繼第22篇已經可以綁定fragment跟viewpager那我們就在fragment中加入一些東西吧，今天來試著生成QRcode
首先是xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.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">

    <Button
        android:id="@+id/qrbutton"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginStart="56dp"
        android:text="   生成QRcode   "
        android:background="@drawable/nsq"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="@+id/camerabutton"
        app:layout_constraintVertical_bias="0.0" />

    <Button
        android:id="@+id/camerabutton"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginBottom="88dp"
        android:text="開啟相機"
        android:background="@drawable/nsq"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.62"
        app:layout_constraintStart_toEndOf="@+id/qrbutton" />

    <EditText
        android:id="@+id/edittext"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginBottom="160dp"
        android:ems="10"
        android:inputType="textPersonName"
        android:hint="請輸入網址或文字"
        android:gravity="center"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="@+id/camerabutton"
        app:layout_constraintHorizontal_bias="0.492"
        app:layout_constraintStart_toStartOf="@+id/qrbutton" />

    <ImageView
        android:id="@+id/qrcode"
        android:layout_width="275dp"
        android:layout_height="275dp"
        app:layout_constraintBottom_toTopOf="@+id/edittext"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintVertical_bias="0.722"/>
</androidx.constraintlayout.widget.ConstraintLayout>

再來是

public class ScanActivity extends BaseActivity implements View.OnClickListener{
    Button qrbutton;
    Button camerabutton;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_scan);
        qrbutton=findViewById(R.id.qrbutton);
        qrbutton.setOnClickListener(this);
        camerabutton=findViewById(R.id.camerabutton);
        camerabutton.setOnClickListener(this);
    }

    @Override
    public void onClick(View view) {
        switch (view.getId()){
            case R.id.qrbutton:
                getCode();
                break;
            case R.id.camerabutton:
                start(CameraActivity.class);
                break;
        }
    }
    public void getCode(){
        ImageView ivCode=findViewById(R.id.qrcode);
        EditText etContent=findViewById(R.id.edittext);
        BarcodeEncoder encoder = new BarcodeEncoder();
        try{
            Bitmap bit = encoder.encodeBitmap(etContent.getText().toString()
                    ,BarcodeFormat.QR_CODE,250,250);
            ivCode.setImageBitmap(bit);
        }catch (WriterException e){
            e.printStackTrace();
        }
    }
}

成果如下