JAVA高级面试进阶训练营视频教程

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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