Question

我创建了一个ListView，它有一个列表项，每个列表项旁边都有一个复选框。可以检查多个盒子。我需要从MainActivity中变量的值来改变，具体取决于检查哪些框。

列表

@SuppressLint("ShowToast")
public class ListOfMajors extends ListActivity {
    public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    setContentView(R.layout.majorslist);
    ListView mylist = (ListView) findViewById(R.id.majorslist);
    String[] list={"Mechanical Engineering","Civil Engineering","Computer Engineering","Electrical Engineering","Environmental Engineering","Manufacturing Engineering"};
    ArrayAdapter<String> adapter = new ArrayAdapter<String>(ListOfMajors.this,android.R.layout.simple_list_item_multiple_choice,list);
    mylist.setChoiceMode(ListView.CHOICE_MODE_MULTIPLE);
    mylist.setAdapter(adapter);

}

MainActivity

public class MainActivity extends Activity {

public static double scoreDouble;
TextView score;
EditText gpa;
EditText sat;
EditText act;
Button calc; 
CheckBox checkbox;

public void Checkbox(View view){
boolean checked = ((CheckBox) checkbox).isChecked();

if(checked){
    Intent myIntent = new Intent(MainActivity.this, ListOfMajors.class);
    MainActivity.this.startActivity(myIntent);
}
}
@Override

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

gpa = (EditText) findViewById(R.id.gpa);
sat = (EditText) findViewById(R.id.sat);
act = (EditText) findViewById(R.id.act);
checkbox = (CheckBox) findViewById(R.id.checkBox);

score = (TextView) findViewById(R.id.score);
calc = (Button) findViewById(R.id.calc);

calc.setOnClickListener(new View.OnClickListener() {
    public void onClick(View v) {
        String gpaString = gpa.getText().toString();
        if (gpaString.equals("")) {
            gpaString = "0";
        }
        double gpaDouble = Double.parseDouble(gpaString);

        String satString = sat.getText().toString();
        if (satString.equals("")) {
            satString = "0";
        }
        int satInt = Integer.parseInt(satString);

        String actString = act.getText().toString();
        if (actString.equals("")) {
            actString = "0";
        }
        int actInt = Integer.parseInt(actString);
        if (actInt / 36.0 < satInt / 2400.0) {
            scoreDouble = (0.6 * gpaDouble * 25)
                    + (0.4 * ((double) satInt / 2400.0) * 100.0);
        } else {
            scoreDouble = (0.6 * gpaDouble * 25)
                    + (0.4 * ((double) actInt / 36.0) * 100.0);
        }

        Intent myIntent = new Intent(MainActivity.this, CollegeList.class);
        MainActivity.this.startActivity(myIntent);

        }

    }
);
}

}

就我而言，如果＆＃34;机械工程＆＃34;检查后，变量scoreDouble应该增加100，如果＆＃34;土木工程＆＃34;检查它应该增加1000，等等。我将如何做到这一点？

Answer 1

您可以使用listView方法getCheckedItemPositions()来查找列表中的哪些元素已被选中。该方法返回一个带有检查位置的稀疏布尔数组。然后，您可以根据给定数组中的元素修改相应的变量。

使用Checkable ListView更改变量值

1 个答案: