需要用到的jar包：zxing3.3.jar
下載地址：https://pan.baidu.com/s/1UTazz8raimOkB8VTCyLQMQ 提取碼: sc5s
下載后，放入項目的libs目錄下，如圖：

圖1.png

圖2.png

右擊zxing3.3.jar文件，選擇Add As Library:

圖3.png

將下列代碼根據(jù)需要放入指定地方

   try {
                  String str="哈哈哈";
                  Map<EncodeHintType, Object> hints = null;
                  String encoding = getEncoding(str);//獲取字符編碼
                  if (encoding != null) {
                      hints = new EnumMap<>(EncodeHintType.class);
                      hints.put(EncodeHintType.CHARACTER_SET, encoding);
                  }
                  BitMatrix result=new MultiFormatWriter().encode(str,BarcodeFormat.QR_CODE,350,350,hints);//通過字符串創(chuàng)建二維矩陣
                  int width = result.getWidth();
                  int height = result.getHeight();
                  int[] pixels = new int[width * height];

                  for (int y = 0; y < height; y++) {
                      int offset = y * width;
                      for (int x = 0; x < width; x++) {
                          pixels[offset + x] = result.get(x, y) ? BLACK : WHITE;//根據(jù)二維矩陣數(shù)據(jù)創(chuàng)建數(shù)組
                      }
                  }

                  Bitmap bitmap = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888);//創(chuàng)建位圖
                  bitmap.setPixels(pixels, 0, width, 0, 0, width, height);//將數(shù)組加載到位圖中
                  ivShow.setImageBitmap(bitmap);//顯示二維碼
     } catch (WriterException e) {
                  e.printStackTrace();
     }

獲取編碼的方法：

    private static String getEncoding(CharSequence contents) {
        // Very crude at the moment
        for (int i = 0; i < contents.length(); i++) {
            if (contents.charAt(i) > 0xFF) {
                return "UTF-8";
            }
        }
        return null;
    }

最后貼出完整示例代碼：
1、布局文件 activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 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">
    <EditText
        android:id="@+id/et_content"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" />
    <Button
        android:id="@+id/btn_encode"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="生成二維碼"/>
    <ImageView
        android:id="@+id/iv_show"
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:layout_weight="1"/>

</LinearLayout>

2、java文件 MainActivity.java

public class MainActivity extends AppCompatActivity {

    @BindView(R.id.et_content)
    EditText etContent;
    @BindView(R.id.iv_show)
    ImageView ivShow;

    private static final int WHITE = 0xFFFFFFFF;
    private static final int BLACK = 0xFF000000;

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

    @OnClick(R.id.btn_encode)
    public void onViewClicked() {
        String content=etContent.getText().toString();
        if (content.equals("")){
            Toast.makeText(MainActivity.this,"內(nèi)容不能為空！",Toast.LENGTH_SHORT).show();
        }else {
            try {
                Map<EncodeHintType, Object> hints = null;
                String encoding = getEncoding(content);//獲取編碼格式
                if (encoding != null) {
                    hints = new EnumMap<>(EncodeHintType.class);
                    hints.put(EncodeHintType.CHARACTER_SET, encoding);
                }
                BitMatrix result=new MultiFormatWriter().encode(content,BarcodeFormat.QR_CODE,350,350,hints);//通過字符串創(chuàng)建二維矩陣
                int width = result.getWidth();
                int height = result.getHeight();
                int[] pixels = new int[width * height];

                for (int y = 0; y < height; y++) {
                    int offset = y * width;
                    for (int x = 0; x < width; x++) {
                        pixels[offset + x] = result.get(x, y) ? BLACK : WHITE;//根據(jù)二維矩陣數(shù)據(jù)創(chuàng)建數(shù)組
                    }
                }

                Bitmap bitmap = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888);//創(chuàng)建位圖
                bitmap.setPixels(pixels, 0, width, 0, 0, width, height);//設(shè)置位圖像素集為數(shù)組
                ivShow.setImageBitmap(bitmap);//顯示二維碼
            } catch (WriterException e) {
                e.printStackTrace();
            }
        }
    }

    private static String getEncoding(CharSequence contents) {
        // Very crude at the moment
        for (int i = 0; i < contents.length(); i++) {
            if (contents.charAt(i) > 0xFF) {
                return "UTF-8";
            }
        }
        return null;
    }
}

歡迎各位大牛指正^ _ ^