Android项目实战（二十八）：使用Zxing实现二维码及优化实例

 <activity android:name="com.zxing.activity.CaptureActivity"/>

<uses-permission android:name="android.permission.CAMERA" />
  <uses-permission android:name="android.permission.VIBRATE" />
  <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
  <uses-permission android:name="android.permission.MOUNT_UNMOUNT_FILESYSTEMS" />
　　<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
  xmlns:tools="http://schemas.android.com/tools"
  android:layout_width="match_parent"
  android:layout_height="match_parent"
  android:orientation="vertical"
  tools:context="com.maiji.zxingdemo.CreateActivity">


  <ImageView
    android:id="@+id/create_img"
    android:layout_width="300dp"
    android:layout_height="300dp"
    android:scaleType="fitXY"
    android:layout_gravity="center_horizontal"
    />

  <Button
    android:id="@+id/create_btn"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_gravity="center_horizontal"
    android:text="开始生成二维码"
    />

  <EditText
    android:id="@+id/create_edit"
    android:layout_width="match_parent"
    android:layout_height="wrap_content" />
</LinearLayout>

private ImageView create_img;
  private Button create_btn;
  private EditText create_edit;

  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_create);

    initView();
    initEvent();

  }

  private void initEvent() {
    create_btn.setOnClickListener(this);
  }

  private void initView() {
    create_img = (ImageView) findViewById(R.id.create_img);
    create_btn = (Button) findViewById(R.id.create_btn);
    create_edit = (EditText) findViewById(R.id.create_edit);
  }

  @Override
  public void onClick(View v) {
    switch (v.getId()){
      case R.id.create_btn:
        String content = "" ;
        if (create_edit.getText().toString().equals("")){
          Toast.makeText(this,"请输入二维码信息",Toast.LENGTH_SHORT).show();
          return;
        }
        content = create_edit.getText().toString();
        try {
          //生成二维码图片，第一个参数是二维码的内容，第二个参数是正方形图片的边长，单位是像素
          Bitmap qrcodeBitmap = EncodingHandler.createQRCode(content, 800);
          if (qrcodeBitmap!=null) {
            create_img.setImageBitmap(qrcodeBitmap);
          }else{
            Toast.makeText(this,"生成二维码失败",Toast.LENGTH_SHORT).show();
          }
        } catch (Exception e) {
          // TODO Auto-generated catch block
          e.printStackTrace();
        }
        break;
    }
  }

  public byte[] Bitmap2Bytes(Bitmap bm) {
    ByteArrayOutputStream baos = new ByteArrayOutputStream();
    bm.compress(Bitmap.CompressFormat.PNG, 100, baos);
    return baos.toByteArray();
  }

private TextView zxing_content;

@Override
protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.activity_scan);
  zxing_content = (TextView) findViewById(R.id.zxing_content);
  Intent startScan = new Intent(this,CaptureActivity.class);
  startActivityForResult(startScan, 0); //实际打开了一个zxing提供给我们的扫描activity，当然我们后面会对这个activity进行一些优化修改

}

/**
 * 扫一扫，成功后返回值进行判断
 */
@Override
public void onActivityResult(int requestCode, int resultCode, Intent data) {
  super.onActivityResult(requestCode, resultCode, data);
  if (resultCode == -1) {
    String result = data.getExtras().getString("result");
    zxing_content.setText(result); //显示扫描二维码得到的数据
  }
}

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
  xmlns:tools="http://schemas.android.com/tools"
  android:layout_width="match_parent"
  android:layout_height="match_parent"
  tools:context="com.maiji.zxingdemo.ScanActivity">

  <TextView
    android:id="@+id/zxing_content"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_centerInParent="true"
    android:textSize="30sp"
    />
</RelativeLayout>

 private static final int MIN_FRAME_WIDTH = 240;
 private static final int MIN_FRAME_HEIGHT = 240;
 private static final int MAX_FRAME_WIDTH = 480;
 private static final int MAX_FRAME_HEIGHT = 480;

 public static int Dp2Px( Context context,float dp) {
  final float scale = context.getResources().getDisplayMetrics().density;
  return (int) (dp * scale + 0.5f);
 }

 canvas.drawRect(frame.left + 2, middle - 1, frame.right - 1, middle + 2, paint);

   Collection<ResultPoint> currentPossible = possibleResultPoints;

canvas.drawRect(frame.left + 2, middle - 1, frame.right - 1, middle + 2, paint);
　　　 TextPaint textPaint = new TextPaint();
   textPaint.setARGB(0xFF, 0xFF, 0xFF,0xFF);  //字体颜色
   textPaint.setTextSize(32);  //字体大小
   textPaint.setAntiAlias(true); //设置抗锯齿，否则字迹会很模糊
   StaticLayout layout = new StaticLayout("将二维码放入框内，即可自动扫描",textPaint,
       frame.right-frame.left, Layout.Alignment.ALIGN_NORMAL,1.0F,0.0F,true);
   canvas.translate(frame.left+5, (float) (frame.bottom + (float)30)); //绘制起始位置
   layout.draw(canvas);
　　 Collection<ResultPoint> currentPossible = possibleResultPoints;

initFromCameraParameters方法中，在 Log.d(TAG, "Screen resolution: " + screenResolution);这句之后增加
Point screenResolutionForCamera = new Point();
screenResolutionForCamera.x = screenResolution.x;
screenResolutionForCamera.y = screenResolution.y;
    
if (screenResolution.x < screenResolution.y) {
screenResolutionForCamera.x = screenResolution.y;
screenResolutionForCamera.y = screenResolution.x;
 }

cameraResolution = getCameraResolution(parameters, screenResolutionForCamera);