android 实用方法整理

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在经过几年的经验累积之后，我终于决定整理一下曾经遇到的各种问题，给各位走在android开发路上的朋友一点帮助，更多相关问题，请访问我的博客：http://blog.csdn.net/xiaoliluote 如果您对该问题有更多的解决方式，请留言，验证之后我会编辑博客

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编写过好些个程序之后，我发现每个程序中都有一些方法是常常用到的，这里呢，就整理出来，下次使用的时候就不用再去到处找或者重新写啦。
俗话说，站在巨人的肩膀上，事半功倍嘛。

方法一：快捷获取网络数据，写入数据到文件中

//获取网络数据//传入数据网址，以及将要存放的名字public void getUrlData(String url,String file_name){try{HttpURLConnection conn=(HttpURLConnection) new URL(url).openConnection();               conn.setRequestMethod("GET");        if(conn.getResponseCode() ==200){        InputStream inputStream=conn.getInputStream();                             byte[]jsonBytes=convertIsToByteArray(inputStream);        FileOutputStream outStream =_context.openFileOutput(file_name, Context.MODE_PRIVATE);          outStream.write(jsonBytes);//向文件中写入数据，将字符串转换为字节          outStream.close();         return true;        }}catch(Exception e){}}//上面方法中，用到了一个叫做convertIsToByteArray的方法读取数据转换为byte[]public static byte[] convertIsToByteArray(InputStream inputStream) {        // TODO Auto-generated method stub             ByteArrayOutputStream baos=new ByteArrayOutputStream();        byte buffer[]=new byte[1024];        int length=0;        try {            while ((length=inputStream.read(buffer))!=-1) {                baos.write(buffer, 0, length);                         }            inputStream.close();            baos.flush();        } catch (IOException e) {            // TODO Auto-generated catch block            e.printStackTrace();        }        return baos.toByteArray();    }

方法二，快速读取文件，与方法一共用的哦

//输入方法一存放的文件名，就可以读取出数据啦public  String read(String filename) throws Exception{          //得到输入流之后          FileInputStream inStream =_context.openFileInput(filename);          //创建一个往内存输出流对象          ByteArrayOutputStream outStream =new ByteArrayOutputStream();          byte[] buffer =new byte[1024];          int len =0;          while((len=inStream.read(buffer))!=-1){              //把每次读到的数据写到内存中              outStream.write(buffer,0,len);          }          //得到存放在内存中的所有的数据           byte [] data =outStream.toByteArray();        String result = new String(data,"UTF8");        return result;      }

方法三，读取assets目录下的图片资源

//传入context，以及文件名就OK了，比如文件目录是assets/image/1.png，那么这里就传入image/1.png就可以了public static  Bitmap getImageFromAssetsFile(Context context, String fileName) {           Bitmap image = null;           AssetManager am = context.getResources().getAssets();           try {               InputStream is = am.open(fileName);               image = BitmapFactory.decodeStream(is);               is.close();           } catch (IOException e) {               e.printStackTrace();           }           return image;       }

方法四，将base64转换成bitmap

public Bitmap stringtoBitmap(String string){        //将字符串转换成Bitmap类型        Bitmap bitmap=null;        try {        byte[]bitmapArray;        bitmapArray=Base64.decode(string, Base64.DEFAULT);        bitmap=BitmapFactory.decodeByteArray(bitmapArray, 0, bitmapArray.length);        } catch (Exception e) {        e.printStackTrace();        }        return bitmap;        }

方法五，合成两张图片变成一张图片

//传入合成后想要的图片的宽，高，以及需要合成的两张图片，这里请留意两张图片的顺序，是secondBitmap覆盖在firstBitmap上面的public Bitmap mergeBitmap(int width,int height,Bitmap firstBitmap, Bitmap secondBitmap) {        firstBitmap =resizeImage(firstBitmap,width,height);        secondBitmap =resizeImage(secondBitmap,width,height);        Bitmap bitmap = Bitmap.createBitmap(width, height,                firstBitmap.getConfig());        Canvas canvas = new Canvas(bitmap);        canvas.drawBitmap(firstBitmap, new Matrix(), null);        canvas.drawBitmap(secondBitmap, new Matrix(), null);        return bitmap;    }    public  Bitmap resizeImage(Bitmap bitmap, int w, int h)       {            Bitmap BitmapOrg = bitmap;            int width = BitmapOrg.getWidth();            int height = BitmapOrg.getHeight();            int newWidth = w;            int newHeight = h;            float scaleWidth = ((float) newWidth) / width;            float scaleHeight = ((float) newHeight) / height;            Matrix matrix = new Matrix();            matrix.postScale(scaleWidth, scaleHeight);            // 如果你想旋转图片的话          // matrix.postRotate(45);             Bitmap resizedBitmap = Bitmap.createBitmap(BitmapOrg, 0, 0, width,                            height, matrix, true);            return   resizedBitmap;    } 

