通過谷歌官方例子手把手教你改造自己的Zxing掃描android程序（二）

上篇文章，我們大概了解了zxing掃描的整個流程，現(xiàn)在我們就仿照Google爸爸的例子，來自己做一個掃碼程序。開啟瘋狂模（chao）仿（xi）模式。
Android studio新建一個工程或者一個module。從Google Demo工程里，復(fù)制過來一些關(guān)鍵類。
首先在build.gradle里加入zxing的依賴

dependencies {
        implementation 'com.google.zxing:core:3.3.3'
        implementation 'com.google.zxing:android-core:3.3.0'
    }

將camera包的所有類復(fù)制到自己的工程


image.png

此時工程會報一些錯，一些是包名修改導(dǎo)致import 不對，重新引入即可，還有一些是獲取一些設(shè)置的類沒有找到，這個我們?nèi)寄J(rèn)改成True 或者false 的默認(rèn)值 就好了，自己可以做標(biāo)記，后期再做處理。


image.png

把紅色錯誤搞定后，再將下面這些類也復(fù)制過來。

AmbientLightManager
BeepManager
CaptureActivity
CaptureActivityHandler
DecodeHandler
DecodeThread
InactivityTimer
ViewfinderResultPointCallback
DecodeFormatManager
ViewfinderView
Intents

看到一堆錯誤 是不是很慌，沒關(guān)系，我們一點(diǎn)點(diǎn)來改。AndroidManifest.xml 加入各種相機(jī)權(quán)限，直接從例子中的文件復(fù)制過來即可，color，ids資源文件復(fù)制

6.0系統(tǒng)，代碼權(quán)限申請，很重要，要不相機(jī)打不開 只能看到一片黑

<uses-permission android:name="android.permission.CAMERA"/>
  <uses-permission android:name="android.permission.INTERNET"/>
  <uses-permission android:name="android.permission.VIBRATE"/>
  <uses-permission android:name="android.permission.FLASHLIGHT"/>
  <uses-permission android:name="android.permission.READ_CONTACTS"/>

  <uses-feature android:name="android.hardware.camera.any"/>
  <uses-feature android:name="android.hardware.camera.autofocus" android:required="false"/>
  <uses-feature android:name="android.hardware.camera.flash" android:required="false"/>
  <uses-feature android:name="android.hardware.screen.landscape"/>
  <uses-feature android:name="android.hardware.wifi" android:required="false"/>

CaptureActivity.class
import 錯誤導(dǎo)入各種類就好了，由于我們只做掃描功能，頁面的布局文件layout就可以很簡單了

<?xml version="1.0" encoding="utf-8"?>

<merge xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools">

    <SurfaceView android:id="@+id/preview_view"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"/>

    <com.jian.zxingdemo.ViewfinderView
        android:id="@+id/viewfinder_view"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"/>

</merge>

刪除無用類和代碼，onResume中的getIntent 相關(guān)均可刪除，captureActivity類基本只需保留initCamera和 handledecode()兩個方法 handleDecode 里代碼基本也可以刪除，以下為刪除后的代碼，可直接復(fù)制。這里沒有加 申請權(quán)限的的代碼，直接在應(yīng)用權(quán)限管理打開的。

  public void onCreate(Bundle icicle) {
        super.onCreate(icicle);
        Window window = getWindow();
        window.addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON);
        setContentView(R.layout.activity_capture);
        hasSurface = false;
        inactivityTimer = new InactivityTimer(this);
        beepManager = new BeepManager(this);
        ambientLightManager = new AmbientLightManager(this);
    }

    @Override
    protected void onResume() {
        super.onResume();
        // historyManager must be initialized here to update the history preference

