更改工具栏后退箭头颜色

import android.support.v7.app.ActionBar;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
//...

public class LoginActivity extends AppCompatActivity {
    protected void onCreate(Bundle savedInstanceState) {

        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);
        ActionBar actionBar = getSupportActionBar();
        actionBar.setDisplayHomeAsUpEnabled(true);
      //...
    }
    //...
}