Question

我有两个旋转器的活动。一种是头发的类型，另一种是头发的颜色。我希望根据从微调器中选择的两个项目来改变图片（在头上）。

这是它应该做的：

活动已加载（旋转器设置为“Bald”和“Black”）
- 头发是光头。
将发型改为'男短'
- 头发变成短的黑色男性头发。
将颜色更改为'Blonde'
- 头发变成短金发男性头发。

但第3步不起作用!!!

继承我的代码：

public class HeadZoom extends MainActivity implements AdapterView.OnItemSelectedListener{

private Spinner hairSpinner;
private Spinner hairColor;
private String type;
private String color;
private ImageView imageView;
private List<String> hairTypeArray = new ArrayList<String>();
private List<String> hairColorArray = new ArrayList<String>();

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.head_zoom);
    Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
    setSupportActionBar(toolbar);

    imageView = (ImageView) findViewById(R.id.head);
    type="Bald";

    hairSpinner = (Spinner) findViewById(R.id.hairSpinner);
    hairSpinner.setOnItemSelectedListener(this);
    List<String> hairTypeArray = new ArrayList<String>();
    hairTypeArray.add("Bald");
    hairTypeArray.add("Female Short");
    hairTypeArray.add("Female Medium");
      (...)
    ArrayAdapter<String> hairTypeAdapter = new ArrayAdapter<String>(this,
            android.R.layout.simple_spinner_item, hairTypeArray);
    hairTypeAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
    hairSpinner.setAdapter(hairTypeAdapter);

    color = "Black";

    hairColor = (Spinner) findViewById(R.id.hairColor);
    hairColor.setOnItemSelectedListener(this);
    List<String> hairColorArray = new ArrayList<>();
    hairColorArray.add("Black");
    hairColorArray.add("Blonde");
    hairColorArray.add("Blue");
      (...)
    ArrayAdapter<String> hairColorAdapter = new ArrayAdapter<String>(this,
            android.R.layout.simple_spinner_item, hairColorArray);
    hairColorAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
    hairColor.setAdapter(hairColorAdapter);
}

public void onItemSelected(AdapterView<?> parent, View view, int position, long id){
    if(parent.getId()==hairSpinner.getId())
        type = hairTypeArray.get(position);
    else
        color = hairColorArray.get(position);

    switch(type){
        case "Bald":
            imageView.setImageResource((R.drawable.sw_head));
            break;
        case "Female Short":
            if(color=="Black")
                imageView.setImageResource(R.drawable.fhair_short_black);
            else if(color=="Blonde")
                imageView.setImageResource(R.drawable.fhair_short_blonde);
            else if(color=="Blue")
                imageView.setImageResource(R.drawable.fhair_short_blue);
            else if(color=="Brown")
                (...)
                break;
        case "Female Medium":
            if(color=="Black")
                imageView.setImageResource(R.drawable.fhair_med_black);
            else if(color=="Blonde")
                imageView.setImageResource(R.drawable.fhair_med_blonde);
            else if(color=="Blue")
                imageView.setImageResource(R.drawable.fhair_med_blue);
            else if(color=="Brown")
                (...)
                break;
        case "Female Long":
               (...)
        default:
            break;
    }
}

public void onNothingSelected(AdapterView<?> parent){

}

我需要能够同时知道在两个微调器上选择了什么。

我在活动时收到此错误报告（btw在活动打开后立即崩溃）

    04-27 15:39:17.165 9934-9934/cameron.myapplication E/AndroidRuntime: FATAL EXCEPTION: main
                                                                 Process: cameron.myapplication, PID: 9934
                                                                 java.lang.IndexOutOfBoundsException: Invalid index 0, size is 0
                                                                     at java.util.ArrayList.throwIndexOutOfBoundsException(ArrayList.java:255)
                                                                     at java.util.ArrayList.get(ArrayList.java:308)
                                                                     at cameron.myapplication.HeadZoom.onItemSelected(HeadZoom.java:83)
                                                                     at android.widget.AdapterView.fireOnSelected(AdapterView.java:931)
                                                                     at android.widget.AdapterView.dispatchOnItemSelected(AdapterView.java:920)
                                                                     at android.widget.AdapterView.-wrap1(AdapterView.java)
                                                                     at android.widget.AdapterView$SelectionNotifier.run(AdapterView.java:890)
                                                                     at android.os.Handler.handleCallback(Handler.java:739)
                                                                     at android.os.Handler.dispatchMessage(Handler.java:95)
                                                                     at android.os.Looper.loop(Looper.java:148)
                                                                     at android.app.ActivityThread.main(ActivityThread.java:5417)
                                                                     at java.lang.reflect.Method.invoke(Native Method)
                                                                     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
                                                                     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)

Answer 1

因为您正在使用==运算符比较两个String对象。如果在两个String对象之间使用==运算符，它将检查两个字符串是否具有相同的引用，而不管它们保存的值。

你需要像这样比较：

if(color.equalsIgnoreCase("Black"))

OR

if(color.equals("Black"))

这将检查String对象值而不是其引用。

正如@sasikumar建议也删除那个局部变量

List<String> hairColorArray = new ArrayList<>();
List<String> hairTypeArray = new ArrayList<String>();

Answer 2

原因是已经初始化全局的ArrayList。

BABA

因为oncreate方法只取全局变量值。但是你只添加了本地arraylist oncreate方法的值。所以在oncreate方法中删除以下代码

 private List<String> hairTypeArray = new ArrayList<String>();
 private List<String> hairColorArray = new ArrayList<String>();

Android：基于两个微调器选择的组合的动作

2 个答案: