INA219 current sensor not working properly with DC motor
I had the same problem, it helps to change the sample amount configuration. At 1 sample (which is the Adafruit default) the current value keeps jumping around. When the configuration is changed to 128 samples I get a very stable reading (that varies as expected, when the motor load is increased, the current increases).
The following needs to be changed:
INA219_CONFIG_SADCRES_12BIT_1S_532US to INA219_CONFIG_SADCRES_12BIT_128S_69MS

You can also change the following (for the bus voltage), but this seems stable also with the original setting:
INA219_CONFIG_BADCRES_12BIT to INA219_CONFIG_BADCRES_12BIT_128S_69MS

(changes to be made in Adafruit_INA219.cpp)