手把手教你完成Android期末大作业（多功能应用型APP）
前言Android期末作业，估摸着也花了整整5天。里面可能会缺少某些细节，如果跟着做有不会的评论就行，每天都会看，尽力解答。
功能
[*]待办
[*]专注计时
[*]音乐
[*]天气
实现步骤
一、底部菜单栏切换页
1.添加依赖
dependencies { implementation 'com.google.android.material:material:1.2.1'} 2.在res资源文件夹下新建一个menu文件夹，创建底部导航的菜单布局文件
[*]创建对应数量的item，为每个菜单栏选项
[*]给每个item定义title（标题），icon（图标）
3.在activity_main布局页面引入 com.google.android.material.bottomnavigation.BottomNavigationView 控件
控件属性：
[*]app:labelVisibilityMode="labeled"取消定义三个以上按钮文字不显示的效果
[*]app:itemBackground="@null" 取消水波纹的效果
[*]app:itemIconTint设置图标的颜色
[*]app:itemTextColor设置字体的颜色
[*]app:menu="@menu/bottom_navi_menu"将menu引入
4.依次创建每个页面的Fragment类及布局文件，如Task页面
// TaskFragment.javapublic class TaskFragment extends Fragment { //重写onCreateView, fragment绑定布局文件 @Nullable @Override public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) { View view = inflater.inflate(R.layout.task_fragment, container, false); return view; }} 5.在MainActivity.java中进行设置BottomNavigation选择监听事件对fragment进行管理。
public List fragmentList = new ArrayList();private FragmentManager fragmentManager;// 底部导航栏模块public void InitBottomNavigation() { // 添加五个fragment实例到fragmentList，以便管理 fragmentList.add(new TaskFragment()); fragmentList.add(new AbsorbedFragment()); fragmentList.add(new MusicFragment()); fragmentList.add(new WeatherFragment()); //建立fragment管理器 fragmentManager = getSupportFragmentManager(); //管理器开启事务，将fragment实例加入管理器 fragmentManager.beginTransaction() .add(R.id.FragmentLayout, fragmentList.get(0), "TASK") .add(R.id.FragmentLayout, fragmentList.get(1), "ABSOTBED") .add(R.id.FragmentLayout, fragmentList.get(2), "MUSIC") .add(R.id.FragmentLayout, fragmentList.get(3), "WEATHER") .commit(); //设置fragment显示初始状态 fragmentManager.beginTransaction() .show(fragmentList.get(1)) .hide(fragmentList.get(0)) .hide(fragmentList.get(2)) .hide(fragmentList.get(3)) .commit(); //设置底部导航栏点击选择监听事件 BottomNavigationView bottomNavigationView = findViewById(R.id.BottomNavigation); bottomNavigationView.setOnNavigationItemSelectedListener(new BottomNavigationView.OnNavigationItemSelectedListener() { @SuppressLint("NonConstantResourceId") @Override public boolean onNavigationItemSelected(@NonNull MenuItem item) { // return true : show selected style // return false: do not show switch (item.getItemId()) { case R.id.menu_task: ShowFragment(0); return true; case R.id.menu_accounts: ShowFragment(1); return true; case R.id.menu_absorbed: ShowFragment(2); return true; case R.id.menu_weather: ShowFragment(3); return true; default: Log.i(TAG, "onNavigationItemSelected: Error"); break; } return false; } });}public void ShowFragment(int index) { fragmentManager.beginTransaction() .show(fragmentList.get(index)) .hide(fragmentList.get((index + 1) % 4)) .hide(fragmentList.get((index + 2) % 4)) .hide(fragmentList.get((index + 3) % 4)) .commit();} 二、天气显示界面
1、添加依赖（用于获取和解析天气数据）
implementation 'com.google.code.gson:gson:2.8.6' implementation 'com.squareup.okhttp3:okhttp:4.9.0' 2、获取天气API接口，这里以临海市为例。使用OkHttp请求天气数据，使用Log打印测试是否能成功获取
public void RefreshWeatherData() { OkHttpClient client = new OkHttpClient(); Request request = new Request.Builder().url(weatherUrl).build(); client.newCall(request).enqueue(new Callback() { @Override public void onFailure(@NonNull Call call, @NonNull IOException e) { e.printStackTrace(); } @Override public void onResponse(@NonNull Call call, @NonNull Response response) throws IOException { String weatherJson = response.body().string(); Weather weather = new Gson().fromJson(weatherJson, Weather.class); Log.i(TAG, "onResponse: "+weatherJson); } }); } 3、Json数据获取成功后，根据Json数据的结构建立Weather类用于解析Json数据。
