如果用户未输入任何输入，如何在 Android 中的 Edittext 上设置占位符并使用它？
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How do I set a placeholder on Edittext in Android and use it if no input has been typed by user?
提问by Vanquiza
I would like to have an EditText in android where I have a placeholder, which will be used AS my input if the user types nothing. The edit text is used in a prompt in my case.
我想在 android 中有一个 EditText，我有一个占位符，如果用户没有输入任何内容，它将用作我的输入。在我的情况下，在提示中使用了编辑文本。
I am aware of "hint" excisting, which is a placeholder, but it doesn't use it as an input. If I have hint set to "AAA" and the user types nothing and presses "OK" I will get an empty string, not "AAA".
我知道“提示” excisting，这是一个占位符，但它不将其用作输入。如果我将提示设置为“AAA”并且用户不输入任何内容并按“OK”，我将得到一个空字符串，而不是“AAA”。
Here's my code:
这是我的代码：
private void promptForUsername(){
// get prompts.xml view
LayoutInflater layoutInflater = LayoutInflater.from(context);
View promptView = layoutInflater.inflate(R.layout.prompts, null);
AlertDialog.Builder alertDialogBuilder = new AlertDialog.Builder(context);
// set prompts.xml to be the layout file of the alertdialog builder
alertDialogBuilder.setView(promptView);
final EditText input = (EditText) promptView.findViewById(R.id.userInput);
//setup a dialog window
alertDialogBuilder
.setCancelable(false)
.setPositiveButton("OK", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int id) {
// get user input and set it to result
addEvent(levelSelected, input.getText().toString(), Integer.parseInt(points), time + "s");
sqlLogic();
}
})
.setNegativeButton("Cancel",
new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int id) {
sqlLogic();
dialog.cancel();
}
});
// create an alert dialog
AlertDialog alertD = alertDialogBuilder.create();
alertD.show();
input.setFocusableInTouchMode(true);
input.requestFocusFromTouch();
InputMethodManager lManager = (InputMethodManager)this.getSystemService(Context.INPUT_METHOD_SERVICE);
lManager.showSoftInput(input, 0);
}
version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/layout_root"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical"
android:padding="10dp" >
<TextView
android:id="@+id/textView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Type username:"
android:textAppearance="?android:attr/textAppearanceLarge" />
<EditText
android:id="@+id/userInput"
android:layout_width="match_parent"
android:inputType="text"
android:layout_height="wrap_content"
android:maxLength="13"
android:hint="AAA">
<requestFocus />
</EditText>
</LinearLayout>
回答by CommonsWare
Add this static method somewhere:
在某处添加这个静态方法：
static CharSequence getTextOrHint(TextView tv) {
return(TextUtils.isEmpty(getText()) ? getHint() : getText());
}
Then use that method to retrieve your value, which will return the text if it exists, or the hint if it does not.
然后使用该方法来检索您的值，如果存在则返回文本，如果不存在则返回提示。
回答by Nicholas Pickering
Add android:hint="Hint Text"to the EditTextdeclaration.
添加android:hint="Hint Text"到EditText声明中。
回答by zgc7009
Just create a string variable and check conditionally to see what it should be.
只需创建一个字符串变量并有条件地检查它应该是什么。
String text = (input.getText().toString().equals("")? "AAA": input.getText().toString();
ddEvent(levelSelected, text, Integer.parseInt(points), time + "s");
As a note, in case you aren't up on your ternary formatting the first line is the same as the following (in it's most simple form)
请注意，如果您不了解三元格式，则第一行与以下内容相同（以最简单的形式）
String text = "";
if(input.getText().toString().equals(""){
text = "AAA";
}
else{
text = input.getText().toString();
}
