How can I mine bitcoin from my android mobile phone?
No way you can mine it on Android devices because the other miners in the network are using ASIC machinery for the same purpose and lot of GPU power is consumed at this time so you can't even mine it on some good laptops also so just elude this thought of btc mining on mobile phone.See here are some images of bitcoin mining farms which mine btc blocks to earn reward with coinbase transaction:
What do you think is capable of mining btc at faster pace or in technical way which system will compute the hash faster to generate next valid blocks and earn 6.25 bitcoins at this time?
The early days were when mining difficulty was low but now it's too high that there are mining pools setup for the same purpose and combined power is used to mine bitcoin blocks and Android devices are not capable of doing so.
To be honest I haven't even seen any altcoins that could be mined with a mobile phone either. There has been a bunch of them that claimed to be able to do that and some applications were released but those that I have seen were all scams that sometimes infected the device.
There are certain application which have in built wallet also and they claim it's too simple but most of them are fraud as this will only damage your system using your power and will not give you anything or say after giving out whole time power to your devices and spending funds on their maintainence due to heat generated by them you will get too low so no fun of do such things.But yes i have also heard this specially for Laptop as phones have some issues with it.