編輯：關於Android編程
開發隨筆，小結項目開發中的得與失，要點如下：
進展-推薦功能及相關頁面：
1.相關控件的使用：TimePicker、RadioGroup、RadioButton、Button的隱藏；
時間選擇控件TimePicker，
A view for selecting the time of day, ineither 24 hour or AM/PM mode. The hour, each minute digit, and AM/PM (ifapplicable) can be conrolled by vertical spinners. The hour can be entered bykeyboard input. Entering in two digit hours can be accomplished by hitting twodigits within a timeout of about a second (e.g. '1' then '2' to select 12). Theminutes can be entered by entering single digits. Under AM/PM mode, the usercan hit 'a', 'A", 'p' or 'P' to pick.
最好的學習材料，官方文檔：http://www.android-doc.com/reference/android/widget/TimePicker.html
常見方法包括：setIs24HourView設置24小時制、setOnTimeChangedListener實時監聽最新時間。
startTime_tp_suggest.setIs24HourView(true);
startTime_tp_suggest.setOnTimeChangedListener(new TimePicker.OnTimeChangedListener() {
@Override
public void onTimeChanged(TimePicker view, int hour, int minute) {
mStartHour = hour;
mStartMinute = minute;
}
});
lou_rg_suggest = (RadioGroup) findViewById(R.id.lou_rg_suggest);
lou_rg_suggest.setOnCheckedChangeListener(new RadioGroup.OnCheckedChangeListener() {
@Override
public void onCheckedChanged(RadioGroup radioGroup, int id) {
switch (id){
case R.id.e11_rb_suggest:
Toast.makeText(SuggestActivity.this, "E11", Toast.LENGTH_SHORT).show();
mLou = "E11";
break;
case R.id.e13_rb_suggest:
Toast.makeText(SuggestActivity.this, "E13", Toast.LENGTH_SHORT).show();
mLou = "E13";
break;
default:
break;
}
}
});
Button的隱藏，很簡單，在xml文件中添加：
android:visibility="invisible"
需要時只需要調用相關方法顯示即可。
xxx.setVisibility(View.VISIBLE);
相關背景知識：
android view的setVisibility方法值有3個：
1.View.VISIBLE,常量值為0，意思是可見的
2.View.INVISIBLE,常量值是4，意思是不可見的
3.View.GONE,常量值是8，意思是不可見的，並且不占用布局空間。
View.class官方源代碼：
public static final int VISIBLE = 0;
public static final int INVISIBLE = 4;
public static final int GONE = 8;
2.推薦邏輯，樓層的匹配，時間安排分情況討論；
以安排會議情況為例，畫了一個示意圖，簡單梳理邏輯：
3.數據庫查詢query()函數參數，多游標的使用以及判斷：
Cursor cursor = db.query("Room", null, null, null, null, null,
"name,time");
末尾參數ORDER BY 語句用於根據指定的列對結果集進行排序，可以多關鍵字，像本條語句先按name後按time排序。
Cursor：
This interface provides random read-writeaccess to the result set returned by a database query.
Cursor implementations are not required tobe synchronized so code using a Cursor from multiple threads should perform itsown synchronization when using the Cursor.
最好的學習材料，官方文檔：http://www.android-doc.com/reference/android/database/Cursor.html多游標的使用，類似多指針，可以跟著走，也可以隨意走，妙用多多哈，數據庫和游標用完一定要關閉，重要的事情說一遍。
Cursor cursorNext = cursor;
//public Cursor query (String table, String[] columns, String selection, String[] selectionArgs, String groupBy, String having, String orderBy)
if (cursor.moveToFirst() && cursorNext.moveToFirst()) {
do {
cursorNext.moveToPosition(cursor.getPosition() + 1);
}
} while (cursor.moveToNext());
}
cursor.close();
db.close();
4.字符串的處理：分割，比較，格式化；
經常變化的字符串用StringBuffer和它的append方法，提升效率，
time_tv_suggest.setText(new StringBuffer().append(" ").append(FormatTime(mStartHour))
.append(":").append(FormatTime(mStartMinute))
.append("-").append(FormatTime(mEndHour))
.append(":").append(FormatTime(mEndMinute)));
do {
String local = cursor.getString(cursor
.getColumnIndex("local"));
String time = cursor.getString(cursor
.getColumnIndex("time"));
String name = cursor.getString(cursor.getColumnIndex("name"));
Log.d("權興權意-Cursor", "name-" + name + " time-" + time + " local-" + local);
String localArray[] = local.split("-");
String timeArray[] = time.split("-");
if(localArray[0].equals(mLou) && localArray[1].equals(mCeng)){
mStartTime = mStartHour + ":" + mStartMinute;
