实际上，我试图通过引用this question来扩展editText以添加cursorChangedListener，但我不知道为什么我在使用时会收到错误在活动中。我试图引用一些相关的问题，但没有一个是有帮助的。我想知道问题出在哪里以及为什么它会出现错误。当我从EditTextSelectable类中删除了侦听器部分时，它没有给出任何错误，但添加了selectionChange部分给出错误。
MainActivity：
protected void onCreate(Bundle savedInstanceState) {
EditTextSelectable editTxt=findViewById(R.id.editTxt);
editTxt.addOnSelectionChangedListener(new
EditTextSelectable.onSelectionChangedListener() {
@Override
public void onSelectionChanged(int selStart, int selEnd) {
Toast.makeText(getApplicationContext(),selStart+"",Toast.LENGTH_SHORT).show();
}
});
}
XML：
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
xmlns:app="http://schemas.android.com/tools"
app:ignore="NamespaceTypo">
<community.testing.EditTextSelectable
android:id="@+id/editTxt"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:textColor="#fff"/>
</RelativeLayout>
代码：
public class EditTextSelectable extends EditText {
public interface onSelectionChangedListener {
void onSelectionChanged(int selStart, int selEnd);
}
private List<onSelectionChangedListener> listeners;
public EditTextSelectable(Context context) {
super(context);
listeners = new ArrayList<onSelectionChangedListener>();
}
public EditTextSelectable(Context context, AttributeSet attrs) {
super(context, attrs);
listeners = new ArrayList<onSelectionChangedListener>();
}
public EditTextSelectable(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
listeners = new ArrayList<onSelectionChangedListener>();
}
public void addOnSelectionChangedListener(onSelectionChangedListener o) {
listeners.add(o);
}
protected void onSelectionChanged(int selStart, int selEnd) {
for (onSelectionChangedListener l : listeners)
l.onSelectionChanged(selStart, selEnd);
}
}
错误：
FATAL EXCEPTION: main
java.lang.RuntimeException: Unable to start activity ComponentInfo{community.testing/community.testing.MainActivity}: android.view.InflateException: Binary XML file line #0: Error inflating class community.testing.EditTextSelectable
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2180)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230)
at android.app.ActivityThread.access$600(ActivityThread.java:141)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1234)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:5041)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:511)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
at dalvik.system.NativeStart.main(Native Method)
Caused by: android.view.InflateException: Binary XML file line #0: Error inflating class community.testing.EditTextSelectable
at android.view.LayoutInflater.createView(LayoutInflater.java:613)
at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:687)
at android.view.LayoutInflater.rInflate(LayoutInflater.java:746)
at android.view.LayoutInflater.inflate(LayoutInflater.java:489)
at android.view.LayoutInflater.inflate(LayoutInflater.java:396)
at android.view.LayoutInflater.inflate(LayoutInflater.java:352)
at android.support.v7.app.AppCompatDelegateImplV9.setContentView(AppCompatDelegateImplV9.java:287)
at android.support.v7.app.AppCompatActivity.setContentView(AppCompatActivity.java:139)
at community.testing.MainActivity.onCreate(MainActivity.java:65)
at android.app.Activity.performCreate(Activity.java:5104)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1080)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2144)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230)
at android.app.ActivityThread.access$600(ActivityThread.java:141)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1234)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:5041)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:511)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
at dalvik.system.NativeStart.main(Native Method)
Caused by: java.lang.reflect.InvocationTargetException
at java.lang.reflect.Constructor.constructNative(Native Method)
at java.lang.reflect.Constructor.newInstance(Constructor.java:417)
at android.view.LayoutInflater.createView(LayoutInflater.java:587)
at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:687)
at android.view.LayoutInflater.rInflate(LayoutInflater.java:746)
at android.view.LayoutInflater.inflate(LayoutInflater.java:489)
at android.view.LayoutInflater.inflate(LayoutInflater.java:396)
at android.view.LayoutInflater.inflate(LayoutInflater.java:352)
at android.support.v7.app.AppCompatDelegateImplV9.setContentView(AppCompatDelegateImplV9.java:287)
at android.support.v7.app.AppCompatActivity.setContentView(AppCompatActivity.java:139)
at community.testing.MainActivity.onCreate(MainActivity.java:65)
at android.app.Activity.performCreate(Activity.java:5104)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1080)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2144)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230)
at android.app.ActivityThread.access$600(ActivityThread.java:141)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1234)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:5041)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:511)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
at dalvik.system.NativeStart.main(Native Method)
Caused by: java.lang.NullPointerException
at community.testing.EditTextSelectable.onSelectionChanged(EditTextSelectable.java:47)
at android.widget.TextView.spanChange(TextView.java:7340)
at android.widget.TextView$ChangeWatcher.onSpanAdded(TextView.java:8907)
at android.text.SpannableStringBuilder.sendSpanAdded(SpannableStringBuilder.java:979)
at android.text.SpannableStringBuilder.setSpan(SpannableStringBuilder.java:688)
at android.text.SpannableStringBuilder.setSpan(SpannableStringBuilder.java:588)
at android.text.Selection.setSelection(Selection.java:78)
at android.text.Selection.setSelection(Selection.java:87)
at android.text.method.ArrowKeyMovementMethod.initialize(ArrowKeyMovementMethod.java:302)
at android.widget.TextView.setText(TextView.java:3684)
at android.widget.TextView.setText(TextView.java:3554)
at android.widget.EditText.setText(EditText.java:80)
at android.widget.TextView.<init>(TextView.java:1213)
at android.widget.EditText.<init>(EditText.java:60)
at android.widget.EditText.<init>(EditText.java:56)
at community.testing.EditTextSelectable.<init>(EditTextSelectable.java:33)
at java.lang.reflect.Constructor.constructNative(Native Method)
at java.lang.reflect.Constructor.newInstance(Constructor.java:417)
at android.view.LayoutInflater.createView(LayoutInflater.java:587)
at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:687)
at android.view.LayoutInflater.rInflate(LayoutInflater.java:746)
at android.view.LayoutInflater.inflate(LayoutInflater.java:489)
at android.view.LayoutInflater.inflate(LayoutInflater.java:396)
at android.view.LayoutInflater.inflate(LayoutInflater.java:352)
at android.support.v7.app.AppCompatDelegateImplV9.setContentView(AppCompatDelegateImplV9.java:287)
at android.support.v7.app.AppCompatActivity.setContentView(AppCompatActivity.java:139)
at community.testing.MainActivity.onCreate(MainActivity.java:65)
at android.app.Activity.performCreate(Activity.java:5104)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1080)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2144)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230)
at android.app.ActivityThread.access$600(ActivityThread.java:141)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1234)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:5041)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:511)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
at dalvik.system.NativeStart.main(Native Method)