Android的支持库中有一个SearchView类就是这样做的。(虽然不是从EditText派生的，所以必须使用一个SearchView。OnQueryTextListener代替TextWatcher)

在XML中像这样使用:

  <android.support.v7.widget.SearchView
            android:id="@+id/searchView"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:iconifiedByDefault="false"
            android:queryHint="@string/SearchHint"
            app:iconifiedByDefault="false"
            app:queryHint="@string/SearchHint" />

Drawable x = getResources().getDrawable(R.drawable.x);
x.setBounds(0, 0, x.getIntrinsicWidth(), x.getIntrinsicHeight());
mEditText.setCompoundDrawables(null, null, x, null);

式中x为:

    <EditText
    android:id="@+id/idSearchEditText"
    android:layout_width="match_parent"
    android:layout_height="@dimen/dimen_40dp"
    android:drawableStart="@android:drawable/ic_menu_search"
    android:drawablePadding="8dp"
    android:ellipsize="start"
    android:gravity="center_vertical"
    android:hint="Search"
    android:imeOptions="actionSearch"
    android:inputType="text"
    android:paddingStart="16dp"
    android:paddingEnd="8dp"
/>

EditText mSearchEditText = findViewById(R.id.idSearchEditText);
mSearchEditText.addTextChangedListener(this);
mSearchEditText.setOnTouchListener(this);


@Override
public void afterTextChanged(Editable aEditable) {
    int clearIcon = android.R.drawable.ic_notification_clear_all;
    int searchIcon = android.R.drawable.ic_menu_search;
    if (aEditable == null || TextUtils.isEmpty(aEditable.toString())) {
        clearIcon = 0;
        searchIcon = android.R.drawable.ic_menu_search;
    } else {
        clearIcon = android.R.drawable.ic_notification_clear_all;
        searchIcon = 0;
    }
    Drawable leftDrawable =  null;
    if (searchIcon != 0) {
        leftDrawable = getResources().getDrawable(searchIcon);
    }
    Drawable rightDrawable = null;
    if (clearIcon != 0) {
        rightDrawable = getResources().getDrawable(clearIcon);
    }

    mSearchEditText.setCompoundDrawablesWithIntrinsicBounds(leftDrawable, null, rightDrawable, null);
}


@Override
public boolean onTouch(View aView, MotionEvent aEvent) {
    if (aEvent.getAction() == MotionEvent.ACTION_UP){
        if (aEvent.getX() > ( mSearchEditText.getWidth() - 
         mSearchEditText.getCompoundPaddingEnd())){
            mSearchEditText.setText("");
        }
    }
    return false;
}

我的UI部分如下所示:

<RelativeLayout
    android:layout_width="fill_parent"
    android:layout_height="50dp"
    android:layout_marginTop="9dp"
    android:padding="5dp">

    <EditText
        android:id="@+id/etSearchToolbar"
        android:layout_width="fill_parent"
        android:layout_height="match_parent"
        android:textSize="13dp"
        android:padding="10dp"
        android:textColor="@android:color/darker_gray"
        android:textStyle="normal"
        android:hint="Search"
        android:imeOptions="actionSearch"
        android:inputType="text"
        android:background="@drawable/edittext_bg"
        android:maxLines="1" />

    <ImageView
        android:id="@+id/ivClearSearchText"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerVertical="true"
        android:layout_marginRight="6dp"
        android:src="@drawable/balloon_overlay_close"
        android:layout_alignParentRight="true"
        android:layout_alignParentEnd="true" />
</RelativeLayout>

edittext_bg.xml

<?xml version="1.0" encoding="utf-8"?>
<!-- res/drawable/rounded_edittext_focused.xml -->
<shape xmlns:android="http://schemas.android.com/apk/res/android"
    android:padding="10dp"
    android:shape="rectangle" >

    <solid android:color="#FFFFFF" />

    <stroke
        android:width="1dp"
        android:color="#C9C9CE" />

    <corners
        android:bottomLeftRadius="15dp"
        android:bottomRightRadius="15dp"
        android:topLeftRadius="15dp"
        android:topRightRadius="15dp" />

</shape>

balloon_overlay_close.png

交叉/清除按钮隐藏/显示:

searchBox.addTextChangedListener(new TextWatcher() {
    @Override
    public void beforeTextChanged(CharSequence charSequence, int i, int i1, int i2) {}

    @Override
    public void onTextChanged(CharSequence charSequence, int i, int i1, int i2) {
        if(charSequence.length() > 0){
            clearSearch.setVisibility(View.VISIBLE);
        }else{
            clearSearch.setVisibility(View.GONE);
        }
    }

    @Override
    public void afterTextChanged(Editable editable) {}
});

处理搜索内容(即当用户从软键盘点击搜索时)

searchBox.setOnEditorActionListener(new TextView.OnEditorActionListener() {
    @Override
    public boolean onEditorAction(TextView v, int actionId, KeyEvent event) {
        if (actionId == EditorInfo.IME_ACTION_SEARCH) {
            String contents = searchBox.getText().toString().trim();
            if(contents.length() > 0){
                //do search

            }else{
                //if something to do for empty edittext
            }

            return true;
        }
        return false;
    }
});

明确/十字按钮

clearSearch.setOnClickListener(new View.OnClickListener() {
    @Override
    public void onClick(View view) {
        searchBox.setText("");
    }
});

Android的支持库中有一个SearchView类就是这样做的。(虽然不是从EditText派生的，所以必须使用一个SearchView。OnQueryTextListener代替TextWatcher)

在XML中像这样使用:

  <android.support.v7.widget.SearchView
            android:id="@+id/searchView"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:iconifiedByDefault="false"
            android:queryHint="@string/SearchHint"
            app:iconifiedByDefault="false"
            app:queryHint="@string/SearchHint" />

下面是带有小部件的完整库: https://github.com/opprime/EditTextField

要使用它，你应该添加依赖:

compile 'com.optimus:editTextField:0.2.0'

在layout.xml文件中，你可以设置小部件:

xmlns:app="http://schemas.android.com/apk/res-auto"

app:clearButtonMode,can有这样的值: 从来没有 总是 whileEditing unlessEditing 应用:clearButtonDrawable

实际例子: