Android Crash友好提示

方案概述
APP在后台时，不提示Crash；
APP刚启动时，因为无法启动Crash处理的Activity，就调用默认的CrashHandler；
其他情况下，弹出不可取消的对话框，用户可选择退出应用或者重启应用（忽略Crash会导致不可知的程序行为，所以没有忽略的选项，只是让用户自主退出，提升用户体验）
效果：

crash_deal_dialog.jpeg

代码：
在Application中注册Crash处理类

class BaseApplication : Application() {

override fun onCreate() {
        super.onCreate()
       /// other code
      //首先配置自定义crash处理，这样不会覆盖神策，友盟等第三方SDK的crash处理
       setCustomCrashHandler()
      /// other code
}

   private fun setCustomCrashHandler() {
        //一个进程一个DefaultUncaughtExceptionHandler
        val defaultHandler = Thread.getDefaultUncaughtExceptionHandler()
        Thread.setDefaultUncaughtExceptionHandler { thread, exception ->
            exception?.printStackTrace()
            //程序是否在后台
            val isBackground = ActivityLifecycleCallbackImp.activityForgroundCount == 0
            //APP初始化中，还未启动任何Activity，此时无法启动Crash处理的Activity
            if(ActiivtyStackHolder.instance.activityCount() == 0){
                defaultHandler?.uncaughtException(thread,exception)
            }else if (isBackground) {
                Log.d("MyApplication", "isBackground just kill the process without annoying users")
                Runtime.getRuntime().exit(1)
            } else {
                // 跳转到崩溃提示Activity
                var intent = intentFor<CrashDialogActivity>()
                intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK)// In case we are called with non-Activity context.
                startActivity(intent);

        }
    }

 object ActivityLifecycleCallbackImp : Application.ActivityLifecycleCallbacks {
        var activityForgroundCount: Int = 0
        override fun onActivityPaused(activity: Activity?) {
        }

        override fun onActivityResumed(activity: Activity?) {
        }

        override fun onActivityStarted(activity: Activity?) {
            activityForgroundCount++
        }

        override fun onActivityDestroyed(activity: Activity?) {
        }

        override fun onActivitySaveInstanceState(activity: Activity?, outState: Bundle?) {
        }

        override fun onActivityStopped(activity: Activity?) {
            activityForgroundCount--
        }

        override fun onActivityCreated(activity: Activity?, savedInstanceState: Bundle?) {
        }
    }

fun restartToMainActivity(){
      startActivity(intentFor<IndexActivity>().newTask().clearTask())
    }

处理Crash的Activity

import android.content.Intent
import android.os.Bundle
import com.afollestad.materialdialogs.GravityEnum
import com.afollestad.materialdialogs.MaterialDialog
import kotlinx.android.synthetic.main.activity_crash_dialog.*
import android.content.Intent.FLAG_ACTIVITY_NEW_TASK
import android.content.Intent.FLAG_ACTIVITY_CLEAR_TOP

/**
 * 弹出crash处理对话框的页面
 */
class CrashDialogActivity : BaseActivity() {

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_crash_dialog)
        showCrashDialog()
    }

    private fun showCrashDialog() {
        MaterialDialog.Builder(this)
                .cancelable(false)
                .contentGravity(GravityEnum.CENTER)
                .content("很抱歉,程序出现异常")
                .positiveText("重启应用")
                .negativeText("退出应用")
                .onNegative{dialog, which ->
                    //退出应用
                    //某些情况下，比如从最近使用的APP中恢复应用（重新调用了Activity的onCreate方法）后，在当前页面发生crash，可能还是重启的效果，
                    ActiivtyStackHolder.instance.clearAllActivity()
                   /* Runtime.getRuntime().exit(1)*/ //调用此方法系统会自动重启APP，所以不调用
                }
                .onPositive { dialog, which ->
                    //重启应用
                    BaseApplication.instance.restartToMainActivity()
                    Runtime.getRuntime().exit(1)
                }
                .show()
    }


}

Activity管理类

import android.app.Activity
import java.lang.ref.WeakReference
import java.util.*

/**
 * Created by Administrator on 2017/9/19.
 */
class ActiivtyStackHolder  private constructor() {
    private val activityStack = Stack<WeakReference<Activity>>()

    companion object {
        val instance: ActiivtyStackHolder by lazy {ActiivtyStackHolder() }
    }

    fun activityCount() : Int{
        return activityStack.size
    }

    // 将当前Activity推入栈中
    fun pushActivity(activity: Activity) {
        activityStack.add(WeakReference(activity))
    }

    /**
     * 结束指定的 Activity
     * @param activity Activity
     */
    fun removeActivity(activity: Activity?) {
        if (activity != null) {
            activityStack.forEach {
                if (it.get() == activity){
                    activityStack.remove(it)
                    return
                }
            }
        }
    

    }

    // 退出栈中所有Activity
    fun clearAllActivity() {
            while (!activityStack.isEmpty()) {
                val activity = activityStack.pop()?.get()
                activity?.finish()
            }
    }
}

感谢以下文章的作者：
Android中实现用户无感知处理后台崩溃
Android全局异常捕获并弹窗提示