本人總結(jié)的一些android的小知識(shí)點(diǎn)，會(huì)一直持續(xù)更新的，忘關(guān)注！

PS:由于簡書上不支持markdown 的[TOC]語法，所以沒法顯示目錄，

android 常用小知識(shí)點(diǎn) tips (一)
android 常用小知識(shí)點(diǎn) tips (二)
[TOC]

1、android 6.0 權(quán)限申請(qǐng)

    /**
     * android 6.0 申請(qǐng)權(quán)限
     */
    private void requestLocalPermission() {
        if (ContextCompat.checkSelfPermission(this, Manifest.permission.WRITE_EXTERNAL_STORAGE)
                != PackageManager.PERMISSION_GRANTED
                || ContextCompat.checkSelfPermission(this, Manifest.permission.READ_PHONE_STATE)
                != PackageManager.PERMISSION_GRANTED
                ) {
            //申請(qǐng)WRITE_EXTERNAL_STORAGE權(quán)限
            ActivityCompat.requestPermissions(this, new String[]{
                            Manifest.permission.WRITE_EXTERNAL_STORAGE,
                            Manifest.permission.READ_PHONE_STATE,
                    },
                    0);
        }
    }
    /**
     * 申請(qǐng)權(quán)限完成后回調(diào)
     */
    @Override
    public void onRequestPermissionsResult(int requestCode, String[] permissions, int[] grantResults) {
        super.onRequestPermissionsResult(requestCode, permissions, grantResults);
    }

2、URLDecoder

URLDecoder.decode(value, "utf-8");
URLEncoder.encode(value, "utf-8");

 -----------------------------------java端另一種解決方法--------------------------------------------

jsp頁面上有一個(gè)文本框：
<input type="text" name="companyName" value='<%=request.getAttribute("companyName") %>'/>

當(dāng)文本框內(nèi)容是漢字或者日文的時(shí)候，servlet中獲得此文本框內(nèi)容時(shí)是亂碼：
request.getParameter("companyName");

解決：
String str = request.getParameter("companyName");

當(dāng)文本框是中文時(shí)：
new String(str.getBytes("ISO-8859-1"), "GB2312");
當(dāng)文本框是日文時(shí)：
new String(str.getBytes("ISO8859-1"), "UTF-8");

3、Url 解析

// https://www.baidu.com?action=jump&target_page=ZZ1103&current_page=ZZ11000;
 private void dispatchUriTest(Uri uri) {
        try {
                 String domain = uri.getAuthority();
                 String buffer = uri.getQueryParameter("action");
                 String page = uri.getQueryParameter("target_page");
                 String cur_page = uri.getQueryParameter("current_page");
                Toast.makeText(this, type + "  " + buffer, Toast.LENGTH_SHORT).show();
        } catch (Exception e) {
            Log.e(TAG, "Uri Parse Error");
        }
    }

PS：url地址中不能有#號(hào)，如有的話，請(qǐng)主動(dòng)替換掉。

4、activity 和 fragment 里面數(shù)據(jù)備份

    //fragment 
    @Override
    public void onSaveInstanceState(Bundle outState) {
        super.onSaveInstanceState(outState);
        outState.putString("requestDate", requestDate);
        outState.putParcelableArrayList("dates", dates);
    }

    @Override
    public void onViewStateRestored(@Nullable Bundle savedInstanceState) {
        super.onViewStateRestored(savedInstanceState);
        if(savedInstanceState!=null)
        {
            requestDate = savedInstanceState.getString("requestDate");
            dates = savedInstanceState.getParcelableArrayList("dates");
        }
    }



    //Activity
     @Override
    public void onSaveInstanceState(Bundle outState) {
        super.onSaveInstanceState(outState);
        outState.putString("matchId", matchId);
    }

    @Override
    protected void onRestoreInstanceState(Bundle savedInstanceState) {
        super.onRestoreInstanceState(savedInstanceState);
        if (savedInstanceState != null) {
            matchId = savedInstanceState.getString("matchId");
        }
    }

5、gradle 打包命令

gradlew assembleReleaseA8FlavorReleaseA8

gradlew assemble+ flavor + buildType 的格式組成的

6、android 藍(lán)牙開發(fā)

