Android has no built-in functions, and the process is not at all trivial. If you want to try and program it yourself, I suggest looking at algorithms such as PSOLA, WSOLA and Phase Vocoder to change the pitch. DAFX's book by Udo Selser discusses many of them pretty well, and most of them are pretty simple. Phase Vocoder, I believe, works the fastest, but also requires more DSP and mathematical knowledge to understand. PSOLA is perhaps the least mathematically complex. I personally prefer WSOLA and Enhanced WSOLA (EWSOLA), but they require quite a lot of computing power.
For correlation methods (if you are using WSOLA), I suggest doing this if the frequency domain (Google-based FFT correlation). It is much faster.
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