使用zxing扫描二维码，横屏转竖屏

使用zxing进行QR code扫描，默认是横屏扫描。如何才能做到竖屏呢。

具体可以参考：http://blog.whomeninja.in/android-barcode-scanner-vertical-orientation-and-camera-flash/

方法是使用上面的方法，这里简单总结一下：

1.首先参考的网址的竖屏方法并没有用，而是下载了它的github源码（https://github.com/rajdeol/android-barcode-scanner-bulk-scan-with-flash），发现使用的是另外一个方法。

2.先放上代码：

package in.whomeninja.android_barcode_scanner_bulk_scan_with_flash;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.support.annotation.NonNull;
import android.view.KeyEvent;
import android.view.View;

import com.journeyapps.barcodescanner.CaptureManager;
import com.journeyapps.barcodescanner.DecoratedBarcodeView;

/**
 * Created by RajinderPal on 1/29/2017.
 */

public class TorchOnCaptureActivity extends Activity {
    private CaptureManager capture;
    private DecoratedBarcodeView barcodeScannerView;
    private View turnflashOn, turnflashOff;
    private boolean cameraFlashOn = false;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        barcodeScannerView = initializeContent();
        TorchEventListener torchEventListener = new TorchEventListener(this);
        barcodeScannerView.setTorchListener(torchEventListener);

        turnflashOn = findViewById(R.id.switch_flashlight_on);
        turnflashOff = findViewById(R.id.switch_flashlight_off);

        // turn the flash on if set via intent
        Intent scanIntent = getIntent();
        if(scanIntent.hasExtra(appConstants.CAMERA_FLASH_ON)){
            if(scanIntent.getBooleanExtra(appConstants.CAMERA_FLASH_ON,false)){
                barcodeScannerView.setTorchOn();
                updateView();
            }
        }

        capture = new CaptureManager(this, barcodeScannerView);
        capture.initializeFromIntent(getIntent(), savedInstanceState);
        capture.decode();
    }

    /**
     * Override to use a different layout.
     *
     * @return the DecoratedBarcodeView
     */
    protected DecoratedBarcodeView initializeContent() {
        setContentView(R.layout.capture_flash);
        //setContentView(com.google.zxing.client.android.R.layout.zxing_capture);
        return (DecoratedBarcodeView)findViewById(com.google.zxing.client.android.R.id.zxing_barcode_scanner);
    }

    @Override
    protected void onResume() {
        super.onResume();
        capture.onResume();
    }

    @Override
    protected void onPause() {
        super.onPause();
        capture.onPause();
    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
        capture.onDestroy();
    }

    @Override
    protected void onSaveInstanceState(Bundle outState) {
        super.onSaveInstanceState(outState);
        capture.onSaveInstanceState(outState);
    }

    @Override
    public void onRequestPermissionsResult(int requestCode, @NonNull String permissions[], @NonNull int[] grantResults) {
        capture.onRequestPermissionsResult(requestCode, permissions, grantResults);
    }

    @Override
    public boolean onKeyDown(int keyCode, KeyEvent event) {
        return barcodeScannerView.onKeyDown(keyCode, event) || super.onKeyDown(keyCode, event);
    }

    public void toggleFlash(View view){
        if(cameraFlashOn){
            barcodeScannerView.setTorchOff();
        }else{
            barcodeScannerView.setTorchOn();
        }
    }

    public void updateView(){
        if(cameraFlashOn){
            turnflashOn.setVisibility(View.GONE);
            turnflashOff.setVisibility(View.VISIBLE);
        }else{
            turnflashOn.setVisibility(View.VISIBLE);
            turnflashOff.setVisibility(View.GONE);
        }
    }

    class TorchEventListener implements DecoratedBarcodeView.TorchListener{
        private TorchOnCaptureActivity activity;

        TorchEventListener(TorchOnCaptureActivity activity){
            this.activity = activity;
        }

        @Override
        public void onTorchOn() {
            this.activity.cameraFlashOn = true;
            this.activity.updateView();
        }

        @Override
        public void onTorchOff() {
            this.activity.cameraFlashOn = false;
            this.activity.updateView();
        }
    }
}

<?xml version="1.0" encoding="UTF-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="match_parent">
    <Button
        android:id="@+id/switch_flashlight_on"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/turn_on_flashlight"
        android:layout_alignParentTop="true"
        android:layout_centerHorizontal="true"
        android:visibility="visible"
        android:onClick="toggleFlash"/>
    <Button
        android:id="@+id/switch_flashlight_off"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/turn_off_flashlight"
        android:layout_alignParentTop="true"
        android:layout_centerHorizontal="true"
        android:visibility="gone"
        android:onClick="toggleFlash"/>


    <com.journeyapps.barcodescanner.DecoratedBarcodeView
        android:layout_alignParentLeft="true"
        android:layout_alignParentRight="true"
        android:layout_alignParentBottom="true"
        android:layout_alignParentTop="true"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_marginLeft="50dp"
        android:layout_marginRight="50dp"
        android:layout_marginTop="150dp"
        android:layout_marginBottom="150dp"
        android:id="@+id/zxing_barcode_scanner"
        app:zxing_use_texture_view="false"
        app:zxing_preview_scaling_strategy="fitXY"/>

</RelativeLayout>

3.竖屏分析：直接调用zxing的代码，默认只有全屏横屏的样式。经过多次试验，发现核心就是直接引用它的布局：

protected DecoratedBarcodeView initializeContent() {
        setContentView(R.layout.capture_flash);
        //setContentView(com.google.zxing.client.android.R.layout.zxing_capture);
        return (DecoratedBarcodeView)findViewById(com.google.zxing.client.android.
R.id.zxing_barcode_scanner);
    }

这里findViewById用的实际是zxing自己的布局，同时xml布局文件里面，<com.journeyapps.barcodescanner.DecoratedBarcodeView>这个控件的id也要和zxing包的一样，即

android:id="@+id/zxing_barcode_scanner"

如此这般，就不会直接调用默认的横屏布局了，但是仅仅这样并不够，因为build app后发现不没有打开摄像头。这就需要下面这些关键语句：

private CaptureManager capture;
private DecoratedBarcodeView barcodeScannerView;

barcodeScannerView = initializeContent();

capture = new CaptureManager(this, barcodeScannerView);
        capture.initializeFromIntent(getIntent(), savedInstanceState);
        capture.decode();

 @Override
    protected void onResume() {
        super.onResume();
        capture.onResume();
    }

    @Override
    protected void onPause() {
        super.onPause();
        capture.onPause();
    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
        capture.onDestroy();
    }

这些都是初始化

CaptureManager、DecoratedBarcodeView

的语句，加上后就可以调用摄像头，正常使用了，而且是竖屏样式。

只需要以上操作，即使不添加

android:screenOrientation="fullSensor"

也完全不影响。具体原理并不清楚，大概是使用原生布局，可以转换为竖屏吧。

使用zxing扫描二维码，横屏转竖屏

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