Dharma-ending age in suttas and solution? What are signs of the dharma-ending age according to the sutras and is there a solution?
Below is "Exhortation to Protect and Propagate" by Tripitaka Master Hsuan Hua, prefacing the  "Shurangama Sutra."


  Within Buddhism, there are very many important sutras. However, the
  most important Sutra is the Shurangama Sutra. If there are places
  which have the Shurangama Sutra, then the Proper Dharma dwells in the
  world. If there is no Shurangama Sutra, then the Dharma Ending Age
  appears. Therefore, we Buddhist disciples, each and every one, must
  bring our strength, must bring our blood, and must bring our sweat to
  protect the Shurangama Sutra. In the Sutra of the Ultimate
  Extinction of the Dharma, it says very, very clearly that in the
  Dharma Ending Age, the Shurangama Sutra is the first to disappear, and
  the rest of the sutras disappear after it. If the Shurangama Sutra
  does not disappear, then the Proper Dharma Age is present. Because of
  that, we Buddhist disciples must use our lives to protect the
  Shurangama Sutra, must use vows and resolution to protect the
  Shurangama Sutra, and cause the Shurangama Sutra to be known far and
  wide, reaching every nook and cranny, reaching into each and every
  dust-mote, reaching out to the exhaustion of empty space and of the
  Dharma Realm. If we can do that, then there will be a time of Proper
  Dharma radiating great light.
  
  Why would the Shurangama Sutra be destroyed? It is because it is too
  true. The Shurangama Sutra is the Buddha’s true body. The Shurangama
  Sutra is the Buddha’s sharira. The Shurangama Sutra is the Buddha’s
  true and actual stupa and shrine. Therefore, because the Shurangama
  Sutra is so true, all the demon kings use all kinds of methods to
  destroy the Shurangama Sutra. They begin by starting rumors, saying
  that the Shurangama Sutra is phony. Why do they say the Shurangama
  Sutra is phony? It is because the Shurangama Sutra speaks too truly,
  especially in the sections on The Four Decisive Deeds, the Twenty-five
  Sages Describing Perfect Penetration, and the States of the Fifty
  Skandha Demons. Those of off-center persuasions and
  externally-oriented ways, weird demons and strange freaks, are unable
  to stand it. Consequently there are a good many senseless people who
  claim that the Shurangama Sutra is a forgery.
  
  Now, the principles set forth in the Shurangama Sutra are on the one
  hand proper, and on the other in accord with principle, and the weird
  demons and strange freaks, those in various cults and sects, all
  cannot hide away their forms. Most senseless people, in particular
  unwise scholars and garbage-collecting professors “Tread upon the holy
  writ.” With their extremely scant and partial understanding, they are
  confused and unclear, lacking real erudition and true and actual
  wisdom. That is why they falsely criticize. We who study the
  Buddhadharma should very deeply be aware of these circumstances.
  Therefore, wherever we go, we should bring up the Shurangama Sutra.
  Wherever we go, we should propagate the Shurangama Sutra. Wherever we
  go, we should introduce the Shurangama Sutra to people. Why is that?
  It is because we wish to cause the Proper Dharma long to dwell in the
  world.
  
  If the Shurangama Sutra is regarded as true, then there is no problem.
  To verify its truth, let me say that if the Shurangama Sutra were
  phony, then I would willingly fall into the hells forever through all
  eternity—for being unable to recognize the Buddhadharma—for mistaking
  the false for true. If the Shurangama Sutra is true, then life after
  life in every time I make the vow to propagate the Great Dharma of the
  Shurangama, that I shall in every time and every place propagate the
  true principles of the Shurangama.
  
  Everyone should pay attention to the following point. How could the
  Shurangama Sutra not have been spoken by the Buddha? No one else could
  have spoken the Shurangama Sutra. And so I hope that all those people
  who make senseless accusations will wake up fast and stop creating the
  causes for suffering in the Hell of Pulling Out Tongues. No matter who
  the scholar is, no matter what country students of the Buddhadharma
  are from, all should quickly mend their ways, admit their mistakes,
  and manage to change. There is no greater good than that. I can then
  say that all who look at the Shurangama Sutra, all who listen to the
  Shurangama Sutra, and all who investigate the Shurangama Sutra, will
  very quickly accomplish Buddhahood.
  
  Composed by Gold Mountain Shramana Tripitaka Master Hua Translated by
  Bhikshuni Heng Hsien Reviewed by Shramanerika Heng Wen


The answer to the first part of the question is provided in the sutra that is mentioned in bold in the above quote.

Below is the sutra:


  The Buddha Speaks the Ultimate Extinction of the Dharma Sutra
  
  Thus I have heard. At one time the Buddha was in the state of
  Kushinagara. The Tathagata was to enter nirvana within three months
  and the bhikshus and Bodhisattvas as well as the great multitude of
  beings had come to pay homage to the Buddha and to bow in reverence.
  The World Honored One was tranquil and silent. He spoke not a word and
  his light did not appear. Worthy Ananda bowed and asked the Buddha, 
  
  ”0 Bhagavan, heretofore whenever you spoke the Dharma, awesome light
  would naturally appear. Yet today among this great assembly there is
  no such radiance. There must be a good cause for this and we wish to
  hear the Bhagavan’s explanation.”
  
  The Buddha remained silent and did not answer until the request had
  been repeated three times. He then told Ananda, 
  
  ”After I enter nirvana, when the Dharma is about to perish, during the
  evil age of the five turbidities, the way of demons will flourish.
  Demonic beings will become shramanas; they will pervert and destroy my
  teachings. Monastics will wear the garb of laypersons and will prefer
  handsome clothes. Their precept sashes will be made of multi-colored
  cloth. They will use intoxicants, eat meat, kill other beings and they
  will indulge in their desire for flavorful food. They will lack
  compassion and they will bear hatred and exhibit jealousy even among
  themselves. 
  
  ”Even then Bodhisattvas, Pratyekabuddhas, and Arhats will reverently
  and diligently cultivate immaculate virtue. They will be respected by
  all people and their teachings will be fair and egalitarian. These
  cultivators of the Way will take pity on the poor, they will be
  mindful of the aged, and they will save and give counsel to those
  people they find in difficult circumstances. They will at all times
  exhort others to worship and to protect sutras and images of the
  Buddha. They will do meritorious deeds, be resolute and kind, and
  never harm others. They will make physical sacrifices for others’
  benefit. They will hold no great regard for themselves but will be
  patient, yielding, humane, and peaceful. 
  
  ”As long as such people exist, the hordes of demonic bhikshus will be
  jealous of them. The demons will harass them, slander and defame them,
  expel them from their midst and degrade them. They will ostracize the
  good monks from the monastic community. Thereafter these demons derive
  no virtue from their practice. Their monastic buildings will be vacant
  and overgrown with weeds. For want of care and maintenance their
  Way-places will drift into ruin and oblivion. The demonic bhikshus
  will increase their greed for wealth and will amass great heaps of
  goods. They will refuse to distribute any of it or to use it to gain
  blessings and virtue.
  
  ”At this time, the evil monks will buy and sell slaves to till their
  fields and to slash and burn the mountain forests. They will do harm
  to living creatures and they will feel not the least bit of
  compassion. These slaves will themselves become bhikshus and
  maidservants will become bhikshunis. Totally lacking in Way-virtue,
  these people will run amok, indulging in licentious behavior. In their
  turbid confusion they will fail to separate the men from the women in
  the monastic communities.
  
  From this generation on, the Way will be weakened. Fugitives from the
  law will seek refuge in my Way, wishing to be shramanas but failing to
  observe the moral regulations. Monastics will continue to recite the
  precepts twice a month, but in name alone. Being lazy and lax, no one
  will want to listen any longer. These evil shramanas will be unwilling
  to recite the sutras in their entirety and they will make
  abbreviations at the beginning and at the end of the texts as they
  please. Soon the practice of reciting sutras will stop altogether.
  Even if there are people who recite texts, they will be unlettered,
  unqualified people who will insist, nonetheless, that they are
  correct. Bumptious, arrogant, and vain, these people will seek fame
  and glory. They will put on airs in the hope of attracting offerings
  from other people.
  