// class Weatherpublic class Weather { private String city; //城市名 private String update_time; //更新时间 private List data; //每天的天气数据列表，data.get(0)为当天数据 /* getter and setter */}// class DayDatapublic class DayData { private String wea; //天气状况 private String tem; //当前温度 private String tem1; //最高温 private String tem2; //最低温 private String humidity; //湿度 private String air_level; //空气质量等级 private String air_tips; //空气质量小提示 /* getter and setter */} 4、由于OkHttp的请求是在子线程中进行的，需要使用Handler消息队列机制将解析出来的Weather实例发送到主线程用以显示在界面上。
//消息处理类public class MyHandler extends Handler { @Override public void handleMessage(@NonNull Message msg) { super.handleMessage(msg); //what == 1 天气消息 if (msg.what == 1) ShowWeatherInfo((Weather) msg.obj); }}public void ShowWeatherInfo(Weather weather) { String city = weather.getCity(); String wea = weather.getData().get(0).getWea(); String maxTem = weather.getData().get(0).getTem1(); String minTem = weather.getData().get(0).getTem2(); String tem = weather.getData().get(0).getTem(); String humidity = "湿度 " + weather.getData().get(0).getHumidity(); String air_level = "空气指数 " + weather.getData().get(0).getAir_level(); // temtem1tem2citywearainpmimage ((TextView) findViewById(R.id.cityView)).setText(city); ((TextView) findViewById(R.id.weaView)).setText(wea); ((TextView) findViewById(R.id.mmtemView)).setText( String.format("%s° / %s°", minTem.substring(0, minTem.length() - 1), maxTem.substring(0, maxTem.length() - 1))); ((TextView) findViewById(R.id.temView)).setText(tem.substring(0, tem.length() - 1) + "°"); ((TextView) findViewById(R.id.humidityView)).setText(humidity); ((TextView) findViewById(R.id.levelView)).setText(air_level); ShowWeatherImage(wea); //根据天气状况wea显示对应的天气图片，这里不详细说明，使用switch就行 } 5、别忘了在OkHttp请求完成时发送消息
public void RefreshWeatherData() { OkHttpClient client = new OkHttpClient(); Request request = new Request.Builder().url(weatherUrl).build(); client.newCall(request).enqueue(new Callback() { @Override public void onFailure(@NonNull Call call, @NonNull IOException e) { e.printStackTrace(); } @Override public void onResponse(@NonNull Call call, @NonNull Response response) throws IOException { String weatherJson = response.body().string(); Weather weather = new Gson().fromJson(weatherJson, Weather.class); Message message = new Message(); message.what = 1; message.obj = weather; myHandler.sendMessage(message); } });} 6、优化xml布局
三、待办事项界面
这里由于ListView是放在Fragment中的，所以直接在MainAcitivity.java中设置适配器可能会出现数据没法显示的bug。所以我直接把从数据库获取数据,Adapter的定义，ListView设置适配器的模块搬到了TaskFragment.java中。
1.在task.xml中添加ListView，先不用设置UI样式，先把数据拿到并显示在界面上
2.创建task_item.xml布局文件(这里注意线性布局的方向及宽高，以保证task_item能放在ListView中)
3.新建TaskItem类，存放事项数据
package com.example.daily.tasks;public class TaskItem { private int id; private String content; private String type; private int status; public TaskItem(int id, String type, String content, int status){ this.id = id; this.type = type; this.content = content; this.status = status; } // 自行添加Get和Set方法} 4.在TaskFragment.java中创建SQLite数据库并获取待办事项的数据
