Java 从textwatcher访问edittext

我正在使用textWatcher：

final EditText et = (EditText) findViewById(R.id.editText1);
final TextView tv = (TextView) findViewById(R.id.textView2);

    et.addTextChangedListener(new TextWatcher()
    {
            public void afterTextChanged(Editable s){
                    if(s.length() > 0) {
                    tv.setText(s.toString().substring(s.length()-1));
                    et.setText("");
                }
            }
            public void beforeTextChanged(CharSequence s,int start,int count, int after){} 
            public void onTextChanged(CharSequence s, int start, int before, int count) {}
    });

这个返回错误，我无法访问et.setText，因为它可能是最终的，或者因为它被键盘锁定，知道吗

日志类别：

06-02 13:35:25.139: D/AndroidRuntime(12532): Shutting down VM
06-02 13:35:25.139: W/dalvikvm(12532): threadid=1: thread exiting with uncaught exception (group=0x40018578)
06-02 13:35:25.219: E/AndroidRuntime(12532): FATAL EXCEPTION: main
06-02 13:35:25.219: E/AndroidRuntime(12532): java.lang.StackOverflowError
06-02 13:35:25.219: E/AndroidRuntime(12532):    at android.widget.TextView$InsertionPointCursorController.hide(TextView.java:8609)
06-02 13:35:25.219: E/AndroidRuntime(12532):    at android.widget.TextView.hideInsertionPointCursorController(TextView.java:9088)
06-02 13:35:25.219: E/AndroidRuntime(12532):    at android.widget.TextView.hideControllers(TextView.java:9105)
06-02 13:35:25.219: E/AndroidRuntime(12532):    at android.widget.TextView.setText(TextView.java:2677)
06-02 13:35:25.219: E/AndroidRuntime(12532):    at android.widget.TextView.setText(TextView.java:2662)
06-02 13:35:25.219: E/AndroidRuntime(12532):    at android.widget.EditText.setText(EditText.java:178)
06-02 13:35:25.219: E/AndroidRuntime(12532):    at android.widget.TextView.setText(TextView.java:2637)
06-02 13:35:25.219: E/AndroidRuntime(12532):    at com.pack.witch.Input$1.beforeTextChanged(Input.java:27)
06-02 13:35:25.219: E/AndroidRuntime(12532):    at android.widget.TextView.sendBeforeTextChanged(TextView.java:6554)
06-02 13:35:25.219: E/AndroidRuntime(12532):    at android.widget.TextView.setText(TextView.java:2702)
06-02 13:35:25.219: E/AndroidRuntime(12532):    at android.widget.TextView.setText(TextView.java:2662)
06-02 13:35:25.219: E/AndroidRuntime(12532):    at android.widget.EditText.setText(EditText.java:178)
06-02 13:35:25.219: E/AndroidRuntime(12532):    at android.widget.TextView.setText(TextView.java:2637)
06-02 13:35:25.219: E/AndroidRuntime(12532):    at com.pack.witch.Input$1.beforeTextChanged(Input.java:27)
06-02 13:35:25.219: E/AndroidRuntime(12532):    at android.widget.TextView.sendBeforeTextChanged(TextView.java:6554)
06-02 13:35:25.219: E/AndroidRuntime(12532):    at android.widget.TextView.setText(TextView.java:2702)
06-02 13:35:25.219: E/AndroidRuntime(12532):    at android.widget.TextView.setText(TextView.java:2662)
06-02 13:35:25.219: E/AndroidRuntime(12532):    at android.widget.EditText.setText(EditText.java:178)
06-02 13:35:25.219: E/AndroidRuntime(12532):    at android.widget.TextView.setText(TextView.java:2637)
06-02 13:35:25.219: E/AndroidRuntime(12532):    at com.pack.witch.Input$1.beforeTextChanged(Input.java:27)
06-02 13:35:25.219: E/AndroidRuntime(12532):    at android.widget.TextView.sendBeforeTextChanged(TextView.java:6554)
06-02 13:35:25.219: E/AndroidRuntime(12532):    at android.widget.TextView.setText(TextView.java:2702)
06-02 13:35:25.219: E/AndroidRuntime(12532):    at android.widget.TextView.setText(TextView.java:2662)
06-02 13:35:25.219: E/AndroidRuntime(12532):    at android.widget.EditText.setText(EditText.java:178)
06-02 13:35:25.219: E/AndroidRuntime(12532):    at android.widget.TextView.setText(TextView.java:2637)
06-02 13:35:25.219: E/AndroidRuntime(12532):    at com.pack.witch.Input$1.beforeTextChanged(Input.java:27)
06-02 13:35:25.219: E/AndroidRuntime(12532):    at android.widget.TextView.sendBeforeTextChanged(TextView.java:6554)
06-02 13:35:25.219: E/AndroidRuntime(12532):    at android.widget.TextView.setText(TextView.java:2702)
06-02 13:35:25.219: E/AndroidRuntime(12532):    at android.widget.TextView.setText(TextView.java:2662)
