Question

我有一个名为alt的edittext。它的输入类型是十进制数。我无法捕获空指针异常。如果edittext为空或未输入任何值，则我的应用程序崩溃。我在stackoverflow中搜索了很多，但找不到解决方案。我尝试过使用以下

alt.getText().toString().equals("");
alt.getText().toString().matches("");
alt.getText().toString().contains("");
alt.getText().toString().trim().length() == 0;
Textutill.isEmpty(alt.getText());

我在try / catch语句中做了什么

这是我的代码

  <EditText
    android:id="@+id/eps"
    android:layout_width="123dp"
    android:layout_height="19dp"
    android:layout_marginBottom="8dp"
    android:layout_marginLeft="8dp"
    android:layout_marginRight="8dp"
    android:layout_marginTop="8dp"
    android:background="@android:color/white"
    android:ems="10"
    android:inputType="number|numberSigned|numberDecimal"
    android:text="500"
    android:textColor="@android:color/black"
    app:layout_constraintBottom_toBottomOf="parent"
    app:layout_constraintHorizontal_bias="0.502"
    app:layout_constraintLeft_toLeftOf="parent"
    app:layout_constraintRight_toRightOf="parent"
    app:layout_constraintTop_toTopOf="parent"
    app:layout_constraintVertical_bias="0.056" />

的java

     @Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_abu);
    calculate = (Button) findViewById(R.id.button);
    alt = (EditText) findViewById(R.id.eps);
    public void calculateABU() {
    calculate.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            altValue = Float.valueOf(alt.getText().toString());
             try{
                if (altValue > 10000 || altValue < -400) {
                    Toast.makeText(getApplicationContext(), "-400 <= Altitude <= 10000 m", Toast.LENGTH_LONG).show();
                }

            }
            catch (NullPointerException e){
                if(TextUtils.isEmpty(alt.getText())){
                    Toast.makeText(getApplicationContext(), "error", Toast.LENGTH_LONG).show();
                }
            }

Answer 1

在召集浮动之前尝试Nullcheck

calculate.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {

                if(!TextUtils.isEmpty(alt.getText().toString())){
                altValue = Float.valueOf(alt.getText().toString());
                 if (altValue > 10000 || altValue < -400) {
                    Toast.makeText(getApplicationContext(), "-400 <= Altitude <= 10000 m", Toast.LENGTH_LONG).show();
                }else{

                    Toast.makeText(getApplicationContext(), "error", Toast.LENGTH_LONG).show();
                }
}

如何检查输入类型为decimal的edittext是否为空？

1 个答案: