongclicklistener，长点击之后会弹出一个dialog对话框提醒要不要删除该日志文件。

public boolean onItemLongClick(AdapterView<?  arg0, View arg1, int arg2, 
long arg3) { 
final int n=arg2; 
Builder builder = new AlertDialog.Builder(this); 
builder.setTitle("删除该日志"); 
builder.setMessage("确认删除吗？"); 
builder.setPositiveButton("确定", new DialogInterface.OnClickListener() { 
@Override 
public void onClick(DialogInterface dialog, int which) { 
String content = listview.getItemAtPosition(n) + ""; 
String content1 = content.substring(content.indexOf("=") + 1, 
content.indexOf(",")); 
Cursor c = dbread.query("note", null, "content=" + "'" 
+ content1 + "'", null, null, null, null); 
while (c.moveToNext()) { 
String id = c.getString(c.getColumnIndex("_id")); 
String sql_del = "update note set content='' where _id=" 
+ id; 
dbread.execSQL(sql_del); 
RefreshNotesList(); 
} 
} 
}); 
builder.setNegativeButton("取消", new DialogInterface.OnClickListener() { 
@Override 
public void onClick(DialogInterface dialog, int which) { 
} 
}); 
builder.create(); 
builder.show(); 
return true; 
}

注意最后将返回值设为true，否则会和OnItemClickListener产生冲突。

附上长点击删除的效果。