每当我的EditText为空并且按下按钮时，我的应用程序就会崩溃
[英]My app crashes whenever my EditText is empty and I press a button
问题描述
The problem is that each time I click on the button in my app, then whenever one of my EditText or both are empty, the app will crash. 
问题是，每当我单击应用程序中的按钮时，只要我的一个或两个EditText为空，该应用程序就会崩溃。
The idea is that I will write the calories in the EditText called caloriesIn and it will put out an int in the caloriesOut which is a textfield. 这个想法是，我会写在卡路里EditText称为caloriesIn，它将推出一个int在caloriesOut这是一个文本框。 The same idea goes for "fat". “脂肪”也有同样的想法。
The problem just to sum up is that if I write something in the calories, but don't write anything in fat, or just don't write anything in either of them, the app will crash. 综上所述，问题是，如果我用卡路里写一些东西，但是不写任何脂肪，或者只是不写任何东西，那么应用程序将崩溃。
My Code: 我的代码：
public class MainActivity extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Button button = (Button) findViewById(R.id.button);
button.setOnClickListener( new View.OnClickListener() {
@Override
public void onClick(View view) {
EditText caloriesIn = (EditText) findViewById(R.id.caloriesIn);
EditText fatIn = (EditText) findViewById(R.id.fatIn);
TextView caloriesOut = (TextView) findViewById(R.id.caloriesOut);
TextView fatOut = (TextView) findViewById(R.id.fatOut);
int calories = Integer.parseInt(caloriesIn.getText().toString());
int fat = Integer.parseInt(fatIn.getText().toString());
int caloriesResult = calories;
int fatResult = fat;
caloriesOut.setText(caloriesResult + "");
fatOut.setText(fatResult + "");
}
});
}
}
Crash report: 崩溃报告：
03-22 17:20:02.512 22193-22193/ottolopez.healthynote I/Choreographer: Skipped 47 frames!
3 个解决方案
解决方案1
0 已采纳 2018-03-22 17:07:46
Define this methode on your activity : 在您的活动中定义此方法：
public boolean isParsable(String input){
boolean parsable = true;
try{
Integer.parseInt(input);
}catch(NumberFormatException e){
parsable = false;
}
return parsable;
}
Then updated your code like this : 然后像这样更新您的代码：
public class MainActivity extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Button button = (Button) findViewById(R.id.button);
button.setOnClickListener( new View.OnClickListener() {
@Override
public void onClick(View view) {
EditText caloriesIn = (EditText) findViewById(R.id.caloriesIn);
EditText fatIn = (EditText) findViewById(R.id.fatIn);
TextView caloriesOut = (TextView) findViewById(R.id.caloriesOut);
TextView fatOut = (TextView) findViewById(R.id.fatOut);
String caloriesString = caloriesIn.getText().toString();
int calories = 0;
if (isParsable(caloriesString)){
calories = Integer.parseInt(caloriesString);
int caloriesResult = calories;
caloriesOut.setText(caloriesResult + "");
}
String fatString = caloriesIn.getText().toString();
int fat = 0;
if (isParsable(fatString)){
fat = Integer.parseInt(fatString);
int fatResult = fat;
fatOut.setText(fatResult + "");
}
}
});
}
public static boolean isParsable(String input){
boolean parsable = true;
try{
Integer.parseInt(input);
}catch(NumberFormatException e){
parsable = false;
}
return parsable;
}
}
Hope this helps 希望这可以帮助
解决方案2
0 2018-03-22 17:43:21
The thing is Integer.parseInt() doesn't handle empty string which is not a number. 问题是Integer.parseInt()不能处理不是数字的空字符串。 So, you need to check for text emptiness and then use Integer.parseInt() . 因此，您需要检查文本是否为空，然后使用Integer.parseInt() 。 Also you can use isDigitsOnly method before using parseInt. 您也可以在使用parseInt之前使用isDigitsOnly方法。
解决方案3
0 2018-03-22 19:11:59
int calories = Integer.parseInt(caloriesIn.getText().toString());
int fat = Integer.parseInt(fatIn.getText().toString());
The main problem is in these lines, it will give error is you pass any character here or leave it blank, to solve these add these lines to your code 主要问题是在这些行中，如果您在此处传递任何字符或将其保留为空白，则会产生错误，以解决这些问题，并将这些行添加到代码中
String calIn = caloriesIn.getText().toString(); //first take input in String for checking
String fatInStr = fatIn.getText().toString(); //first take input in String for checking
if (calIn.isEmpty()) {
Toast.makeText(...);//inform user that calories input field is empty
return;
} else if (fatInStr.isEmpty()) {
Toast.makeText(...);//inform user that fat input field is empty
return;
} else if (!calIn.matches("[0-9]+")) {
Toast.makeText(...);//inform user that calories input field contains invalid data
return;
} else if (!fatInStr.matches("[0-9]+")) {
// Toast.makeText(...);//inform user that fat input field contains invalid data
return;
}
int calories = Integer.parseInt(calIn.trim()); // trim method removes any leading and trailing spaces
int fat = Integer.parseInt(fatInStr.trim());
Now app is safe when text is empty and is not a digit :) 现在，当文本为空且不是数字时，应用是安全的:)
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