方法六，将图片裁剪成圆角

//传入需要裁剪的图片，以及四个圆角的角度public Bitmap getRoundedCornerBitmap(Bitmap bitmap,float roundPx){          Bitmap output = Bitmap.createBitmap(bitmap.getWidth(), bitmap                  .getHeight(), Config.ARGB_8888);          Canvas canvas = new Canvas(output);          final int color = 0xff424242;          final Paint paint = new Paint();          final Rect rect = new Rect(0, 0, bitmap.getWidth(), bitmap.getHeight());          final RectF rectF = new RectF(rect);          paint.setAntiAlias(true);          canvas.drawARGB(0, 0, 0, 0);          paint.setColor(color);          canvas.drawRoundRect(rectF, roundPx, roundPx, paint);          paint.setXfermode(new PorterDuffXfermode(Mode.SRC_IN));          canvas.drawBitmap(bitmap, rect, rect, paint);          return output;      } 

方法七，md5加密数据

public static String md5(String string) {        byte[] hash;        try {            hash = MessageDigest.getInstance("MD5").digest(string.getBytes("UTF-8"));        } catch (NoSuchAlgorithmException e) {            throw new RuntimeException("卧槽，不支持md5加密？", e);        } catch (UnsupportedEncodingException e) {            throw new RuntimeException("卧槽，不支持utf-8编码？", e);        }        StringBuilder hex = new StringBuilder(hash.length * 2);        for (byte b : hash) {            if ((b & 0xFF) < 0x10) hex.append("0");            hex.append(Integer.toHexString(b & 0xFF));        }        return hex.toString();    }    public final static String getMessageDigest(byte[] buffer) {        char hexDigits[] = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f' };        try {            MessageDigest mdTemp = MessageDigest.getInstance("MD5");            mdTemp.update(buffer);            byte[] md = mdTemp.digest();            int j = md.length;            char str[] = new char[j * 2];            int k = 0;            for (int i = 0; i < j; i++) {                byte byte0 = md[i];                str[k++] = hexDigits[byte0 >>> 4 & 0xf];                str[k++] = hexDigits[byte0 & 0xf];            }            return new String(str);        } catch (Exception e) {            return null;        }    }

方法八，给某个控件画圆角
//某些时候，我们为了美观效果，会让一些控件以圆角的形式展现，比如下图

//比如这张微信的图片，去评分，欢迎页 外部的这个白色背景，就是圆角的，这样看起来比较美观//那么这里我以LinearLayout为例子public class MYLinearLayout extends LinearLayout{    float _corners;    public MYLinearLayout(Context context) {        super(context);        // TODO Auto-generated constructor stub    }    public MYLinearLayout(Context context, AttributeSet attrs) {        super(context, attrs);        // TODO Auto-generated constructor stub    }    public MYLinearLayout(Context context, AttributeSet attrs, int defStyle) {        super(context, attrs, defStyle);        // TODO Auto-generated constructor stub    }//记得调用该方法，传入要生成的角度，这里我只传入了一个参数，是因为我要求四个角度都是一样的，如果你要求上面和下面的角度不一样，那么请设定两个参数public void set_corners(float corners){        _corners = corners;}    @Override    public void draw(Canvas canvas) {        super.draw(canvas);        Paint paint = new Paint();        paint.setAntiAlias(true);        paint.setColor(StaticParameter.shape_color);        paint.setStyle(Paint.Style.STROKE);        //这个就是画圆角的方法啦，通过 _corners这个参数来设定圆角大小        canvas.drawRoundRect(new RectF(1,1,this.getWidth() - 1,this.getHeight() - 1), _corners, _corners, paint);    }}

方法九，java反射

//有时我们的东西是提供给第三方使用，第三方在我们的代码操作后，需要回调给第三方，而我们并不知道第三方的东西，于是就有了反射机制@SuppressWarnings("rawtypes")        Class handMachine = Class.forName("反射的类名，请写完整包名+类名");        @SuppressWarnings("unchecked")        Method method1 = handMachine.getMethod("反射到上述类名中的哪个方法，这里后面我带了两个String.class，是代表这个方法有两个参数，如果没有的话，就可以不写啦",String.class,String.class);        @SuppressWarnings("unused")        Object handMachineInstance= method1.invoke(handMachine.newInstance(),"这里就是上面第一个String参数的值","第二个String参数的值");

