Question

我想创建一个对输入长度有限制的edittext。当edittext长度大于5时，它应显示错误Toast消息。该应用程序编译但它在模拟器中崩溃并且无法打开。我的代码如下，任何帮助都将不胜感激。

<EditText
  android:layout_width="match_parent"
  android:layout_height="50dp"
  android:id="@+id/etext1"
  />



    <Button
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:onClick="B1"
    android:id="@+id/one"
    android:text="1"
    android:layout_below="@+id/etext1"
    android:gravity="center"

    />

Java代码如下所示：

public class MainActivity extends ActionBarActivity {

EditText tx=(EditText)findViewById(R.id.etext1);
String a;
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
  }



     public void B1(View v) {

         if (tx.getText().toString().length()>5)

         {


             LayoutInflater inflater = getLayoutInflater();

             View erro = inflater.inflate(R.layout.error, (ViewGroup) findViewById(R.id.idoferror));


             Toast dis = Toast.makeText(this, "er", Toast.LENGTH_LONG);
             dis.setGravity(Gravity.CENTER | Gravity.RIGHT, 0, 0);
             dis.setView(erro);
             dis.show();


         }

         else {

             a=tx.getText().toString();
             a=a+1;
             tx.setText(a);




         }

     }

}

Answer 1

移动这个

EditText tx=(EditText)findViewById(R.id.etext1);

onCreate()中的一行并设置android:maxLength="5"

修改

EditText tx;


@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    tx=(EditText)findViewById(R.id.etext1);
  }

Answer 2

要在达到限制字符时显示Toast。您需要将TextWatcher添加到EditText 每次向EditText输入文字后，请检查EditText的长度，然后再次显示Toast和setText()，如果需要，请EditText < / p>

final int MAX_CHARACTERS = 5;
...
yourEditText.addTextChangedListener(new TextWatcher() {
    @Override
    public void onTextChanged(CharSequence s, int start, int before, int count) {
        // TODO Auto-generated method stub
    }

    @Override
    public void beforeTextChanged(CharSequence s, int start, int count, int after) {
        // TODO Auto-generated method stub
    }

    @Override
    public void afterTextChanged(Editable s) {

        if (yourEditText.toString().length() > MAX_CHARACTERS) {
            yourEditText.setText(yourEditText.getText().toString().substring(0, MAX_CHARACTERS));
            Toast.makeText(getActivity(), "Maximum number of characters reached.", Toast.LENGTH_SHORT).show();
        }

    }
});

===
如果您只想限制文本长度，请不要显示Toast。你可以使用

yourEditText.setFilters(new InputFilter[] {new InputFilter.LengthFilter(MAX_CHARACTERS)});

或XML

android:maxLength="5"

希望这个帮助

设置在java代码中插入edittext长度的限制

2 个答案:

修改