Question

我正在尝试开发一个Android移动应用程序，我需要显示至少包含100个项目的列表视图的一部分。现在，作为一所大学的管理者，我列出了100个要教授的科目。（所有这些都列在列表视图中。所有科目都有一个观点，并且为了让一个学生申请这门课程他/她需要具有更高的分数。一个指示性样本如下：英语：24 西班牙：16 数学：28 科学：26 法国：16 管理：22 法：30 亚洲语言：10

现在，学生需要输入他/她的观点并以此为基础（确切或较低点），他/她将获得他/她有资格申请的科目列表。

E.g输入你的积分：24

listview中的输出应该提供以下内容：法国：16 管理：22 英语：24 亚洲语言：10

我尝试了这个但是卡住了，无法完成代码：

Course.java

public class Course {

private String name;
private int points;

public Course(String name, int points) {
    this.name = name;
    this.points = points;
}

public String getName() {
    return name;
}

public int getPoints() {
    return points;
}

@Override
public String toString() {
    return getName();
}
}

Course[] courses = new Course[]{
    new Course("Medicine", 30),
    new Course("Physics", 28),
    new Course("Math", 24),
    new Course("English", 20)
 };  


Button searchButton = (Button) findViewById(R.id.btn_search);
searchButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
List<Course> courseList = new ArrayList<Course>(Arrays.asList(courses));
// initialize the adapter with courseList... //

// this code inside the Button's onClick                    
int points = Integer.parseInt(editText.getText().toString());
for (Course c : courses) {
if (c.getPoints() <= points) {
    adapter.add(c);
}
}




course.xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
          android:layout_width="match_parent"
          android:layout_height="match_parent"
          android:orientation="vertical">

<LinearLayout android:layout_width="match_parent"
              android:layout_height="wrap_content"
              android:orientation="horizontal">
    <EditText
            android:layout_width="0dp"
            android:layout_weight="1"
            android:maxLines="1"
            android:inputType="number"
            android:layout_height="wrap_content"
            android:hint="Enter your points:"
            android:id="@+id/editText"/>
    <Button
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Search"
            android:id="@+id/btn_search"/>
</LinearLayout>

<ListView
        android:id="@+id/courseNames"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"/>
</LinearLayout>

Answer 1

我的解决方案如下 -

MainActivity

public class MainActivity extends AppCompatActivity {

ListView myList;
EditText edtSearch;
Button btnSearch;

listAdapter adapter;
ArrayList<Course> alSearchCourses;
Course[] courses;

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);

myList = (ListView) findViewById(R.id.myList);
edtSearch = (EditText) findViewById(R.id.edtSearch);
btnSearch = (Button) findViewById(R.id.btnSearch);

courses = new Course[]{
        new Course("Medicine", 30),
        new Course("Physics", 28),
        new Course("Math", 24),
        new Course("English", 20)
};

adapter = new listAdapter(this, courses);
myList.setAdapter(adapter);

edtSearch.addTextChangedListener(new TextWatcher() {
    @Override
    public void beforeTextChanged(CharSequence s, int start, int count, int after) {
    }

    @Override
    public void onTextChanged(CharSequence s, int start, int before, int count) {
        if (count == 0) {
            adapter = new listAdapter(MainActivity.this, courses);
            myList.setAdapter(adapter);
        }
    }

    @Override
    public void afterTextChanged(Editable s) {
    }
});

btnSearch.setOnClickListener(new View.OnClickListener() {
    @Override
    public void onClick(View v) {

        alSearchCourses = new ArrayList<>();

        int points = Integer.parseInt(edtSearch.getText().toString());
        for (int i = 0; i < courses.length; i++) {

            Course c2 = courses[i];

            if (c2.getPoints() <= points) {
                alSearchCourses.add(c2);
            }

        }

        Course searchCourses [] = new Course[alSearchCourses.size()];
        searchCourses = alSearchCourses.toArray(searchCourses);

        adapter = new listAdapter(MainActivity.this, searchCourses);
        myList.setAdapter(adapter);

    }

});

}
}

listAdapter

public class listAdapter extends BaseAdapter {

Context context;
Course[] courses;
LayoutInflater inflater;

public listAdapter(Context context, Course[] courses) {
this.context = context;
this.courses = courses;
inflater = LayoutInflater.from(context);
}

@Override
public int getCount() {
return courses.length;
}

@Override
public Object getItem(int position) {
return null;
}

@Override
public long getItemId(int position) {
return 0;
}

@Override
public View getView(int position, View convertView, ViewGroup parent) {

if(convertView == null){
    convertView = inflater.inflate(R.layout.list_item_layout, null);
}

TextView txtCourse = (TextView) convertView.findViewById(R.id.txtCourse);
txtCourse.setText(courses[position].getName() + "-" +     courses[position].getPoints());

return convertView;
}
}

希望有所帮助：）

如何根据用户的不同要求仅选择列表视图的一部分？

1 个答案: