Question

我正在尝试在Android中运行程序，以便在用户按下全部清除按钮时清除EditText字段中的所有文本。下面是我到目前为止的代码，目前它没有按计划运行。我是java和adroid app开发的新手。如果可能的话，请通过示例告诉我如何解决这个问题。非常感谢提前。

CEMMainActivity.java

public class CEMMainActivity extends ActionBarActivity {
@Override
protected void onCreate(Bundle savedInstanceState) { // runs every time the app runs
    super.onCreate(savedInstanceState); // loads saved instant state
    setContentView(R.layout.activity_cemmain);//sets what the app will look like based on the graphical design created

    if (savedInstanceState == null) {// action if app does not start up correctly
        getSupportFragmentManager().beginTransaction()
                .add(R.id.container, new PlaceholderFragment()).commit();
    }

    // Clears all text in EditText fields

    Button clearalltext  = (Button) findViewById(R.id.cleartext); 
    clearalltext.setOnClickListener(new OnClickListener() {
        public void onClick(View c) {           
        ViewGroup group = (ViewGroup) findViewById(R.id.cleartext);
        clearText(group);       
        });
    }

        private void clearText((ViewGroup)group); {
            // TODO Auto-generated method stub
            for (int i = 0, count = group.getChildCount(); i < count; ++i) {
        View view = group.getChildAt(i);
        if (view instanceof EditText) {
            ((EditText)view).setText("");

        ViewGroup view;
        if(view instanceof ViewGroup && (((ViewGroup)view).getChildCount() > 0))
            clearText((ViewGroup)group);
        }
        }
            }

fragment_cemmain.xml

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context="clinical.equipment.monitor.CEMMainActivity$PlaceholderFragment" >
.....

<Button
    android:id="@+id/cleartext"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignParentLeft="true"
    android:layout_below="@+id/findequip"
    android:layout_marginTop="56dp"
    android:onClick="cleartext"
    android:text="@string/cleartext" />

....

</RelativeLayout>

Answer 1

(ViewGroup) findViewById(R.id.cleartext);我认为明文是按钮而不是视图组，你可以使用onclick参数c的getParent（）方法，如 c.getParent（），返回ViewGroup Relative Layout然后你可以获取所有将由您在clearText方法中定义的孩子......

或者你也可以给relativelayout提供id

  // Clears all text in EditText fields

    Button clearalltext  = (Button) findViewById(R.id.cleartext); 
    clearalltext.setOnClickListener(new OnClickListener() {
        public void onClick(View c) {           
        ViewGroup group = (ViewGroup) c.getParent();
        clearText(group);       
        });
    }

Answer 2

我认为你的问题是将按钮ID传递给视图组，因此它的子计数将为零。请将父布局ID传递给视图组。对以下内容进行更改

ViewGroup group = (ViewGroup) findViewById(R.id.cleartext);

用您的父布局ID替换明文。即RelativeLayout id

Answer 3

 ViewGroup group = (ViewGroup) findViewById(R.id.cleartext);

它将访问按钮，只会清除按钮的文本。为RelativeLayout分配一个id，并用它来清除所有孩子的文本。

清除EditText字段按钮中的所有文本

3 个答案: