动态添加和删除Spinner（ArrayList与Widget的依赖性）

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#android #Spinner #TextView #EditText #Button

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4.9、动态添加和删除Spinner（ArrayList与Widget的依赖性）

新建一个继承Activity类的SpinnerItemAddOrDeleteActivity，并设置布局文件为：spinneritemaddordelete.xml。

在布局文件中添加一个TextView和一个EditText，2个Button按钮。

<TextView

android:id="@+id/spinneritemaddordelete_tv01"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:layout_gravity="center_horizontal"

android:text="@string/show_information"

android:textSize="20sp" />

<EditText

android:id="@+id/spinneritemaddordelete_edit01"

android:layout_width="fill_parent"

android:layout_height="wrap_content" />

<Button

android:id="@+id/spinneritemaddordelete_btn01"

style="@android:style/Widget.Button.Inset"

android:layout_width="fill_parent"

android:layout_height="wrap_content"

android:text="@string/add01" />

<Button

android:id="@+id/spinneritemaddordelete_btn02"

style="@android:style/Widget.Button.Inset"

android:layout_width="fill_parent"

android:layout_height="wrap_content"

android:text="@string/delete" />

<Spinner

android:id="@+id/spinneritemaddordelete_spinner"

android:layout_width="fill_parent"

android:layout_height="wrap_content"

android:entries="@array/spinnerItem"

android:prompt="@string/spinnersetdropdownviewresource_spinner_prompt"

android:spinnerMode="dialog" />

而后在Activity类中获取这些组件。

package lyx.feng.second;

import java.util.ArrayList;

import java.util.List;

import lyx.feng.simpletextdemo.R;

import android.app.Activity;

import android.os.Bundle;

import android.view.View;

import android.view.View.OnClickListener;

import android.widget.AdapterView;

import android.widget.AdapterView.OnItemSelectedListener;

import android.widget.ArrayAdapter;

import android.widget.Button;

import android.widget.EditText;

import android.widget.Spinner;

import android.widget.TextView;

public class SpinnerItemAddOrDeleteActivity extends Activity {

private TextView tv = null;

private EditText edit = null;

private Button add = null;

private Button delete = null;

private Spinner spinner = null;

private ArrayAdapter<String> adapter = null;

private String item[];

private List<String> lists = new ArrayList<String>();

@SuppressWarnings("unchecked")

@Override

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

super.setContentView(R.layout.spinneritemaddordelete);

this.tv = (TextView) super

.findViewById(R.id.spinneritemaddordelete_tv01);

this.edit = (EditText) super

.findViewById(R.id.spinneritemaddordelete_edit01);

this.add = (Button) super

.findViewById(R.id.spinneritemaddordelete_btn01);

this.delete = (Button) super

.findViewById(R.id.spinneritemaddordelete_btn02);

this.spinner = (Spinner) super

.findViewById(R.id.spinneritemaddordelete_spinner);

this.item = getResources().getStringArray(R.array.spinnerItem);

for (int i = 0; i < item.length; i++) {

lists.add(item[i]);

}

this.adapter = (ArrayAdapter<String>) this.spinner.getAdapter();

this.adapter = new ArrayAdapter<String>(this,

android.R.layout.simple_spinner_dropdown_item, this.lists);

this.spinner.setAdapter(adapter);

this.add.setOnClickListener(new OnClickListener() {

@Override

public void onClick(View v) {

for (int i = 0; i < adapter.getCount(); i++) {

if (edit.getText().toString().trim()

.equals(adapter.getItem(i))) {

return;

}

if (edit.getText().toString().trim().equals("")) {

return;

}

tv.setText("你添加的是：" + edit.getText().toString());

adapter.add(edit.getText().toString());

edit.setText("");

}

});

this.delete.setOnClickListener(new OnClickListener() {

@Override

public void onClick(View v) {

if (adapter.getCount() > 0) {

tv.setText("你删除的是：" + spinner.getSelectedItem().toString());

adapter.remove(spinner.getSelectedItem().toString());

}

});

this.spinner.setOnItemSelectedListener(new OnItemSelectedListener() {

@Override

public void onItemSelected(AdapterView<?> parent, View view,

int position, long id) {

tv.setText("你选择的是：" + adapter.getItem(position).toString());

}

@Override

public void onNothingSelected(AdapterView<?> parent) {

}

});

}

注意这里要使用List集合，否则在使用ArrayAdapter类的add或者removed方法的时候会报错。