public class TaskFragment extends Fragment { private static final String TAG = TaskFragment.class.getName(); private List taskList = new ArrayList(); @Nullable @Override public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) { View view = inflater.inflate(R.layout.task, container, false); ReadTaskDataFromSQL(); //测试数据获取是否正常 for(TaskItem item : taskList){ Log.i(TAG, "taskList "+item.getId()+" "+item.getContent()); } return view; } //读取数据库并将数据存到taskList public void ReadTaskDataFromSQL(){ MySQLiteOpenHelper openHelper = new MySQLiteOpenHelper(getActivity()); SQLiteDatabase readDatabase = openHelper.getReadableDatabase(); Cursor cursor = readDatabase.query( "task", new String[]{"id", "type", "content", "status"}, null,null,null,null,null ); while(cursor.moveToNext()){ TaskItem task = new TaskItem( cursor.getInt(0), cursor.getString(1), cursor.getString(2), cursor.getInt(3) ); taskList.add(task); } } //创建SQLite数据库 public class MySQLiteOpenHelper extends SQLiteOpenHelper{ public MySQLiteOpenHelper(@Nullable Context context) { super(context, "Daily.db", null, 1); } @Override public void onCreate(SQLiteDatabase db) { Log.i(TAG, "onCreate: sqlite"); //创建待办事项数据表 String create_sql = "create table task(" + "id INTEGER PRIMARY KEY AUTOINCREMENT, " + "content varchar(50), " + "type varchar(50), " + "status int);"; db.execSQL(create_sql); } @Override public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {} }} 5.数据获取正常以后，建立ListView适配器。这里涉及到缓存convertView的使用，使用convertView可以防止每创建一个item时就解析一个布局，这样效率肯定不高。convertView是Android提供的用于缓存的View，在第一次渲染item时，将将解析出来的View放入缓存convertView，在下一次渲染item的时候，判断convertView是否为空即可。
public class TaskAdapter extends BaseAdapter{ @Override public int getCount() { //测试getCount返回值是否正常 Log.i(TAG, "getCount: "+taskList.size()); return taskList.size(); } @Override public Object getItem(int position) { return taskList.get(position); } @Override public long getItemId(int position) { return taskList.get(position).getId(); } @Override public View getView(int position, View convertView, ViewGroup parent) { //测试getView是否执行 Log.i(TAG, "getView: "+position); ViewHolder viewHolder; TaskItem task = (TaskItem) getItem(position); if(convertView == null){ viewHolder = new ViewHolder(); convertView = LayoutInflater.from(getActivity()).inflate(R.layout.task_item, null); viewHolder.taskItemTextView = convertView.findViewById(R.id.task_content); convertView.setTag(viewHolder); }else{ viewHolder = (ViewHolder) convertView.getTag(); } viewHolder.taskItemTextView.setText(task.getId()+""+task.getContent()); return convertView; }}public class ViewHolder{ TextView taskItemTextView;} 6.在onCreateView中设置ListView的适配器
private List taskList = new ArrayList();private TaskAdapter taskAdapter;private ListView taskListView;@Nullable@Overridepublic View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) { View view = inflater.inflate(R.layout.task, container, false); taskListView = view.findViewById(R.id.taskListView); taskAdapter = new TaskAdapter(); taskListView.setAdapter(taskAdapter); ReadTaskDataFromSQL(); return view;} 7.设计每一条待办事项的布局样式，如图所示，布局设计就不放原码了，使用多个线性布局的嵌套,gravity,margin属性即可实现。
img：task-2.jpg
8.根据待办事项的状态显示不同按钮，并标记待办事项的重要程度。
