开发项目中学到的东西

1：谷歌自带的底部按钮最多只支持5个item
2：自己的那个解决scrollview和listview滑动冲突的方法有错了，代码应该如下：

 ListAdapter listAdapter = listView.getAdapter();
        if(listAdapter != null) {
            int totalHeight = 0;
            int params = 0;
            for(int len = listAdapter.getCount(); params < len; ++params) {
                View listItem = listAdapter.getView(params, (View)null, listView);
                listItem.measure(0, 0);
                totalHeight += listItem.getMeasuredHeight();
            }
            ViewGroup.LayoutParams var6 = listView.getLayoutParams();
            var6.height = totalHeight + listView.getDividerHeight() * (listAdapter.getCount() - 1);
            listView.setLayoutParams(var6);

就是把1300去掉
3：一个圆形图片库
添加如下依赖：compile "de.hdodenhof:circleimageview:2.1.0"
示例如下：

这里必须用framelayout才能使圆形头像图片位于背景之上
4：一个漂亮的cardview布局，由多种布局共同构造出来的，代码如下：

再来一个漂亮的cardview的布局，代码如下：

5：可以通过对appbarlayout的滑动监听来控制floatingactionbutton的出现和消失，代码片段如下：

...
 appBarLayout.addOnOffsetChangedListener(this);

    }

    @Override
    public void onOffsetChanged(AppBarLayout appBarLayout, int verticalOffset) {
        if (verticalOffset == 0) {
            floatingActionButton.show();
        } else {
            floatingActionButton.hide();
        }
    }
...

xml代码如下：

6：android中颜色可以是8位16进制数，也可以是6位16进制数，区别就是8位的前两位是透明度的值，后6位是rgb的值，有的还是3位16进制数，这个3位的没百度到，记得做完项目之后百度

7：几个drawable中的文件，自己总结一下，代码如下

//shape设置外形
    //solid设置实心，及其颜色
    //corners设置四个角的度数

    //stroke设置空心，及其颜色和宽度
    

我的电脑的E:\Project_Model\app\src\main\res\drawable路径下有大量的文件形式的drawable，欢迎参考

8：是时候好好研究一下style.xml文件中的值了
E:\Project_Model\app\src\main\res\values路径下的styles.xml，E:\siruanbei\app\src\main\res\values路径下的styles.xml（这个里面还可以直接给主题设置背景了）欢迎参考

9：一个漂亮的登陆页面，及注册账号，忘记密码，具体在E:\Project_Model\app\src\main\res\layout下的activity_login.xml，activity_forget.xml，activity_register.xml，代码如下

10：不在value文件夹下的color的值，在color文件夹下的以文件形式存在的color的值，研究一下，具体在E:\Project_Model\app\src\main\res\color

11：一个动画库，添加如下依赖，这两个依赖是共同使用的，因为一个库中用到了另外一个库中的东西：
compile 'com.daimajia.androidanimations:library:1.1.3@aar'
compile 'com.nineoldandroids:library:2.4.0'
示例如下：

YoYo.with(Techniques.Shake).duration(700).playOn(layAccPw);//其中layAccPw是要使用动画的view

12：一个实现城市三级联动的view库，地址为https://github.com/open-android/CityPickerWebView，这个库是拿js写的，还是用https://github.com/Bigkoo/Android-PickerView这个吧，依赖为：compile 'com.contrarywind:Android-PickerView:3.2.7'，这个也能实现一样的效果，而且功能更加强大，还是日期选择之类的。

13：RetrofitUtils库，网址为https://github.com/open-android/RetrofitUtils，这个框架只能上传文件和从服务器获取数据，不能通过post上传数据到服务器，并且不能返回数据到客户端，不能了解服务器端的接收情况，很伤
我自己的示例如下：

get方式
ItheimaHttp.getAsync("", new HttpResponseListener() {//注意这个范型必须是String才行，如果是object会报错
                    @Override
                    public void onResponse(String o) {
                        Log.i("xinxi", "onResponseduidele: "+o);
                        Toast.makeText(RegisterActivity.this, ""+o, Toast.LENGTH_SHORT).show();
                    }

