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這期內(nèi)容當(dāng)中小編將會(huì)給大家?guī)碛嘘P(guān)怎么在Android應(yīng)用中實(shí)現(xiàn)一個(gè)圖案解鎖功能,文章內(nèi)容豐富且以專業(yè)的角度為大家分析和敘述,閱讀完這篇文章希望大家可以有所收獲。
1.最關(guān)健的就是那個(gè)自定義九宮格View,代碼來自framework下:LockPatternView,原生系統(tǒng)用的圖片資源比較多,好像有7、8張吧,而且繪制的比較復(fù)雜,我找尋半天,眼睛都找瞎了,發(fā)現(xiàn)解壓的QQ里面就3張圖片,一個(gè)圈圈,兩個(gè)點(diǎn),沒辦法,只能修改代碼了,在修改的過程中,才發(fā)現(xiàn),其實(shí)可以把原生的LockPatternView給簡化,繪制更少的圖片,達(dá)到更好的效果??偣矁?yōu)化有:①去掉了連線的箭頭,②原生的連線只有白色一種,改成根據(jù)不同狀態(tài)顯示黃色和紅色兩張色,③.原生view是先畫點(diǎn)再畫線,使得線覆蓋在點(diǎn)的上面,影響美觀,改成先畫連線再畫點(diǎn)。
關(guān)健部分代碼onDraw函數(shù):
@Override protected void onDraw(Canvas canvas) { final ArrayList<Cell> pattern = mPattern; final int count = pattern.size(); final boolean[][] drawLookup = mPatternDrawLookup; if (mPatternDisplayMode == DisplayMode.Animate) { // figure out which circles to draw // + 1 so we pause on complete pattern final int oneCycle = (count + 1) * MILLIS_PER_CIRCLE_ANIMATING; final int spotInCycle = (int) (SystemClock.elapsedRealtime() - mAnimatingPeriodStart) % oneCycle; final int numCircles = spotInCycle / MILLIS_PER_CIRCLE_ANIMATING; clearPatternDrawLookup(); for (int i = 0; i < numCircles; i++) { final Cell cell = pattern.get(i); drawLookup[cell.getRow()][cell.getColumn()] = true; } // figure out in progress portion of ghosting line final boolean needToUpdateInProgressPoint = numCircles > 0 && numCircles < count; if (needToUpdateInProgressPoint) { final float percentageOfNextCircle = ((float) (spotInCycle % MILLIS_PER_CIRCLE_ANIMATING)) / MILLIS_PER_CIRCLE_ANIMATING; final Cell currentCell = pattern.get(numCircles - 1); final float centerX = getCenterXForColumn(currentCell.column); final float centerY = getCenterYForRow(currentCell.row); final Cell nextCell = pattern.get(numCircles); final float dx = percentageOfNextCircle * (getCenterXForColumn(nextCell.column) - centerX); final float dy = percentageOfNextCircle * (getCenterYForRow(nextCell.row) - centerY); mInProgressX = centerX + dx; mInProgressY = centerY + dy; } // TODO: Infinite loop here... invalidate(); } final float squareWidth = mSquareWidth; final float squareHeight = mSquareHeight; float radius = (squareWidth * mDiameterFactor * 0.5f); mPathPaint.setStrokeWidth(radius); final Path currentPath = mCurrentPath; currentPath.rewind(); // TODO: the path should be created and cached every time we hit-detect // a cell // only the last segment of the path should be computed here // draw the path of the pattern (unless the user is in progress, and // we are in stealth mode) final boolean drawPath = (!mInStealthMode || mPatternDisplayMode == DisplayMode.Wrong); // draw the arrows associated with the path (unless the user is in // progress, and // we are in stealth mode) boolean oldFlag = (mPaint.getFlags() & Paint.FILTER_BITMAP_FLAG) != 0; mPaint.setFilterBitmap(true); // draw with higher quality since we // render with transforms // draw the lines if (drawPath) { boolean anyCircles = false; for (int i = 0; i < count; i++) { Cell cell = pattern.get(i); // only draw the part of the pattern stored in // the lookup table (this is only different in the case // of animation). if (!drawLookup[cell.row][cell.column]) { break; } anyCircles = true; float centerX = getCenterXForColumn(cell.column); float centerY = getCenterYForRow(cell.row); if (i == 0) { currentPath.moveTo(centerX, centerY); } else { currentPath.lineTo(centerX, centerY); } } // add last in progress section if ((mPatternInProgress || mPatternDisplayMode == DisplayMode.Animate) && anyCircles) { currentPath.lineTo(mInProgressX, mInProgressY); } // chang the line color in different DisplayMode if (mPatternDisplayMode == DisplayMode.Wrong) mPathPaint.setColor(Color.RED); else mPathPaint.setColor(Color.YELLOW); canvas.drawPath(currentPath, mPathPaint); } // draw the circles final int paddingTop = getPaddingTop(); final int paddingLeft = getPaddingLeft(); for (int i = 0; i < 3; i++) { float topY = paddingTop + i * squareHeight; // float centerY = mPaddingTop + i * mSquareHeight + (mSquareHeight // / 2); for (int j = 0; j < 3; j++) { float leftX = paddingLeft + j * squareWidth; drawCircle(canvas, (int) leftX, (int) topY, drawLookup[i][j]); } } mPaint.setFilterBitmap(oldFlag); // restore default flag }