public void ShowTaskContent(View convertView, TaskItem task){ //显示事项内容 TextView content = ((ViewHolder) convertView.getTag()).taskContent; int status = task.getStatus(); content.setText(task.getContent()); //事项已完成 中划线 灰色 if(status == 1){ content.getPaint().setFlags(Paint.STRIKE_THRU_TEXT_FLAG); content.setTextColor(getResources().getColor(R.color.GRAY, null)); } //事项未完成 无中划线 黑色 if(status == 0){ content.getPaint().setFlags(0); content.setTextColor(getResources().getColor(R.color.black, null)); } //事项失败 无中划线 灰色 if(status == -1){ content.getPaint().setFlags(0); content.setTextColor(getResources().getColor(R.color.GRAY, null)); } }public void ShowTaskLevel(View convertView, int level){ // 显示事项重要级别 level :0~3 四个优先级 Ⅰ Ⅱ Ⅲ Ⅳ TextView levelText = ((ViewHolder) convertView.getTag()).taskLevel; if(level == 0){ levelText.setText("Ⅰ"); levelText.setTextColor(getResources().getColor(R.color.level_0, null)); } if(level == 1){ levelText.setText("Ⅱ"); levelText.setTextColor(getResources().getColor(R.color.level_1, null)); } if(level == 2){ levelText.setText("Ⅲ"); levelText.setTextColor(getResources().getColor(R.color.level_2, null)); } if(level == 3){ levelText.setText("Ⅳ"); levelText.setTextColor(getResources().getColor(R.color.level_3, null)); } } 9.在顶部添加五个TextView作为分类查看事项菜单，点击某一分类即可查看该分类下的所有事项，并修改被点击TextView 的样式。
/** 菜单栏模块 **/public void SetTypeMenuOnClick(View view){ typeMenuList.add((TextView) view.findViewById(R.id.TypeMenu_default)); typeMenuList.add((TextView) view.findViewById(R.id.TypeMenu_work)); typeMenuList.add((TextView) view.findViewById(R.id.TypeMenu_study)); typeMenuList.add((TextView) view.findViewById(R.id.TypeMenu_life)); int[] color = { getResources().getColor(R.color.defaultColor, null), getResources().getColor(R.color.workColor, null), getResources().getColor(R.color.studyColor, null), getResources().getColor(R.color.lifeColor, null), }; for(int i=0; i { // 点击分类的一项后设置样式 typeMenuList.get(finalI).setTextColor(Color.BLACK); typeMenuList.get(finalI).setBackgroundColor(Color.WHITE); typeMenuList.get((finalI+1) % 4).setBackgroundColor(color[(finalI+1) % 4]); typeMenuList.get((finalI+1) % 4).setTextColor(Color.WHITE); typeMenuList.get((finalI+2) % 4).setBackgroundColor(color[(finalI+2) % 4]); typeMenuList.get((finalI+2) % 4).setTextColor(Color.WHITE); typeMenuList.get((finalI+3) % 4).setBackgroundColor(color[(finalI+3) % 4]); typeMenuList.get((finalI+3) % 4).setTextColor(Color.WHITE); // 显示某一类待办数据，这里筛选taskList即可 List typeTaskList = new ArrayList(); String[] types = {"全部", "工作","学习","生活"}; /*分类索引值 0 全部 1 工作 2 学习 3 生活 */ // 点击工作 学习 生活时分类 // TypeNow 是一个全局变量，表示当前的分类 TypeNow = types; Log.i(TAG, "SetTypeMenuOnClick: "+TypeNow); ReadTaskFromDatabase(); }); }} 10.task.xml布局右上角加入一个switch控件用以隐藏已完成事项。
//隐藏已完成Switch Switch hideCompletedTaskSwitch = view.findViewById(R.id.HideCompletedTaskView); hideCompletedTaskSwitch.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() { @Override public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) { if(isChecked) isHideCompleted = true; else isHideCompleted = false; // isHideCompleted 是一个全局变量，表示当前是否隐藏已完成事项 ReadTaskFromDatabase(); } }); 完成9，10步之后就需要修改读取数据库的模块，加入TypeNow和isHideCompleted变量加以控制。
public void ReadTaskFromDatabase(){ if (taskList.size()!=0) { taskList.clear(); } Cursor cursor = readDatabase.query( "task", new String[]{"id", "type", "level","content", "info", "status"}, null, null, null, null, null ); //隐藏，有分类 if(isHideCompleted && !TypeNow.equals("全部")){ //只获取未完成事项 while(cursor.moveToNext()){ if((cursor.getInt(5) == 0 ) && (cursor.getString(1).equals(TypeNow))){ TaskItem task = new TaskItem( cursor.getInt(0), cursor.getString(1), cursor.getInt(2), cursor.getString(3), cursor.getString(4), cursor.getInt(5) ); taskList.add(task); } } } //不隐藏，有分类 