为什么键盘在ScrollView内部时在AutoCompleteTextView上重叠

我有一个简单的android布局和代码,但是AutoCompleteTextView当我点击它时键盘总是重叠.注意:ScrollView内部的AutoCompleteTextView.注意:平台是6.0.1

package com.example.jason_wu.search;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.widget.AutoCompleteTextView;

public class Main2Activity extends AppCompatActivity {
    private AutoCompleteTextView mAtv;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main2);
        mAtv = (AutoCompleteTextView) findViewById(R.id.location_auto_complete);
        //issue 1
        //mAtv.setBackground(getDrawable(R.drawable.search_input_focus));
        //issue 2
        mAtv.setHeight(300);
    }
}

和我的AndroidManifest.xml在这里:

Layout.xml:

看到