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.setOnClickListener(new View.OnClickListener() { //點擊按鈕掃描二維碼   @Override   public void onClick(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, "您的輸入為空!", 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,"掃描"+content,Toast.LENGTH_SHORT).show();   }  } }}

<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:app="http://schemas.android.com/apk/res-auto" xmlns: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="掃一掃"/> <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16implementation'com.github.yuzhiqiang1993:zxing:2.2.1' //依賴

allprojects { repositories {  google()  jcenter()  maven { url 'https://jitpack.io' } //加這行代碼 }}