本文介绍了检查Edittext是否为空，仅接受数字的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
我有2个Edittext，仅接受数字.
I have 2 Edittext which only accepts numbers.
我想确保在按下提交按钮以防止应用程序崩溃之前，这些字段不为空.
I want to make sure that the fields are not empty before the submit button is pressed to stop the application from crashing.
这些是我拥有的2个edittext字段.
These are the 2 edittext fields i have.
EditText weightText = (EditText)findViewById(R.id.WeightText);
EditText heightText = (EditText)findViewById(R.id.Heighttext);
代码:
public class BMI extends Activity {
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.bmi);
}
public void calculateHandler(View view) {
// make sure we handle the click of the calculator button
if (view.getId() == R.id.calculate) {
// get the references to the widgets
EditText weightText = (EditText)findViewById(R.id.WeightText);
EditText heightText = (EditText)findViewById(R.id.Heighttext);
TextView resultText = (TextView)findViewById(R.id.resultLabel);
// get the users values from the widget references
float weight = Float.parseFloat(weightText.getText().toString());
float height = Float.parseFloat(heightText.getText().toString());
// calculate the bmi value
float bmiValue = calculateBMI(weight, height);
// interpret the meaning of the bmi value
String bmiInterpretation = interpretBMI(bmiValue);
// now set the value in the result text
resultText.setText(bmiValue + " = " + bmiInterpretation);
}
}
private float calculateBMI (float weight, float height) {
return (float)Math.round((weight / (height * height)) * 100) / 100 ;
}
// interpret what BMI means
private String interpretBMI(float bmiValue) {
if (bmiValue < 16) {
return "Severely underweight";
} else if (bmiValue < 18.5) {
return "Underweight";
} else if (bmiValue < 25) {
return "Normal";
} else if (bmiValue < 30) {
return "Overweight";
} else {
return "Obese";
}
}
}
推荐答案
您可以检查您的EditText是否为空，如下所示:
You can check that your EditTexts are not empty like below:
weightText.getText().length() != 0 && heightText.getText().length() != 0
您可以在onClick(View)方法中使用此条件，该方法在单击按钮时调用，如下所示:
And you can use this condition inside the onClick(View) method, which is called when your button is clicked like below:
yourButton.setOnClickListener( new OnClickListener(){
public void onClick(){
if(weightText.getText().length() != 0 && heightText.getText().length() != 0){
//do sth
}
});
第二种方法，您可以创建同时设置为EditTexts的TextWatcher，并在onTextChanged()中检查两个EditText都不为空，如下所示:
The second way, you can create TextWatcher which set to both EditTexts and in onTextChanged() you can check that both EditTexts are not empty like below:
private class YourTextWatcher implements TextWatcher{
@Override
public void beforeTextChanged(CharSequence charSequence, int i, int i2, int i3) {
}
@Override
public void onTextChanged(CharSequence charSequence, int i, int i2, int i3) {
yourButton.setEnabled(weightText.getText().length() != 0 && heightText.getText().length() != 0)
}
@Override
public void afterTextChanged(Editable editable) {
}
}
您可以为EditText设置此TextWatcher，如下所示:
you can set this TextWatcher for your EditText like below:
weightText.addTextChangedListener(new YourTextWatcher());
heightText.addTextChangedListener(new YourTextWatcher());
以下是您的活动"应如下所示的代码:
Here is code that your Activity should look like:
public class BMI extends Activity {
EditText weightText;
EditText heightText;
TextView resultText;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.bmi);
weightText = (EditText) findViewById(R.id.WeightText);
heightText = (EditText) findViewById(R.id.Heighttext);
resultText = (TextView) findViewById(R.id.resultLabel);
Button button = (Button) findViewById(R.id.calulate);
button.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
calculateHandler();
}
});
}
public void calculateHandler() {
// make sure we handle the click of the calculator button
if (weightText.getText().length() == 0 || heightText.getText().length() == 0) {
return;
}
// get the users values from the widget references
float weight = Float.parseFloat(weightText.getText().toString());
float height = Float.parseFloat(heightText.getText().toString());
// calculate the bmi value
float bmiValue = calculateBMI(weight, height);
// interpret the meaning of the bmi value
String bmiInterpretation = interpretBMI(bmiValue);
// now set the value in the result text
resultText.setText(bmiValue + " = " + bmiInterpretation);
// display toast additionally to example
Toast.makeText(this, bmiValue + " = " + bmiInterpretation, Toast.LENGTH_LONG).show();
}
private float calculateBMI(float weight, float height) {
return (float) Math.round((weight / (height * height)) * 100) / 100;
}
// interpret what BMI means
private String interpretBMI(float bmiValue) {
if (bmiValue < 16) {
return "Severely underweight";
} else if (bmiValue < 18.5) {
return "Underweight";
} else if (bmiValue < 25) {
return "Normal";
} else if (bmiValue < 30) {
return "Overweight";
} else {
return "Obese";
}
}
}
计算方法
public void calculateHandler() {
// make sure we handle the click of the calculator button
if (weightText.getText().toString().trim().length() == 0 || heightText.getText().toString().trim().length() == 0) {
Toast.makeText(this, "Please fill all field by numbers", Toast.LENGTH_LONG).show();
return;
}
// get the users values from the widget references
float weight = Float.parseFloat(weightText.getText().toString());
float height = Float.parseFloat(heightText.getText().toString());
// calculate the bmi value
float bmiValue = calculateBMI(weight, height);
// interpret the meaning of the bmi value
String bmiInterpretation = interpretBMI(bmiValue);
// now set the value in the result text
resultText.setText(bmiValue + " = " + bmiInterpretation);
// display toast additionally to example
}
这篇关于检查Edittext是否为空，仅接受数字的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！