4

“我们已经有一个 EditText,只能有一个”

我为我的应用程序(LoginFragment)构建了一个片段,它可以处理两种主要的身份验证模式;即登录并注册用户。有一个按钮允许用户在“登录模式”和“注册”模式之间切换。每个“模式”都有一些其他视图不需要的额外视图。因此,有必要在切换模式时添加和删除视图。

我在 TextInputLayout 布局中使用 EditText 视图。当我执行以下操作时,我的应用程序崩溃:

  • 以编程方式添加 EditText
  • 以编程方式删除 EditText
  • 以编程方式添加 EditText -> 崩溃

这是我得到的错误是:

java.lang.IllegalArgumentException: We already have an EditText, can only have one
                at android.support.design.widget.TextInputLayout.setEditText(TextInputLayout.java:166)
                at android.support.design.widget.TextInputLayout.addView(TextInputLayout.java:155)
                at android.view.ViewGroup.addView(ViewGroup.java:3985)
                at android.view.ViewGroup.addView(ViewGroup.java:3961)
                at com.mydomain.myapp.fragments.LoginFragment.showActivateAccountViews(LoginFragment.java:317)

这来自 android.support.design.widget.TextInputLayout 它有一个内部私有 EditText 变量,该变量在添加视图时设置(下面的源代码)。看来,当我第二次尝试将视图添加到 TextInputLayout 时,mEditText 变量已经设置了。该类没有自己的 .removeView() 方法,所以我不知道应该如何删除它?

我怀疑我错误地删除了 EditText 视图,但无法弄清楚我做错了什么。我还阅读了其他一些有关删除视图的 Stack Overflow 帖子,但这些方法也没有解决问题。

有人对我如何使它起作用有任何想法吗?

下面是我自己的代码供参考。

登录片段.java

...
import android.support.design.widget.TextInputLayout;
import android.widget.EditText;

public class LoginFragment extends Fragment {

    private RelativeLayout mContainer;

    ...

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {

        final View view = inflater.inflate(R.layout.fragment_login, container, false);
        mContainer = ((RelativeLayout) view.findViewById(R.id.login_container));

        showLoginViews();

        LayoutTransition layoutTransition = mContainer.getLayoutTransition();
        layoutTransition.enableTransitionType(LayoutTransition.CHANGING);

        return view;
    }

    /**
     * Show the view elements for Login mode
     */
    private void showLoginViews() {

        LayoutInflater li = (LayoutInflater)getActivity().getSystemService(
                Context.LAYOUT_INFLATER_SERVICE);

        // Configure the button for the primary action
        Button loginButton = (Button)mContainer.findViewById(R.id.button_login_fragment_primary_action);
        ...

        // Configure the toggle button to navigate to Activate Account mode
        TextView toggleButton = (TextView)mContainer.findViewById(R.id.button_toggle_mode);
        toggleButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                LoginFragment.this.showActivateAccountViews();
            }
        });
        toggleButton.setText(getResources().getString(R.string.action_activate_account));

        // Hide the Member ID EditText
        ((TextInputLayout)mContainer.findViewById(R.id.member_id_inputlayout)).removeView(mContainer.findViewById(R.id.editText_member_id_field));
    }

    /**
     * Show view elements for Activate Account mode
     */
    private void showActivateAccountViews() {
        LayoutInflater li = (LayoutInflater)getActivity().getSystemService(
                Context.LAYOUT_INFLATER_SERVICE);

        // Configure the primary button for the primary action - Activate Account
        Button activateAccountButton = (Button)mContainer.findViewById(R.id.button_login_fragment_primary_action);
        ...

        // Add the Member ID EditText
        ((TextInputLayout)mContainer.findViewById(R.id.member_id_inputlayout)).addView(li.inflate(R.layout.login_member_id_element_layout, (ViewGroup)mContainer.findViewById(R.id.member_id_inputlayout), false));

        // Configure the toggle button to navigate to Login mode
        TextView toggleButton = (TextView)mContainer.findViewById(R.id.button_toggle_mode);
        toggleButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                LoginFragment.this.showLoginViews();
            }
        });
        toggleButton.setText(getResources().getString(R.string.action_login));
    }

    ...
}

login_member_id_element_layout.xml

<?xml version="1.0" encoding="utf-8"?>
<EditText xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/editText_member_id_field"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:hint="@string/member_id" />

login_fragment.xml

<android.support.design.widget.CoordinatorLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    tools:context="com.mydomain.myapp.fragments.LoginFragment">

    <RelativeLayout
        android:id="@+id/login_container"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:animateLayoutChanges="true">

        <!--placeholder layout with params for activate account elements-->
        <android.support.design.widget.TextInputLayout
            android:id="@+id/member_id_inputlayout"
            android:layout_width="match_parent"
            android:layout_height="wrap_content">
            <!-- a view can be added here-->
        </android.support.design.widget.TextInputLayout>

        <android.support.design.widget.TextInputLayout
            android:id="@+id/email_inputlayout"
            android:layout_width="match_parent"
            android:layout_height="wrap_content">

            <EditText
                android:id="@+id/editText_email_field"
                android:layout_width="match_parent"
                android:layout_height="match_parent"
                android:inputType="textEmailAddress" />

        </android.support.design.widget.TextInputLayout>

        <Button
            android:id="@+id/button_login_fragment_primary_action"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_below="@id/password_inputlayout"
            android:text="@string/action_login" />

        <!-- Toggle button for Login/Activate Account-->
        <TextView
            android:id="@+id/button_toggle_mode"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="@string/action_activate_account" />

    </RelativeLayout>

</android.support.design.widget.CoordinatorLayout>

android.support.design.widget.TextInputLayout(来自最新的22.2.1支持库)

public class TextInputLayout extends LinearLayout {

    private EditText mEditText;

    ...

    public void addView(View child, int index, LayoutParams params) {
        if(child instanceof EditText) {
            android.widget.LinearLayout.LayoutParams params1 = this.setEditText((EditText)child, params);
            super.addView(child, 0, params1);
        } else {
            super.addView(child, index, params);
        }

    }

    private android.widget.LinearLayout.LayoutParams setEditText(EditText editText, LayoutParams lp) {
        if(this.mEditText != null) {
            throw new IllegalArgumentException("We already have an EditText, can only have one");
        } else {
            this.mEditText = editText;
            this.mCollapsingTextHelper.setExpandedTextSize(this.mEditText.getTextSize());
            this.mEditText.addTextChangedListener(new TextWatcher() {
                public void afterTextChanged(Editable s) {
                    TextInputLayout.this.mHandler.sendEmptyMessage(0);
                }

                public void beforeTextChanged(CharSequence s, int start, int count, int after) {
                }

                public void onTextChanged(CharSequence s, int start, int before, int count) {
                }
            });
            this.mDefaultTextColor = this.mEditText.getHintTextColors().getDefaultColor();
            this.mEditText.setOnFocusChangeListener(new OnFocusChangeListener() {
                public void onFocusChange(View view, boolean focused) {
                    TextInputLayout.this.mHandler.sendEmptyMessage(0);
                }
            });
            if(TextUtils.isEmpty(this.mHint)) {
                this.setHint(this.mEditText.getHint());
                this.mEditText.setHint((CharSequence)null);
            }

            if(this.mErrorView != null) {
                ViewCompat.setPaddingRelative(this.mErrorView, ViewCompat.getPaddingStart(this.mEditText), 0, ViewCompat.getPaddingEnd(this.mEditText), this.mEditText.getPaddingBottom());
            }

            this.updateLabelVisibility(false);
            android.widget.LinearLayout.LayoutParams newLp = new android.widget.LinearLayout.LayoutParams(lp);
            Paint paint = new Paint();
            paint.setTextSize(this.mCollapsingTextHelper.getExpandedTextSize());
            newLp.topMargin = (int)(-paint.ascent());
            return newLp;
        }
    }
}
4

2 回答 2

3

com.android.support.design 库 (v22.2.1) 中似乎存在限制。您不能在运行时直接删除然后将 EditText 添加到 TextInputLayout。您可以在此处为这个错误加注星标。

我已经为这个问题设计了一个解决方法。我修改了 xml 布局,以便在运行时从 TextInputLayout 中添加/删除 EditText 视图(这不起作用),我们将 TextInputLayout 本身添加/删除到 LinearLayout 持有人。使用此解决方案,我们永远不需要从 TextInputLayout 中实际删除 EditText。

关于这个解决方案唯一需要注意的是,它使您的视图层次结构比其他需要的更深。因此,如果您已经遇到 UI 性能问题,请记住这一点。如果当您阅读本文并且 com.android.support.design v22.2.1 版本可用时,可能值得检查此问题是否已解决。