Android 藍(lán)牙編程的基本步驟：
 獲取藍(lán)牙適配器BluetoothAdapter blueadapter=BluetoothAdapter.getDefaultAdapter(); 
如果BluetoothAdapter 為null，說明android手機(jī)沒有藍(lán)牙模塊。
判斷藍(lán)牙模塊是否開啟，blueadapter.isEnabled() true表示已經(jīng)開啟，false表示藍(lán)牙并沒啟用。
啟動(dòng)配置藍(lán)牙可見模式，即進(jìn)入可配對(duì)模式Intent in=new Intent(BluetoothAdapter.ACTION_REQUEST_DISCOVERABLE);  
in.putExtra(BluetoothAdapter.EXTRA_DISCOVERABLE_DURATION, 200);  
startActivity(in);  ，200就表示200秒。
獲取藍(lán)牙適配器中已經(jīng)配對(duì)的設(shè)備Set<BluetoothDevice> device=blueadapter.getBondedDevices(); 
還需要在androidManifest.xml中聲明藍(lán)牙的權(quán)限
 <uses-permission android:name="android.permission.BLUETOOTH" />
 <uses-permission android:name="android.permission.BLUETOOTH_ADMIN" />  

接下來就是根據(jù)自己的需求對(duì)BluetoothAdapter 的操作了。

7、gps 獲取經(jīng)緯度

 /*************************  GPS定位 相關(guān) end  *****************************/

    /**
     * android 6.0 申請(qǐng)權(quán)限
     */
    private void requestLocalPermission() {
        if (ContextCompat.checkSelfPermission(context, Manifest.permission.ACCESS_FINE_LOCATION)
                != PackageManager.PERMISSION_GRANTED
                || ContextCompat.checkSelfPermission(context, Manifest.permission.ACCESS_COARSE_LOCATION)
                != PackageManager.PERMISSION_GRANTED
                ) {
            //申請(qǐng)WRITE_EXTERNAL_STORAGE權(quán)限
            ActivityCompat.requestPermissions(getActivity(), new String[]{
                            Manifest.permission.ACCESS_COARSE_LOCATION,
                            Manifest.permission.ACCESS_COARSE_LOCATION,
                    },
                    0);
        }
    }
    /**
     * 申請(qǐng)權(quán)限完成后回調(diào)
     */
    @Override
    public void onRequestPermissionsResult(int requestCode, String[] permissions, int[] grantResults) {
        super.onRequestPermissionsResult(requestCode, permissions, grantResults);
        getLocation(context);
    }


    private LocationManager locationManager;
    private String locationProvider;       //位置提供器
    private String locationStr  = "";

    private void getLocation(Context context) {
        //1.獲取位置管理器
        locationManager = (LocationManager) context.getSystemService(Context.LOCATION_SERVICE);
        //2.獲取位置提供器，GPS或是NetWork
        List<String> providers = locationManager.getProviders(true);
        if (providers.contains(LocationManager.NETWORK_PROVIDER)) {
            //如果是網(wǎng)絡(luò)定位
            locationProvider = LocationManager.NETWORK_PROVIDER;
        } else if (providers.contains(LocationManager.GPS_PROVIDER)) {
            //如果是GPS定位
            locationProvider = LocationManager.GPS_PROVIDER;
        } else {
            Toast.makeText(context, "沒有可用的位置提供器", Toast.LENGTH_SHORT).show();
            return;
        }

        //3.獲取上次的位置，一般第一次運(yùn)行，此值為null
        if (ActivityCompat.checkSelfPermission(context, Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(context, Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
            return;
        }
        Location location = locationManager.getLastKnownLocation(locationProvider);
        if (location!=null){
            showLocation(location);
        }else{
            // 監(jiān)視地理位置變化，第二個(gè)和第三個(gè)參數(shù)分別為更新的最短時(shí)間minTime和最短距離minDistace
            locationManager.requestLocationUpdates(locationProvider, 0, 0,mListener);
        }
    }

    private void showLocation(Location location){
        locationStr = location.getLatitude()+","+location.getLongitude();
        Log.i(TAG, "gps : " + locationStr);
    }

