经过数小时的研究和测试后，我无法弄清楚当我调用此应用程序时崩溃的原因
inputLocation.setText(""); inputLocation.setText(null);
它可以正常使用：
inputLocation.setText("your text");
或
inputLocation.setText(editText.getText().toString());
等
任何帮助都将受到高度赞赏。 感谢。
inputLocation.addTextChangedListener
// / Execute code without the use of the save changes button.
// ///////////////////////////////////////////
inputLocation.addTextChangedListener(new TextWatcher() {
public void onTextChanged(CharSequence s, int start, int before,
int count) {
/* Process to check type */
String location_string = inputLocation.getText().toString();
String first_location_char = location_string.substring(0, 1);
if (inputLocation.getText().toString().length() == locationsize) {
String last_location_char = location_string.substring(8);
if (last_location_char.equals("L")
&& first_location_char.equals("L")) {
inputLocation.setText(location_string.substring(1, 8),
TextView.BufferType.EDITABLE);
new UpdateLocation().execute();
} else if (!first_location_char.isEmpty()
&& !last_location_char.isEmpty()) {
alertDialog = new AlertDialog.Builder(
CheckLocationActivity.this).create();
alertDialog.setTitle("Wrong Code for Location");
alertDialog
.setMessage("Please scan one more time the correct barcode!");
alertDialog.setButton(-1, getString(R.string.Ok),
new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog,
int which) {
inputLocation.setText("",
TextView.BufferType.EDITABLE);
}
});
/*
* alertDialog.setButton(-2, getString(R.string.No), new
* DialogInterface.OnClickListener() {
*
* @Override public void onClick(DialogInterface dialog,
* int which) { // do nothing dialog will dismiss } });
*/
alertDialog.show();
}
}
}
public void beforeTextChanged(CharSequence s, int start, int count,
int after) {
}
public void afterTextChanged(Editable s) {
}
});
// / Execute code without the use of the save changes button.
// ///////////////////////////////////////////
代码部分
alertDialog = new AlertDialog.Builder(
CheckLocationActivity.this).create();
alertDialog.setTitle("Wrong Code for Location");
alertDialog
.setMessage("Please scan one more time the correct barcode!");
alertDialog.setButton(-1, getString(R.string.Ok),
new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog,
int which) {
inputLocation.setText("",
TextView.BufferType.EDITABLE);
}
});
/*
* alertDialog.setButton(-2, getString(R.string.No), new
* DialogInterface.OnClickListener() {
*
* @Override public void onClick(DialogInterface dialog,
* int which) { // do nothing dialog will dismiss } });
*/
alertDialog.show();
日志文件
11-05 16:41:33.638: W/dalvikvm(19191): threadid=1: thread exiting with uncaught exception (group=0x41513700) 11-05 16:41:33.648: E/AndroidRuntime(19191): FATAL EXCEPTION: main 11-05 16:41:33.648: E/AndroidRuntime(19191): java.lang.StringIndexOutOfBoundsException: length=0; regionStart=0; regionLength=1 11-05 16:41:33.648: E/AndroidRuntime(19191): at java.lang.String.startEndAndLength(String.java:583) 11-05 16:41:33.648: E/AndroidRuntime(19191): at java.lang.String.substring(String.java:1464) 11-05 16:41:33.648: E/AndroidRuntime(19191): at com.dev.assetlocation.CheckLocationActivity$3.onTextChanged(CheckLocationActivity.java:162) 11-05 16:41:33.648: E/AndroidRuntime(19191): at android.widget.TextView.sendOnTextChanged(TextView.java:7318) 11-05 16:41:33.648: E/AndroidRuntime(19191): at android.widget.TextView.setText(TextView.java:3774) 11-05 16:41:33.648: E/AndroidRuntime(19191): at android.widget.TextView.setText(TextView.java:3629) 11-05 16:41:33.648: E/AndroidRuntime(19191): at