二维码的生成和扫描

极客学院的视频，讲解了扫描二维码，和生成二维码
http://www.jikexueyuan.com/course/134_2.html?ss=1
在写这些代码之前要先导一个包的，BarCodeTest
 1 package com.example.ewm;
 2 
 3 import com.google.zxing.WriterException;
 4 import com.zxing.activity.CaptureActivity;
 5 import com.zxing.encoding.EncodingHandler;
 6 
 7 import android.os.Bundle;
 8 import android.app.Activity;
 9 import android.content.Intent;
10 import android.graphics.Bitmap;
11 import android.view.View;
12 import android.view.View.OnClickListener;
13 import android.widget.Button;
14 import android.widget.EditText;
15 import android.widget.ImageView;
16 import android.widget.TextView;
17 import android.widget.Toast;
18 
19 public class MainActivity extends Activity {
20     private Button scanButton,genButton;
21     private TextView textView;
22     private EditText editText;
23     private ImageView imageView;
24     @Override
25     protected void onCreate(Bundle savedInstanceState) {
26         super.onCreate(savedInstanceState);
27         setContentView(R.layout.activity_main);
28         scanButton = (Button) findViewById(R.id.scan);
29         genButton = (Button) findViewById(R.id.button1);
30         editText = (EditText) findViewById(R.id.editText1);
31         imageView = (ImageView) findViewById(R.id.imageView1);
32         textView = (TextView) findViewById(R.id.textView1);
33         //扫描
34         scanButton.setOnClickListener(new OnClickListener() {
35 
36             @Override
37             public void onClick(View v) {
38                 // TODO Auto-generated method stub
39                 Toast.makeText(MainActivity.this, "你可以扫描条形码或者二维码", 100).show();
40                 //captureactivity是在类库里面的一个页面，
41                 Intent intent = new Intent(MainActivity.this, CaptureActivity.class);
42                 //这个跳转方式是能 获得一个返回值。配合下面的onActivityResult方法一起使用的
43                 startActivityForResult(intent, 0);
44             }
45         });
46         //生成
47         genButton.setOnClickListener(new OnClickListener() {
48 
49             @Override
50             public void onClick(View v) {
51                 // TODO Auto-generated method stub
52                 //获得EditText里面的String值
53                 String in = editText.getText().toString();
54                 //如果获得值为空，提示输入文本
55                 if(in.equals("")){
56                     Toast.makeText(MainActivity.this, "请输入文本", Toast.LENGTH_SHORT).show();
57                 //否则，
58                 }else {
59                     try {
60                         //调用类库里面的EncodingHandler这个方法来将字符串转换成二维码
61                         Bitmap qrcode = EncodingHandler.createQRCode(in, 300);
62                         //设置成Imageview的图片
63                         imageView.setImageBitmap(qrcode);
64                     } catch (WriterException e) {
65                         // TODO Auto-generated catch block
66                         e.printStackTrace();
67                     }
68                 }
69             }
70         });
71     }
72 
73     @Override
74     protected void onActivityResult(int requestCode, int resultCode, Intent data) {
75         // TODO Auto-generated method stub
76         super.onActivityResult(requestCode, resultCode, data);
77 
78         if(resultCode == RESULT_OK){
79             //获得Intent返回值里面一个KEY是result的String值。
80             String result = data.getExtras().getString("result");
81             //加到Textview里面
82             textView.setText(result);
83         }
84     }
85 
86 }