if(!isHideCompleted && !TypeNow.equals("全部")){ while(cursor.moveToNext()){ if(cursor.getString(1).equals(TypeNow)){ TaskItem task = new TaskItem( cursor.getInt(0), cursor.getString(1), cursor.getInt(2), cursor.getString(3), cursor.getString(4), cursor.getInt(5) ); taskList.add(task); } } } //隐藏，不分类 if(isHideCompleted && TypeNow.equals("全部")){ while(cursor.moveToNext()){ if(cursor.getInt(5) == 0){ TaskItem task = new TaskItem( cursor.getInt(0), cursor.getString(1), cursor.getInt(2), cursor.getString(3), cursor.getString(4), cursor.getInt(5) ); taskList.add(task); } } } else{ while(cursor.moveToNext()){ TaskItem task = new TaskItem( cursor.getInt(0), cursor.getString(1), cursor.getInt(2), cursor.getString(3), cursor.getString(4), cursor.getInt(5) ); taskList.add(task); } } // 别忘了通知ListView适配器数据变化 taskAdapter.notifyDataSetChanged();} 11、添加事项，这里使用的是在整个RelativeLayout布局中添加一个ImageView作为添加事项的按钮，并定义点击事件，点击时弹出对话框，在对话框中输入添加事项的信息。
自定义对话框需要先设计一个layout布局文件add_task_dialog.xml
12、定义一个方法，实现弹出添加事项界面的对话框，并设置确认和取消按钮的点击事件，确认按钮即添加该事项到数据库并显示
public void ShowAddTaskDialog(){ //获取添加事项布局实例 View addView = getLayoutInflater().inflate(R.layout.add_task_dialog, null); // 将该布局添加到对话框 final AlertDialog addDialog = new AlertDialog.Builder(getActivity()).setView(addView).create(); addDialog.show(); //获取对话框中的布局控件 Button cancelButton = (Button) addView.findViewById(R.id.cancelAddButton); Button confirmButton = (Button) addView.findViewById(R.id.confirmAddButton); EditText contentEdit = (EditText) addView.findViewById(R.id.addTaskContentEdit); EditText infoEdit = (EditText) addView.findViewById(R.id.addTaskInfoEdit); RadioGroup typeGroup = (RadioGroup) addView.findViewById(R.id.typeRadioGroup); RadioGroup levelGroup = (RadioGroup) addView.findViewById(R.id.levelRadioGroup); typeGroup.setOnCheckedChangeListener(new RadioGroup.OnCheckedChangeListener() { @Override public void onCheckedChanged(RadioGroup group, int checkedId) { } }); levelGroup.setOnCheckedChangeListener(new RadioGroup.OnCheckedChangeListener() { @Override public void onCheckedChanged(RadioGroup group, int checkedId) { } }); //确定按钮 confirmButton.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { // 获取输入的事项内容和备注 String addContent = contentEdit.getText().toString(); String addInfo = infoEdit.getText().toString(); //RadioGroup的选择项 RadioButton typeSelectBtn = (RadioButton) addView.findViewById(typeGroup.getCheckedRadioButtonId()); String addType = typeSelectBtn.getText().toString(); RadioButton levelSelectBtn = (RadioButton) addView.findViewById(levelGroup.getCheckedRadioButtonId()); int addLevel = Integer.parseInt(levelSelectBtn.getText().toString().substring(0,1)); //插入数据库 InsertTaskToDatabase( new TaskItem(addType, addLevel, addContent, addInfo, 0) ); addDialog.dismiss(); } }); // 取消按钮 cancelButton.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { addDialog.dismiss(); } });} 13、然后在添加事项的点击事件中调用ShowAddTaskDialog()即可
//添加事项的按钮ImageView addTaskImage = (ImageView) view.findViewById(R.id.addTaskImage);addTaskImage.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { ShowAddTaskDialog(); }}); 14.长按某条事项弹出对话框，显示事项信息，可以修改，删除，标记失败。和添加事项的对话框实现原理相同，这里不详细说明，给出代码供参考
