Android自定义View跟随手指移动的正方形移动范围不超过屏幕

[{"title":"（3122个子文件30.09MB）Android自定义View跟随手指移动的正方形移动范围不超过屏幕","children":[{"title":".gitignore <span style='color:#111;'>127B</span>","children":null,"spread":false},{"title":".gitignore <span style='color:#111;'>8B</span>","children":null,"spread":false},{"title":"build.gradle <span style='color:#111;'>955B</span>","children":null,"spread":false},{"title":"ExampleInstrumentedTest.java <span style='color:#111;'>773B</span>","children":null,"spread":false},{"title":"AndroidManifest.xml <span style='color:#111;'>788B</span>","children":null,"spread":false},{"title":"......","children":null,"spread":false},{"title":" <span style='color:steelblue;'>文件过多，未全部展示</span>","children":null,"spread":false}],"spread":true}]