方法十，新浪微博的分享功能

//当我们的应用需要和社交软件分享的时候，用到，这里是新浪分享的代码//传入在新浪开放平台申请的appid，以及要分享出去的内容public void shareToWB(String content,String WB_APP_ID){        IWeiboShareAPI  mWeiboShareAPI  = WeiboShareSDK.createWeiboAPI(_context,WB_APP_ID);        if (mWeiboShareAPI.checkEnvironment(true)) {            mWeiboShareAPI.registerApp();            if (mWeiboShareAPI.isWeiboAppSupportAPI()) {                int supportApi = mWeiboShareAPI.getWeiboAppSupportAPI();                if (supportApi >= 10351 ) {                    // 1. 初始化微博的分享消息                    WeiboMultiMessage weiboMessage = new WeiboMultiMessage();                        TextObject textObject = new TextObject();                        textObject.text = content;                        weiboMessage.textObject = textObject;                    // 2. 初始化从第三方到微博的消息请求                    SendMultiMessageToWeiboRequest request = new SendMultiMessageToWeiboRequest();                    // 用transaction唯一标识一个请求                    request.transaction = String.valueOf(System.currentTimeMillis());                    request.multiMessage = weiboMessage;                    // 3. 发送请求消息到微博，唤起微博分享界面                    mWeiboShareAPI.sendRequest(request);                } else {                    WeiboMessage weiboMessage = new WeiboMessage();                    TextObject textObject = new TextObject();                    textObject.text = content;                    weiboMessage.mediaObject = textObject;                     // 2. 初始化从第三方到微博的消息请求                    SendMessageToWeiboRequest request = new SendMessageToWeiboRequest();                    // 用transaction唯一标识一个请求                    request.transaction = String.valueOf(System.currentTimeMillis());                    request.message = weiboMessage;                    // 3. 发送请求消息到微博，唤起微博分享界面                    mWeiboShareAPI.sendRequest(request);                }            } else {                Toast.makeText(_context,"微博客户端不支持 SDK 分享或微博客户端未安装或微博客户端是非官方版本。",                        Toast.LENGTH_SHORT).show();            }        }    }

方法十一，QQ空间的分享以及回调

//分享的type，指分享到空间，还是分享给某个朋友（群），分享的title，summary标题，描述等内容，分享的url，网址，用户点击进去查看的网址，分享的image_json，图片内容，这里由于我想分享多张图片，于是用了一个Jsonarray，但好像只能显示一张图片出来, QQ_API_ID是在腾讯开放平台申请的IDpublic void shareToQQ(final String type,final String title,final String summary,final String url,final String image_json,String QQ_API_ID){             mHandler.post(new Runnable(){                    @Override                    public void run() {         Tencent mTencent= Tencent.createInstance(QQ_API_ID,(Activity) _context);         Bundle params = new Bundle();         params.putInt(QzoneShare.SHARE_TO_QZONE_KEY_TYPE, QzoneShare.SHARE_TO_QZONE_TYPE_IMAGE_TEXT);         params.putString(QzoneShare.SHARE_TO_QQ_TITLE, title);         params.putString(QzoneShare.SHARE_TO_QQ_SUMMARY, summary);         params.putString(QzoneShare.SHARE_TO_QQ_TARGET_URL, url);         String image_url="";         ArrayList<String> imageUrls = new ArrayList<String>();         try {            JSONArray json_arr = new JSONArray(image_json);            for(int i=0;i<json_arr.length();i++){                image_url=json_arr.getString(i);                imageUrls.add(json_arr.getString(i));            }        } catch (JSONException e) {            // TODO Auto-generated catch block            e.printStackTrace();        }         if(mTencent != null){         if(type.equals("qzone")){             StaticParameter.QQ_SHARE_TYPE ="qzone";         params.putStringArrayList(QzoneShare.SHARE_TO_QQ_IMAGE_URL, imageUrls);         mTencent.shareToQzone((Activity) _context, params, qZoneShareListener);         }else if(type.equals("qq")){             StaticParameter.QQ_SHARE_TYPE ="qq";         params.putString(QQShare.SHARE_TO_QQ_IMAGE_URL,image_url);         mTencent.shareToQQ((Activity) _context, params, qZoneShareListener);         }         }else{             Log.e("QQ空间分享失败", "参数配置错误");         }            }});    }        IUiListener qZoneShareListener = new IUiListener() {        @Override        public void onCancel() {           Log.i("QQ空间分享", "用户取消分享");        }        @Override        public void onError(UiError e) {           Log.e("QQ空间分享失败", e.errorMessage);        }        @Override        public void onComplete(Object response) {            Log.i("QQ空间分享成功", response.toString());        }    };