2.第二個(gè)值得學(xué)習(xí)的地方是(代碼來自設(shè)置應(yīng)用中):在創(chuàng)建解鎖圖案時(shí)的枚舉使用,原生代碼中使用了很多枚舉,將繪制圖案時(shí)的狀態(tài)、底部兩個(gè)按鈕狀態(tài)、頂部一個(gè)TextView顯示的提示文字都緊密的聯(lián)系起來。因此,只用監(jiān)聽LockPatternView動(dòng)態(tài)變化,對(duì)應(yīng)改變底部Button和頂部TextView的狀態(tài)即可實(shí)現(xiàn)聯(lián)動(dòng),簡單的方法可以實(shí)現(xiàn)很多代碼才能實(shí)現(xiàn)的邏輯,個(gè)人很喜歡。
①全局的狀態(tài):
/** * Keep track internally of where the user is in choosing a pattern. */ protected enum Stage { // 初始狀態(tài) Introduction(R.string.lockpattern_recording_intro_header, LeftButtonMode.Cancel, RightButtonMode.ContinueDisabled, ID_EMPTY_MESSAGE, true), // 幫助狀態(tài) HelpScreen(R.string.lockpattern_settings_help_how_to_record, LeftButtonMode.Gone, RightButtonMode.Ok, ID_EMPTY_MESSAGE, false), // 繪制過短 ChoiceTooShort(R.string.lockpattern_recording_incorrect_too_short, LeftButtonMode.Retry, RightButtonMode.ContinueDisabled, ID_EMPTY_MESSAGE, true), // 第一次繪制圖案 FirstChoiceValid(R.string.lockpattern_pattern_entered_header, LeftButtonMode.Retry, RightButtonMode.Continue, ID_EMPTY_MESSAGE, false), // 需要再次繪制確認(rèn) NeedToConfirm(R.string.lockpattern_need_to_confirm, LeftButtonMode.Cancel, RightButtonMode.ConfirmDisabled, ID_EMPTY_MESSAGE, true), // 確認(rèn)出錯(cuò) ConfirmWrong(R.string.lockpattern_need_to_unlock_wrong, LeftButtonMode.Cancel, RightButtonMode.ConfirmDisabled, ID_EMPTY_MESSAGE, true), // 選擇確認(rèn) ChoiceConfirmed(R.string.lockpattern_pattern_confirmed_header, LeftButtonMode.Cancel, RightButtonMode.Confirm, ID_EMPTY_MESSAGE, false); /** * @param headerMessage * The message displayed at the top. * @param leftMode * The mode of the left button. * @param rightMode * The mode of the right button. * @param footerMessage * The footer message. * @param patternEnabled * Whether the pattern widget is enabled. */ Stage(int headerMessage, LeftButtonMode leftMode, RightButtonMode rightMode, int footerMessage, boolean patternEnabled) { this.headerMessage = headerMessage; this.leftMode = leftMode; this.rightMode = rightMode; this.footerMessage = footerMessage; this.patternEnabled = patternEnabled; } final int headerMessage; final LeftButtonMode leftMode; final RightButtonMode rightMode; final int footerMessage; final boolean patternEnabled; }
②.底部兩個(gè)按鈕的狀態(tài)枚舉:
/** * The states of the left footer button. */ enum LeftButtonMode { // 取消 Cancel(android.R.string.cancel, true), // 取消時(shí)禁用 CancelDisabled(android.R.string.cancel, false), // 重試 Retry(R.string.lockpattern_retry_button_text, true), // 重試時(shí)禁用 RetryDisabled(R.string.lockpattern_retry_button_text, false), // 消失 Gone(ID_EMPTY_MESSAGE, false); /** * @param text * The displayed text for this mode. * @param enabled * Whether the button should be enabled. */ LeftButtonMode(int text, boolean enabled) { this.text = text; this.enabled = enabled; } final int text; final boolean enabled; } /** * The states of the right button. */ enum RightButtonMode { // 繼續(xù) Continue(R.string.lockpattern_continue_button_text, true), //繼續(xù)時(shí)禁用 ContinueDisabled(R.string.lockpattern_continue_button_text, false), //確認(rèn) Confirm(R.string.lockpattern_confirm_button_text, true), //確認(rèn)是禁用 ConfirmDisabled(R.string.lockpattern_confirm_button_text, false), //OK Ok(android.R.string.ok, true); /** * @param text * The displayed text for this mode. * @param enabled * Whether the button should be enabled. */ RightButtonMode(int text, boolean enabled) { this.text = text; this.enabled = enabled; } final int text; final boolean enabled; }