                    @Override
                    public void onFailure(Call call, Throwable e) {
                        super.onFailure(call, e);
                        Log.i("xinxi", "onResponse: "+e+call.toString());
                    }
                });
以下是post方式，注意了postAsync方法虽说是post方式，但是它不能携带数据
ItheimaHttp.postAsync("", new HttpResponseListener() {
                    @Override
                    public void onResponse(String o) {
                        Log.i("xinxi", "onResponseduidele: "+o);
                        Toast.makeText(RegisterActivity.this, ""+o, Toast.LENGTH_SHORT).show();
                    }

                    @Override
                    public void onFailure(Call call, Throwable e) {
                        super.onFailure(call, e);
                        Log.i("xinxi", "onResponse: "+e+call.toString());
                    }
                });

14：注意了耗时较长的操作千万不敢放在主线程中，比如

HttpUtil.sendPostRequest("http://39.107.104.102:8080/",map,"GBK");就这句代码，我当时放在主线程中，这是一个网络请求的代码，，这个方法是返回一个String类型的数据了，但是当时就是啥也没有返回，最后放在子线程中，才打印出了数据，当一个操作耗时较长时，系统将会放弃操作他，谨记

15：这个是java中的知识，将一个字符串快速写入文件的方式，用的是PrintStream

<%
            if (request.getParameter("mima") != null) {
                request.setCharacterEncoding("UTF-8");
                File f=new File("C:\\Users\\liang\\Workspaces\\MyEclipse 8.5\\fuwuduan\\WebRoot\\log.txt");
                FileOutputStream ff=new FileOutputStream(f);
                PrintStream p=new PrintStream(ff); 
                System.out.println(request.getCharacterEncoding());
                p.write(request.getParameter("mima").getBytes("gbk"));
                ff.close();
                p.close();
                System.out.println(request.getParameter("mima"));
                zhuce = request.getParameter("mima").split(",");
                try {
                    Class.forName(driver);
                    Connection conn = DriverManager.getConnection(url, user,
                            password);
                    if (!conn.isClosed())
                        System.out.println("连接数据库成功");
                    Statement statement = conn.createStatement();
                    String sql = null;
                    System.out.println("zhuce[0]为" + zhuce[0]);
                    if (zhuce[0].equals(String.valueOf(0))) {
                        sql = "insert into guanliyuan values ('" + zhuce[1]
                                + "','" + zhuce[2] + "','" + zhuce[3] + "');";
                    } else if (zhuce[0].equals(String.valueOf(1))) {
                        sql = "insert into laoshi values ('" + zhuce[1] + "','"
                                + zhuce[2] + "','" + zhuce[3] + "');";
                    } else if (zhuce[0].equals(String.valueOf(2))) {
                        sql = "insert into xuesheng values ('" + zhuce[1]
                                + "','" + zhuce[2] + "','" + zhuce[3] + "');";
                    }
                    statement.execute(sql);
                    System.out.println("-----------------");
                    conn.close();
                } catch (ClassNotFoundException e) {
                    System.out.println("找不到驱动");
                    e.printStackTrace();
                } catch (SQLException e) {
                    e.printStackTrace();
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
        %>

16：通过点击一个view来强制隐藏软键盘

 public void onClick(View v) {
        hideSoft(v);
    }
 public void hideSoft(View view)
    {
        InputMethodManager imm = (InputMethodManager) getSystemService(Context.INPUT_METHOD_SERVICE);
        imm.hideSoftInputFromWindow(view.getWindowToken(), 0);
    }

博客如下：http://blog.csdn.net/h7870181/article/details/8332991

17：解决Error:Failed to resolve: com.android.support:support-annotations:26.0.1 错误的方法
在build.gradle的顶部加上
configurations.all {
resolutionStrategy.force 'com.android.support:support-annotations:23.1.0'
}
参考来自http://blog.csdn.net/pyfysf/article/details/77894331

18：android的数据库框架DBFlow
首先添加如下依赖 compile 'com.github.Raizlabs.DBFlow:dbflow:4.2.4'

19：litepal框架的补充

 Cursor cursor = DataSupport.findBySQL("select * from UserXinXi where name=?", view.loadData().getName());
                        while (cursor.moveToNext()){
                            Log.i("xinxing", cursor.getString(cursor.getColumnIndex("biaoshi")));
                        }
update的用法，和以前的不一样了
 ContentValues contentValues = new ContentValues();
                        contentValues.put("title", wenZiRenWuModel.getWenZiRenWuGuanLiModel().getTitle());
                        contentValues.put("content", wenZiRenWuModel.getWenZiRenWuGuanLiModel().getContent());
                        contentValues.put("time", new SimpleDateFormat("MM月dd日HH:mm:ss").format(new Date(System.currentTimeMillis())));
                        contentValues.put("jiezhitime", wenZiRenWuModel.getWenZiRenWuGuanLiModel().getJieZhiTime());
                        int i = DataSupport.updateAll(WenZiRenWu.class, contentValues, "time=?", wenZiRenWuModel.getAgeTime());