        // CameraManager must be initialized here, not in onCreate(). This is necessary because we don't
        // want to open the camera driver and measure the screen size if we're going to show the help on
        // first launch. That led to bugs where the scanning rectangle was the wrong size and partially
        // off screen.
        cameraManager = new CameraManager(getApplication());
        viewfinderView = (ViewfinderView) findViewById(R.id.viewfinder_view);
        viewfinderView.setCameraManager(cameraManager); //viewfinderView 中設(shè)置camera 這個很重要
        handler = null;
        setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_SENSOR_LANDSCAPE);
        beepManager.updatePrefs();    //手機(jī)震動
        ambientLightManager.start(cameraManager); //閃關(guān)燈
        inactivityTimer.onResume(); //檢查手機(jī)電量，低電量關(guān)閉掃碼
        decodeFormats = null;
        characterSet = null;
        SurfaceView surfaceView = (SurfaceView) findViewById(R.id.preview_view);
        SurfaceHolder surfaceHolder = surfaceView.getHolder();
        if (hasSurface) {
            // The activity was paused but not stopped, so the surface still exists. Therefore
            // surfaceCreated() won't be called, so init the camera here.
            initCamera(surfaceHolder);
        } else {
            // Install the callback and wait for surfaceCreated() to init the camera.
            surfaceHolder.addCallback(this);
        }
    }

    private int getCurrentOrientation() {
        int rotation = getWindowManager().getDefaultDisplay().getRotation();
        if (getResources().getConfiguration().orientation == Configuration.ORIENTATION_LANDSCAPE) {
            switch (rotation) {
                case Surface.ROTATION_0:
                case Surface.ROTATION_90:
                    return ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE;
                default:
                    return ActivityInfo.SCREEN_ORIENTATION_REVERSE_LANDSCAPE;
            }
        } else {
            switch (rotation) {
                case Surface.ROTATION_0:
                case Surface.ROTATION_270:
                    return ActivityInfo.SCREEN_ORIENTATION_PORTRAIT;
                default:
                    return ActivityInfo.SCREEN_ORIENTATION_REVERSE_PORTRAIT;
            }
        }
    }
    @Override
    protected void onPause() {
        if (handler != null) {
            handler.quitSynchronously();
            handler = null;
        }
        inactivityTimer.onPause();
        ambientLightManager.stop();
        beepManager.close();
        cameraManager.closeDriver();
        //historyManager = null; // Keep for onActivityResult
        if (!hasSurface) {
            SurfaceView surfaceView = (SurfaceView) findViewById(R.id.preview_view);
            SurfaceHolder surfaceHolder = surfaceView.getHolder();
            surfaceHolder.removeCallback(this);
        }
        super.onPause();
    }

    @Override
    protected void onDestroy() {
        inactivityTimer.shutdown();
        super.onDestroy();
    }
    @Override
    public boolean onKeyDown(int keyCode, KeyEvent event) {
        switch (keyCode) {

            case KeyEvent.KEYCODE_FOCUS:
            case KeyEvent.KEYCODE_CAMERA:
                // Handle these events so they don't launch the Camera app
                return true;
            // Use volume up/down to turn on light
            case KeyEvent.KEYCODE_VOLUME_DOWN:
                cameraManager.setTorch(false);
                return true;
            case KeyEvent.KEYCODE_VOLUME_UP:
                cameraManager.setTorch(true);
                return true;
        }
        return super.onKeyDown(keyCode, event);
    }
    private void decodeOrStoreSavedBitmap(Bitmap bitmap, Result result) {
        // Bitmap isn't used yet -- will be used soon
        if (handler == null) {
            savedResultToShow = result;
        } else {
            if (result != null) {
                savedResultToShow = result;
            }
            if (savedResultToShow != null) {
                Message message = Message.obtain(handler, R.id.decode_succeeded, savedResultToShow);
                handler.sendMessage(message);
            }
            savedResultToShow = null;
        }
    }
    @Override
    public void surfaceCreated(SurfaceHolder holder) {
        if (holder == null) {
            Log.e(TAG, "*** WARNING *** surfaceCreated() gave us a null surface!");
        }
        if (!hasSurface) {
            hasSurface = true;
            initCamera(holder);
        }
    }
    @Override
    public void surfaceDestroyed(SurfaceHolder holder) {
        hasSurface = false;
    }
    @Override
    public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {
        // do nothing
    }

