Android 开发中的一些小技巧详解手机开发

dip转px

    public int convertDipOrPx(int dip) { 
        float scale = MarketApplication.getMarketApplicationContext() 
                .getResources().getDisplayMetrics().density; 
        return (int) (dip * scale + 0.5f * (dip >= 0 ? 1 : -1)); 
    }

获取当前窗体,并添加自定义view:

getWindowManager() 
                .addView( 
                        overlay, 
                        new WindowManager.LayoutParams( 
                                LayoutParams.WRAP_CONTENT, 
                                LayoutParams.WRAP_CONTENT, 
                                WindowManager.LayoutParams.TYPE_APPLICATION, 
                                WindowManager.LayoutParams.FLAG_NOT_FOCUSABLE 
                                        | WindowManager.LayoutParams.FLAG_NOT_TOUCHABLE, 
                                PixelFormat.TRANSLUCENT)); 

自定义fastScrollBar图片样式:

        try { 
            Field f = AbsListView.class.getDeclaredField("mFastScroller"); 
            f.setAccessible(true); 
            Object o = f.get(listView); 
            f = f.getType().getDeclaredField("mThumbDrawable"); 
            f.setAccessible(true); 
            Drawable drawable = (Drawable) f.get(o); 
            drawable = getResources().getDrawable(R.drawable.ic_launcher); 
            f.set(o, drawable); 
            Toast.makeText(this, f.getType().getName(), 1000).show(); 
        } catch (Exception e) { 
            throw new RuntimeException(e); 
        }

=网络==================================

判断网络是否可用:

/** 
	 * 网络是否可用 
	 *  
	 * @param context 
	 * @return 
	 */ 
	public static boolean isNetworkAvailable(Context context) { 
		ConnectivityManager mgr = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE); 
		NetworkInfo[] info = mgr.getAllNetworkInfo(); 
	    if (info != null) { 
	    	for (int i = 0; i < info.length; i++) { 
	    		if (info[i].getState() == NetworkInfo.State.CONNECTED) { 
	    			return true; 
	    		} 
	    	} 
	    } 
		return false; 
	}

方法二:

    /* 
     * 判断网络连接是否已开 2012-08-20true 已打开 false 未打开 
     */ 
    public static boolean isConn(Context context) { 
        boolean bisConnFlag = false; 
        ConnectivityManager conManager = (ConnectivityManager) context 
                .getSystemService(Context.CONNECTIVITY_SERVICE); 
        NetworkInfo network = conManager.getActiveNetworkInfo(); 
        if (network != null) { 
            bisConnFlag = conManager.getActiveNetworkInfo().isAvailable(); 
        } 
        return bisConnFlag; 
    }

判断是不是Wifi连接:

    public static boolean isWifiActive(Context icontext) { 
        Context context = icontext.getApplicationContext(); 
        ConnectivityManager connectivity = (ConnectivityManager) context 
                .getSystemService(Context.CONNECTIVITY_SERVICE); 
        NetworkInfo[] info; 
        if (connectivity != null) { 
            info = connectivity.getAllNetworkInfo(); 
            if (info != null) { 
                for (int i = 0; i < info.length; i++) { 
                    if (info[i].getTypeName().equals("WIFI") 
                            && info[i].isConnected()) { 
                        return true; 
                    } 
                } 
            } 
        } 
        return false; 
    }
判断当前网络类型
/** 
	 * 网络方式检查 
	 */ 
	private static int netCheck(Context context) { 
		ConnectivityManager conMan = (ConnectivityManager) context 
				.getSystemService(Context.CONNECTIVITY_SERVICE); 
		State mobile = conMan.getNetworkInfo(ConnectivityManager.TYPE_MOBILE) 
				.getState(); 
		State wifi = conMan.getNetworkInfo(ConnectivityManager.TYPE_WIFI) 
				.getState(); 
		if (wifi.equals(State.CONNECTED)) { 
			return DO_WIFI; 
		} else if (mobile.equals(State.CONNECTED)) { 
			return DO_3G; 
		} else { 
			return NO_CONNECTION; 
		} 
	}