就這樣,只要LockPatternView的狀態(tài)一發(fā)生改變,就會(huì)動(dòng)態(tài)改變底部兩個(gè)Button的文字和狀態(tài)。很簡潔,邏輯性很強(qiáng)。
3.第三個(gè)個(gè)人覺得比較有用的就是加密這一塊了,為了以后方便使用,我把圖案加密和字符加密分成兩個(gè)工具類:LockPatternUtils和LockPasswordUtils兩個(gè)文件,本文使用到的是LockPatternUtils。其實(shí)所謂的圖案加密也是將其通過SHA-1加密轉(zhuǎn)化成二進(jìn)制數(shù)再保存到文件中(原生系統(tǒng)保存在/system/目錄下,我這里沒有權(quán)限,就保存到本應(yīng)用目錄下),解密時(shí),也是將獲取到用戶的輸入通過同樣的方法加密,再與保存到文件中的對(duì)比,相同則密碼正確,不同則密碼錯(cuò)誤。關(guān)健代碼就是以下4個(gè)函數(shù):
/** * Serialize a pattern. 加密 * * @param pattern * The pattern. * @return The pattern in string form. */ public static String patternToString(List<LockPatternView.Cell> pattern) { if (pattern == null) { return ""; } final int patternSize = pattern.size(); byte[] res = new byte[patternSize]; for (int i = 0; i < patternSize; i++) { LockPatternView.Cell cell = pattern.get(i); res[i] = (byte) (cell.getRow() * 3 + cell.getColumn()); } return new String(res); } /** * Save a lock pattern. * * @param pattern * The new pattern to save. * @param isFallback * Specifies if this is a fallback to biometric weak */ public void saveLockPattern(List<LockPatternView.Cell> pattern) { // Compute the hash final byte[] hash = LockPatternUtils.patternToHash(pattern); try { // Write the hash to file RandomAccessFile raf = new RandomAccessFile(sLockPatternFilename, "rwd"); // Truncate the file if pattern is null, to clear the lock if (pattern == null) { raf.setLength(0); } else { raf.write(hash, 0, hash.length); } raf.close(); } catch (FileNotFoundException fnfe) { // Cant do much, unless we want to fail over to using the settings // provider Log.e(TAG, "Unable to save lock pattern to " + sLockPatternFilename); } catch (IOException ioe) { // Cant do much Log.e(TAG, "Unable to save lock pattern to " + sLockPatternFilename); } } /* * Generate an SHA-1 hash for the pattern. Not the most secure, but it is at * least a second level of protection. First level is that the file is in a * location only readable by the system process. * * @param pattern the gesture pattern. * * @return the hash of the pattern in a byte array. */ private static byte[] patternToHash(List<LockPatternView.Cell> pattern) { if (pattern == null) { return null; } final int patternSize = pattern.size(); byte[] res = new byte[patternSize]; for (int i = 0; i < patternSize; i++) { LockPatternView.Cell cell = pattern.get(i); res[i] = (byte) (cell.getRow() * 3 + cell.getColumn()); } try { MessageDigest md = MessageDigest.getInstance("SHA-1"); byte[] hash = md.digest(res); return hash; } catch (NoSuchAlgorithmException nsa) { return res; } } /** * Check to see if a pattern matches the saved pattern. If no pattern * exists, always returns true. * * @param pattern * The pattern to check. * @return Whether the pattern matches the stored one. */ public boolean checkPattern(List<LockPatternView.Cell> pattern) { try { // Read all the bytes from the file RandomAccessFile raf = new RandomAccessFile(sLockPatternFilename, "r"); final byte[] stored = new byte[(int) raf.length()]; int got = raf.read(stored, 0, stored.length); raf.close(); if (got <= 0) { return true; } // Compare the hash from the file with the entered pattern's hash return Arrays.equals(stored, LockPatternUtils.patternToHash(pattern)); } catch (FileNotFoundException fnfe) { return true; } catch (IOException ioe) { return true; } }
上述就是小編為大家分享的怎么在Android應(yīng)用中實(shí)現(xiàn)一個(gè)圖案解鎖功能了,如果剛好有類似的疑惑,不妨參照上述分析進(jìn)行理解。如果想知道更多相關(guān)知識(shí),歡迎關(guān)注億速云行業(yè)資訊頻道。
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