    LocationListener mListener = new LocationListener() {
        @Override
        public void onStatusChanged(String provider, int status, Bundle extras) {
        }
        @Override
        public void onProviderEnabled(String provider) {
        }
        @Override
        public void onProviderDisabled(String provider) {
        }
        // 如果位置發(fā)生變化，重新顯示
        @Override
        public void onLocationChanged(Location location) {
            showLocation(location);
        }
    };


    /*************************  GPS定位 相關(guān) end  *****************************/

8、ibeacon 藍(lán)牙設(shè)備

    /*************************  藍(lán)牙ibeacon 相關(guān) begin  *****************************/
    private BluetoothAdapter mBluetoothAdapter;

    private void initBlueTooth() {
        mBluetoothAdapter = BluetoothAdapter.getDefaultAdapter();
        scanBLE();
        openRemoveTimeOutDevicesTimer();
    }

    @SuppressWarnings("deprecation")
    @SuppressLint("NewApi")
    public void scanBLE() {
        mBluetoothAdapter.startLeScan(mLeScanCallback);
    }


    @SuppressLint("NewApi")
    private BluetoothAdapter.LeScanCallback mLeScanCallback = new BluetoothAdapter.LeScanCallback() {

        @Override
        public void onLeScan(final BluetoothDevice device, int rssi, byte[] scanRecord) {
            final iBeaconClass.iBeacon ibeacon = iBeaconClass.fromScanData(device, rssi, scanRecord);

            addDevicesToMap(ibeacon);

        }
    };

    Timer mRemoveTimeOutDevicesTimer;

    private void openRemoveTimeOutDevicesTimer() {
        mRemoveTimeOutDevicesTimer = new Timer();
        mRemoveTimeOutDevicesTimer.schedule(new TimerTask() {

            @Override
            public void run() {
                if (mBleDeviceMaps.size() == 0) {
                    scanBLE();
                }
            }
        }, 1000, 1000);
    }

    private void stopTimer() {
        mRemoveTimeOutDevicesTimer.cancel();
    }

    private ConcurrentHashMap<String, iBeaconClass.iBeacon> mBleDeviceMaps = new ConcurrentHashMap<String, iBeaconClass.iBeacon>();
    //    private ConcurrentHashMap<String, Long> mBlePutTime = new ConcurrentHashMap<String, Long>();
    private ConcurrentHashMap<String, Integer> mBleRssi = new ConcurrentHashMap<String, Integer>();

    private void addDevicesToMap(iBeaconClass.iBeacon device) {
        if (device == null) {
            Log.d("TAG", "device==null ");
            return;
        }
        // 只搜索與我們自己布置的iBeacon  // TODO 章魚彩票測試的時(shí)候,可以先把這段代碼去掉
        if (device.getProximityUuid() != null) {
            if (!(device.getProximityUuid().equals(ConstantUtil.HH_IBEACON_UUID))) {
                return;
            }
        } else {
            return;
        }

        // 鍵值對(duì)存起來
        // 接收到一個(gè)信號(hào),如果沒有,就存入
        // 通過address比較
        // 如果已有就更新
        // 如果長時(shí)間不更新,就刪除
        // 用另一個(gè)map記錄時(shí)間
        // 如果3秒沒有信號(hào)
        // 刪除兩個(gè)map中的數(shù)據(jù)

        mBleDeviceMaps.put(device.bluetoothAddress, device);
//        mBlePutTime.put(device.bluetoothAddress, System.currentTimeMillis());
        mBleRssi.put(device.bluetoothAddress, device.rssi);
    }

    //---------------------------工具函數(shù)------------------------------------

    public String[] sortMapvalues(ConcurrentHashMap map) {

        // 排序hashmap的值
        List<Map.Entry<String, Integer>> retArray = null;
        retArray = new ArrayList<Map.Entry<String, Integer>>(map.entrySet());
        Collections.sort(retArray, new Comparator<Map.Entry<String, Integer>>() {
            public int compare(Map.Entry<String, Integer> o1, Map.Entry<String, Integer> o2) {
                if (o2.getValue() != null && o1.getValue() != null && o2.getValue().compareTo(o1.getValue()) > 0) {
                    return 1;
                } else {
                    return -1;
                }
            }
        });