获取下载文件的真实名字

    public String getReallyFileName(String url) { 
        StrictMode.setThreadPolicy(new StrictMode.ThreadPolicy.Builder() 
                .detectDiskReads().detectDiskWrites().detectNetwork() // 这里可以替换为detectAll() 
                                                                      // 就包括了磁盘读写和网络I/O 
                .penaltyLog() // 打印logcat,当然也可以定位到dropbox,通过文件保存相应的log 
                .build()); 
        StrictMode.setVmPolicy(new StrictMode.VmPolicy.Builder() 
                .detectLeakedSqlLiteObjects() // 探测SQLite数据库操作 
                .penaltyLog() // 打印logcat 
                .penaltyDeath().build()); 
 
        String filename = ""; 
        URL myURL; 
        HttpURLConnection conn = null; 
        if (url == null || url.length() < 1) { 
            return null; 
        } 
 
        try { 
            myURL = new URL(url); 
            conn = (HttpURLConnection) myURL.openConnection(); 
            conn.connect(); 
            conn.getResponseCode(); 
            URL absUrl = conn.getURL();// 获得真实Url 
            // 打印输出服务器Header信息 
            // Map<String, List<String>> map = conn.getHeaderFields(); 
            // for (String str : map.keySet()) { 
            // if (str != null) { 
            // Log.e("H3c", str + map.get(str)); 
            // } 
            // } 
            filename = conn.getHeaderField("Content-Disposition");// 通过Content-Disposition获取文件名,这点跟服务器有关,需要灵活变通 
            if (filename == null || filename.length() < 1) { 
                filename = URLDecoder.decode(absUrl.getFile(), "UTF-8"); 
            } 
        } catch (MalformedURLException e) { 
            e.printStackTrace(); 
        } catch (IOException e) { 
            e.printStackTrace(); 
        } finally { 
            if (conn != null) { 
                conn.disconnect(); 
                conn = null; 
            } 
        } 
 
        return filename; 
    }

=图片==========================

bitmap转Byte数组(微信分享就需要用到)

public byte[] bmpToByteArray(final Bitmap bmp, final boolean needRecycle) { 
        ByteArrayOutputStream output = new ByteArrayOutputStream(); 
        bmp.compress(CompressFormat.PNG, 100, output); 
        if (needRecycle) { 
            bmp.recycle(); 
        } 
 
        byte[] result = output.toByteArray(); 
        try { 
            output.close(); 
        } catch (Exception e) { 
            e.printStackTrace(); 
        } 
 
        return result; 
    }

Resources转Bitmap

public Bitmap loadBitmap(Resources res, int id) { 
        BitmapFactory.Options opt = new BitmapFactory.Options(); 
        opt.inPreferredConfig = Bitmap.Config.RGB_565; 
        opt.inPurgeable = true; 
        opt.inInputShareable = true; 
 
        InputStream is = res.openRawResource(id);// 获取资源图片 
        return BitmapFactory.decodeStream(is, null, opt); 
    }

保存图片到SD卡

public void saveBitmapToFile(String url, String filePath) { 
        File iconFile = new File(filePath); 
        if (!iconFile.getParentFile().exists()) { 
            iconFile.getParentFile().mkdirs(); 
        } 
 
        if (iconFile.exists() && iconFile.length() > 0) { 
            return; 
        } 
 
        FileOutputStream fos = null; 
        InputStream is = null; 
        try { 
            fos = new FileOutputStream(filePath); 
            is = new URL(url).openStream(); 
 
            int data = is.read(); 
            while (data != -1) { 
                fos.write(data); 
                data = is.read(); 
            } 
        } catch (IOException e) { 
            e.printStackTrace(); 
        } finally { 
            try { 
                if (is != null) { 
                    is.close(); 
                } 
                if (fos != null) { 
                    fos.close(); 
                } 
            } catch (IOException e) { 
                e.printStackTrace(); 
            } 
        } 
    }

