Android實用代碼

pxdb 9年前發布 | 4K 次閱讀 Java Android

一、獲取應用程序下所有Activity

public static ArrayList getActivities(Context ctx) {
      ArrayList result = new ArrayList();
      Intent intent = new Intent(Intent.ACTION_MAIN, null);
      intent.setPackage(ctx.getPackageName());
      for (ResolveInfo info : ctx.getPackageManager().queryIntentActivities(intent, 0)) {
          result.add(info.activityInfo.name);
      }
      return result;
}

二、檢測字符串中是否包含漢字
public static boolean checkChinese(String sequence) {

       final String format = "[\\u4E00-\\u9FA5\\uF900-\\uFA2D]";
        boolean result = false;
        Pattern pattern = Pattern.compile(format);
        Matcher matcher = pattern.matcher(sequence);
        result = matcher.find();
        return result;
    }

三、檢測字符串中只能包含：中文、數字、下劃線(_)、橫線(-)

public static boolean checkNickname(String sequence) {
        final String format = "[^\\u4E00-\\u9FA5\\uF900-\\uFA2D\\w-_]";
        Pattern pattern = Pattern.compile(format);
        Matcher matcher = pattern.matcher(sequence);
        return !matcher.find();
    }

四、使用TransitionDrawable實現漸變效果
private void setImageBitmap(ImageView imageView, Bitmap bitmap) {
        // Use TransitionDrawable to fade in.
        final TransitionDrawable td = new TransitionDrawable(new Drawable[] { new ColorDrawable(android.R.color.transparent), new BitmapDrawable(mContext.getResources(), bitmap) });
        //noinspection deprecation
            imageView.setBackgroundDrawable(imageView.getDrawable());
        imageView.setImageDrawable(td);
        td.startTransition(200);
    }

比使用AlphaAnimation效果要好，可避免出現閃爍問題。

五、掃描指定的文件

sendBroadcast(new Intent(Intent.ACTION_MEDIA_SCANNER_SCAN_FILE, uri));

用途：從本軟件新增、修改、刪除圖片、文件某一個文件（音頻、視頻）需要更新系統媒體庫時使用，不必掃描整個SD卡。

六、Dip轉px

  public static int dipToPX(final Context ctx, float dip) {
        return (int)TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, dip, ctx.getResources().getDisplayMetrics());
    }
用途：難免在Activity代碼中設置位置、大小等，本方法就很有用了！

七、發送不重復的通知（Notification）

  public static void sendNotification(Context context, String title,
            String message, Bundle extras) {
        Intent mIntent = new Intent(context, FragmentTabsActivity.class);
        mIntent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
        mIntent.putExtras(extras);

        int requestCode = (int) System.currentTimeMillis();

        PendingIntent mContentIntent = PendingIntent.getActivity(context,
                requestCode, mIntent, 0);

        Notification mNotification = new NotificationCompat.Builder(context)
                .setContentTitle(title).setSmallIcon(R.drawable.app_icon)
                .setContentIntent(mContentIntent).setContentText(message)
                .build();
        mNotification.flags |= Notification.FLAG_AUTO_CANCEL;
        mNotification.defaults = Notification.DEFAULT_ALL;

        NotificationManager mNotificationManager = (NotificationManager) context
                .getSystemService(Context.NOTIFICATION_SERVICE);

        mNotificationManager.notify(requestCode, mNotification);
    }

代碼說明：關鍵點在這個requestCode，這里使用的是當前系統時間，巧妙的保證了每次都是一個新的Notification產生。

八、代碼設置TextView的樣式

使用過自定義Dialog可能馬上會想到用如下代碼：

new TextView(this,null,R.style.text_style);

但你運行這代碼你會發現毫無作用！正確用法：

new TextView(new ContextThemeWrapper(this, R.style.text_style))

九、 ip地址轉成8位十六進制串

    public static String ipToHex(String ips) {
        StringBuffer result = new StringBuffer();
        if (ips != null) {
            StringTokenizer st = new StringTokenizer(ips, ".");
            while (st.hasMoreTokens()) {
                String token = Integer.toHexString(Integer.parseInt(st.nextToken()));
                if (token.length() == 1)
                    token = "0" + token;
                result.append(token);
            }
        }
        return result.toString();
    }


    public static String texToIp(String ips) {
        try {
            StringBuffer result = new StringBuffer();
            if (ips != null && ips.length() == 8) {
                for (int i = 0; i < 8; i += 2) {
                    if (i != 0)
                        result.append('.');
                    result.append(Integer.parseInt(ips.substring(i, i + 2), 16));
                }
            }
            return result.toString();
        } catch (NumberFormatException ex) {
            Logger.e(ex);
        }
        return "";
    }

ip:192.168.68.128 16 =>hex :c0a84480

十、WebView保留縮放功能但隱藏縮放控件

mWebView.getSettings().setSupportZoom(true);
mWebView.getSettings().setBuiltInZoomControls(true);
if (DeviceUtils.hasHoneycomb())
mWebView.getSettings().setDisplayZoomControls(false);