20：rxjava的链式写法，就我最近的那个项目里面有很多

  Observable observable = Observable.just("http://39.107.104.102:8080/").observeOn(Schedulers.newThread())
                .map(new Function() {
                    String ss;
                    @Override
                    public String apply(String s) throws Exception {
                        Map map = new ArrayMap<>();
                        map.put("mima", view.loadData().toString());
                        try {
                            ss = HttpUtils.sendPostRequest(s, map, "UTF-8");
                            Log.i("xinxi", "onNext: " + ss);
                        } catch (Exception e) {
                            e.printStackTrace();
                        }
                        return ss;
                    }
                }).observeOn(AndroidSchedulers.mainThread()).map(new Function() {
                    String biaoji;
                    @Override
                    public String apply(String s) throws Exception {
                        if (s.equals("xinxi=chenggong")) {
                            view.zhuCheSuccess();
                            biaoji = "0";
                        } else {
                            view.zhuCheFail();
                            biaoji = "1";
                        }
                        return biaoji;
                    }
                }).observeOn(Schedulers.newThread()).map(new Function() {
                    boolean b;
                    @Override
                    public String apply(String s) throws Exception {
                        if(s.equals("0")){
                            UserXinXi userXinXi=new UserXinXi();
                            userXinXi.setBiaoshi(view.loadData().getBiaoshi());
                            userXinXi.setName(view.loadData().getName());
                            b=userXinXi.save();
                            Log.i("xinxi", "biaoShi.save(): "+b);
                        }
                        return b+"";
                    }
                }).observeOn(AndroidSchedulers.mainThread());
        Observer observer = new Observer() {
            @Override
            public void onSubscribe(Disposable d) {

            }

            @Override
            public void onNext(String value) {
                Toast.makeText((Context)view, value, Toast.LENGTH_SHORT).show();
            }

            @Override
            public void onError(Throwable e) {

            }

            @Override
            public void onComplete() {

            }
        };
        observable.subscribe(observer);

比如

 Observable.just("http://39.107.104.102:8080/").observeOn(Schedulers.newThread())
                .map(new Function() {
                    String ss;
                    @Override
                    public String apply(String s) throws Exception {
                        Map map = new ArrayMap<>();
                        map.put("mima", view.loadData().toString());
                        try {
                            ss = HttpUtils.sendPostRequest(s, map, "UTF-8");
                            Log.i("xinxi", "onNext: " + ss);
                        } catch (Exception e) {
                            e.printStackTrace();
                        }
                        return ss;
                    }
                }).observeOn(AndroidSchedulers.mainThread()).map(new Function() {
                
                    @Override
                    public String apply(String s) throws Exception {
                        if (s.equals("xinxi=chenggong")) {
                            view.zhuCheSuccess();
                        } else {
                            view.zhuCheFail();
                        }
                        return "";
                    }
                }).subscribe();

以下代码中用到了range，我以为会重复添加，其实不是，只是日志是那样打印的，实际上list中的数据没有那样重复添加，让日志给迷糊了，发射的事件都是一个做完，另外一个才开始做的，上一个并不会重复做，脑子不在线啊

 public void loadData() {
        list = new ArrayList<>();
        Observable.range(1, 7).observeOn(Schedulers.newThread()).map(new Function>() {
            Document documents;
            JiaoYuNewsModel jiaoYuNewsModel;

