java - 如何替换 Activity 中的 textChangedListener

Question

对于我的 android 应用程序，每次 RadioButton 切换状态时，我都需要更改 textChangedListener。有 4 个可能的按钮，每个按钮都有一个相应的 EditText 框。我目前只实现了 4 个按钮中的 2 个，当我从一个已实现的按钮(即按钮 1)切换到一个未实现的按钮时，没有问题。但是，当我尝试选择另一个已实现的按钮(即按钮 2)时，应用程序崩溃了。

下面是我的一些代码，显示了我的 textChangedListener 的实现。

public TextWatcher last;
public TextWatcher _list1;
public TextWatcher _list2;

public EditText active;
public RadioButton checked;

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);

    final EditText t1 = (EditText) findViewById(R.id.1text);
    final EditText t2 = (EditText) findViewById(R.id.2text);
    final EditText t3 = (EditText) findViewById(R.id.3text);
    final EditText t4 = (EditText) findViewById(R.id.4text);

    final RadioGroup g1 = (RadioGroup) findViewById(R.id.radioGroup1);
    g1.setOnCheckedChangeListener(new OnCheckedChangeListener() {
        public void onCheckedChanged(RadioGroup group, int checkedId) {
            checked = (RadioButton)g1.findViewById(g1.getCheckedRadioButtonId());

            if (((String) checked.getText()).equalsIgnoreCase("But1"))
            {
                active.removeTextChangedListener(last);
                active = t1;
                active.setText("");
                active.addTextChangedListener(_list1);
                last = _list1;
            }
            else if (((String) checked.getText()).equalsIgnoreCase("But2"))
            {
                active.removeTextChangedListener(last);
                active = t2;
                active.setText("");
                active.addTextChangedListener(_list2);
                last = _list2;
            }
            else if (((String) checked.getText()).equalsIgnoreCase("But3"))
            {
                active = t3;
            }
            else if (((String) checked.getText()).equalsIgnoreCase("But4"))
            {
                active = t4;
            }
        }
    });

    checked = (RadioButton)g1.findViewById(g1.getCheckedRadioButtonId());

    active = t1;
    active.setText("");
    _list1 = (new TextWatcher(){
        public void afterTextChanged(Editable s) {}
        public void beforeTextChanged(CharSequence s, int start, int count, int after){}
        public void onTextChanged(CharSequence s, int start, int before, int count)
        {
            %Useful stuff
        }
    });
    _list2 = (new TextWatcher(){
        public void afterTextChanged(Editable s) {}
        public void beforeTextChanged(CharSequence s, int start, int count, int after){}
        public void onTextChanged(CharSequence s, int start, int before, int count)
        {
            %Different useful stuff
        }
    });
    active.addTextChangedListener(_list1);
    last = _list1;
}

同样，我的问题是，当我尝试从一个 TextChangedListener 切换到另一个时，无论每个监听器中实现了什么，我的应用程序都会崩溃。对于 TextChangeListener 的特性和实现，我觉得有一些非常明显的东西被我忽略了。任何帮助将不胜感激!

谢谢!

我的错误日志:(注意: Activity 名称是“Number”)

01-31 08:29:17.673: INFO/ActivityManager(59): Displayed activity com.ikiar.engtools/.Number: 659 ms (total 659 ms)
01-31 08:29:24.083: DEBUG/AndroidRuntime(276): Shutting down VM
01-31 08:29:24.083: WARN/dalvikvm(276): threadid=1: thread exiting with uncaught exception (group=0x4001d800)
01-31 08:29:24.103: ERROR/AndroidRuntime(276): FATAL EXCEPTION: main
01-31 08:29:24.103: ERROR/AndroidRuntime(276): java.lang.ClassCastException: android.text.SpannableStringBuilder
01-31 08:29:24.103: ERROR/AndroidRuntime(276):     at com.ikiar.engtools.Number$3.onTextChanged(Number.java:122)
01-31 08:29:24.103: ERROR/AndroidRuntime(276):     at android.widget.TextView.sendOnTextChanged(TextView.java:6131)
01-31 08:29:24.103: ERROR/AndroidRuntime(276):     at android.widget.TextView.setText(TextView.java:2691)
01-31 08:29:24.103: ERROR/AndroidRuntime(276):     at android.widget.TextView.setText(TextView.java:2556)
01-31 08:29:24.103: ERROR/AndroidRuntime(276):     at android.widget.EditText.setText(EditText.java:75)
01-31 08:29:24.103: ERROR/AndroidRuntime(276):     at android.widget.TextView.setText(TextView.java:2531)
01-31 08:29:24.103: ERROR/AndroidRuntime(276):     at com.ikiar.engtools.Number$1.onCheckedChanged(Number.java:71)
01-31 08:29:24.103: ERROR/AndroidRuntime(276):     at android.widget.RadioGroup.setCheckedId(RadioGroup.java:172)
01-31 08:29:24.103: ERROR/AndroidRuntime(276):     at android.widget.RadioGroup.access$600(RadioGroup.java:52)
01-31 08:29:24.103: ERROR/AndroidRuntime(276):     at android.widget.RadioGroup$CheckedStateTracker.onCheckedChanged(RadioGroup.java:342)
01-31 08:29:24.103: ERROR/AndroidRuntime(276):     at android.widget.CompoundButton.setChecked(CompoundButton.java:127)
01-31 08:29:24.103: ERROR/AndroidRuntime(276):     at android.widget.CompoundButton.toggle(CompoundButton.java:86)
01-31 08:29:24.103: ERROR/AndroidRuntime(276):     at android.widget.RadioButton.toggle(RadioButton.java:69)
01-31 08:29:24.103: ERROR/AndroidRuntime(276):     at android.widget.CompoundButton.performClick(CompoundButton.java:98)
01-31 08:29:24.103: ERROR/AndroidRuntime(276):     at android.view.View$PerformClick.run(View.java:8816)
01-31 08:29:24.103: ERROR/AndroidRuntime(276):     at android.os.Handler.handleCallback(Handler.java:587)
01-31 08:29:24.103: ERROR/AndroidRuntime(276):     at android.os.Handler.dispatchMessage(Handler.java:92)
01-31 08:29:24.103: ERROR/AndroidRuntime(276):     at android.os.Looper.loop(Looper.java:123)
01-31 08:29:24.103: ERROR/AndroidRuntime(276):     at android.app.ActivityThread.main(ActivityThread.java:4627)
01-31 08:29:24.103: ERROR/AndroidRuntime(276):     at java.lang.reflect.Method.invokeNative(Native Method)
01-31 08:29:24.103: ERROR/AndroidRuntime(276):     at java.lang.reflect.Method.invoke(Method.java:521)
01-31 08:29:24.103: ERROR/AndroidRuntime(276):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
01-31 08:29:24.103: ERROR/AndroidRuntime(276):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
01-31 08:29:24.103: ERROR/AndroidRuntime(276):     at dalvik.system.NativeStart.main(Native Method)
01-31 08:29:24.113: WARN/ActivityManager(59):   Force finishing activity com.ikiar.engtools/.Number
01-31 08:29:24.523: INFO/ARMAssembler(59): generated scanline__00000077:03515104_00000000_00000000 [ 33 ipp] (47 ins) at [0x3659b0:0x365a6c] in 365498 ns
01-31 08:29:24.653: WARN/ActivityManager(59): Activity pause timeout for HistoryRecord{450232b0 com.ikiar.engtools/.Number}

