1.Program type already present
依赖包冲突
All com.android.support libraries must use the exact same version specification (mixing versions can lead to runtime crashes). Found versions 27.1.1, 25.3.0. Examples include com.android.support:animated-vector-drawable:27.1.1 and com.android.support:design:25.3.0 less... (Ctrl+F1)
There are some combinations of libraries, or tools and libraries, that are incompatible, or can lead to bugs. One such incompatibility is compiling with a version of the Android support libraries that is not the latest version (or in particular, a version lower than your targetSdkVersion.)
若按提示加入
//noinspection GradleCompatible
编译不会出现问题但在调试的时候就会报错
看提示应该是com.android.support:design版本和com.android.support:appcompat中显示的版本冲突，这时候把design版本置换即可，在dependencies中加入：
implementation 'com.android.support:design:27.1.1'
2.Attempt to invoke virtual method 'void android.widget.TextView.setText(java.lang.CharSequence)' on a null object reference
textview绑定错误，检查xml文件下id或xml文件是否绑定正确
3.Attempt to invoke interface method 'boolean java.util.List.add(java.lang.Object)' on a null object reference
原因：定义了 List<E> lists; 但并没有初始化
解决方法：
在使用前加入：
List<E> lists = new ArrayList<>();
4.Error:Unable to start the daemon process.
This problem might be caused by incorrect configuration of the daemon.
For example, an unrecognized jvm option is used.
解决方法：
找到gradle.properties文件，将为注释掉的内容更换为：
org.gradle.jvmargs=-Xmx512m
然后重启项目