从编辑文本在android中动态填充Spinner

Question

我有一个微调器,其中很少有来自strings.xml的值,我想使用Button的onclick事件动态地从编辑文本填充该微调器,但不知何故它不起作用,我每次都得到强制关闭.任何帮助将不胜感激.

package com.example.expense;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Spinner;

public class Expense3 extends Activity {
    //private TextView t1;

    private Spinner spinner;
    private EditText Text;
    private ArrayAdapter<CharSequence> adapter;
    private Button addButton;

    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        Text = (EditText)findViewById(R.id.widget4);
        addButton = (Button)findViewById(R.id.add_new);

        spinner = (Spinner) findViewById(R.id.hhj);

         adapter = ArrayAdapter.createFromResource(
                this, R.array.planets_array, android.R.layout.simple_spinner_item);
        adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
        spinner.setAdapter(adapter);





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

                addNewSpinnerItem();
         }

            });

        }

    protected void addNewSpinnerItem() {
        // TODO Auto-generated method stub
        CharSequence textHolder = "" + Text.getText().toString();
        adapter.add(textHolder);


    }
}

Logcat错误: -

05-14 01:07:19.934: ERROR/AndroidRuntime(802): FATAL EXCEPTION: main
05-14 01:07:19.934: ERROR/AndroidRuntime(802): java.lang.UnsupportedOperationException
05-14 01:07:19.934: ERROR/AndroidRuntime(802):     at java.util.AbstractList.add(AbstractList.java:411)
05-14 01:07:19.934: ERROR/AndroidRuntime(802):     at java.util.AbstractList.add(AbstractList.java:432)
05-14 01:07:19.934: ERROR/AndroidRuntime(802):     at android.widget.ArrayAdapter.add(ArrayAdapter.java:178)
05-14 01:07:19.934: ERROR/AndroidRuntime(802):     at com.example.expense.Expense3.addNewSpinnerItem(Expense3.java:50)
05-14 01:07:19.934: ERROR/AndroidRuntime(802):     at com.example.expense.Expense3$1.onClick(Expense3.java:40)
05-14 01:07:19.934: ERROR/AndroidRuntime(802):     at android.view.View.performClick(View.java:2408)
05-14 01:07:19.934: ERROR/AndroidRuntime(802):     at android.view.View$PerformClick.run(View.java:8816)
05-14 01:07:19.934: ERROR/AndroidRuntime(802):     at android.os.Handler.handleCallback(Handler.java:587)
05-14 01:07:19.934: ERROR/AndroidRuntime(802):     at android.os.Handler.dispatchMessage(Handler.java:92)
05-14 01:07:19.934: ERROR/AndroidRuntime(802):     at android.os.Looper.loop(Looper.java:123)
05-14 01:07:19.934: ERROR/AndroidRuntime(802):     at android.app.ActivityThread.main(ActivityThread.java:4627)
05-14 01:07:19.934: ERROR/AndroidRuntime(802):     at java.lang.reflect.Method.invokeNative(Native Method)
05-14 01:07:19.934: ERROR/AndroidRuntime(802):     at java.lang.reflect.Method.invoke(Method.java:521)
05-14 01:07:19.934: ERROR/AndroidRuntime(802):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
05-14 01:07:19.934: ERROR/AndroidRuntime(802):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
05-14 01:07:19.934: ERROR/AndroidRuntime(802):     at dalvik.system.NativeStart.main(Native Method)

Answer 1

您正在尝试在从资源创建的适配器中添加项目,因此它将为您提供不受支持的结果.要解决此问题,您可以创建一个空白列表,然后从资源中添加列表中的项目.为此你可以使用Arrays.asList()或者你可以创建一个循环并在List中添加单个项目,在创建List之后,你将不得不使用该List创建一个适配器.

现在要在微调器的适配器中添加项,您可以使用该adapter.add()方法在微调器适配器中添加项.下面是一个示例,说明如何创建适配器并在微调器中添加项目.

adapter = new ArrayAdapter<String>(this, 
android.R.layout.simple_spinner_item, array);

这里的数组是一个List.

要在微调器中添加项,可以使用add方法.

adapter.add("String to insert into spinner");

Answer 2

问题是ArrayAdapter.createFromResource()使用Arrays.asList()返回不可变列表,这意味着您无法向适配器添加任何项(这是"不支持"操作).尝试创建一个空的适配器,只需添加项目:

adapter = new ArrayAdapter(this, android.R.layout.simple_spinner_item, 
              new ArrayList<CharSequence>());