Answer 1

我认为您的布局文件中存在一些问题。

我编辑了代码并创建了 main.xml 并将 EditText id 从 1text、2text、3text、4text 更改为 text1、text2、text3、text4

下面给出的代码有效。

Activity 代码如下

    public TextWatcher last;
    public TextWatcher _list1;
    public TextWatcher _list2;

    public EditText active;
    public RadioButton checked;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        final EditText t1 = (EditText) findViewById(R.id.text1);
        final EditText t2 = (EditText) findViewById(R.id.text2);
        final EditText t3 = (EditText) findViewById(R.id.text3);
        final EditText t4 = (EditText) findViewById(R.id.text4);
        final Context c = getApplicationContext();

        final RadioGroup g1 = (RadioGroup) findViewById(R.id.radioGroup1);
        g1.setOnCheckedChangeListener(new OnCheckedChangeListener() {
            public void onCheckedChanged(RadioGroup group, int checkedId) {
                checked = (RadioButton) g1.findViewById(g1.getCheckedRadioButtonId());

                if (((String) checked.getText()).equalsIgnoreCase("But1")) {
                    active.removeTextChangedListener(last);
                    active = t1;
                    active.setText("");
                    active.addTextChangedListener(_list1);
                    last = _list1;
                } else if (((String) checked.getText()).equalsIgnoreCase("But2")) {
                    active.removeTextChangedListener(last);
                    active = t2;
                    active.setText("");
                    active.addTextChangedListener(_list2);
                    last = _list2;
                } else if (((String) checked.getText()).equalsIgnoreCase("But3")) {
                    active = t3;
                } else if (((String) checked.getText()).equalsIgnoreCase("But4")) {
                    active = t4;
                }
            }
        });

        checked = (RadioButton) g1.findViewById(g1.getCheckedRadioButtonId());

        active = t1;
        active.setText("");
        _list1 = (new TextWatcher() {
            public void afterTextChanged(Editable s) {
            }

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

            public void onTextChanged(CharSequence s, int start, int before, int count) {
                Toast.makeText(c, "onTextChanged called(_list1 watcher)", Toast.LENGTH_SHORT).show();
            }
        });
        _list2 = (new TextWatcher() {
            public void afterTextChanged(Editable s) {
            }

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

            public void onTextChanged(CharSequence s, int start, int before, int count) {
                Toast.makeText(c, "onTextChanged called(_list2 watcher)", Toast.LENGTH_SHORT).show();
            }
        });
        active.addTextChangedListener(_list1);
        last = _list1;
    }

}

以下是main.xml文件的代码

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical" >

    <RadioGroup
        android:id="@+id/radioGroup1"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" >

        <RadioButton
            android:id="@+id/But1"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="But1" />

        <EditText
            android:id="@+id/text1"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:inputType="text" />

        <RadioButton
            android:id="@+id/But2"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="But2" />

        <EditText
            android:id="@+id/text2"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:inputType="text" />

        <RadioButton
            android:id="@+id/But3"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="But3" />

        <EditText
            android:id="@+id/text3"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:inputType="text" />

        <RadioButton
            android:id="@+id/But4"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="But4" />

        <EditText
            android:id="@+id/text4"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:inputType="text" >
        </EditText>
    </RadioGroup>

</LinearLayout>

试试这个。它的工作。