mEndTime = mEndHour + ":" + mEndMinute;
//區間比較-APP時間位於會議兩組時間之間
if(mStartTime.compareTo(timeArray[1]) > 0){
cursorNext.moveToPosition(cursor.getPosition() + 1);
if(name.equals(cursorNext.getString(cursor.getColumnIndex("name")))){
String timeNext = cursorNext.getString(cursor
.getColumnIndex("time"));
String timeArrayNext[] = timeNext.split("-");
if(timeArrayNext[0].compareTo(mEndTime) > 0){
roomName = name;
break;
}
}else{
//一個房間只有一個會議,會議晚於最晚時間
roomName = name;
break;
}
}
}
} while (cursor.moveToNext());
private String FormatTime(int time){
String s = Integer.toString(time);
if(s.length() == 1){
s = "0" + s;
}
return s;
}
文末小彩蛋：
android studio怎麼查看類中已有的方法：
查詢本類裡面所有的方式快捷鍵：Ctrl+o (需要把AS的快捷鍵設置成Eclipse)
ctrl查看源碼必備操作，至於怎麼把AS快捷鍵設置成Eclipse，請看上一遍博客哈。
小結：
進展-推薦功能及相關頁面：
1.相關控件的使用：TimePicker、RadioGroup、RadioButton、Button的隱藏；
2.推薦邏輯，樓層的匹配，時間安排分情況討論；
3.數據庫查詢query()函數參數，多游標的使用以及判斷；
4.字符串的處理：分割，比較，格式化；
附上核心源碼，教學相長，歡迎交流。
package com.quan.car.qmeeting;
import android.app.Activity;
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.widget.Button;
import android.widget.RadioGroup;
import android.widget.TextView;
import android.widget.TimePicker;
import android.widget.Toast;
import dbutils.MyDatabaseHelper;
/**
* Created by 權興權意 on 2016/8/23.
*/
public class SuggestActivity extends Activity{
private TimePicker startTime_tp_suggest;
private TimePicker endTime_tp_suggest;
private TextView time_tv_suggest;
private Button yesTime_btn_suggest;
private int mStartHour;
private int mStartMinute;
private int mEndHour;
private int mEndMinute;
private String mStartTime;
private String mEndTime;
private RadioGroup lou_rg_suggest;
private RadioGroup ceng_rg_suggest;
private TextView floor_tv_suggest;
private Button yesFloor_btn_suggest;
private String mLou;
private String mCeng;
private Button suggest_btn_suggest;
private MyDatabaseHelper dbHelper;
private String roomName = "Room1";
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.suggest);
dbHelper = new MyDatabaseHelper(this, "Meeting.db", null, MyDatabaseHelper.DB_VERSION);
time_tv_suggest = (TextView) findViewById(R.id.time_tv_suggest);
startTime_tp_suggest = (TimePicker) findViewById(R.id.startTime_tp_suggest);
startTime_tp_suggest.setIs24HourView(true);
startTime_tp_suggest.setOnTimeChangedListener(new TimePicker.OnTimeChangedListener() {
@Override
public void onTimeChanged(TimePicker view, int hour, int minute) {
mStartHour = hour;
mStartMinute = minute;
}
});
endTime_tp_suggest = (TimePicker) findViewById(R.id.endTime_tp_suggest);
endTime_tp_suggest.setIs24HourView(true);
endTime_tp_suggest.setOnTimeChangedListener(new TimePicker.OnTimeChangedListener() {
@Override
public void onTimeChanged(TimePicker view, int hour, int minute) {
mEndHour = hour;
mEndMinute = minute;
}
});
yesTime_btn_suggest = (Button) findViewById(R.id.yesTime_btn_suggest);
yesTime_btn_suggest.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
time_tv_suggest.setText(new StringBuffer().append(" ").append(FormatTime(mStartHour))
.append(":").append(FormatTime(mStartMinute))
.append("-").append(FormatTime(mEndHour))
.append(":").append(FormatTime(mEndMinute)));
}
});
floor_tv_suggest = (TextView) findViewById(R.id.floor_tv_suggest);
lou_rg_suggest = (RadioGroup) findViewById(R.id.lou_rg_suggest);
lou_rg_suggest.setOnCheckedChangeListener(new RadioGroup.OnCheckedChangeListener() {
@Override
public void onCheckedChanged(RadioGroup radioGroup, int id) {
switch (id){
case R.id.e11_rb_suggest:
Toast.makeText(SuggestActivity.this, "E11", Toast.LENGTH_SHORT).show();
mLou = "E11";
break;
