1. iPhoneX 适配
import { TabbarSafeBottomMargin } from '../../utils/Device';
<View style={styles.safeBottom}></View>
safeBottom: {
    backgroundColor: 'white',
    height: TabbarSafeBottomMargin
}

2. android.support.annotation.Nullable
Android工程中javax annotation Nullable找不到的替代方案
我们在某些Android开源库中会遇到下面的引用找不到的问题：
import javax.annotation.Nonnull;
import javax.annotation.Nullable;

其实Android实现了javax的类似注解，可以使用下面的引用替换：
import android.support.annotation.NonNull;
import android.support.annotation.Nullable;

当然，后者需要引入库的声明：
dependencies {
    compile 'com.android.support:support-annotations:21.0.2'
}

3. Undefined symbols for architecture x86_64:
  "_sqlite3_close", referenced from:
      -[UMUaDB initlizeDB:] in UMAnalytics(UMUaDB.o)
      -[UMUaDB closeDB:] in UMAnalytics(UMUaDB.o)
  "_sqlite3_column_count", referenced from:
      -[UMUaDB existColumnName:withTableName:] in UMAnalytics(UMUaDB.o)
  "_sqlite3_column_int", referenced from:
      -[UMUaDB rowCountInTable:] in UMAnalytics(UMUaDB.o)
      -[UMUaDB rowSdCountInTable:sessionId:] in UMAnalytics(UMUaDB.o)
  "_sqlite3_column_name", referenced from:
      -[UMUaDB existColumnName:withTableName:] in UMAnalytics(UMUaDB.o)
  "_sqlite3_column_text", referenced from:
      -[UMUaDB existColumnName:withTableName:] in UMAnalytics(UMUaDB.o)
      -[UMUaDB loadErTable:] in UMAnalytics(UMUaDB.o)
      -[UMUaDB loadErTableWithVersion:] in UMAnalytics(UMUaDB.o)
      -[UMUaDB loadErTableWithVersion:withSid:] in UMAnalytics(UMUaDB.o)
      -[UMUaDB loadEtTable:] in UMAnalytics(UMUaDB.o)
      -[UMUaDB loadEtTableWithVersion:] in UMAnalytics(UMUaDB.o)
      -[UMUaDB loadEtTableWithVersion:withSid:] in UMAnalytics(UMUaDB.o)
      ...
  "_sqlite3_errcode", referenced from:
      -[UMUaDB runSql:] in UMAnalytics(UMUaDB.o)
  "_sqlite3_errmsg", referenced from:
      -[UMUaDB rowCountInTable:] in UMAnalytics(UMUaDB.o)
      -[UMUaDB loadErTable:] in UMAnalytics(UMUaDB.o)
      -[UMUaDB loadErTableWithVersion:] in UMAnalytics(UMUaDB.o)
      -[UMUaDB loadErTableWithVersion:withSid:] in UMAnalytics(UMUaDB.o)
      -[UMUaDB loadEtTable:] in UMAnalytics(UMUaDB.o)
      -[UMUaDB loadEtTableWithVersion:] in UMAnalytics(UMUaDB.o)
      -[UMUaDB loadEtTableWithVersion:withSid:] in UMAnalytics(UMUaDB.o)
      ...
  "_sqlite3_exec", referenced from:
      -[UMUaDB initlizeDB:] in UMAnalytics(UMUaDB.o)
      -[UMUaDB runSql:] in UMAnalytics(UMUaDB.o)
  "_sqlite3_finalize", referenced from:
      -[UMUaDB existColumnName:withTableName:] in UMAnalytics(UMUaDB.o)
      -[UMUaDB rowCountInTable:] in UMAnalytics(UMUaDB.o)
      -[UMUaDB loadErTable:] in UMAnalytics(UMUaDB.o)
      -[UMUaDB loadErTableWithVersion:] in UMAnalytics(UMUaDB.o)
      -[UMUaDB loadErTableWithVersion:withSid:] in UMAnalytics(UMUaDB.o)
      -[UMUaDB loadEtTable:] in UMAnalytics(UMUaDB.o)
      -[UMUaDB loadEtTableWithVersion:] in UMAnalytics(UMUaDB.o)
      ...
  "_sqlite3_free", referenced from:
      -[UMUaDB runSql:] in UMAnalytics(UMUaDB.o)
  "_sqlite3_open_v2", referenced from:
      -[UMUaDB initlizeDB:] in UMAnalytics(UMUaDB.o)
  "_sqlite3_prepare_v2", referenced from:
      -[UMUaDB existColumnName:withTableName:] in UMAnalytics(UMUaDB.o)
      -[UMUaDB rowCountInTable:] in UMAnalytics(UMUaDB.o)
      -[UMUaDB loadErTable:] in UMAnalytics(UMUaDB.o)
      -[UMUaDB loadErTableWithVersion:] in UMAnalytics(UMUaDB.o)
      -[UMUaDB loadErTableWithVersion:withSid:] in UMAnalytics(UMUaDB.o)
      -[UMUaDB loadEtTable:] in UMAnalytics(UMUaDB.o)
      -[UMUaDB loadEtTableWithVersion:] in UMAnalytics(UMUaDB.o)
      ...
  "_sqlite3_step", referenced from:
      -[UMUaDB existColumnName:withTableName:] in UMAnalytics(UMUaDB.o)
      -[UMUaDB rowCountInTable:] in UMAnalytics(UMUaDB.o)
      -[UMUaDB loadErTable:] in UMAnalytics(UMUaDB.o)
      -[UMUaDB loadErTableWithVersion:] in UMAnalytics(UMUaDB.o)
      -[UMUaDB loadErTableWithVersion:withSid:] in UMAnalytics(UMUaDB.o)
      -[UMUaDB loadEtTable:] in UMAnalytics(UMUaDB.o)
      -[UMUaDB loadEtTableWithVersion:] in UMAnalytics(UMUaDB.o)
      ...
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)

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Undefined symbol: _sqlite3_close

3. [Android]Cannot fit requested classes in a single dex file. Try supplying a main-dex list.
解决问题有3步
步骤1
在app module中的build.gradle中添加依赖
implementation 'com.android.support:multidex:1.0.3'

步骤2
在app module中的build.gradle中的defaultConfig中添加以下代码
multiDexEnabled true

步骤3
如果你自定义了Application需要在类中重写一个方法
    override fun attachBaseContext(base: Context?) {
        super.attachBaseContext(base)
        // 主要是添加下面这句代码
        MultiDex.install(this)
    }
    
https://www.jianshu.com/p/95211b445154/