            @Override
            public List apply(Integer integer) throws Exception {
                Log.i("apply", "apply: " + integer);
                try {
                    documents = Jsoup.connect("http://edu.people.com.cn/GB/227057/index" + integer + ".html").get();
                } catch (IOException e) {
                    e.printStackTrace();
                }
                Elements elements = documents.select("li");
                Log.i("xia", "run: " + elements.size());
                for (Element element : elements) {
                    if ((element.text().contains("-")) && (!element.select("li>a[href]").contains("http"))) {
                        Log.i("JiaoYuNews", element.select("li>a").text() + "~~" + element.select("li>em").text() + "~~" + element.select("li>a").attr("href") + "\n");
                        jiaoYuNewsModel = new JiaoYuNewsModel();
                        jiaoYuNewsModel.setTitle(element.select("li>a").text());
                        jiaoYuNewsModel.setDate(element.select("li>em").text());
                        jiaoYuNewsModel.setWangzhi(element.select("li>a").attr("href"));
                        list.add(jiaoYuNewsModel);
                    }
                }
                return list;
            }
        }).observeOn(AndroidSchedulers.mainThread()).subscribe(new Consumer>() {
            @Override
            public void accept(List list) throws Exception {
                for (JiaoYuNewsModel j : list) {
                    Log.i("dedaode", j.getTitle());
                }
            }
        });
    }

flatMap的用法，一对多，多对一，多对多

 Observable.range(1, 7).observeOn(Schedulers.newThread()).flatMap(new Function>() {
            Document documents;
            JiaoYuNewsModel jiaoYuNewsModel;

            @Override
            public ObservableSource apply(Integer integer) throws Exception {
                try {
                    documents = Jsoup.connect("http://edu.people.com.cn/GB/227057/index" + integer + ".html").get();
                } catch (IOException e) {
                    e.printStackTrace();
                }
                Elements elements = documents.select("li");
                for (Element element : elements) {
                    if ((element.text().contains("-")) && (!element.select("li>a[href]").contains("http"))) {
                        Log.i("JiaoYuNews", element.select("li>a").text() + "~~" + element.select("li>em").text() + "~~" + element.select("li>a").attr("href") + "\n");
                        jiaoYuNewsModel = new JiaoYuNewsModel();
                        jiaoYuNewsModel.setTitle(element.select("li>a").text());
                        jiaoYuNewsModel.setDate(element.select("li>em").text());
                        jiaoYuNewsModel.setWangzhi(element.select("li>a").attr("href"));
                        jiaoYuNewsModel.setI(integer);
                        list.add(jiaoYuNewsModel);
                    }
                }
                return Observable.fromIterable(list);//然后返回的这个Observable就会发射出它列表中的JiaoYuNewsModel，然后通过subscribe进行消费
            }
        }).subscribe(new Consumer() {
            @Override
            public void accept(JiaoYuNewsModel jiaoYuNewsModel) throws Exception {
            
            }
        });

下面这个才是最终版，通过flatmap正确的，就是多了个把list.clear（）

 Observable.range(1, 7).observeOn(Schedulers.newThread()).flatMap(new Function>() {
            Document documents;
            JiaoYuNewsModel jiaoYuNewsModel;

            @Override
            public ObservableSource apply(Integer integer) throws Exception {
                try {
                    documents = Jsoup.connect("http://edu.people.com.cn/GB/227057/index" + integer + ".html").get();
                } catch (IOException e) {
                    e.printStackTrace();
                }
                Elements elements = documents.select("li");
                list.clear();
                for (Element element : elements) {
                    if ((element.text().contains("-")) && (!element.select("li>a[href]").contains("http"))) {
                        Log.i("JiaoYuNews", element.select("li>a").text() + "~~" + element.select("li>em").text() + "~~" + element.select
                                ("li>a").attr("href") + "\n");
                        jiaoYuNewsModel = new JiaoYuNewsModel();
                        jiaoYuNewsModel.setTitle(element.select("li>a").text());
                        jiaoYuNewsModel.setDate(element.select("li>em").text());
                        jiaoYuNewsModel.setWangzhi(element.select("li>a").attr("href"));
                        jiaoYuNewsModel.setI(integer);
                        list.add(jiaoYuNewsModel);
                    }
                }
                return Observable.fromIterable(list);
            }
        }).observeOn(AndroidSchedulers.mainThread()).subscribe(new Consumer() {
            @Override
            public void accept(JiaoYuNewsModel jiaoYuNewsModel) throws Exception {
                view.showList(jiaoYuNewsModel);
            }
        });

map和flatmap的连用

 Observable.just("select * from ZuiJinJiLu").observeOn(Schedulers.newThread())
                .map(new Function() {
                    @Override
                    public Cursor apply(String s) throws Exception {
                        Cursor cursor = DataSupport.findBySQL(s);
                        return cursor;
                    }
                }).flatMap(new Function>() {
            List list = new ArrayList<>();

