Java 未输入任何内容时如何在edittext中将默认值设置为0？
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How to set default value to 0 in edittext when nothing is inputted?
提问by Kerv
I have an app here which adds the number. I have 4 edittexts here. What I want to happen is that when i entered none in one of the edittexts, it will assume that I entered 0. How can it be done? Here is my code:
我在这里有一个应用程序可以添加数字。我这里有 4 个编辑文本。我想要发生的是，当我在其中一个编辑文本中输入 none 时，它会假设我输入了 0。怎么做？这是我的代码：
public class Order extends Activity {
Button GoBackHome;
private Button button1;
private EditText txtbox1,txtbox2,txtbox3,txtbox4;
private TextView tv;
Button PayNow;
@Override
public void onBackPressed() {
}
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.order);
GoBackHome = (Button) findViewById(R.id.gohomebutton);
PayNow = (Button) findViewById(R.id.button2);
txtbox1= (EditText) findViewById(R.id.editText1);
button1 = (Button) findViewById(R.id.button1);
tv = (TextView) findViewById(R.id.editText5);
txtbox2= (EditText) findViewById(R.id.editText2);
txtbox3= (EditText) findViewById(R.id.editText3);
txtbox4= (EditText) findViewById(R.id.editText4);
button1.setOnClickListener(new clicker());
GoBackHome.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
final Intent i = new Intent(Order.this, MainActivity.class);
startActivity(i);
}
});
PayNow.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
final Intent i = new Intent(Order.this, Payment.class);
startActivity(i);
}
});
}
class clicker implements Button.OnClickListener
{
public void onClick(View v)
{
String a,b,c,d;
Integer vis;
a = txtbox1.getText().toString();
b = txtbox2.getText().toString();
c = txtbox3.getText().toString();
d = txtbox4.getText().toString();
vis = Integer.parseInt(a)*2+Integer.parseInt(b)*3+Integer.parseInt(c)*4+Integer.parseInt(d)*5;
tv.setText(vis.toString());
}
}
}
采纳答案by Andrew G
You can do as Tushar said or you can initialize the value in the XML. Something like
您可以按照 Tushar 所说的去做，也可以初始化 XML 中的值。就像是
<EditText
android:name="@+id/editText1"
android:text="0"/>
FYI you might also find it cleaner to handle your button clicks on xml like:
仅供参考，您可能还会发现处理 xml 上的按钮点击更干净，例如：
<Button
android:name="@+id/btn1"
android:onClick="handleClicks"/>
and then in java you'd have a public void method:
然后在java中你会有一个public void方法：
public void handleClicks(View clickedView){
if(clickedView.getId() == btn1.getId(){
...
} else if (...){}
}
回答by Tushar
initialize as :
初始化为：
txtbox1.setText("0");
回答by Hugo Hideki Yamashita
You can set android:hint="0"in your XML file, then, in your code, you can check if it's empty (maybe using TextUtils.isEmpty()) and setting some variable to 0.
您可以android:hint="0"在您的 XML 文件中进行设置，然后在您的代码中，您可以检查它是否为空（可能使用TextUtils.isEmpty()）并将某些变量设置为 0。
android:hint="0"will make a "0" appear in your EditTexts, but the "0" will disappear when anything is inputted.
android:hint="0"将使“0”出现在您的EditTexts 中，但输入任何内容时“0”都会消失。
Then you can change the onClick()to this:
然后您可以将其更改onClick()为：
class clicker implements Button.OnClickListener {
public void onClick(View v) {
String a,b,c,d;
Integer vis;
a = txtbox1.getText().toString();
b = txtbox2.getText().toString();
c = txtbox3.getText().toString();
d = txtbox4.getText().toString();
try {
vis = Integer.parseInt(a)*2+Integer.parseInt(b)*3+Integer.parseInt(c)*4+Integer.parseInt(d)*5;
tv.setText(vis.toString());
} catch (NumberFormatException e) {
vis = "0";
}
// Do something with "vis"
}
}
Or you can create a method to check a value, try to parse to an int or return a default value.
或者您可以创建一个方法来检查一个值，尝试解析为一个 int 或返回一个默认值。
public int getInt(String edtValue, int defaultValue) {
int value = defaultValue;
if (edtValue != null) {
try {
value = Integer.parseInt(edtValue);
} catch (NumberFormatException e) {
value = defaultValue;
}
}
return value;
}
Then you change your call to
然后你改变你的电话
vis = this.getInt(a, 0) * 2 + this.getInt(b, 0) * 3 + this.getInt(c, 0) * 4 + this.getInt(d, 0) * 5;
回答by Rachit Mishra
Check the EditText length when you get it
得到 EditText 时检查它的长度
String value = null;
if(ed.getText().length()){
value = textBox.getText().toString();
} else
value = 0+"";