否则,请参阅下面的示例代码以了解我的解决方法的实现。

登录片段.java

import android.support.design.widget.TextInputLayout;
import android.widget.EditText;

public class LoginFragment extends Fragment {

    private RelativeLayout mContainer;

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {

        final View view = inflater.inflate(R.layout.fragment_login, container, false);
        mContainer = ((RelativeLayout) view.findViewById(R.id.login_container));

        showLoginViews();

        LayoutTransition layoutTransition = mContainer.getLayoutTransition();
        layoutTransition.enableTransitionType(LayoutTransition.CHANGING);

        return view;
    }

    /**
     * Show the view elements for Login mode
     */
    private void showLoginViews() {

        LayoutInflater li = (LayoutInflater)getActivity().getSystemService(
                Context.LAYOUT_INFLATER_SERVICE);

        // Configure the toggle button to navigate to Activate Account mode
s        TextView toggleButton = (TextView)mContainer.findViewById(R.id.button_toggle_mode);
        toggleButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                LoginFragment.this.showActivateAccountViews();
            }
        });
        toggleButton.setText(getResources().getString(R.string.action_activate_account));

        // Hide the Member ID EditText
        ((LinearLayout)mContainer.findViewById(R.id.member_id_holderlayout)).removeView(mContainer.findViewById(R.id.member_id_inputlayout));
    }

    /**
     * Show view elements for Activate Account mode
     */
    private void showActivateAccountViews() {
        LayoutInflater li = (LayoutInflater)getActivity().getSystemService(
                Context.LAYOUT_INFLATER_SERVICE);

        // Configure the primary button for the primary action - Activate Account
        Button activateAccountButton = (Button)mContainer.findViewById(R.id.button_login_fragment_primary_action);

        // Add the Member ID EditText
        ((LinearLayout)mContainer.findViewById(R.id.member_id_holderlayout)).addView(li.inflate(R.layout.login_member_id_element_layout, (ViewGroup) mContainer.findViewById(R.id.member_id_inputlayout), false));

        // Configure the toggle button to navigate to Login mode
        TextView toggleButton = (TextView)mContainer.findViewById(R.id.button_toggle_mode);
        toggleButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                LoginFragment.this.showLoginViews();
            }
        });
        toggleButton.setText(getResources().getString(R.string.action_login));
    }
}

login_member_id_element_layout.xml

<?xml version="1.0" encoding="utf-8"?>
<android.support.design.widget.TextInputLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/member_id_inputlayout"
    android:layout_width="match_parent"
    android:layout_height="wrap_content">

    <EditText
        android:id="@+id/editText_member_id_field"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:hint="@string/member_id" />

</android.support.design.widget.TextInputLayout>

login_fragment.xml

<android.support.design.widget.CoordinatorLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    xmlns:app="http://schemas.android.com/apk/res-auto">

    <RelativeLayout
        android:id="@+id/login_container"
        android:layout_width="match_parent"
        android:layout_height="match_parent">

        <!--placeholder for TextInputLayout to be dynamically added at runtime-->
        <LinearLayout
            android:id="@+id/member_id_holderlayout"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:orientation="vertical">
            <!-- a login_member_id_element_layout can be dynamically added/removed here at runtime-->
        </LinearLayout>


        <!--TextInputLayout for static fields, the EditText is not removed at runtime-->
        <android.support.design.widget.TextInputLayout
            android:id="@+id/email_inputlayout"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_below="@id/member_id_holderlayout">

            <EditText
                android:id="@+id/editText_email_field"
                android:layout_width="match_parent"
                android:layout_height="match_parent"
                android:drawablePadding="@dimen/edittext_drawable_padding"
                android:drawableStart="?emailIcon"
                android:focusable="true"
                android:hint="Email"
                android:inputType="textEmailAddress" />
        </android.support.design.widget.TextInputLayout>

    </RelativeLayout>

</android.support.design.widget.CoordinatorLayout>
于 2015-07-29T16:41:44.290 回答
0

TextInputLayout恭喜,您(也许?)发现了一个可能的错误(或者我应该说删除's时的非预期行为EditText?)

您可以看到这removeView()是 ViewGroup 中的一个方法。它将您从ViewGroupView的子视图数组中删除,但不是您对.InputTextLayoutEditText

那我该怎么办?

您必须扩展TextInputLayout并创建自己的设置super.mEditTextnull. 问题是您仍然需要调用这两个方法,因为仅设置Layout对 null 的引用可能会使您的旧布局在您的应用程序生命周期中留在内存中。

于 2015-07-23T17:07:03.970 回答