=系统==============================

根据包名打开一个应用程序

    public boolean openApp(String packageName) { 
        PackageInfo pi = null; 
        try { 
            pi = mPM.getPackageInfo(packageName, 0); 
        } catch (NameNotFoundException e) { 
            e.printStackTrace(); 
            return false; 
        } 
 
        if (pi == null) { 
            return false; 
        } 
 
        Intent resolveIntent = new Intent(Intent.ACTION_MAIN, null); 
        resolveIntent.addCategory(Intent.CATEGORY_LAUNCHER); 
        resolveIntent.setPackage(pi.packageName); 
 
        List<ResolveInfo> apps = mPM.queryIntentActivities(resolveIntent, 0); 
 
        ResolveInfo ri = null; 
        try { 
            ri = apps.iterator().next(); 
        } catch (Exception e) { 
            return true; 
        } 
        if (ri != null) { 
            String tmpPackageName = ri.activityInfo.packageName; 
            String className = ri.activityInfo.name; 
 
            Intent intent = new Intent(Intent.ACTION_MAIN); 
            intent.addCategory(Intent.CATEGORY_LAUNCHER); 
 
            ComponentName cn = new ComponentName(tmpPackageName, className); 
 
            intent.setComponent(cn); 
            intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK); 
            MarketApplication.getMarketApplicationContext().startActivity( 
                    intent); 
        } else { 
            return false; 
        } 
        return true; 
    }

判断是否APK是否安装过

public boolean checkApkExist(Context context, String packageName) { 
        if (packageName == null || "".equals(packageName)) 
            return false; 
        try { 
            ApplicationInfo info = context.getPackageManager() 
                    .getApplicationInfo(packageName, 
                            PackageManager.GET_UNINSTALLED_PACKAGES); 
            return true; 
        } catch (NameNotFoundException e) { 
            return false; 
        } catch (NullPointerException e) { 
            return false; 
        } 
    }

安装APK

    public void installApk(Context context, String strFileAllName) { 
        File file = new File(strFileAllName); 
        Intent intent = new Intent(); 
        intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK); 
        intent.setAction(Intent.ACTION_VIEW); 
        String type = "application/vnd.android.package-archive"; 
        intent.setDataAndType(Uri.fromFile(file), type); 
        context.startActivity(intent); 
    }

卸载APK

    public void UninstallApk(Context context, String strPackageName) { 
        Uri packageURI = Uri.parse("package:" + strPackageName); 
        Intent uninstallIntent = new Intent(Intent.ACTION_DELETE, packageURI); 
        context.startActivity(uninstallIntent); 
    }

判断SD卡是否可用

    public boolean CheckSD() { 
        if (android.os.Environment.getExternalStorageState().equals( 
                android.os.Environment.MEDIA_MOUNTED)) { 
            return true; 
        } else { 
            return false; 
        } 
    }

创建快捷方式:

    public void createShortCut(Context contxt) { 
        // if (isInstallShortcut()) {// 如果已经创建了一次就不会再创建了 
        // return; 
        // } 
 
        Intent sIntent = new Intent(Intent.ACTION_MAIN); 
        sIntent.addCategory(Intent.CATEGORY_LAUNCHER);// 加入action,和category之后,程序卸载的时候才会主动将该快捷方式也卸载 
        sIntent.setClass(contxt, Login.class); 
 
        Intent installer = new Intent(); 
        installer.putExtra("duplicate", false); 
        installer.putExtra("android.intent.extra.shortcut.INTENT", sIntent); 
        installer.putExtra("android.intent.extra.shortcut.NAME", "名字"); 
        installer.putExtra("android.intent.extra.shortcut.ICON_RESOURCE", 
                Intent.ShortcutIconResource 
                        .fromContext(contxt, R.drawable.icon)); 
        installer.setAction("com.android.launcher.action.INSTALL_SHORTCUT"); 
        contxt.sendBroadcast(installer); 
    }

