最近公司需要，准备开发扫描枪。
话不多说，直接开始
一，创建新项目
1 如果遇到
Error:Execution failed for task ‘:app:preDebugAndroidTestBuild‘.
> Conflict with dependency ‘com.android.support:support-annotations‘ in project ‘:app‘. Resolved versions for app (26.1.0) and test app (27.1.1) differ. See https://d.android.com/r/tools/test-apk-dependency-conflicts.html for details.
参见：https://www.cnblogs.com/hanjun0612/p/10141393.html
2 使用更加美观的android material design
在build.gradle中，增加如下
dependencies {
compile ‘com.github.navasmdc:MaterialDesign:1.5@aar‘
}
如果遇到错误：
注释build.gradle中的design
dependencies { // implementation ‘com.android.support:design:26.1.0‘ compile ‘com.github.navasmdc:MaterialDesign:1.5@aar‘ }
3 在res/layout/activity_main.xml中添加如下代码：
<?xml version="1.0" encoding="utf-8"?> <android.support.constraint.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" tools:context="com.example.tyler.scangun_kps.MainActivity"> <TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="Hello World!111" app:layout_constraintBottom_toBottomOf="parent" app:layout_constraintLeft_toLeftOf="parent" app:layout_constraintRight_toRightOf="parent" app:layout_constraintTop_toTopOf="parent" /> <com.gc.materialdesign.views.ButtonRectangle android:id="@+id/button" android:layout_width="wrap_content" android:layout_height="wrap_content" android:background="#1E88E5" android:text="Button" /> </android.support.constraint.ConstraintLayout>
4 显示效果
android material design帮助：https://android-arsenal.com/details/1/1156