//1.默认选项启动意图
new IntentIntegrator(MainActivity.this).initiateScan(); // `this` is the current Activity
//2.获取得到的结果：
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
 IntentResult result = IntentIntegrator.parseActivityResult(requestCode, resultCode, data);
 if(result != null) {
  if(result.getContents() == null) {
   Toast.makeText(this, "取消扫码", Toast.LENGTH_LONG).show();
  } else {
   Toast.makeText(this, "扫码结果：" + result.getContents(), Toast.LENGTH_LONG).show();
  }
 } else {
  super.onActivityResult(requestCode, resultCode, data);
 }
}

apply plugin: 'com.android.application'
android {
 compileSdkVersion 25
 buildToolsVersion "25.0.2"
 defaultConfig {
  applicationId "wei.shm.zxingscancode"
  minSdkVersion 15
  targetSdkVersion 25
  versionCode 1
  versionName "1.0"
  testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
 }
 buildTypes {
  release {
   minifyEnabled false
   proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
  }
 }
}
dependencies {
 compile fileTree(dir: 'libs', include: ['*.jar'])
 androidTestCompile('com.android.support.test.espresso:espresso-core:2.2.2', {
  exclude group: 'com.android.support', module: 'support-annotations'
 })
 compile 'com.android.support:appcompat-v7:25.2.0'
 compile 'com.android.support.constraint:constraint-layout:1.0.1'
 testCompile 'junit:junit:4.12'
 //新建项目只增加这个
 compile 'com.journeyapps:zxing-android-embedded:3.5.0'
 //需要核对的有：
 //1.备置仓库：repositories里的jcenter()
 //2.com.android.support:appcompat-v7：版本号必须大于23以上
 //3.buildToolsVersion：版本需要大于等于23.0.2，旧版本可能会导致编译错误
 //以上条件都满足则只需要添加 compile 'com.journeyapps:zxing-android-embedded:3.5.0'
}