06-02 13:35:25.219: E/AndroidRuntime(12532):    at android.widget.EditText.setText(EditText.java:178)
06-02 13:35:25.219: E/AndroidRuntime(12532):    at android.widget.TextView.setText(TextView.java:2637)
06-02 13:35:25.219: E/AndroidRuntime(12532):    at com.pack.witch.Input$1.beforeTextChanged(Input.java:27)
06-02 13:35:25.219: E/AndroidRuntime(12532):    at android.widget.TextView.sendBeforeTextChanged(TextView.java:6554)
06-02 13:35:25.219: E/AndroidRuntime(12532):    at android.widget.TextView.setText(TextView.java:2702)
06-02 13:35:25.219: E/AndroidRuntime(12532):    at android.widget.TextView.setText(TextView.java:2662)
06-02 13:35:25.219: E/AndroidRuntime(12532):    at android.widget.EditText.setText(EditText.java:178)
06-02 13:35:25.219: E/AndroidRuntime(12532):    at android.widget.TextView.setText(TextView.java:2637)
06-02 13:35:25.219: E/AndroidRuntime(12532):    at com.pack.witch.Input$1.beforeTextChanged(Input.java:27)
06-02 13:35:25.219: E/AndroidRuntime(12532):    at android.widget.TextView.sendBeforeTextChanged(TextView.java:6554)
06-02 13:35:25.219: E/AndroidRuntime(12532):    at android.widget.TextView.setText(TextView.java:2702)
06-02 13:35:25.219: E/AndroidRuntime(12532):    at android.widget.TextView.setText(TextView.java:2662)
06-02 13:35:25.219: E/AndroidRuntime(12532):    at android.widget.EditText.setText(EditText.java:178)
06-02 13:35:25.219: E/AndroidRuntime(12532):    at android.widget.TextView.setText(TextView.java:2637)
06-02 13:35:25.219: E/AndroidRuntime(12532):    at com.pack.witch.Input$1.beforeTextChanged(Input.java:27)
06-02 13:35:25.219: E/AndroidRuntime(12532):    at android.widget.TextView.sendBeforeTextChanged(TextView.java:6554)
06-02 13:35:25.219: E/AndroidRuntime(12532):    at android.widget.TextView.setText(TextView.java:2702)
06-02 13:35:25.219: E/AndroidRuntime(12532):    at android.widget.TextView.setText(TextView.java:2662)
06-02 13:35:25.219: E/AndroidRuntime(12532):    at android.widget.EditText.setText(EditText.java:178)
06-02 13:35:25.219: E/AndroidRuntime(12532):    at android.widget.TextView.setText(TextView.java:2637)
06-02 13:35:25.219: E/AndroidRuntime(12532):    at com.pack.witch.Input$1.beforeTextChanged(Input.java:27)
06-02 13:35:25.219: E/AndroidRuntime(12532):    at android.widget.TextView.sendBeforeTextChanged(TextView.java:6554)
06-02 13:35:25.219: E/AndroidRuntime(12532):    at android.widget.TextView.setText(TextView.java:2702)
06-02 13:35:25.219: E/AndroidRuntime(12532):    at android.widget.TextView.setText(TextView.java:2662)
06-02 13:35:25.219: E/AndroidRuntime(12532):    at android.widget.EditText.setText(EditText.java:178)
06-02 13:35:25.219: E/AndroidRuntime(12532):    at android.widget.TextView.setText(TextView.java:2637)
06-02 13:35:25.219: E/AndroidRuntime(12532):    at com.pack.witch.Input$1.beforeTextChanged(Input.java:27)
06-02 13:35:25.219: E/AndroidRuntime(12532):    at android.widget.TextView.sendBeforeTextChanged(TextView.java:6554)
06-02 13:35:25.219: E/AndroidRuntime(12532):    at android.widget.TextView.setText(TextView.java:2702)
06-02 13:35:25.219: E/AndroidRuntime(12532):    at android.widget.TextView.setText(TextView.java:2662)
06-02 13:35:25.219: E/AndroidRuntime(12532):    at android.widget.EditText.setText(EditText.java:178)
06-02 13:35:25.219: E/AndroidRuntime(12532):    at android.widget.TextView.setText(TextView.java:2637)
06-02 13:35:25.219: E/AndroidRuntime(12532):    at com.pack.witch.Input$1.beforeTextChanged(Input.java:27)
06-02 13:35:25.219: E/AndroidRuntime(12532):    at android.widget.TextView.sendBeforeTextChanged(TextView.java:6554)
06-02 13:35:25.219: E/AndroidRuntime(12532):    at android.widget.TextView.setText(TextView.java:2702)
06-02 13:35:25.219: E/AndroidRuntime(12532):    at android.widget.TextView.setText(TextView.java:2662)
06-02 13:35:25.219: E/AndroidRuntime(12532):    at android.widget.EditText.setText(EditText.java:178)
06-02 13:35:25.219: E/AndroidRuntime(12532):    at android.widget.TextView.setText(TextView.java:2637)
06-02 13:35:25.219: E/AndroidRuntime(12532):    at com.pack.witch.Input

