Android扫描和生成二维码

public class MainActivity extends AppCompatActivity {

 private ImageView mImageView;

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

  Button button =findViewById(R.id.btn);
  mImageView =findViewById(R.id.img);
  button.set Listener(new View. Listener() { //点击按钮扫描二维码
   @Override
   public void  (View view) {
    Intent intent = new Intent(MainActivity.this,CaptureActivity.class);


    startActivityForResult(intent,2);
   }
  });

 }

 @Override
 protected void onActivityResult(int requestCode, int resultCode, Intent data) {
  super.onActivityResult(requestCode, resultCode, data);
  if (requestCode==200&& resultCode==RESULT_OK){

   if (data!=null){
    String content = data.getStringExtra(Constant.CODED_CONTENT);
    if (TextUtils.isEmpty(content)){

     Toast.makeText(MainActivity.this, \"您的输入为空!\", Toast.LENGTH_SHORT).show();
     return;

    }

    Bitmap logo = BitmapFactory.decodeResource(getResources(), R.mipmap.ic_launcher);
    try {
     Bitmap bitmap = CodeCreator.createQRCode(content, 400, 400, logo);
     mImageView.setImageBitmap(bitmap);
    } catch (WriterException e) {
     e.printStackTrace();
    }

    Toast.makeText(MainActivity.this,\"扫描\"+content,Toast.LENGTH_SHORT).show();


   }
  }
 }
}

<android.support.constraint.ConstraintLayout  ns:android=\"http://schemas.android.com/apk/res/android\"
  ns:app=\"http://schemas.android.com/apk/res-auto\"
  ns:tools=\"http://schemas.android.com/tools\"
 android:layout_width=\"match_parent\"
 android:layout_height=\"match_parent\"
 tools:context=\".MainActivity\"
 android:orientation=\"vertical\">

 <Button
  android:id=\"@+id/btn\"
  android:layout_width=\"wrap_content\"
  android:layout_height=\"wrap_content\"
  android:text=\"扫一扫\"/>

 <ImageView
  android:id=\"@+id/img\"
  android:layout_width=\"wrap_content\"
  android:layout_height=\"wrap_content\"
  />

</android.support.constraint.ConstraintLayout>

<uses-permission android:name=\"android.permission.INTERNET\"/>
 <uses-permission android:name=\"android.permission.CAMERA\"></uses-permission>
 <uses-permission android:name=\"android.permission.VIBRATE\" />
 <uses-permission android:name=\"android.permission.WRITE_EXTERNAL_STORAGE\"></uses-permission>
 <uses-feature android:name=\"android.hardware.camera\" />
 <uses-feature android:name=\"android.hardware.camera.autofocus\" />
 <uses-permission android:name=\"android.permission.FLASHLIGHT\" />

minSdkVersion 16  //配置16
implementation\'com.github.yuzhiqiang1993:zxing:2.2.1\' //依赖

allprojects {
 repositories {
  google()
  jcenter()
  maven { url \'https://jitpack.io\' } //加这行代码
 }
}