我想开发一个带有三个下拉框的安卓应用程序。这三个下拉框将包含有关汽车的信息,即品牌、型号和发动机。
感谢所有试图帮助我的人。当我重新测试回答Hip Hip Array的代码时,我发现了问题。我在addListenerOnSpnModelItemSelection()中使用了错误的变量。我错误地使用了spnBrand而不是spnModel。现在这两个版本都可以工作,所以我进行了更正,并希望它们能帮助其他尝试在Android中使用多旋转器的人。
- 因此,在选择第一个下拉框(品牌)后,应根据所选品牌添加第二个下拉框(型号)的内容。
- 接下来,选择第二个下拉框,然后添加第三个下拉框(发动机)。
因此,我有两个版本的源代码,但都没有起作用。(已编辑:现在工作正常) 对于第一个版本以下是我编写代码时获取灵感的链接
import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemSelectedListener;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.Spinner;
public class AddCarActivity extends Activity {
private Spinner spnBrand, spnModel, spnEngine;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.add_car);
addItemsOnSpnBrand();
}
public void addItemsOnSpnBrand() {
spnBrand = (Spinner) findViewById(R.id.spnBrand);
List<String> list = new ArrayList<String>();
//Get Brand Database and Add to List
ArrayAdapter<String> dataAdapter = new ArrayAdapter<String>(this, android.R.layout.simple_spinner_item, list);
dataAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
spnBrand.setAdapter(dataAdapter);
addListenerOnSpnBrandItemSelection();
}
public void addListenerOnSpnBrandItemSelection() {
spnBrand = (Spinner) findViewById(R.id.spnBrand);
spnBrand.setOnItemSelectedListener(new OnItemSelectedListener() {
public void onItemSelected(AdapterView<?> parent, View view, int pos, long id) {
addItemOnSpnModel(parent.getItemAtPosition(pos).toString());
}
public void onNothingSelected(AdapterView<?> parent) {
return;
}
});
}
public void addItemOnSpnModel(String inBrand) {
spnModel = (Spinner) findViewById(R.id.spnModel);
List<String> list = new ArrayList<String>();
//Get Model Database and Add to List
ArrayAdapter<String> dataAdapter = new ArrayAdapter<String>(this, android.R.layout.simple_spinner_item, list);
dataAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
spnSeries.setAdapter(dataAdapter);
addListenerOnSpnModelItemSelection();
}
public void addListenerOnSpnModelItemSelection() {
spnModel = (Spinner) findViewById(R.id.spnModel);
spnModel.setOnItemSelectedListener(new OnItemSelectedListener() {
public void onItemSelected(AdapterView<?> parent, View view, int pos, long id) {
addItemOnSpnEngine(parent.getItemAtPosition(pos).toString());
}
public void onNothingSelected(AdapterView<?> parent) {
return;
}
});
}
public void addItemOnSpnEngine(String inModel) {
spnEngine = (Spinner) findViewById(R.id.spnEngine);
List<String> list = new ArrayList<String>();
//Get Engine Database and Add to List
ArrayAdapter<String> dataAdapter = new ArrayAdapter<String>(this, android.R.layout.simple_spinner_item, list);
dataAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
spnEngine.setAdapter(dataAdapter);
}
}
这是我的第二个版本
public class AddCarActivity extends Activity implements OnItemSelectedListener {
private Spinner spnBrand, spnModel, spnEngine;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.add_car);
addItemsOnSpnBrand();
}
public void onItemSelected(AdapterView<?> parent, View view, int position,long arg3) {
int id = parent.getId();
switch (id)
{
case R.id.spnBrand:
addItemOnSpnModel(parent.getItemAtPosition(position).toString()); break;
case R.id.spnModel:
addItemOnSpnEngine(parent.getItemAtPosition(position).toString()); break;
}
}
public void onNothingSelected(AdapterView<?> arg0) {
return;
}
public void addItemsOnSpnBrand() {
spnBrand = (Spinner) findViewById(R.id.spnBrand);
List<String> list = new ArrayList<String>();
//Get Brand Database and Add to List
ArrayAdapter<String> dataAdapter = new ArrayAdapter<String>(this, android.R.layout.simple_spinner_item, list);
dataAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
spnBrand.setAdapter(dataAdapter);
spnBrand.setOnItemSelectedListener(this);
}
public void addItemOnSpnModel(String inBrand) {
spnModel = (Spinner) findViewById(R.id.spnModel);
List<String> list = new ArrayList<String>();
//Get Model Database and Add to List
ArrayAdapter<String> dataAdapter = new ArrayAdapter<String>(this, android.R.layout.simple_spinner_item, list);
dataAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
spnModel.setAdapter(dataAdapter);
spnModel.setOnItemSelectedListener(this);
}
public void addItemOnSpnEngine(String inModel) {
spnEngine = (Spinner) findViewById(R.id.spnEngine);
List<String> list = new ArrayList<String>();
//Get Engine Database and Add to List
ArrayAdapter<String> dataAdapter = new ArrayAdapter<String>(this, android.R.layout.simple_spinner_item, list);
dataAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
spnEngine.setAdapter(dataAdapter);
}
}
感谢所有试图帮助我的人。当我重新测试回答Hip Hip Array的代码时,我发现了问题。我在addListenerOnSpnModelItemSelection()中使用了错误的变量。我错误地使用了spnBrand而不是spnModel。现在这两个版本都可以工作,所以我进行了更正,并希望它们能帮助其他尝试在Android中使用多旋转器的人。