---

Ps：我需要更改用户键入的内容，例如，如果他键入“A”，我将显示“D”，使其看起来像是他键入了“D”

这是堆栈溢出。文本正在更改，它调用文本观察者，它更改文本，它调用你的文本观察者，它更改文本，它调用你的文本观察者

在更改文本监视程序中的文本之前，应先删除它。

可能会）

调用此方法是为了通知您，在s中的某个位置，文本已更改。从这个回调对s进行进一步的更改是合法的，但是要小心不要让自己陷入无限循环，因为您所做的任何更改都会导致再次递归调用这个方法。（由于其他afterTextChanged（）方法可能已经进行了其他更改并使偏移无效，因此不会告诉您更改发生在何处。但是如果您需要知道

不是最好的溶液，但看看 试试这个

或

最终EditText et=（EditText）findViewById（R.id.editText1）； 最终文本视图电视=（文本视图）findViewById（R.id.textView2）； 布尔值isManulChange=false

et.addTextChangedListener(new TextWatcher()
{
        public void afterTextChanged(Editable s){

                if(isManulChange ){
                     isManulChange   = false;
                     return;
                   }

                if(s.length() > 0) {
                tv.setText(s.toString().substring(s.length()-1));
                et.setText("");
                isManulChange   = true;//
            }
        }
        public void beforeTextChanged(CharSequence s,int start,int count, int after){} 
        public void onTextChanged(CharSequence s, int start, int before, int count) {}
});

这样试试

final EditText et = (EditText) findViewById(R.id.editText1);
final TextView tv = (TextView) findViewById(R.id.textView2);

et.addTextChangedListener(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) {
                if(s.length() > 0) {
                tv.setText(s.toString().substring(s.length()-1));
                et.setText("");}
         }
});

---

这样可以防止无限循环

@Override
public void onTextChanged(CharSequence charSequence, int i, int i2, int i3) {
    if (textWatchEdited) {
        textWatchEdited = false;
        return;
    }
    String str = charSequence.toString();
    // do something
    textWatchEdited = true;
    view.setText(str);
}

---

最终应该不是问题……你能提供日志猫吗……但我需要更改用户键入的内容，例如，如果他键入“A”，我将显示“D”，使它看起来像他键入的“D”因此，我需要在虚拟键盘上使用一个侦听器，该侦听器为我提供按下的字符。在调用setText之前，您的TextWatcher从EditText中删除该侦听器。在调用setText之后，立即使用AddTextChangedListener重新添加TextWatcher。无法退出无限循环：/！！我没有观察到任何无限循环e循环？s.长度（）将为1，第二次为0@Agarwal：也许你是对的，这是我的看法，因为在代码中，et在后文本更改中被设置，所以它将再次调用文本观察程序等等…这就是为什么他会得到Stackoverflow异常…即使我有点怀疑，如果他每次设置“”那么应该生成相同的文本textchange调用吗？但是查看log cat，它是这样的，因为存在Stackoverflow异常…@Agarwal运行回调代码替代调用…。我编辑了答案，请查看…。当我将et.setText（“”）替换为et.setText（“任何”）时；我再次遇到堆栈溢出et必须保持为空提供的代码可能会有所帮助，但为了使其成为一个好的答案，您还应该描述/解释您的代码解决问题的原因/方式。