  ”When the lives of these demonic bhikshus come to an end their
  essential spirits will fall into the Avichi Hell. Having committed the
  five evil deeds, they will suffer successive rebirths as hungry ghosts
  and as animals. They will know all such states of woe as they pass on
  through eons as numerous as sands on the banks of the Ganges River.
  When their offenses are accounted for they will be reborn in a border
  land where the Triple Jewel is unknown. 
  
  ”When the Dharma is about to disappear, women will become vigorous and
  will at all times do deeds of virtue. Men will grow lax and will no
  longer speak the Dharma. Those who are genuine shramanas will be
  looked upon as dung and no one will have faith in them. When the
  Dharma is about to perish, all the gods will begin to weep. Rivers
  will dry up and the five grains will not ripen. Pestilences will
  frequently take millions of lives. The masses will toil and suffer
  while the local officials will plot and scheme. No one will adhere to
  principles. Instead, the human race will multiply, becoming like the
  sands of the ocean-bed.
  
  Good persons will be hard to find; at most there will be one or two.
  As the eon comes to a close, the revolutions of the sun and the moon
  will grow short and the lifespan of people will decrease. Their hair
  will turn white by the time they are forty. Because of excessive
  licentious behavior they will quickly exhaust their seminal fluids and
  will die at a young age, usually before sixty years. As the lifespan
  of males decreases, that of females will increase to seventy, eighty,
  ninety, or one hundred years. 
  
  ”The mighty rivers will flood and lose harmony with their natural
  cycles, yet people will not take notice or feel concern. Extremes of
  climate will soon be taken for granted. Beings of all races will mix
  together at random, without regard for the noble and the mean. Their
  births and rebirths will cause them to sink and float, like feeding
  aquatic creatures. 
  
  ”Even then Bodhisattvas, Pratyekabuddhas, and Arhats will gather
  together in an unprecedented assembly because they will all have been
  harried and pursued by the hordes of demons. They will no longer dwell
  in the assemblies but the Three Vehicles will retreat to the
  wilderness. In a tranquil place they will find shelter, happiness, and
  long life. Gods will protect them and the moon will shine down upon
  them. The Three Vehicles will have an opportunity to meet together and
  the Way will flourish.
  
  However, within fifty-two years the Shurangama Sutra and the
  Pratyutpanna [Standing Buddha] Samadhi, will be the first to change
  and then to disappear. The twelve divisions of the canon will
  gradually follow until they vanish completely, never to appear again.
  Its words and texts will be totally unknown ever after. The precept
  sashes of shramanas will turn white of themselves. When my Dharma
  disappears it will be just like an oil lamp that flares brightly for
  an instant just before it goes out. So too, will the Dharma flare and
  die. After this time it is difficult to speak with certainty of what
  will follow.
  
  ”A period of ten million years will follow before the time when
  Maitreya is about to appear in the world to become the next Buddha. At
  that time the planet will be entirely peaceful. Evil vapors will have
  dissipated, rain will be ample and regular, and crops will grow
  abundantly. Trees will grow to a great height and people will grow to
  be eighty feet tall. The average lifespan will extend to 84,000 years.
  It will be impossible to count all the beings who will be taken across
  to liberation.”
  
  Worthy Ananda addressed the Buddha, “What should we call this Sutra
  and how shall we uphold it?” 
  
  The Buddha said, “Ananda, this sutra is called The Ultimate Extinction
  of the Dharma. Tell everyone to propagate it widely; the merit of your
  actions will be measureless, beyond reckoning.” 
  
  When the four-fold assembly of disciples heard this sutra they grieved
  and wept. Each of them resolved to attain the true path of the Supreme
  Sage. Then bowing to the Buddha, they withdrew. 
  
  End of The Buddha Speaks the Ultimate Extinction of the Dharma Sutra.
  
  From the Seng You Records, translator anonymous. Appended to the Song
  Annals.


Is there a solution?

The solution once again is as Master Hsuan Hua says in the top-most quote: to protect the first to disappear sutra: The Surangama Sutra.

It is a gem of an exegesis of the Shakyamuni's original teachings and a consummating addition to Theravadin sutras...