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

package com.example.ewm;

import com.google.zxing.WriterException;
import com.zxing.activity.CaptureActivity;
import com.zxing.encoding.EncodingHandler;

import android.os.Bundle;
import android.app.Activity;
import android.content.Intent;
import android.graphics.Bitmap;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ImageView;
import android.widget.TextView;
import android.widget.Toast;

public class MainActivity extends Activity {
    private Button scanButton,genButton;
    private TextView textView;
    private EditText editText;
    private ImageView imageView;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        scanButton = (Button) findViewById(R.id.scan);
        genButton = (Button) findViewById(R.id.button1);
        editText = (EditText) findViewById(R.id.editText1);
        imageView = (ImageView) findViewById(R.id.imageView1);
        textView = (TextView) findViewById(R.id.textView1);
        //扫描
        scanButton.setOnClickListener(new OnClickListener() {

            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub
                Toast.makeText(MainActivity.this, "你可以扫描条形码或者二维码", 100).show();
                //captureactivity是在类库里面的一个页面，
                Intent intent = new Intent(MainActivity.this, CaptureActivity.class);
                //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
                startActivityForResult(intent, 0);
            }
        });
        //生成
        genButton.setOnClickListener(new OnClickListener() {

            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub
                //获得EditText里面的String值
                String in = editText.getText().toString();
                //如果获得值为空，提示输入文本
                if(in.equals("")){
                    Toast.makeText(MainActivity.this, "请输入文本", Toast.LENGTH_SHORT).show();
                //否则，
                }else {
                    try {
                        //调用类库里面的EncodingHandler这个方法来将字符串转换成二维码
                        Bitmap qrcode = EncodingHandler.createQRCode(in, 300);
                        //设置成Imageview的图片
                        imageView.setImageBitmap(qrcode);
                    } catch (WriterException e) {
                        // TODO Auto-generated catch block
                        e.printStackTrace();
                    }
                }
            }
        });
    }

    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        // TODO Auto-generated method stub
        super.onActivityResult(requestCode, resultCode, data);

        if(resultCode == RESULT_OK){
            //获得Intent返回值里面一个KEY是result的String值。
            String result = data.getExtras().getString("result");
            //加到Textview里面
            textView.setText(result);
        }
    }

}