BarcodeScanner.java

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// -*- mode: java; c-basic-offset: 2; -*-
// Copyright 2009-2011 Google, All Rights reserved
// Copyright 2011-2020 MIT, All rights reserved
// Released under the Apache License, Version 2.0
// http://www.apache.org/licenses/LICENSE-2.0
 
package com.google.appinventor.components.runtime;
 
import android.Manifest;
import android.app.Activity;
import android.content.ActivityNotFoundException;
import android.content.ComponentName;
import android.content.Intent;
 
import com.google.appinventor.components.annotations.DesignerComponent;
import com.google.appinventor.components.annotations.DesignerProperty;
import com.google.appinventor.components.annotations.PropertyCategory;
import com.google.appinventor.components.annotations.SimpleEvent;
import com.google.appinventor.components.annotations.SimpleFunction;
import com.google.appinventor.components.annotations.SimpleObject;
import com.google.appinventor.components.annotations.SimpleProperty;
import com.google.appinventor.components.annotations.UsesActivities;
import com.google.appinventor.components.annotations.UsesLibraries;
import com.google.appinventor.components.annotations.UsesPermissions;
import com.google.appinventor.components.annotations.androidmanifest.ActivityElement;
import com.google.appinventor.components.common.ComponentCategory;
import com.google.appinventor.components.common.PropertyTypeConstants;
import com.google.appinventor.components.common.YaVersion;
import com.google.appinventor.components.runtime.util.ErrorMessages;
import com.google.appinventor.components.runtime.util.SdkLevel;
 
@DesignerComponent(version = YaVersion.BARCODESCANNER_COMPONENT_VERSION,
    description = "Component for using the Barcode Scanner to read a barcode",
    category = ComponentCategory.SENSORS,
    nonVisible = true,
    iconName = "images/barcodeScanner.png")
@SimpleObject
@UsesActivities(activities = {
    @ActivityElement(name = "com.google.zxing.client.android.AppInvCaptureActivity",
                     screenOrientation = "landscape",
                     stateNotNeeded = "true",
                     configChanges = "orientation|keyboardHidden",
                     theme = "@android:style/Theme.NoTitleBar.Fullscreen",
                     windowSoftInputMode = "stateAlwaysHidden")
})
@UsesPermissions(permissionNames = "android.permission.CAMERA")
@UsesLibraries(libraries = "Barcode.jar,QRGenerator.jar")
public class BarcodeScanner extends AndroidNonvisibleComponent
    implements ActivityResultListener, Component {
 
  private static final String SCAN_INTENT = "com.google.zxing.client.android.SCAN";
  private static final String LOCAL_SCAN = "com.google.zxing.client.android.AppInvCaptureActivity";
  private static final String SCANNER_RESULT_NAME = "SCAN_RESULT";
  private String result = "";
  private boolean useExternalScanner = true;
  private final ComponentContainer container;
  private boolean havePermission = false; // Do we have CAMERA permission?
 
  /* Used to identify the call to startActivityForResult. Will be passed back into the
  resultReturned() callback method. */
  private int requestCode;
 
  public BarcodeScanner(ComponentContainer container) {
    super(container.$form());
    this.container = container;
  }
 
  @SimpleProperty(description = "Text result of the previous scan.",
      category = PropertyCategory.BEHAVIOR)
  public String Result() {
    return result;
  }
 
  @SimpleFunction(description = "Begins a barcode scan, using the camera. When the scan " +
      "is complete, the AfterScan event will be raised.")
  public void DoScan() {
    Intent intent = new Intent(SCAN_INTENT);
    if (!useExternalScanner && (SdkLevel.getLevel() >= SdkLevel.LEVEL_ECLAIR)) {  // Should we attempt to use an internal scanner?
      // Make sure we have CAMERA permission
      if (!havePermission) {
        container.$form()
          .askPermission(Manifest.permission.CAMERA,
                         new PermissionResultHandler() {
                           @Override
                           public void HandlePermissionResponse(String permission, boolean granted) {
                             if (granted) {
                               BarcodeScanner.this.havePermission = true;
                               DoScan();
                             } else {
                               form.dispatchPermissionDeniedEvent(BarcodeScanner.this, "DoScan",
                                   Manifest.permission.CAMERA);
                             }
                           }
                         });
        return;
      }
      String packageName = container.$form().getPackageName();
      intent.setComponent(new ComponentName(packageName, "com.google.zxing.client.android.AppInvCaptureActivity"));
    }
    if (requestCode == 0) {
      requestCode = form.registerForActivityResult(this);
    }
    try {
      container.$context().startActivityForResult(intent, requestCode);
    } catch (ActivityNotFoundException e) {
      e.printStackTrace();
      container.$form().dispatchErrorOccurredEvent(this, "BarcodeScanner",
        ErrorMessages.ERROR_NO_SCANNER_FOUND, "");
    }
  }
 
  @Override
  public void resultReturned(int requestCode, int resultCode, Intent data) {
    if (requestCode == this.requestCode && resultCode == Activity.RESULT_OK) {
      if (data.hasExtra(SCANNER_RESULT_NAME)) {
        result = data.getStringExtra(SCANNER_RESULT_NAME);
      } else {
        result = "";
      }
      AfterScan(result);
    }
  }
 
  @SimpleEvent
  public void AfterScan(String result) {
    EventDispatcher.dispatchEvent(this, "AfterScan", result);
  }
 
  @SimpleProperty(category = PropertyCategory.BEHAVIOR,
    description = "If true App Inventor will look for and use an external scanning" +
    " program such as \"Bar Code Scanner.\"")
  public boolean UseExternalScanner() {
    return useExternalScanner;
  }
 
  @DesignerProperty(editorType = PropertyTypeConstants.PROPERTY_TYPE_BOOLEAN, defaultValue = "True")
  @SimpleProperty()
  public void UseExternalScanner(boolean useExternalScanner) {
    this.useExternalScanner = useExternalScanner;
  }
 
}