public void ShowTaskInfoDialog(TaskItem task){ // 获取传入的事项数据 String content = task.getContent(); String type = task.getType(); int level = task.getLevel(); String info = task.getInfo(); //获取布局 View infoView = getLayoutInflater().inflate(R.layout.task_info_dialog, null); final AlertDialog infoDialog = new AlertDialog.Builder(getActivity()).setView(infoView).create(); infoDialog.show(); //获取对话框中的布局控件 EditText contentEdit = (EditText) infoView.findViewById(R.id.addTaskContentEdit); EditText infoEdit = (EditText) infoView.findViewById(R.id.addTaskInfoEdit); RadioGroup typeGroup = (RadioGroup) infoView.findViewById(R.id.typeRadioGroup); RadioGroup levelGroup = (RadioGroup) infoView.findViewById(R.id.levelRadioGroup); ImageView deleteImage = (ImageView) infoView.findViewById(R.id.deleteTaskButton); ImageView modifyImage = (ImageView) infoView.findViewById(R.id.modifyTaskButton); ImageView failImage = (ImageView) infoView.findViewById(R.id.failTaskButton); //显示task事项信息 contentEdit.setText(content); infoEdit.setText(info); SetTypeRadioGroupSelected(typeGroup, type); SetLevelRadioGroupSelected(levelGroup, level); //删除按钮 deleteImage.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { DeleteTaskToDatabase(task); infoDialog.dismiss(); } }); //失败按钮 failImage.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { task.setStatus(-1); UpDateTaskToDatabase(task); //别忘记关闭对话框 infoDialog.dismiss(); } }); //修改按钮 modifyImage.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { // 获取输入的事项内容和备注 String modifyContent = contentEdit.getText().toString(); String modifyInfo = infoEdit.getText().toString(); //RadioGroup的选择项 RadioButton typeSelectBtn = (RadioButton) infoView.findViewById(typeGroup.getCheckedRadioButtonId()); String modifyType = typeSelectBtn.getText().toString(); RadioButton levelSelectBtn = (RadioButton) infoView.findViewById(levelGroup.getCheckedRadioButtonId()); int modifyLevel = Integer.parseInt(levelSelectBtn.getText().toString().substring(0,1)); task.setContent(modifyContent); task.setInfo(modifyInfo); task.setType(modifyType); task.setLevel(modifyLevel); UpDateTaskToDatabase(task); //别忘记关闭对话框 infoDialog.dismiss(); } }); } //在适配器的getView中，设置每条事项的长按事件：调用ShowTaskInfoDialog弹出对话框显示事项的内容convertView.setOnLongClickListener(new View.OnLongClickListener() { @Override public boolean onLongClick(View v) { ShowTaskInfoDialog(task); return false; }}); 四、专注计时界面
计时的原理是使用Android四大组件之一的Service开启计时线程，并每隔一秒钟发送一次本地广播通知主界面更新布局。
1、创建服务类TimeService，继承自Service。这里在Service类里面定义了一个TimeThread自定义线程类，用以方便线程的挂起和恢复。
public class TimeService extends Service { private static final String TAG = TimeService.class.getName(); //计时秒数 private int second = 0; public int getSecond() { return second; } public void setSecond(int second) { this.second = second; } @Nullable @Override public IBinder onBind(Intent intent) { return new LocalBinder(); } @Override public void onCreate() { Log.i(TAG, "TimeService onCreate: "); super.onCreate(); } @Override public int onStartCommand(Intent intent, int flags, int startId) { Log.i(TAG, "TimeService onStartCommand: "); //创建计时线程实例 timeThread = new TimeThread(); timeThread.start(); isRunning = true; return super.onStartCommand(intent, flags, startId); } @Override public void onDestroy() { Log.i(TAG, "TimeService onDestroy: "); super.onDestroy(); } @Override public boolean onUnbind(Intent intent) { Log.i(TAG, "TimeService onUnbind: "); return super.onUnbind(intent); } //用于返回本地服务 public class LocalBinder extends Binder{ public TimeService getService(){ return TimeService.this; } } public class TimeThread extends Thread{ private final Object lock = new Object(); private