请教老师两个问题。一个是关于seekbar，另一个是关于toast信息有问题。

//Book类
public class Book {
    private String name;
    private boolean his,sus,lite;
    private int age;
    private int pic;

    public Book(){
    }

    public Book(String name, boolean his, boolean sus, boolean lite, int age, int pic) {
        this.name = name;
        this.his = his;
        this.sus = sus;
        this.lite = lite;
        this.age = age;
        this.pic = pic;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;

    }

    public boolean isHis() {
        return his;
    }

    public void setHis(boolean his) {
        this.his = his;
    }

    public boolean isSus() {
        return sus;
    }

    public void setSus(boolean sus) {
        this.sus = sus;
    }

    public boolean isLite() {
        return lite;
    }

    public void setLite(boolean lite) {
        this.lite = lite;
    }

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }

    public int getPic(){
        return pic;
    }

    public void setPic(int pic){
        this.pic = pic;
    }

    @Override
    public String toString() {
        return "Book{" +
                "name='" + getName() + '\'' +
                ", his=" + isHis() +
                ", sus=" + isSus() +
                ", lite=" + isLite() +
                ", age=" + getAge() +
                ", pic=" + getPic() +
                '}';
    }
}
///////////////////////////////////////////////////////////////////////////////////////////////
//Person类
public class Person {
    private String name;
    private String gender;
    private String time;
    Book book;

    public Person(){ }

    public Person(String name, String gender, String time, Book book) {
        this.name = name;
        this.gender = gender;
        this.time = time;
        this.book = book;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getGender() {
        return gender;
    }

    public void setGender(String gender) {
        this.gender = gender;
    }

    public String getTime() {
        return time;
    }

    public void setTime(String time) {
        this.time = time;
    }

    public Book getBook() {
        return book;
    }

    public void setBook(Book book) {
        this.book = book;
    }

    @Override
    public String toString() {
        return "Person{" +
                "name='" + getName() + '\'' +
                ", gender='" + getGender() + '\'' +
                ", time='" + getTime() + '\'' +
                ", book=" + book +
                '}';
    }
}
//////////////////////////////////////////////////////////////////////////////////////////
//seekbar选择年龄
class seekListener implements SeekBar.OnSeekBarChangeListener{

    @Override
    public void onProgressChanged(SeekBar seekBar, int progress, boolean fromUser) {

    }

    @Override
    public void onStartTrackingTouch(SeekBar seekBar) {

    }

    @Override
    public void onStopTrackingTouch(SeekBar seekBar) {
        f_age = seekBar.getProgress();
        tv_sb.setText(f_age+"");
    }
}
////////////////////////////////////////////////////////////////////////////////////////////
//点击查找和下一个
class buttonListener implements View.OnClickListener{

    @Override
    public void onClick(View v) {
        switch (v.getId()){
            case R.id.bt_find:
                books.clear();
                count = 0;
                checkData();
                //先进行符合条件的寻找
                if(checkTime(et_time.getText().toString(),tv_time.getText().toString())){
                    Toast.makeText(MainActivity.this,"借书时间晚于归还时间！程序将退出！",Toast.LENGTH_SHORT).show();
                    finish();
                }else{
                    if(books.size() == 0) {
                        iv_book.setImageResource(R.drawable.f);
                        name.setText("书名");
                        type.setText("类型");
                        age.setText("适用年龄");
                        Toast.makeText(MainActivity.this, "未找到任何书籍！请重新选择！", Toast.LENGTH_SHORT).show();
                    }
                    else{
                        showPic(count);
                        String n = name.getText().toString();
                        String t = et_time.getText().toString();
                        person.setName(n);
                        person.setTime(t);
                        Toast.makeText(MainActivity.this, "个人信息为：" + person, Toast.LENGTH_SHORT).show();
                        count++;
                    }

                }
                break;
            case R.id.bt_next:
                //进行切换
                if(count < books.size()) {
                    showPic(count);
                    String n = name.getText().toString();
                    String t = et_time.getText().toString();
                    person.setName(n);
                    person.setTime(t);
                    Toast.makeText(MainActivity.this, "个人信息为：" + person, Toast.LENGTH_SHORT).show();
                    count++;
                }else {
                    Toast.makeText(MainActivity.this, "由于已经是最后一个书籍，从头显示！", Toast.LENGTH_SHORT).show();
                    count = 0;
                    showPic(count);
                    count++;
                }
        }
    }
}

第一个是，我的seekbar还没到进度条最右边无法继续拖动；第二个是，toast个人信息时book显示null是为什么？