            @Override
            public ObservableSource apply(Cursor cursor) throws Exception {
                while (cursor.moveToNext()) {
                    ZuiJinJiLuModel zuiJinJiLuModel=new ZuiJinJiLuModel();
                    Log.i("shuju",cursor.getString(cursor.getColumnIndex("title"))+","+
                            cursor.getString(cursor.getColumnIndex("href"))+","+
                            cursor.getString(cursor.getColumnIndex("time")));
                    zuiJinJiLuModel.setTitle(cursor.getString(cursor.getColumnIndex("title")));
                    zuiJinJiLuModel.setHref(cursor.getString(cursor.getColumnIndex("href")));
                    zuiJinJiLuModel.setTime(cursor.getString(cursor.getColumnIndex("time")));
                    list.add(zuiJinJiLuModel);
                }
                return Observable.fromIterable(list);
            }
                }).observeOn(AndroidSchedulers.mainThread()).subscribe(new Consumer() {
            @Override
            public void accept(ZuiJinJiLuModel zuiJinJiLuModel) throws Exception {
                view.tianChongData(zuiJinJiLuModel);
            }
        });

不带参数的rxjava

  Observable.just("").observeOn(Schedulers.newThread())
                .map(new Function() {
                    @Override
                    public Bitmap apply(String s) throws Exception {
                        //int i=HttpUtil.downloadFile("http://192.168.43.24:8032/fuwuduan/downloadtouxiang.jsp","/storage/emulated/0","a"+".jpg");
                        InputStream inputStream=HttpUtil.getInputStreamFromUrl("http://192.168.43.24:8032/fuwuduan/downloadtouxiang.jsp");
                        Bitmap bitmap=ConvertUtils.bytes2Bitmap(ConvertUtils.inputStream2Bytes(inputStream));
                        //Log.d("liu", ConvertUtils.inputStream2String(inputStream, "UTF-8"));
                        return bitmap;
                    }
                }).observeOn(AndroidSchedulers.mainThread()).subscribe(new Consumer() {
            @Override
            public void accept(Bitmap bitmap) throws Exception {
                view.huanHead(bitmap);
            }
        });

再来一例：写入数据库

  public void writeDatabase(String shoujihao) {
        Observable.just(shoujihao).observeOn(Schedulers.newThread())
                .subscribe(new Consumer() {
                    @Override
                    public void accept(String s) throws Exception {
                        XiaLaLiShiJiLu xiaLaLiShiJiLu = new XiaLaLiShiJiLu(s);
                        xiaLaLiShiJiLu.save();
                    }
                });
    }

timer的使用

Observable.timer(1, TimeUnit.SECONDS)//不加observeOn切换线程的话，默认是在主线程中等待一秒，因为由于网络读取的时间要比读取本地数据库的时间要长，这时如果显示本地数据库的信息的话，会出现误差，因为我写的逻辑是服务器已经删了部分信息后，还要删除本地数据库的信息，由于网络读取的时间比较长，因此本地数据库还没有来得及更新，所以要延迟1秒在读取本地数据库，这样数据就更加可靠了。
                                .subscribe(new Consumer() {
                                               @Override
                                               public void accept(Long aLong) throws Exception {
                                                   renWuGuanLiPresenter.jiaZaiWenZiData();//这两个方法是1秒之后才会执行的
                                                   renWuGuanLiPresenter.isFirst();
                                               }
                                           }
                                );

filter的使用，筛选已经点评了的任务的信息

 Observable.just("http://39.107.104.102:8080/studentwenzirenwu.jsp").observeOn(Schedulers.newThread())
                .map(new Function() {
                    Map map=new ArrayMap();
                    @Override
                    public String apply(String s) throws Exception {
                        map.put("get",user);
                        String response = HttpUtils.postResponse(s,map,"UTF-8");
                        return response;
                    }
                }).flatMap(new Function>() {
            @Override
            public ObservableSource apply(String s) throws Exception {
                Gson gson = new Gson();
                if (s.equals("sendText error!")) {
                    return Observable.just("出错");
                } else if (s.contains("answer")) {
                    List list = gson.fromJson(s, new TypeToken>() {
                    }.getType());
                    return Observable.fromIterable(list);
                } else {
                    return Observable.just("为空");
                }
            }
        }).filter(new Predicate