java - ANDROID:在单个可点击的 TextView 上交换字符串

Question

闪存卡 App

你好，我正在制作一个抽认卡应用程序，我想在用户点击主 fcfront_textView 时交换字符串。主要问题是 switch 语句，因为它没有正确检测不同的情况和/或没有正确交换字符串。我尝试了我所知道的一切，下面是它从前向后交换但不向后交换的最佳情况。

我的想法是，我将预先存储问题/答案字符串，并且 onClick 应该在 Q/A 之间交换。最终我希望 nextButton/prevButton 在一对可点击的 textView 字符串(Q/A)之间导航，并能够添加 QA，但我不知道如何实现。

感谢您的宝贵时间，请按照我的代码操作:

---

.java

public class MainActivity extends splashActivity {


    Button closeButton, addButton, prevButton, nextButton;
    TextView QAText, answerText;

    @Override
    protected void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_flashcard);

        QAText = (TextView) findViewById(R.id.fcfront_textView);
        answerText = (TextView) findViewById(R.id.fcfront_textView); //not used anywhere atm


        QAText.setOnClickListener(new View.OnClickListener()
        {
            //function to toggle between Q/A
            public void onClick(View v)
            {
                // exchange();

                //switch(Resources.getSystem().getString(R.string.fc_back))  //bad!

                 //switch(QAText.getText().toString()) //did not work: char != string
                switch(R.string.fc_front)
                {
                    case R.string.fc_front:
                        ((TextView)findViewById(R.id.fcfront_textView)).setText(R.string.fc_back);
                        Toast.makeText(getApplicationContext(), R.string.fc_front , Toast.LENGTH_LONG).show();
                        //QAText.setVisibility(v.GONE);
                        break;

                    case R.string.fc_back:
                        ((TextView)findViewById(R.id.fcfront_textView)).setText(R.string.fc_front);
                        Toast.makeText(getApplicationContext(), "SWAPPING: back-to-front", Toast.LENGTH_LONG).show();
                        break;
                }
                Toast.makeText(getApplicationContext(), "OUT OF THE SWITCH", Toast.LENGTH_LONG).show();

            }
        });

    }


    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();
        if (id == R.id.action_settings) {
            return true;
        }
        return super.onOptionsItemSelected(item);
    }


    //gets click event directly from xml
    public void next_Clicked(View view)
    {
        //test:
        Toast.makeText(getApplicationContext(), "Next button works!!", Toast.LENGTH_LONG).show();
    }

    public void prev_Clicked(View view)
    {
        //test:
        Toast.makeText(getApplicationContext(), "Prev button works!!", Toast.LENGTH_LONG).show();
    }


    //supposed to swap strings (did not work)
    private void exchange()
    {
        String frontstring = getString(R.string.fc_front);
        String backstring = getString(R.string.fc_back);
        String displaystring = getString(R.string.action_settings);


        //test:
        // Toast.makeText(getApplicationContext(), "textView works!", Toast.LENGTH_LONG).show();

            if (frontstring != displaystring) {
                //displaystring =  getString(R.string.fc_back);
                ((TextView) findViewById(R.id.fcfront_textView)).setText(R.string.fc_back);

            } else {
                //displaystring = getString(R.string.fc_front);
                ((TextView) findViewById(R.id.fcfront_textView)).setText(R.string.fc_front);
            }


//switch case by id did not work:
//        switch(view.getId())
//        {
//            case R.id.fcfront_textView:
//                TextView txtView = (TextView)findViewById(R.id.fcfront_textView);
//                txtView.setVisibility(View.GONE);
//                break;
//        }
        Toast.makeText(getApplicationContext(), "end of exchange()", Toast.LENGTH_LONG).show();

    }




} //end of main

---

布局.xml

<RelativeLayout 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"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    android:paddingBottom="@dimen/activity_vertical_margin"
    tools:context=".MyActivity"
    android:clickable="true"
    android:id="@+id/background"
    android:background="#ff80b5ff">

    <TextView
        android:text="@string/fc_front"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/fcfront_textView"
        android:layout_centerVertical="true"
        android:textSize="30sp"
        android:layout_centerHorizontal="true"
        android:linksClickable="true"
        android:textIsSelectable="false"
        android:singleLine="true"
        android:onClick="OnClick"

        android:clickable="true" />

    <!--<TextView-->
        <!--android:text="@string/fc_back"-->
        <!--android:layout_width="wrap_content"-->
        <!--android:layout_height="wrap_content"-->
        <!--android:layout_below="@+id/fcfront_textView"-->
        <!--android:layout_centerHorizontal="true"-->
        <!--android:id="@+id/fcback_textView"-->
        <!--android:textSize="30sp"-->
        <!--android:linksClickable="true"-->
        <!--android:textIsSelectable="false"-->
        <!--android:singleLine="true"-->
        <!--android:clickable="true" />-->

    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/main_prev"
        android:id="@+id/prevbutton"
        android:layout_alignParentBottom="true"
        android:layout_alignParentLeft="true"
        android:gravity="bottom|center"
        android:layout_weight="1"
        android:textSize="30sp"
        android:layout_alignParentStart="true"
        android:onClick="prev_Clicked"
        />


    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/main_next"
        android:id="@+id/nextbutton"
        android:layout_alignParentBottom="true"
        android:layout_alignParentRight="true"
        android:gravity="bottom|center"
        android:layout_weight="1"
        android:textSize="30sp"
        android:hint="Browse +"
        android:onClick="next_Clicked"


    android:layout_alignParentEnd="true" />


<Button
    style="?android:attr/buttonStyleSmall"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="X"
    android:id="@+id/closebutton"
    android:layout_alignParentTop="true"
    android:layout_alignParentRight="true"
    android:gravity="center"
    android:textSize="30sp"

    android:layout_alignParentEnd="true" />

<Button
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="+"
    android:id="@+id/plusbutton"
    android:layout_alignParentTop="true"
    android:layout_alignParentLeft="true"
    android:gravity="center"
    android:textSize="30sp"

    android:layout_alignParentStart="true" />

</RelativeLayout>

---

字符串.xml

<?xml version="1.0" encoding="utf-8"?>
<resources>

    <string name="app_name">CSCE305HW1</string>
    <string name="fc_front">FLASHCARD: FRONT</string>
    <string name="fc_back">FLASHCARD: BACK</string>
    <string name="Q1">Question1</string>
    <string name="A1">Answer1</string>
    <string name="Q2">Question2</string>
    <string name="A2">Answer2 </string>
    <string name="action_settings">Nothing here yet</string>
    <string name="title_activity_main">MainActivity</string>
    <string name="title_activity_goodbye">goodbye</string>
    <string name="main_next">Next</string>
    <string name="main_prev">Previous</string>

</resources>

Answer 1

尝试使用 if-else 代替 switch 进行字符串比较:

if(QAText.getText().toString().equals(getString(R.string.fc_front))){
   QAText.setText(R.string.fc_back);
   Toast.makeText(getApplicationContext(), R.string.fc_front , Toast.LENGTH_LONG).show();
}else{
   QAText.setText(R.string.fc_front);
   Toast.makeText(getApplicationContext(), "SWAPPING: back-to-front", Toast.LENGTH_LONG).show();
}