android: restore SimpleScannerActivity.java that was used in kivy

for QR code scanning with camera

1c10b1ce00/electrum/gui/kivy/data/java-classes/org/electrum/qr/SimpleScannerActivity.java

electrum/gui/qml/java_classes/org/electrum/qr/SimpleScannerActivity.java

@@ -0,0 +1,90 @@
+package org.electrum.qr;
+
+import android.app.Activity;
+import android.os.Bundle;
+import android.util.Log;
+import android.content.Intent;
+import android.Manifest;
+import android.content.pm.PackageManager;
+
+import androidx.core.app.ActivityCompat;
+
+import java.util.Arrays;
+
+import me.dm7.barcodescanner.zxing.ZXingScannerView;
+
+import com.google.zxing.Result;
+import com.google.zxing.BarcodeFormat;
+
+public class SimpleScannerActivity extends Activity implements ZXingScannerView.ResultHandler {
+    private static final int MY_PERMISSIONS_CAMERA = 1002;
+
+    private ZXingScannerView mScannerView = null;
+    final String TAG = "org.electrum.SimpleScannerActivity";
+
+    @Override
+    public void onResume() {
+        super.onResume();
+        if (this.hasPermission()) {
+            this.startCamera();
+        } else {
+            this.requestPermission();
+        }
+    }
+
+    @Override
+    public void onPause() {
+        super.onPause();
+        if (null != mScannerView) {
+            mScannerView.stopCamera();           // Stop camera on pause
+        }
+    }
+
+    private void startCamera() {
+        mScannerView = new ZXingScannerView(this);   // Programmatically initialize the scanner view
+        mScannerView.setFormats(Arrays.asList(BarcodeFormat.QR_CODE));
+        setContentView(mScannerView);                // Set the scanner view as the content view
+        mScannerView.setResultHandler(this);         // Register ourselves as a handler for scan results.
+        mScannerView.startCamera();                  // Start camera on resume
+    }
+
+    @Override
+    public void handleResult(Result rawResult) {
+        Intent resultIntent = new Intent();
+        resultIntent.putExtra("text", rawResult.getText());
+        resultIntent.putExtra("format", rawResult.getBarcodeFormat().toString());
+        setResult(Activity.RESULT_OK, resultIntent);
+        this.finish();
+    }
+
+    private boolean hasPermission() {
+        return (ActivityCompat.checkSelfPermission(this,
+                                                   Manifest.permission.CAMERA)
+                == PackageManager.PERMISSION_GRANTED);
+    }
+
+    private void requestPermission() {
+        ActivityCompat.requestPermissions(this,
+                    new String[]{Manifest.permission.CAMERA},
+                    MY_PERMISSIONS_CAMERA);
+    }
+
+    @Override
+    public void onRequestPermissionsResult(int requestCode,
+            String permissions[], int[] grantResults) {
+        switch (requestCode) {
+            case MY_PERMISSIONS_CAMERA: {
+                if (grantResults.length > 0
+                    && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
+                    // permission was granted, yay!
+                    this.startCamera();
+                } else {
+                    // permission denied
+                    this.finish();
+                }
+                return;
+            }
+        }
+    }
+
+}