React Native采坑总结

React Native:0.62.2

1.页面上渲染很多个刷新很多次时，报错：

Attempt to invoke virtual method 'android.graphics.drawable.Drawable android.graphics.drawable.Drawable$ConstantState.new Drawable(android.content.res.Resources)'  on a null object reference

解决方案：在android/app/src/main/res/values/styles.xml 文件中加上下面的配置

2.react-native 0.62.2版本打包出错：

[drawable-mdpi-v4/assets_mario] /Users/jeffreyrajan/Tutorials/RN/errorCheck/android/app/src/main/res/drawable-mdpi/assets_mario.png	[drawable-mdpi-v4/assets_mario] /Users/jeffreyrajan/Tutorials/RN/errorCheck/android/app/build/generated/res/react/release/drawable-mdpi-v4/assets_mario.png: Error: Duplicate resources
:app:mergeReleaseResources FAILED

FAILURE: Build failed with an exception.

* What went wrong:
Execution failed for task ':app:mergeReleaseResources'.
> [drawable-mdpi-v4/assets_mario] /Users/jeffreyrajan/Tutorials/RN/errorCheck/android/app/src/main/res/drawable-mdpi/assets_mario.png	[drawable-mdpi-v4/assets_mario] /Users/jeffreyrajan/Tutorials/RN/errorCheck/android/app/build/generated/res/react/release/drawable-mdpi-v4/assets_mario.png: Error: Duplicate resources

* Try:
Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output. Run with --scan to get full insights.

* Get more help at https://help.gradle.org

解决方案：修改 /node_modules/react-native/react.gradle 文件,添加doLast

修改 /node_modules/react-native/react.gradle 文件,添加doLast


doFirst { ... }
doLast {
    def moveFunc = { resSuffix ->
        File originalDir = file("$buildDir/generated/res/react/release/drawable-${resSuffix}");
        if (originalDir.exists()) {
            File destDir = file("$buildDir/../src/main/res/drawable-${resSuffix}");
            ant.move(file: originalDir, tofile: destDir);
        }
    }
    moveFunc.curry("ldpi").call()
    moveFunc.curry("mdpi").call()
    moveFunc.curry("hdpi").call()
    moveFunc.curry("xhdpi").call()
    moveFunc.curry("xxhdpi").call()
    moveFunc.curry("xxxhdpi").call()
}