        // 按順序取出另個(gè)集合中的iBeacon列表
        String ret[] = new String[retArray.size()];
        for (int i = 0; i < retArray.size(); i++) {
            iBeaconClass.iBeacon iB = mBleDeviceMaps.get(retArray.get(i).getKey());
            if (iB != null) {
                ret[i] = iB.getBluetoothAddress();
            }
        }
        return ret;
    }

    private JSONObject makeJsonParam() {
        String retJson = null;
        String[] objects = sortMapvalues(mBleRssi); // 按信號(hào)遠(yuǎn)近進(jìn)行排序
        JSONObject ibeacon = new JSONObject();
        JSONArray iBeaconList = new JSONArray();
        for (int i = 0; i < objects.length; i++) {
            // 最多四條
            if (i > 3) {
                continue;
            }
            // 生成每條內(nèi)容
            try {
                iBeaconClass.iBeacon ibe = mBleDeviceMaps.get(objects[i]);
                ibeacon.put("name", ibe.name);
                ibeacon.put("uuid", ibe.proximityUuid);
                ibeacon.put("address", ibe.bluetoothAddress);
                ibeacon.put("major", ibe.major);
                ibeacon.put("minor", ibe.minor);
                ibeacon.put("txPower", ibe.txPower);
                ibeacon.put("rssi", ibe.rssi);
            } catch (JSONException e3) {
                e3.printStackTrace();
            }
            iBeaconList.put(ibeacon);
            ibeacon = new JSONObject();
        }

        JSONObject paramObj = new JSONObject();
        try {
            JSONObject location = new JSONObject();
            location.put("iBeacons", iBeaconList);
            location.put("gps", locationStr);
            paramObj.put("locationInfo", location);
            paramObj.put("clientInfo", JsonUtil.getInstance().converData2String(getFilledClientInfoWrapper(context)));
        } catch (JSONException e1) {
            e1.printStackTrace();
        }
        return paramObj;
    }

    /***
     * 填充公共參數(shù)clientInfo
     *
     * @param context
     * @return
     */
    protected RequestClientInfoWrapper getFilledClientInfoWrapper(Context context) {
        RequestClientInfoWrapper wrapper = new RequestClientInfoWrapper();
        RequestClientInfoWrapper.fillInfo(context, wrapper);
        return wrapper;
    }

    /*************************  藍(lán)牙ibeacon 相關(guān) end  *****************************/

9、獲取android簽名文件的信息

以管理員方式打開cd到對(duì)應(yīng)目錄，輸入命令：keytool -list -v -keystore debug.keystore

10、android:windowSoftInputMode屬性

熟悉利用配置文件,可以減少很多不必要的麻煩,下面附上android:windowSoftInputMode屬性:
stateUnspecified：軟鍵盤的狀態(tài)并沒有指定，系統(tǒng)將選擇一個(gè)合適的狀態(tài)或依賴于主題的設(shè)置
stateUnchanged：當(dāng)這個(gè)activity出現(xiàn)時(shí)，軟鍵盤將一直保持在上一個(gè)activity里的狀態(tài)，無論是隱藏還是顯示
stateHidden：用戶選擇activity時(shí)，軟鍵盤總是被隱藏
stateAlwaysHidden：當(dāng)該Activity主窗口獲取焦點(diǎn)時(shí)，軟鍵盤也總是被隱藏的
stateVisible：軟鍵盤通常是可見的
stateAlwaysVisible：用戶選擇activity時(shí)，軟鍵盤總是顯示的狀態(tài)
adjustUnspecified：默認(rèn)設(shè)置，通常由系統(tǒng)自行決定是隱藏還是顯示
adjustResize：該Activity總是調(diào)整屏幕的大小以便留出軟鍵盤的空間
adjustPan：當(dāng)前窗口的內(nèi)容將自動(dòng)移動(dòng)以便當(dāng)前焦點(diǎn)從不被鍵盤覆蓋和用戶能總是看到輸入內(nèi)容的部分