boolean pause = false; /** * 调用该方法实现线程的暂停 */ void pauseThread(){ Log.i(TAG, "pauseTimeThread: "); pause = true; } /* 调用该方法实现恢复线程的运行 */ void resumeThread(){ Log.i(TAG, "resumeTimeThread: "); pause = false; synchronized (lock){ lock.notify(); } } /** * 这个方法只能在run 方法中实现，不然会阻塞主线程，导致页面无响应 */ void onPause() { synchronized (lock) { try { lock.wait(); } catch (InterruptedException e) { e.printStackTrace(); } } } @Override public void run() { super.run(); try { while(true){ //当pause为true时，调用onPause挂起该线程 TimeUnit.SECONDS.sleep(1); while(pause) { onPause(); } second++; SendSecondBroadcast(); Log.i(TAG, "run: "+second); } } catch (InterruptedException e) { e.printStackTrace(); } } }} 2、在AndroidManifast注册TimeService类
3、在AbsorbedFragment中绑定服务，运行测试service是否连接成功
public void BindTimeService(){ Intent intent = new Intent(getActivity(), TimeService.class); ServiceConnection connection = new ServiceConnection() { @Override public void onServiceConnected(ComponentName name, IBinder service) { localBinder = (TimeService.LocalBinder) service; if(localBinder.getService() != null){ Log.i(TAG, "onServiceConnected: time service connected"); } } @Override public void onServiceDisconnected(ComponentName name) { Log.i(TAG, "onServiceDisconnected: "); } }; getActivity().bindService(intent, connection, Context.BIND_AUTO_CREATE);} 4、给开始计时按钮添加点击事件，运行测试TimeThread是否每隔一秒打印一次
Intent intent = new Intent();intent.setClass(getActivity(), TimeService.class);getActivity().startService(intent); 5、运行成功后，添加暂停，继续，取消按钮，运行测试观察打印信息是否正常
[*]暂停点击事件：localBinder.getService().PauseTime();
[*]继续点击事件：localBinder.getService().ResumeTime();
[*]取消点击事件：localBinder.getService().CancelTime();
//TimeService中用于在MainActivity调用的方法 public void PauseTime(){ timeThread.pauseThread(); isRunning = false; } public void ResumeTime(){ timeThread.resumeThread(); isRunning = true; } public void CancelTime(){ timeThread.pauseThread(); second = 0; } 6、创建本地广播，用以接收TimeThread发送的秒数，并更新布局界面
//注册接收计时秒数的本地广播IntentFilter timeIntentFilter = new IntentFilter();timeIntentFilter.addAction("SECONDS_CHANGED");BroadcastReceiver timeBroadcastReceiver = new BroadcastReceiver() { @Override public void onReceive(Context context, Intent intent) { int second = localBinder.getService().getSecond(); ShowTimeSecond(second); }};LocalBroadcastManager.getInstance(getActivity()) .registerReceiver(timeBroadcastReceiver, timeIntentFilter); 7、在TimeThread的run方法中每一秒发送一次本地广播，运行测试是否正常
@Overridepublic void run() { super.run(); try { while(true){ //当pause为true时，调用onPause挂起该线程 TimeUnit.SECONDS.sleep(1); while(pause) { onPause(); } second++; SendSecondBroadcast(); } } catch (InterruptedException e) { e.printStackTrace(); }} 8、显示专注计时的记录，使用SQLite数据库实现，和待办事项界面一样，添加完成专注计时的按钮，点击事件为添加计时信息的字符串到数据库。
五、音乐界面
实现原理，使用Service组件和MediaPlayer。点击音乐列表的某条音乐时，在服务中开启MediaPlayer播放音乐，并每隔一秒种发送一次本地广播（内容为当前已播放的秒数），设置界面中的进度条。并给进度条设置拖动的事件，将对应的播放进度传给MediaPlayer跳转至对应的进度。
1、定义Music类，包含音乐名，文件
public class Music { private String name; private File file; // getter and setter } 2、 获取本地音乐文件
由于API 29以后getExternalStorageDirectory()被废弃，所以直接采用指定的路径获取MP3音乐文件。
public void ShowMusicList(){ File musicStorage = new File("/storage/11E9-360F/Music"); File[] musicFiles = musicStorage.listFiles(new FilenameFilter(){ @Override public boolean accept(File dir, String name) { return name.endsWith(".mp3"); } }); for(int i=0; i
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