I don't know why today, but I always encounter various errors, not the bug of the program, but the problem of AS. As programmers, we have to be patient . The error in Log is as follows:
04-10 11:09:48.029 20658-20658/zhuo.myapp E/InstantRun: Could not find slices in APK; aborting.
04-10 11:09:48.039 20658-20658/zhuo.myapp E/dalvikvm: Could not find class 'android.util.ArrayMap', referenced from method com.android.tools.fd.runtime.MonkeyPatcher.monkeyPatchExistingResources
04-10 11:09:48.039 20658-20658/zhuo.myapp E/dalvikvm: Could not find class 'android.util.ArrayMap', referenced from method com.android.tools.fd.runtime.MonkeyPatcher.pruneResourceCache
04-10 11:09:48.059 20658-20658/zhuo.myapp E/dalvikvm: Could not find class 'android.widget.Toolbar', referenced from method zhuo.myapp.MainActivity.access$super
04-10 11:09:48.069 20658-20658/zhuo.myapp E/dalvikvm: Could not find class 'android.app.ActivityManager$TaskDescription', referenced from method zhuo.myapp.MainActivity.access$super
04-10 11:09:48.069 20658-20658/zhuo.myapp E/dalvikvm: Could not find class 'android.app.SharedElementCallback', referenced from method zhuo.myapp.MainActivity.access$super
04-10 11:09:48.069 20658-20658/zhuo.myapp E/dalvikvm: Could not find class 'android.os.PersistableBundle', referenced from method zhuo.myapp.MainActivity.access$super
04-10 11:09:48.069 20658-20658/zhuo.myapp E/dalvikvm: Could not find class 'android.transition.TransitionManager', referenced from method zhuo.myapp.MainActivity.access$super
04-10 11:09:48.079 20658-20658/zhuo.myapp E/dalvikvm: Could not find class 'android.app.assist.AssistContent', referenced from method zhuo.myapp.MainActivity.access$super
04-10 11:09:48.079 20658-20658/zhuo.myapp E/dalvikvm: Could not find class 'android.os.PersistableBundle', referenced from method zhuo.myapp.MainActivity.access$super
The solutions found are as follows:
File-Settings-Build, Execution, Deployment-Instant Run, remove the hook beside Enable Instant Run... and click OK.
This trick worked, removing the warning messages.