    /**
     * A valid barcode has been found, so give an indication of success and show the results.
     *
     * @param rawResult The contents of the barcode.
     * @param scaleFactor amount by which thumbnail was scaled
     * @param barcode   A greyscale bitmap of the camera data which was decoded.
     */
    public void handleDecode(Result rawResult, Bitmap barcode, float scaleFactor) {
        inactivityTimer.onActivity();
        beepManager.playBeepSoundAndVibrate();
        //
        Toast.makeText(this,rawResult.getText(),Toast.LENGTH_SHORT).show();
        restartPreviewAfterDelay(BULK_MODE_SCAN_DELAY_MS);
    }
    private void initCamera(SurfaceHolder surfaceHolder) {
        if (surfaceHolder == null) {
            throw new IllegalStateException("No SurfaceHolder provided");
        }
        if (cameraManager.isOpen()) {
            Log.w(TAG, "initCamera() while already open -- late SurfaceView callback?");
            return;
        }
        try {
            //打開相機(jī)
            cameraManager.openDriver(surfaceHolder);
            // Creating the handler starts the preview, which can also throw a RuntimeException.
            if (handler == null) {
                //將相機(jī)等參數(shù)在此傳給CaptureActivityHandler captureActivityHandler 處理后會 回調(diào)CaptureActivity的
                // handleDecode()方法 handleDecode方法得到 解析結(jié)果 然后做自己的處理
                //decodeFomats:支持掃碼的類型
                handler = new CaptureActivityHandler(this, decodeFormats, null, characterSet, cameraManager);
            }
            decodeOrStoreSavedBitmap(null, null);
        } catch (IOException ioe) {
            Log.w(TAG, ioe);
           // displayFrameworkBugMessageAndExit();
        } catch (RuntimeException e) {
            // Barcode Scanner has seen crashes in the wild of this variety:
            // java.?lang.?RuntimeException: Fail to connect to camera service
            Log.w(TAG, "Unexpected error initializing camera", e);
           // displayFrameworkBugMessageAndExit();
        }
    }
    public void restartPreviewAfterDelay(long delayMS) {
        if (handler != null) {
            handler.sendEmptyMessageDelayed(R.id.restart_preview, delayMS);
        }

    }
    public void drawViewfinder() {
        viewfinderView.drawViewfinder();
    }
}

在decodeThread 類里，

 // The prefs can't change while the thread is running, so pick them up once here.
    if (decodeFormats == null || decodeFormats.isEmpty()) {
      decodeFormats = EnumSet.noneOf(BarcodeFormat.class);
      decodeFormats.addAll(DecodeFormatManager.PRODUCT_FORMATS);

      decodeFormats.addAll(DecodeFormatManager.INDUSTRIAL_FORMATS);

      decodeFormats.addAll(DecodeFormatManager.QR_CODE_FORMATS);

      decodeFormats.addAll(DecodeFormatManager.DATA_MATRIX_FORMATS);

      decodeFormats.addAll(DecodeFormatManager.AZTEC_FORMATS);

      decodeFormats.addAll(DecodeFormatManager.PDF417_FORMATS);

    }

基本就大功告成了，其他類都是一些導(dǎo)入錯誤或者默認(rèn)值，稍作修改即可。
運(yùn)行程序，我們最簡單版，最糙版的掃碼程序就做好了


image.png

下一篇，將進(jìn)行優(yōu)化講解，將該程序打造成一個用戶可用，稍微好看一點(diǎn)的程序。

(通過谷歌官方例子手把手教你改造自己的Zxing掃描android程序（三）)[http://m.itdecent.cn/p/c91ab876ada1]

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