case R.id.e13_rb_suggest:
Toast.makeText(SuggestActivity.this, "E13", Toast.LENGTH_SHORT).show();
mLou = "E13";
break;
default:
break;
}
}
});
ceng_rg_suggest = (RadioGroup) findViewById(R.id.ceng_rg_suggest);
ceng_rg_suggest.setOnCheckedChangeListener(new RadioGroup.OnCheckedChangeListener() {
@Override
public void onCheckedChanged(RadioGroup radioGroup, int id) {
switch (id){
case R.id.ceng1_rb_suggest:
Toast.makeText(SuggestActivity.this, "1", Toast.LENGTH_SHORT).show();
mCeng = "1";
break;
case R.id.ceng2_rb_suggest:
Toast.makeText(SuggestActivity.this, "2", Toast.LENGTH_SHORT).show();
mCeng = "2";
break;
case R.id.ceng3_rb_suggest:
Toast.makeText(SuggestActivity.this, "3", Toast.LENGTH_SHORT).show();
mCeng = "3";
break;
case R.id.ceng4_rb_suggest:
Toast.makeText(SuggestActivity.this, "4", Toast.LENGTH_SHORT).show();
mCeng = "4";
break;
case R.id.ceng5_rb_suggest:
Toast.makeText(SuggestActivity.this, "5", Toast.LENGTH_SHORT).show();
mCeng = "5";
break;
default:
break;
}
}
});
yesFloor_btn_suggest = (Button) findViewById(R.id.yesFloor_btn_suggest);
yesFloor_btn_suggest.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
floor_tv_suggest.setText(new StringBuffer().append(" ").append((mLou))
.append("-").append(mCeng));
}
});
suggest_btn_suggest = (Button) findViewById(R.id.suggest_btn_suggest);
suggest_btn_suggest.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
SQLiteDatabase db = dbHelper.getWritableDatabase();
Cursor cursor = db.query("Room", null, null, null, null, null,
"name,time");
Cursor cursorNext = cursor;
//public Cursor query (String table, String[] columns, String selection, String[] selectionArgs, String groupBy, String having, String orderBy)
if (cursor.moveToFirst() && cursorNext.moveToFirst()) {
do {
String local = cursor.getString(cursor
.getColumnIndex("local"));
String time = cursor.getString(cursor
.getColumnIndex("time"));
String name = cursor.getString(cursor.getColumnIndex("name"));
Log.d("權興權意-Cursor", "name-" + name + " time-" + time + " local-" + local);
String localArray[] = local.split("-");
String timeArray[] = time.split("-");
if(localArray[0].equals(mLou) && localArray[1].equals(mCeng)){
//1.會議室為空，無會議，直接預訂；
if (time.equals("")){
roomName = name;
break;
}
mStartTime = mStartHour + ":" + mStartMinute;
mEndTime = mEndHour + ":" + mEndMinute;
//3.會議室有多場會議，遍歷操作，區間：
//將會議室會議根據時間按降序排列，取區間如圖，
//C的開始時間晚於A的結束時間，
//C的結束時間早於B的開始時間，
if(mStartTime.compareTo(timeArray[1]) > 0){
cursorNext.moveToPosition(cursor.getPosition() + 1);
if(name.equals(cursorNext.getString(cursor.getColumnIndex("name")))){
String timeNext = cursorNext.getString(cursor
.getColumnIndex("time"));
String timeArrayNext[] = timeNext.split("-");
if(timeArrayNext[0].compareTo(mEndTime) > 0){
roomName = name;
break;
}
}else{
//2.2預訂會議開始時間晚於原會議結束時間；
roomName = name;
break;
}
}
//2.會議室只有1場會議：
//2.1預訂會議結束時間早於原會議開始時間；
if(timeArray[0].compareTo(mEndTime) > 0)
roomName = name;
break;
}
// Log.d("權興權意：", "nameCur-" + nameCur);
// Log.d("權興權意：", "passwordCur-" + passwordCur);
// Log.d("權興權意：", "idCur-" + idCur);
} while (cursor.moveToNext());
}
cursor.close();
db.close();
Intent intent = new Intent();
intent.setClass(SuggestActivity.this, RoomListActivity.class);
intent.putExtra("roomName",roomName);
startActivity(intent);
}
});
// Toast.makeText(SuggestActivity.this, "SuggestActivity--" + mHour + ":" + mMinute,
// Toast.LENGTH_SHORT).show();
}
private String FormatTime(int time){
String s = Integer.toString(time);
if(s.length() == 1){
s = "0" + s;
}
return s;
}
}
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