我有2个只接受数字的Edittext。
我想确保在按下提交按钮以停止应用程序崩溃之前字段不为空。
这是我拥有的2个edittext字段。
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";
}
}
}
答案 0 :(得分:1)
您可以检查您的EditTexts是否为空,如下所示:
weightText.getText().length() != 0 && heightText.getText().length() != 0
你可以在onClick(View)方法中使用这个条件,当点击你的按钮时会调用它,如下所示:
yourButton.setOnClickListener( new OnClickListener(){
public void onClick(){
if(weightText.getText().length() != 0 && heightText.getText().length() != 0){
//do sth
}
});
第二种方法,你可以创建设置为EditTexts和onTextChanged()的TextWatcher,你可以检查两个EditTexts都不是空的,如下所示:
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:
weightText.addTextChangedListener(new YourTextWatcher());
heightText.addTextChangedListener(new YourTextWatcher());
以下是您的活动应如下的代码:
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
}
答案 1 :(得分:1)
weightText.getText().toString().isEmpty();
答案 2 :(得分:0)
试试这个..
String weight = weightText.getText().toString();
String height = heightText.getText().toString();
if((Integer.parseInt(weight)!=null) && (Integer.parseInt(height)!=null)){
//Not an empty
}
else{
//empty
}