android - 在 Android 中根据条件隐藏和显示布局

Question

我是 Android 新手。我想根据 if else 条件隐藏和显示 Linearlayout。在我的应用程序中，我使用了 1 个微调器。根据选定的微调器值，我希望我的下一个布局隐藏或可见，但如果它一旦消失，它就不会再次可见。

我的代码是:

    public class Expense extends Activity{
    Spinner datype;

    public void onCreate(Bundle b){
    super.onCreate(b);
    setContentView(R.layout.expense);
    mainlayout=(LinearLayout)this.findViewById(R.id.layout1);
    datype=(Spinner)findViewById(R.id.da_type);
    List<String>data1=new ArrayList<String>();
    data1.add("Local");
    data1.add("Ex-Station Double Side");
    data1.add("Ex-Station Single Side");
    data1.add("Out-Station Double Side");
    data1.add("Out-Station Single Side");
    ArrayAdapter<String>adapter=new ArrayAdapter<String>(this,android.R.layout.simple_spinner_item,data1);
    adapter.setDropDownViewResource(android.R.layout.simple_list_item_single_choice);
    datype.setAdapter(adapter);
    if(datype.getSelectedItem().toString().equals("Local")){

        mainlayout.setVisibility(LinearLayout.GONE);
    }
    else 
        mainlayout.setVisibility(LinearLayout.VISIBLE);


}

}

Answer 1

您需要设置 OnItemSelectedListener 并更改那里的布局。以下是您的 Activity 实现 OnItemSelectedListener 的示例。

public class Expense extends Activity implements OnItemSelectedListener {

private Spinner datype;
private LinearLayout mainlayout;

public void onCreate(Bundle b) {
    super.onCreate(b);
    setContentView(R.layout.expense);
    mainlayout=(LinearLayout)this.findViewById(R.id.layout1);
    datype=(Spinner)findViewById(R.id.da_type);
    List<String>data1=new ArrayList<String>();
    data1.add("Local");
    data1.add("Ex-Station Double Side");
    data1.add("Ex-Station Single Side");
    data1.add("Out-Station Double Side");
    data1.add("Out-Station Single Side");
    ArrayAdapter<String>adapter=new ArrayAdapter<String (this,android.R.layout.simple_spinner_item,data1);
    adapter.setDropDownViewResource(android.R.layout.simple_list_item_single_choice);
    datype.setAdapter(adapter);
    if(datype.getSelectedItem().toString().equals("Local")){
        mainlayout.setVisibility(LinearLayout.GONE);
    }
    else {
        mainlayout.setVisibility(LinearLayout.VISIBLE);
    } 

    // here we set the listener
    datatype.setOnItemSelectedListener(this);
}

public void onItemSelected(AdapterView<?> parent, View view, int pos, long id) {
    // here we change layout visibility again
    if(datype.getSelectedItem().toString().equals("Local")){
        mainlayout.setVisibility(LinearLayout.GONE);
    }
    else {
        mainlayout.setVisibility(LinearLayout.VISIBLE);
    } 
}

public void onNothingSelected(AdapterView<?> parent) {
}
}