android.widget.EditText.setText(EditText.java:80) 11-05 16:41:33.648: E/AndroidRuntime(19191): at android.widget.TextView.setText(TextView.java:3604) 11-05 16:41:33.648: E/AndroidRuntime(19191): at com.dev.assetlocation.CheckLocationActivity$2.onTextChanged(CheckLocationActivity.java:103) 11-05 16:41:33.648: E/AndroidRuntime(19191): at android.widget.TextView.sendOnTextChanged(TextView.java:7318) 11-05 16:41:33.648: E/AndroidRuntime(19191): at android.widget.TextView.handleTextChanged(TextView.java:7377) 11-05 16:41:33.648: E/AndroidRuntime(19191): at android.widget.TextView$ChangeWatcher.onTextChanged(TextView.java:9076) 11-05 16:41:33.648: E/AndroidRuntime(19191): at android.text.SpannableStringBuilder.sendTextChanged(SpannableStringBuilder.java:962) 11-05 16:41:33.648: E/AndroidRuntime(19191): at android.text.SpannableStringBuilder.replace(SpannableStringBuilder.java:496) 11-05 16:41:33.648: E/AndroidRuntime(19191): at android.text.SpannableStringBuilder.replace(SpannableStringBuilder.java:435) 11-05 16:41:33.648: E/AndroidRuntime(19191): at android.text.SpannableStringBuilder.replace(SpannableStringBuilder.java:30) 11-05 16:41:33.648: E/AndroidRuntime(19191): at android.view.inputmethod.BaseInputConnection.replaceText(BaseInputConnection.java:673) 11-05 16:41:33.648: E/AndroidRuntime(19191): at android.view.inputmethod.BaseInputConnection.commitText(BaseInputConnection.java:197) 11-05 16:41:33.648: E/AndroidRuntime(19191): at com.android.internal.widget.EditableInputConnection.commitText(EditableInputConnection.java:183) 11-05 16:41:33.648: E/AndroidRuntime(19191): at com.android.internal.view.IInputConnectionWrapper.executeMessage(IInputConnectionWrapper.java:279) 11-05 16:41:33.648: E/AndroidRuntime(19191): at com.android.internal.view.IInputConnectionWrapper$MyHandler.handleMessage(IInputConnectionWrapper.java:77) 11-05 16:41:33.648: E/AndroidRuntime(19191): at android.os.Handler.dispatchMessage(Handler.java:99) 11-05 16:41:33.648: E/AndroidRuntime(19191): at android.os.Looper.loop(Looper.java:137) 11-05 16:41:33.648: E/AndroidRuntime(19191): at android.app.ActivityThread.main(ActivityThread.java:5103) 11-05 16:41:33.648: E/AndroidRuntime(19191): at java.lang.reflect.Method.invokeNative(Native Method) 11-05 16:41:33.648: E/AndroidRuntime(19191): at java.lang.reflect.Method.invoke(Method.java:525) 11-05 16:41:33.648: E/AndroidRuntime(19191): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737) 11-05 16:41:33.648: E/AndroidRuntime(19191): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553) 11-05 16:41:33.648: E/AndroidRuntime(19191): at dalvik.system.NativeStart.main(Native Method) 11-05 16:41:36.201: D/libEGL(19240): loaded /system/lib/egl/libEGL_adreno200.so 11-05 16:41:36.201: D/libEGL(19240): loaded /system/lib/egl/libGLESv1_CM_adreno200.so 11-05 16:41:36.201: D/libEGL(19240): loaded /system/lib/egl/libGLESv2_adreno200.so 11-05 16:41:36.211: I/Adreno200-EGL(19240): : EGL 1.4 QUALCOMM Build: Iabe52cfaeae4c5fab1acacfe6f056ba15fa93274 11-05 16:41:36.241: D/OpenGLRenderer(19240): Enabling debug mode 0
答案 0 :(得分：0)
java.lang.StringIndexOutOfBoundsException: length=0; regionStart=0;
基于上面的消息，我的猜测是，在你的代码中你正在对该文本进行一些字符串操作（如substring()）。如果字符串为""并且subString()，您将获得StringIndexOutofBoundsException。
如果字符串为null，您将获得NullPointerException。
答案 1 :(得分：0)
com.dev.assetlocation.CheckLocationActivity$3（匿名内部类＃3）侦听该文本的更改。 onTextChanged（在CheckLocationActivity$3中）使用String.substring，这会导致您的错误，因为空String中没有有效索引。
您的监听器（CheckLocationActivi ty.java第162行）应检查文本是否为空或null。