注意：setDisplayZoomControls是在API Level 11中新增。

十一、獲取網絡類型名稱

  public static String getNetworkTypeName(Context context) {
        if (context != null) {
            ConnectivityManager connectMgr = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
            if (connectMgr != null) {
                NetworkInfo info = connectMgr.getActiveNetworkInfo();
                if (info != null) {
                    switch (info.getType()) {
                    case ConnectivityManager.TYPE_WIFI:
                        return "WIFI";
                    case ConnectivityManager.TYPE_MOBILE:
                        return getNetworkTypeName(info.getSubtype());
                    }
                }
            }
        }
        return getNetworkTypeName(TelephonyManager.NETWORK_TYPE_UNKNOWN);
    }

    public static String getNetworkTypeName(int type) {
        switch (type) {
        case TelephonyManager.NETWORK_TYPE_GPRS:
            return "GPRS";
        case TelephonyManager.NETWORK_TYPE_EDGE:
            return "EDGE";
        case TelephonyManager.NETWORK_TYPE_UMTS:
            return "UMTS";
        case TelephonyManager.NETWORK_TYPE_HSDPA:
            return "HSDPA";
        case TelephonyManager.NETWORK_TYPE_HSUPA:
            return "HSUPA";
        case TelephonyManager.NETWORK_TYPE_HSPA:
            return "HSPA";
        case TelephonyManager.NETWORK_TYPE_CDMA:
            return "CDMA";
        case TelephonyManager.NETWORK_TYPE_EVDO_0:
            return "CDMA - EvDo rev. 0";
        case TelephonyManager.NETWORK_TYPE_EVDO_A:
            return "CDMA - EvDo rev. A";
        case TelephonyManager.NETWORK_TYPE_EVDO_B:
            return "CDMA - EvDo rev. B";
        case TelephonyManager.NETWORK_TYPE_1xRTT:
            return "CDMA - 1xRTT";
        case TelephonyManager.NETWORK_TYPE_LTE:
            return "LTE";
        case TelephonyManager.NETWORK_TYPE_EHRPD:
            return "CDMA - eHRPD";
        case TelephonyManager.NETWORK_TYPE_IDEN:
            return "iDEN";
        case TelephonyManager.NETWORK_TYPE_HSPAP:
            return "HSPA+";
        default:
            return "UNKNOWN";
        }
    }

十二、Android解壓Zip包

    public static void UnZipFolder(String zipFileString, String outPathString) throws Exception {
        java.util.zip.ZipInputStream inZip = new java.util.zip.ZipInputStream(new java.io.FileInputStream(zipFileString));
        java.util.zip.ZipEntry zipEntry;
        String szName = "";

        while ((zipEntry = inZip.getNextEntry()) != null) {
            szName = zipEntry.getName();

            if (zipEntry.isDirectory()) {

                // get the folder name of the widget
                szName = szName.substring(0, szName.length() - 1);
                java.io.File folder = new java.io.File(outPathString + java.io.File.separator + szName);
                folder.mkdirs();

            } else {

                java.io.File file = new java.io.File(outPathString + java.io.File.separator + szName);
                file.createNewFile();
                // get the output stream of the file
                java.io.FileOutputStream out = new java.io.FileOutputStream(file);
                int len;
                byte[] buffer = new byte[1024];
                // read (len) bytes into buffer
                while ((len = inZip.read(buffer)) != -1) {
                    // write (len) byte from buffer at the position
                    out.write(buffer, 0, len);
                    out.flush();
                }
                out.close();
            }
        }//end of while

        inZip.close();

    }//end of func

十三、從assets中讀取文本和圖片資源

    public static String getTextFromAssets(final Context context, String fileName) {
        String result = "";
        try {
            InputStream in = context.getResources().getAssets().open(fileName);
            // 獲取文件的字節數
            int lenght = in.available();
            // 創建byte數組
            byte[] buffer = new byte[lenght];
            // 將文件中的數據讀到byte數組中
            in.read(buffer);
            result = EncodingUtils.getString(buffer, "UTF-8");
            in.close();
        } catch (Exception e) {
            e.printStackTrace();
        }
        return result;
    }


    public static Drawable loadImageFromAsserts(final Context ctx, String fileName) {
        try {
            InputStream is = ctx.getResources().getAssets().open(fileName);
            return Drawable.createFromStream(is, null);
        } catch (IOException e) {
            if (e != null) {
                e.printStackTrace();
            }
        } catch (OutOfMemoryError e) {
            if (e != null) {
                e.printStackTrace();
            }
        } catch (Exception e) {
            if (e != null) {
                e.printStackTrace();
            }
        }
        return null;
    }

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