在app模块的build.gradle文件中添加以下依赖： implementation "androidx.lifecycle:lifecycle-extensions:2.2.0" 然后同步Gradle并重新编译项目即可。示例代码如下：

implementation "androidx.lifecycle:lifecycle-extensions:2.2.0"

//在Activity中创建ViewModel对象 MyViewModel myViewModel = new ViewModelProvider(this).get(MyViewModel.class);

//在Fragment中创建ViewModel对象 MyViewModel myViewModel = new ViewModelProvider(this).get(MyViewModel.class);

//在ViewModel中获取数据 LiveData myLiveData = new MutableLiveData<>(); myLiveData.setValue("hello world");

//观察数据变化 myViewModel.getData().observe(this, new Observer() { @Override public void onChanged(String s) { Log.d(TAG, "onChanged: " + s); } });

//在ViewModel中设置数据 public void setData(String data) { myLiveData.setValue(data); }

//在Activity或Fragment中调用ViewModel中的方法 myViewModel.setData("hello ViewModel");