Which is more effective: violent resistance or nonviolent protest?

While violent resistance can certainly seem the most gratifying in giving immediate release and spectacle, nonviolent protest can provide the most effective method in bringing awareness to an issue. Take for instance, the protest of Rosa Parks in Montgomery, Alabama. By refusing to move to a different seat on the bus that fateful December 1, 1955, she was arrested for disobeying the segregation laws. The repercussions of that decision, to peacefully stand her ground, led to the demise of those same segregation laws so that everyone can be treated fairly.1
One can argue, there are many peaceful protests that did not end an evil that was happening at a crucial point in history. One such moment is the Tiananmen Square Massacre. On June 4, 1989, Chinese students were massacred in protest to the Communist Regime. While Communism is still the ruling force in China, the nonviolence of these students only further illuminated how the Communist Party wanted to rule by dictatorship and this event is censored by the Chinese Government to this day.2
In short, peaceful protests, whether they are successful or not, bring an ironic and sometimes iconic shockwave for future change.

Barron, Christina. (2013, February 1). Rosa Parks’s little protest led to big change. Retrieved from: https://www.washingtonpost.com/lifestyle/kidspost/rosa-parkss-little-protest-led-to-big-change/2013/02/01/a2cc0746-5e5b-11e2-a389-ee565c81c565_story.html?noredirect=on&utm_term=.f28a794f7f01.
Langevin, Jacques. (2019, May 31). Tiananmen Square Protests. Retrieved from: https://www.history.com/topics/china/tiananmen-square.

Which form of protest is more effective? There is no definitive answer to this question. It often depends on the local and unique circumstances of the situation and the protest leaders. There is no formula for a successful protest.
A recent nonviolent protest that had some positive results was in Sudan. A venal dictator who had ruled the country for decades was forced to resign. However, this resistance movement also saw the death of approximately one hundred protesters.
Recent protests in France have been somewhat more violent, and monuments have been defaced. These uprisings began as general protests against higher fuel prices and became a general demonstration of discontent with the government of Emanuel Macron. Results have been elusive, though.
In 1989, peaceful student protests were bloodily suppressed in Beijing, China. There have not been any major protests in China—with the exception of Hong Kong—since that time. China's intolerance of protests is not unique among authoritarian governments. In Russia, for example, suppression of dissent is more subtle than in the other dictatorial nations, but it is still palpable.
Mahatma Gandhi is often cited as the unparalleled leader of non-violent protest. His leadership led to India's independence from Britain. Martin Luther King Jr. and Nelson Mandela were both influenced by Gandhi's example.