判断快捷方式是否创建:

private boolean isInstallShortcut() { 
        boolean isInstallShortcut = false; 
        final ContentResolver cr = MarketApplication 
                .getMarketApplicationContext().getContentResolver(); 
        String AUTHORITY = "com.android.launcher.settings"; 
        Uri CONTENT_URI = Uri.parse("content://" + AUTHORITY 
                + "/favorites?notify=true"); 
 
        Cursor c = cr.query(CONTENT_URI, 
                new String[] { "title", "iconResource" }, "title=?", 
                new String[] { "名字" }, null); 
        if (c != null && c.getCount() > 0) { 
            isInstallShortcut = true; 
        } 
 
        if (c != null) { 
            c.close(); 
        } 
 
        if (isInstallShortcut) { 
            return isInstallShortcut; 
        } 
 
        AUTHORITY = "com.android.launcher2.settings"; 
        CONTENT_URI = Uri.parse("content://" + AUTHORITY 
                + "/favorites?notify=true"); 
        c = cr.query(CONTENT_URI, new String[] { "title", "iconResource" }, 
                "title=?", new String[] { "名字" }, null); 
        if (c != null && c.getCount() > 0) { 
            isInstallShortcut = true; 
        } 
 
        if (c != null) { 
            c.close(); 
        } 
 
        AUTHORITY = "com.baidu.launcher"; 
        CONTENT_URI = Uri.parse("content://" + AUTHORITY 
                + "/favorites?notify=true"); 
        c = cr.query(CONTENT_URI, new String[] { "title", "iconResource" }, 
                "title=?", new String[] { "名字" }, null); 
        if (c != null && c.getCount() > 0) { 
            isInstallShortcut = true; 
        } 
 
        if (c != null) { 
            c.close(); 
        } 
 
        return isInstallShortcut; 
    }

过滤特殊字符:

    private String StringFilter(String str) throws PatternSyntaxException { 
        // 只允许字母和数字 
        // String regEx = "[^a-zA-Z0-9]"; 
        // 清除掉所有特殊字符 
        String regEx = "[`~!@#$%^&*()+=|{}':;',//[//].<>/?~!@#¥%……&*()——+|{}【】‘;:”“’。,、?]"; 
        Pattern p = Pattern.compile(regEx); 
        Matcher m = p.matcher(str); 
        return m.replaceAll("").trim(); 
    }

执行shell语句:

    public int execRootCmdSilent(String cmd) { 
        int result = -1; 
        DataOutputStream dos = null; 
 
        try { 
            Process p = Runtime.getRuntime().exec("su"); 
            dos = new DataOutputStream(p.getOutputStream()); 
            dos.writeBytes(cmd + "/n"); 
            dos.flush(); 
            dos.writeBytes("exit/n"); 
            dos.flush(); 
            p.waitFor(); 
            result = p.exitValue(); 
        } catch (Exception e) { 
            e.printStackTrace(); 
        } finally { 
            if (dos != null) { 
                try { 
                    dos.close(); 
                } catch (IOException e) { 
                    e.printStackTrace(); 
                } 
            } 
        } 
        return result; 
    }

获得文件MD5值:

    public String getFileMD5(File file) { 
        if (!file.isFile()) { 
            return null; 
        } 
 
        MessageDigest digest = null; 
        FileInputStream in = null; 
        byte buffer[] = new byte[1024]; 
        int len; 
        try { 
            digest = MessageDigest.getInstance("MD5"); 
            in = new FileInputStream(file); 
            while ((len = in.read(buffer, 0, 1024)) != -1) { 
                digest.update(buffer, 0, len); 
            } 
        } catch (Exception e) { 
            e.printStackTrace(); 
            return null; 
        } finally { 
            if (in != null) { 
                try { 
                    in.close(); 
                } catch (IOException e) { 
                    e.printStackTrace(); 
                } 
            } 
        } 
        BigInteger bigInt = new BigInteger(1, digest.digest()); 
        return bigInt.toString(16); 
    }

转自:http://blog.csdn.net/h3c4lenovo/article/details/16879435

原创文章,作者:ItWorker,如若转载,请注明出处:https://blog.ytso.com/3273.html

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