二维码zbar

权限

布局

//activy

public class MainActivity extends AppCompatActivity implements QRCodeView.Delegate {
private static final int REQUEST_CODE = 666;

private ZBarView mZXingView;

private Button button;

public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    mZXingView = findViewById(R.id.zxingview);
    mZXingView.setDelegate(this);
    button = findViewById(R.id.button);
    button.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            mZXingView.openFlashlight();//开启闪光灯
        }
    });
}

@Override
protected void onStart() {
    super.onStart();

    //ActivityCompat检查和请求权限的类
    //Manifest.permission获取清单文件中所有支持的权限
    //PackageManager使用两个权限常量，一个PERMISSION_GRANTED：允许；一个PERMISSION_DENIED:不予许
    int havePermission = ActivityCompat.checkSelfPermission(this, Manifest.permission.CAMERA);
    if (havePermission == PackageManager.PERMISSION_GRANTED) {//允许使用相机
        mZXingView.startCamera(); // 打开后置摄像头开始预览，但是并未开始识别

// mZXingView.startCamera(Camera.CameraInfo.CAMERA_FACING_FRONT); // 打开前置摄像头开始预览，但是并未开始识别
mZXingView.startSpotAndShowRect(); // 显示扫描框，并开始识别
} else {
ActivityCompat.requestPermissions(this,
new String[]{Manifest.permission.CAMERA},
REQUEST_CODE);
}
}

@Override
public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions,
                                       @NonNull int[] grantResults) {
    super.onRequestPermissionsResult(requestCode, permissions, grantResults);
    if (requestCode == REQUEST_CODE) {
        if (permissions[0].equals(Manifest.permission.CAMERA)
                &&grantResults[0] == PackageManager.PERMISSION_GRANTED){
            mZXingView.startCamera(); // 打开后置摄像头开始预览，但是并未开始识别

// mZXingView.startCamera(Camera.CameraInfo.CAMERA_FACING_FRONT); // 打开前置摄像头开始预览，但是并未开始识别
mZXingView.startSpotAndShowRect(); // 显示扫描框，并开始识别
}
}
}

@Override
protected void onStop() {
    mZXingView.stopCamera(); // 关闭摄像头预览，并且隐藏扫描框
    super.onStop();
}

@Override
protected void onDestroy() {
    mZXingView.onDestroy(); // 销毁二维码扫描控件
    super.onDestroy();
}

@Override
public void onScanQRCodeSuccess(String result) {
    Toast.makeText(getBaseContext(), result, Toast.LENGTH_LONG).show();

    mZXingView.startSpot(); // 开始识别
}

@Override
public void onCameraAmbientBrightnessChanged(boolean isDark) {
    // 这里是通过修改提示文案来展示环境是否过暗的状态，接入方也可以根据 isDark 的值来实现其他交互效果
    if (isDark) {
        button.setVisibility(View.VISIBLE);
        mZXingView.getScanBoxView().setTipText("环境过暗，请打开闪光灯");
    } else {
        button.setVisibility(View.GONE);
        mZXingView.getScanBoxView().setTipText("");
    }
}

@Override
public void onScanQRCodeOpenCameraError() {
    Log.e("dt", "打开相机出错");
}

}