方法十二，微信分享

//传入分享的方式，是分享到朋友圈(wxfriend)，还是给朋友（weixin）,传入title，标题，传入image,图片网址，传入url,点击跳转的网页，WX_APP_ID是在微信开放平台申请的IDpublic void shareToWX(final String way,final String title,final String image,final String url,String WX_APP_ID){        final IWXAPI api;        api =WXAPIFactory.createWXAPI(_context, WX_APP_ID,true);        api.registerApp(WX_APP_ID);        if(api.isWXAppInstalled()){            new Thread(){                public void run(){        WXWebpageObject ob = new WXWebpageObject();        ob.webpageUrl=url;        WXMediaMessage msg = new WXMediaMessage();        msg.mediaObject = ob;        msg.description = title;        if(way.equalsIgnoreCase("wxfriend"))            msg.title =title;        if(image.length()>0){        Bitmap bmp = null;        try {            bmp = BitmapFactory.decodeStream(new URL(image).openStream());        } catch (MalformedURLException e) {            // TODO Auto-generated catch block            e.printStackTrace();        } catch (IOException e) {            // TODO Auto-generated catch block            e.printStackTrace();        }        Bitmap thumbBmp = Bitmap.createScaledBitmap(bmp, 150, 150, true);        bmp.recycle();//      msg.thumbData = bmpToByteArray(thumbBmp, true);        msg.thumbData =getBitmapBytes(thumbBmp,false);        }        SendMessageToWX.Req req = new SendMessageToWX.Req();        req.transaction ="img"+String.valueOf(System.currentTimeMillis());        req.message = msg;        //WXSceneSession 是分享给微信好友，WXSceneTimeline 是朋友圈        req.scene=way.equalsIgnoreCase("weixin")?SendMessageToWX.Req.WXSceneSession:SendMessageToWX.Req.WXSceneTimeline;        boolean result=api.sendReq(req);                }            }.start();        }else{        //这里是我写的一个自定义dialog，请参考方法十三            WXConfirmDialog dialog = new WXConfirmDialog(StaticParameter._context);            dialog.set_content("您尚未安装微信，点击确定安装微信");            dialog.show();        }    }private static byte[] getBitmapBytes(Bitmap bitmap, boolean paramBoolean) {        Bitmap localBitmap = Bitmap.createBitmap(80, 80, Bitmap.Config.RGB_565);        Canvas localCanvas = new Canvas(localBitmap);        int i;        int j;        if (bitmap.getHeight() > bitmap.getWidth()) {            i = bitmap.getWidth();            j = bitmap.getWidth();        } else {            i = bitmap.getHeight();            j = bitmap.getHeight();        }        while (true) {            localCanvas.drawBitmap(bitmap, new Rect(0, 0, i, j), new Rect(0, 0,80, 80), null);            if (paramBoolean)                bitmap.recycle();            ByteArrayOutputStream localByteArrayOutputStream = new ByteArrayOutputStream();            localBitmap.compress(Bitmap.CompressFormat.JPEG, 100,                    localByteArrayOutputStream);            localBitmap.recycle();            byte[] arrayOfByte = localByteArrayOutputStream.toByteArray();            try {                localByteArrayOutputStream.close();                return arrayOfByte;            } catch (Exception e) {            }            i = bitmap.getHeight();            j = bitmap.getHeight();        }    }

方法十三，自定义dialog控件，这里连接方法十二，该控件给方法十二使用，大家可以再自行扩展

public class WXConfirmDialog extends AlertDialog{    public String _title;    public String _content;    private Context _context;    public WXConfirmDialog(Context context) {        super(context);        this._context=context;    }    public void set_title(String title){        this._title=title;    }    public void set_content(String content){        this._content = content;    }    public void show(){        new AlertDialog.Builder(_context)         .setTitle(_title)          .setMessage(_content)            .setPositiveButton("确定", new DialogInterface.OnClickListener() {                @Override                public void onClick(DialogInterface dialog, int arg1) {                    dialog.dismiss();                    Uri uri = Uri.parse("http://weixin.qq.com/cgi-bin/readtemplate?uin=&stype=&fr=&lang=zh_CN&check=false&t=w_down");                    Intent intent = new Intent();                    intent.setAction("android.intent.action.VIEW");                        intent.setData(uri);                      _context.startActivity(intent);                }            })            .setNegativeButton("取消", new DialogInterface.OnClickListener() {                @Override                public void onClick(DialogInterface dialog, int arg1) {                    dialog.dismiss();                }            })            .show();    }}

方法十四，自定义常见动画类

public class AnimationExecuter {    //动画类    //这个animId可以是这里设定的几种简单动画，0,1之类的，也可以是外部的动画，R.anim.xxx    public static void execute( Context context, int animId, View view, AnimSimpleListener listener ){        Animation anim=null;        switch(animId){        case 0:            //从左往右边退出            anim = new TranslateAnimation(                    Animation.RELATIVE_TO_SELF,0f,                    Animation.RELATIVE_TO_SELF,1f,                    Animation.RELATIVE_TO_SELF,0f,                    Animation.RELATIVE_TO_SELF,0f);            anim.setDuration(500);            break;        case 1:            //从上往下退出            anim = new TranslateAnimation(                    Animation.RELATIVE_TO_SELF,0f,                    Animation.RELATIVE_TO_SELF,0f,                    Animation.RELATIVE_TO_SELF,0f,                    Animation.RELATIVE_TO_SELF,1f);            anim.setDuration(500);            break;        case 2:            //360°旋转            anim = new RotateAnimation(0f,360f,Animation.RELATIVE_TO_SELF,0.5f,Animation.RELATIVE_TO_SELF,0.5f);            anim.setDuration(500);            anim.setRepeatCount(-1);            break;        case 3:            //从右往左边推进            anim = new TranslateAnimation(                    Animation.RELATIVE_TO_SELF,1f,                    Animation.RELATIVE_TO_SELF,0f,                    Animation.RELATIVE_TO_SELF,0f,                    Animation.RELATIVE_TO_SELF,0f);            anim.setDuration(500);            break;        case -1:            //不使用动画            anim = new TranslateAnimation(                    Animation.RELATIVE_TO_SELF,1f,                    Animation.RELATIVE_TO_SELF,1f,                    Animation.RELATIVE_TO_SELF,0f,                    Animation.RELATIVE_TO_SELF,0f);            anim.setDuration(500);            break;        default:            anim = AnimationUtils.loadAnimation(context, animId);                break;        }        if(anim != null){        anim.setAnimationListener(listener);        view.startAnimation(anim);        }    }    //这里是监听动画的执行状态    public static class AnimSimpleListener implements AnimationListener{        @Override        public void onAnimationEnd(Animation animation) {        }        @Override        public void onAnimationRepeat(Animation animation) {        }        @Override        public void onAnimationStart(Animation animation){        }    }}//以下是演示调用方法//传入context,动画ID，执行动画的viewAnimationExecuter.execute(_context, 0,                        view, new AnimSimpleListener() {                            @Override                            public void onAnimationEnd(Animation animation) {                                //动画执行完毕，做什么操作                            }                        });

方法十五，检查网络连接状态

//请留意该方法，如果用在部分写机顶盒应用的机器上，会报空指针哦public static boolean checkNetWorkInfo(Context context){        ConnectivityManager conMan = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);        //mobile 2G/3G/4G Data Network        State mobile = conMan.getNetworkInfo(ConnectivityManager.TYPE_MOBILE).getState();        //wifi        State wifi = conMan.getNetworkInfo(ConnectivityManager.TYPE_WIFI).getState();        //如果2G/3G/4G网络和wifi网络都未连接，则return false;        if((mobile == State.DISCONNECTED || mobile == State.DISCONNECTING || mobile == State.UNKNOWN) &&            (wifi == State.DISCONNECTED || wifi == State.DISCONNECTING || wifi == State.UNKNOWN))            return false;        else             return true;    }

方法十六，获取当前是2G/3G/4G网络还是 WIFI网络

public static String getNetWorkAccess(Context context){        ConnectivityManager conMan = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);                //mobile 2G/3G/4G Data Network                State mobile = conMan.getNetworkInfo(ConnectivityManager.TYPE_MOBILE).getState();                //wifi                State wifi = conMan.getNetworkInfo(ConnectivityManager.TYPE_WIFI).getState();                if(mobile ==State.CONNECTED)                    return "WLAN";                if(wifi == State.CONNECTED)                     return "WIFI";                return "UNKNOWN";    }

今天就整理到这里，以上所有内容纯原创，如果转载，请说明出处，国内的各大论坛抄袭的内容太多，经常是一个问题，一搜，csdn是这个答案，eoe也是这个答案，新浪博客也是这个答案，真正有意义的东西太少。