Question

我有一个微调器，显示我的数组数据列表和删除按钮。我想要做的是当我点击删除按钮时，它会自动删除一个选定的微调器值，但我不确定如何做到这一点。

在删除按钮单击功能中，在再次调试我的活动后删除了所选的微调器值但我想在单击删除按钮时自动删除选定的微调器值。

package quesansw.the1;

import java.util.ArrayList;
import android.app.Activity;
import android.app.Dialog;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.net.NetworkInfo.State;
import android.os.Bundle;
import android.view.View;
import android.view.Window;
import android.view.WindowManager;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Spinner;
import android.widget.AdapterView.OnItemSelectedListener;

public class View1 extends Activity { 
    SQLiteDatabase db;
    ArrayAdapter adapter; 
    private String array_spinner[];

    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        db = openOrCreateDatabase("mydatabase.db",
                SQLiteDatabase.CREATE_IF_NECESSARY, null);

        final Dialog d1 = new Dialog(this);
        Window window = d1.getWindow();
        window.setFlags(WindowManager.LayoutParams.FLAG_BLUR_BEHIND,
                WindowManager.LayoutParams.FLAG_BLUR_BEHIND);

        //d1.setTitle("Login");

        d1.setContentView(R.layout.view);
        d1.show();
        Button Click = (Button) d1.findViewById(R.id.Click);
        Button Save = (Button) d1.findViewById(R.id.Save);
        Button Delete = (Button) d1.findViewById(R.id.Delete);

        ArrayList<String> list = new ArrayList<String>();
        Cursor cursor = db.rawQuery("select * from records", null);
        list.add("");
        if (cursor.moveToFirst())
        {
            do
            {
                list.add(cursor.getString(0));
            }
            while (cursor.moveToNext());
        }

        /*array_spinner=new String[20];
        array_spinner[0]=list.get(0);*/
        Spinner s = (Spinner) d1.findViewById(R.id.tittle_spinner);
        adapter = new ArrayAdapter<Object>(this,android.R.layout.simple_spinner_item, list.toArray());

        adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
        s.setAdapter(adapter);


        /*Save.setOnClickListener(new View.OnClickListener() {
            public void onClick(View v) {

                Spinner s = (Spinner) d1.findViewById(R.id.tittle_spinner);
                String str = s.getSelectedItem().toString();
                System.out.println("********"+str);
                Cursor cur1=db.rawQuery("select * from records where tittle='"+str+"' ",null);
                cur1.moveToNext();
                String str1=cur1.getString(1);

                EditText ans = (EditText) d1.findViewById(R.id.text);
                ans.setText(str1);

            }
            });*/

        Delete.setOnClickListener(new View.OnClickListener() {
            public void onClick(View v) {

                Spinner s = (Spinner) d1.findViewById(R.id.tittle_spinner);
                String str = s.getSelectedItem().toString();
                db.execSQL("delete from records where tittle='"+str+"' ");

            }
            });


        Click.setOnClickListener(new View.OnClickListener() {
            public void onClick(View v) {

                Spinner s = (Spinner) d1.findViewById(R.id.tittle_spinner);
                String str = s.getSelectedItem().toString();
                System.out.println("********"+str);
                Cursor cur1=db.rawQuery("select * from records where tittle='"+str+"' ",null);
                cur1.moveToNext();
                String str1=cur1.getString(1);

                EditText ans = (EditText) d1.findViewById(R.id.text);
                ans.setText(str1);


            }
            });
    }
}

1）这是我的活动屏幕截图

Activity Screen Shot

2）使用微调器值拍摄的另一个屏幕：

Spinner Values

Answer 1

在deleteButton的onClickListener中，从数组数据列表中删除选定的微调器值，并在删除后调用onnotifydatasetChanges或再次使用新数组列表调用setSpinner adapter。

public class MainActivity extends Activity {

Spinner spin;
Button delete;

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

    delete  = (Button) findViewById(R.id.button1);
    spin = (Spinner) findViewById(R.id.spinner1);

    final ArrayList<String> spinneritems = new ArrayList<String>();

    spinneritems.add("item 1");
    spinneritems.add("item 2");
    spinneritems.add("item 3");
    spinneritems.add("item 4");
    spinneritems.add("item 5");


    final ArrayAdapter<String> adp = new ArrayAdapter<String>(this,android.R.layout.simple_spinner_item,spinneritems );
    adp.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
    spin.setAdapter(adp);

    delete.setOnClickListener(new OnClickListener() {

        @Override
        public void onClick(View v) {

            String selectedSpinner = spin.getSelectedItem().toString();
            spinneritems.remove(selectedSpinner);
            adp.notifyDataSetChanged();
        }
    });
}
}
}

Answer 2

为什么要宣布和初始化Spinner这么多次？只做一次

public class View1 extends Activity { 
    SQLiteDatabase db;
    ArrayAdapter adapter; 
    private String array_spinner[];
    Spinner spinner;               // Declare your spinner here

然后在onCreate()

public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        db = openOrCreateDatabase("mydatabase.db",
            SQLiteDatabase.CREATE_IF_NECESSARY, null);
        spinner = (Spinner) d1.findViewById(R.id.tittle_spinner);  //initialize your spinner here

        final Dialog d1 = new Dialog(this);

然后当您点击delete button致电adapter.notifyDataSetChanged()来更新您的Array和微调器

Answer 3

在删除按钮上单击侦听器添加以下代码

Spinner s = (Spinner) d1.findViewById(R.id.tittle_spinner);
String str = s.getSelectedItem().toString();
adapter.remove(str);
adapter.notifyDataSetChanged();
s.setSelection(0);

在按钮上单击自动删除选定的微调项目

3 个答案: